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Merge tag 'block-5.11-2021-01-10' of git://git.kernel.dk/linux-block
[linux/fpc-iii.git] / drivers / tty / serial / sc16is7xx.c
blobf86ec2d2635b7c76121914c12b40d564711742da
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * SC16IS7xx tty serial driver - Copyright (C) 2014 GridPoint
4 * Author: Jon Ringle <jringle@gridpoint.com>
5 *
6 * Based on max310x.c, by Alexander Shiyan <shc_work@mail.ru>
7 */
8
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/bitops.h>
12 #include <linux/clk.h>
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/gpio/driver.h>
16 #include <linux/i2c.h>
17 #include <linux/mod_devicetable.h>
18 #include <linux/module.h>
19 #include <linux/property.h>
20 #include <linux/regmap.h>
21 #include <linux/serial_core.h>
22 #include <linux/serial.h>
23 #include <linux/tty.h>
24 #include <linux/tty_flip.h>
25 #include <linux/spi/spi.h>
26 #include <linux/uaccess.h>
27 #include <uapi/linux/sched/types.h>
28
29 #define SC16IS7XX_NAME "sc16is7xx"
30 #define SC16IS7XX_MAX_DEVS 8
31
32 /* SC16IS7XX register definitions */
33 #define SC16IS7XX_RHR_REG (0x00) /* RX FIFO */
34 #define SC16IS7XX_THR_REG (0x00) /* TX FIFO */
35 #define SC16IS7XX_IER_REG (0x01) /* Interrupt enable */
36 #define SC16IS7XX_IIR_REG (0x02) /* Interrupt Identification */
37 #define SC16IS7XX_FCR_REG (0x02) /* FIFO control */
38 #define SC16IS7XX_LCR_REG (0x03) /* Line Control */
39 #define SC16IS7XX_MCR_REG (0x04) /* Modem Control */
40 #define SC16IS7XX_LSR_REG (0x05) /* Line Status */
41 #define SC16IS7XX_MSR_REG (0x06) /* Modem Status */
42 #define SC16IS7XX_SPR_REG (0x07) /* Scratch Pad */
43 #define SC16IS7XX_TXLVL_REG (0x08) /* TX FIFO level */
44 #define SC16IS7XX_RXLVL_REG (0x09) /* RX FIFO level */
45 #define SC16IS7XX_IODIR_REG (0x0a) /* I/O Direction
46 * - only on 75x/76x
47 */
48 #define SC16IS7XX_IOSTATE_REG (0x0b) /* I/O State
49 * - only on 75x/76x
50 */
51 #define SC16IS7XX_IOINTENA_REG (0x0c) /* I/O Interrupt Enable
52 * - only on 75x/76x
53 */
54 #define SC16IS7XX_IOCONTROL_REG (0x0e) /* I/O Control
55 * - only on 75x/76x
56 */
57 #define SC16IS7XX_EFCR_REG (0x0f) /* Extra Features Control */
58
59 /* TCR/TLR Register set: Only if ((MCR[2] == 1) && (EFR[4] == 1)) */
60 #define SC16IS7XX_TCR_REG (0x06) /* Transmit control */
61 #define SC16IS7XX_TLR_REG (0x07) /* Trigger level */
62
63 /* Special Register set: Only if ((LCR[7] == 1) && (LCR != 0xBF)) */
64 #define SC16IS7XX_DLL_REG (0x00) /* Divisor Latch Low */
65 #define SC16IS7XX_DLH_REG (0x01) /* Divisor Latch High */
66
67 /* Enhanced Register set: Only if (LCR == 0xBF) */
68 #define SC16IS7XX_EFR_REG (0x02) /* Enhanced Features */
69 #define SC16IS7XX_XON1_REG (0x04) /* Xon1 word */
70 #define SC16IS7XX_XON2_REG (0x05) /* Xon2 word */
71 #define SC16IS7XX_XOFF1_REG (0x06) /* Xoff1 word */
72 #define SC16IS7XX_XOFF2_REG (0x07) /* Xoff2 word */
73
74 /* IER register bits */
75 #define SC16IS7XX_IER_RDI_BIT (1 << 0) /* Enable RX data interrupt */
76 #define SC16IS7XX_IER_THRI_BIT (1 << 1) /* Enable TX holding register
77 * interrupt */
78 #define SC16IS7XX_IER_RLSI_BIT (1 << 2) /* Enable RX line status
79 * interrupt */
80 #define SC16IS7XX_IER_MSI_BIT (1 << 3) /* Enable Modem status
81 * interrupt */
82
83 /* IER register bits - write only if (EFR[4] == 1) */
84 #define SC16IS7XX_IER_SLEEP_BIT (1 << 4) /* Enable Sleep mode */
85 #define SC16IS7XX_IER_XOFFI_BIT (1 << 5) /* Enable Xoff interrupt */
86 #define SC16IS7XX_IER_RTSI_BIT (1 << 6) /* Enable nRTS interrupt */
87 #define SC16IS7XX_IER_CTSI_BIT (1 << 7) /* Enable nCTS interrupt */
88
89 /* FCR register bits */
90 #define SC16IS7XX_FCR_FIFO_BIT (1 << 0) /* Enable FIFO */
91 #define SC16IS7XX_FCR_RXRESET_BIT (1 << 1) /* Reset RX FIFO */
92 #define SC16IS7XX_FCR_TXRESET_BIT (1 << 2) /* Reset TX FIFO */
93 #define SC16IS7XX_FCR_RXLVLL_BIT (1 << 6) /* RX Trigger level LSB */
94 #define SC16IS7XX_FCR_RXLVLH_BIT (1 << 7) /* RX Trigger level MSB */
95
96 /* FCR register bits - write only if (EFR[4] == 1) */
97 #define SC16IS7XX_FCR_TXLVLL_BIT (1 << 4) /* TX Trigger level LSB */
98 #define SC16IS7XX_FCR_TXLVLH_BIT (1 << 5) /* TX Trigger level MSB */
99
100 /* IIR register bits */
101 #define SC16IS7XX_IIR_NO_INT_BIT (1 << 0) /* No interrupts pending */
102 #define SC16IS7XX_IIR_ID_MASK 0x3e /* Mask for the interrupt ID */
103 #define SC16IS7XX_IIR_THRI_SRC 0x02 /* TX holding register empty */
104 #define SC16IS7XX_IIR_RDI_SRC 0x04 /* RX data interrupt */
105 #define SC16IS7XX_IIR_RLSE_SRC 0x06 /* RX line status error */
106 #define SC16IS7XX_IIR_RTOI_SRC 0x0c /* RX time-out interrupt */
107 #define SC16IS7XX_IIR_MSI_SRC 0x00 /* Modem status interrupt
108 * - only on 75x/76x
109 */
110 #define SC16IS7XX_IIR_INPIN_SRC 0x30 /* Input pin change of state
111 * - only on 75x/76x
112 */
113 #define SC16IS7XX_IIR_XOFFI_SRC 0x10 /* Received Xoff */
114 #define SC16IS7XX_IIR_CTSRTS_SRC 0x20 /* nCTS,nRTS change of state
115 * from active (LOW)
116 * to inactive (HIGH)
117 */
118 /* LCR register bits */
119 #define SC16IS7XX_LCR_LENGTH0_BIT (1 << 0) /* Word length bit 0 */
120 #define SC16IS7XX_LCR_LENGTH1_BIT (1 << 1) /* Word length bit 1
121 *
122 * Word length bits table:
123 * 00 -> 5 bit words
124 * 01 -> 6 bit words
125 * 10 -> 7 bit words
126 * 11 -> 8 bit words
127 */
128 #define SC16IS7XX_LCR_STOPLEN_BIT (1 << 2) /* STOP length bit
129 *
130 * STOP length bit table:
131 * 0 -> 1 stop bit
132 * 1 -> 1-1.5 stop bits if
133 * word length is 5,
134 * 2 stop bits otherwise
135 */
136 #define SC16IS7XX_LCR_PARITY_BIT (1 << 3) /* Parity bit enable */
137 #define SC16IS7XX_LCR_EVENPARITY_BIT (1 << 4) /* Even parity bit enable */
138 #define SC16IS7XX_LCR_FORCEPARITY_BIT (1 << 5) /* 9-bit multidrop parity */
139 #define SC16IS7XX_LCR_TXBREAK_BIT (1 << 6) /* TX break enable */
140 #define SC16IS7XX_LCR_DLAB_BIT (1 << 7) /* Divisor Latch enable */
141 #define SC16IS7XX_LCR_WORD_LEN_5 (0x00)
142 #define SC16IS7XX_LCR_WORD_LEN_6 (0x01)
143 #define SC16IS7XX_LCR_WORD_LEN_7 (0x02)
144 #define SC16IS7XX_LCR_WORD_LEN_8 (0x03)
145 #define SC16IS7XX_LCR_CONF_MODE_A SC16IS7XX_LCR_DLAB_BIT /* Special
146 * reg set */
147 #define SC16IS7XX_LCR_CONF_MODE_B 0xBF /* Enhanced
148 * reg set */
149
150 /* MCR register bits */
151 #define SC16IS7XX_MCR_DTR_BIT (1 << 0) /* DTR complement
152 * - only on 75x/76x
153 */
154 #define SC16IS7XX_MCR_RTS_BIT (1 << 1) /* RTS complement */
155 #define SC16IS7XX_MCR_TCRTLR_BIT (1 << 2) /* TCR/TLR register enable */
156 #define SC16IS7XX_MCR_LOOP_BIT (1 << 4) /* Enable loopback test mode */
157 #define SC16IS7XX_MCR_XONANY_BIT (1 << 5) /* Enable Xon Any
158 * - write enabled
159 * if (EFR[4] == 1)
160 */
161 #define SC16IS7XX_MCR_IRDA_BIT (1 << 6) /* Enable IrDA mode
162 * - write enabled
163 * if (EFR[4] == 1)
164 */
165 #define SC16IS7XX_MCR_CLKSEL_BIT (1 << 7) /* Divide clock by 4
166 * - write enabled
167 * if (EFR[4] == 1)
168 */
169
170 /* LSR register bits */
171 #define SC16IS7XX_LSR_DR_BIT (1 << 0) /* Receiver data ready */
172 #define SC16IS7XX_LSR_OE_BIT (1 << 1) /* Overrun Error */
173 #define SC16IS7XX_LSR_PE_BIT (1 << 2) /* Parity Error */
174 #define SC16IS7XX_LSR_FE_BIT (1 << 3) /* Frame Error */
175 #define SC16IS7XX_LSR_BI_BIT (1 << 4) /* Break Interrupt */
176 #define SC16IS7XX_LSR_BRK_ERROR_MASK 0x1E /* BI, FE, PE, OE bits */
177 #define SC16IS7XX_LSR_THRE_BIT (1 << 5) /* TX holding register empty */
178 #define SC16IS7XX_LSR_TEMT_BIT (1 << 6) /* Transmitter empty */
179 #define SC16IS7XX_LSR_FIFOE_BIT (1 << 7) /* Fifo Error */
180
181 /* MSR register bits */
182 #define SC16IS7XX_MSR_DCTS_BIT (1 << 0) /* Delta CTS Clear To Send */
183 #define SC16IS7XX_MSR_DDSR_BIT (1 << 1) /* Delta DSR Data Set Ready
184 * or (IO4)
185 * - only on 75x/76x
186 */
187 #define SC16IS7XX_MSR_DRI_BIT (1 << 2) /* Delta RI Ring Indicator
188 * or (IO7)
189 * - only on 75x/76x
190 */
191 #define SC16IS7XX_MSR_DCD_BIT (1 << 3) /* Delta CD Carrier Detect
192 * or (IO6)
193 * - only on 75x/76x
194 */
195 #define SC16IS7XX_MSR_CTS_BIT (1 << 4) /* CTS */
196 #define SC16IS7XX_MSR_DSR_BIT (1 << 5) /* DSR (IO4)
197 * - only on 75x/76x
198 */
199 #define SC16IS7XX_MSR_RI_BIT (1 << 6) /* RI (IO7)
200 * - only on 75x/76x
201 */
202 #define SC16IS7XX_MSR_CD_BIT (1 << 7) /* CD (IO6)
203 * - only on 75x/76x
204 */
205 #define SC16IS7XX_MSR_DELTA_MASK 0x0F /* Any of the delta bits! */
206
207 /*
208 * TCR register bits
209 * TCR trigger levels are available from 0 to 60 characters with a granularity
210 * of four.
211 * The programmer must program the TCR such that TCR[3:0] > TCR[7:4]. There is
212 * no built-in hardware check to make sure this condition is met. Also, the TCR
213 * must be programmed with this condition before auto RTS or software flow
214 * control is enabled to avoid spurious operation of the device.
215 */
216 #define SC16IS7XX_TCR_RX_HALT(words) ((((words) / 4) & 0x0f) << 0)
217 #define SC16IS7XX_TCR_RX_RESUME(words) ((((words) / 4) & 0x0f) << 4)
218
219 /*
220 * TLR register bits
221 * If TLR[3:0] or TLR[7:4] are logical 0, the selectable trigger levels via the
222 * FIFO Control Register (FCR) are used for the transmit and receive FIFO
223 * trigger levels. Trigger levels from 4 characters to 60 characters are
224 * available with a granularity of four.
225 *
226 * When the trigger level setting in TLR is zero, the SC16IS740/750/760 uses the
227 * trigger level setting defined in FCR. If TLR has non-zero trigger level value
228 * the trigger level defined in FCR is discarded. This applies to both transmit
229 * FIFO and receive FIFO trigger level setting.
230 *
231 * When TLR is used for RX trigger level control, FCR[7:6] should be left at the
232 * default state, that is, '00'.
233 */
234 #define SC16IS7XX_TLR_TX_TRIGGER(words) ((((words) / 4) & 0x0f) << 0)
235 #define SC16IS7XX_TLR_RX_TRIGGER(words) ((((words) / 4) & 0x0f) << 4)
236
237 /* IOControl register bits (Only 750/760) */
238 #define SC16IS7XX_IOCONTROL_LATCH_BIT (1 << 0) /* Enable input latching */
239 #define SC16IS7XX_IOCONTROL_MODEM_BIT (1 << 1) /* Enable GPIO[7:4] as modem pins */
240 #define SC16IS7XX_IOCONTROL_SRESET_BIT (1 << 3) /* Software Reset */
241
242 /* EFCR register bits */
243 #define SC16IS7XX_EFCR_9BIT_MODE_BIT (1 << 0) /* Enable 9-bit or Multidrop
244 * mode (RS485) */
245 #define SC16IS7XX_EFCR_RXDISABLE_BIT (1 << 1) /* Disable receiver */
246 #define SC16IS7XX_EFCR_TXDISABLE_BIT (1 << 2) /* Disable transmitter */
247 #define SC16IS7XX_EFCR_AUTO_RS485_BIT (1 << 4) /* Auto RS485 RTS direction */
248 #define SC16IS7XX_EFCR_RTS_INVERT_BIT (1 << 5) /* RTS output inversion */
249 #define SC16IS7XX_EFCR_IRDA_MODE_BIT (1 << 7) /* IrDA mode
250 * 0 = rate upto 115.2 kbit/s
251 * - Only 750/760
252 * 1 = rate upto 1.152 Mbit/s
253 * - Only 760
254 */
255
256 /* EFR register bits */
257 #define SC16IS7XX_EFR_AUTORTS_BIT (1 << 6) /* Auto RTS flow ctrl enable */
258 #define SC16IS7XX_EFR_AUTOCTS_BIT (1 << 7) /* Auto CTS flow ctrl enable */
259 #define SC16IS7XX_EFR_XOFF2_DETECT_BIT (1 << 5) /* Enable Xoff2 detection */
260 #define SC16IS7XX_EFR_ENABLE_BIT (1 << 4) /* Enable enhanced functions
261 * and writing to IER[7:4],
262 * FCR[5:4], MCR[7:5]
263 */
264 #define SC16IS7XX_EFR_SWFLOW3_BIT (1 << 3) /* SWFLOW bit 3 */
265 #define SC16IS7XX_EFR_SWFLOW2_BIT (1 << 2) /* SWFLOW bit 2
266 *
267 * SWFLOW bits 3 & 2 table:
268 * 00 -> no transmitter flow
269 * control
270 * 01 -> transmitter generates
271 * XON2 and XOFF2
272 * 10 -> transmitter generates
273 * XON1 and XOFF1
274 * 11 -> transmitter generates
275 * XON1, XON2, XOFF1 and
276 * XOFF2
277 */
278 #define SC16IS7XX_EFR_SWFLOW1_BIT (1 << 1) /* SWFLOW bit 2 */
279 #define SC16IS7XX_EFR_SWFLOW0_BIT (1 << 0) /* SWFLOW bit 3
280 *
281 * SWFLOW bits 3 & 2 table:
282 * 00 -> no received flow
283 * control
284 * 01 -> receiver compares
285 * XON2 and XOFF2
286 * 10 -> receiver compares
287 * XON1 and XOFF1
288 * 11 -> receiver compares
289 * XON1, XON2, XOFF1 and
290 * XOFF2
291 */
292
293 /* Misc definitions */
294 #define SC16IS7XX_FIFO_SIZE (64)
295 #define SC16IS7XX_REG_SHIFT 2
296
297 struct sc16is7xx_devtype {
298 char name[10];
299 int nr_gpio;
300 int nr_uart;
301 };
302
303 #define SC16IS7XX_RECONF_MD (1 << 0)
304 #define SC16IS7XX_RECONF_IER (1 << 1)
305 #define SC16IS7XX_RECONF_RS485 (1 << 2)
306
307 struct sc16is7xx_one_config {
308 unsigned int flags;
309 u8 ier_clear;
310 };
311
312 struct sc16is7xx_one {
313 struct uart_port port;
314 u8 line;
315 struct kthread_work tx_work;
316 struct kthread_work reg_work;
317 struct sc16is7xx_one_config config;
318 bool irda_mode;
319 };
320
321 struct sc16is7xx_port {
322 const struct sc16is7xx_devtype *devtype;
323 struct regmap *regmap;
324 struct clk *clk;
325 #ifdef CONFIG_GPIOLIB
326 struct gpio_chip gpio;
327 #endif
328 unsigned char buf[SC16IS7XX_FIFO_SIZE];
329 struct kthread_worker kworker;
330 struct task_struct *kworker_task;
331 struct mutex efr_lock;
332 struct sc16is7xx_one p[];
333 };
334
335 static unsigned long sc16is7xx_lines;
336
337 static struct uart_driver sc16is7xx_uart = {
338 .owner = THIS_MODULE,
339 .dev_name = "ttySC",
340 .nr = SC16IS7XX_MAX_DEVS,
341 };
342
343 #define to_sc16is7xx_port(p,e) ((container_of((p), struct sc16is7xx_port, e)))
344 #define to_sc16is7xx_one(p,e) ((container_of((p), struct sc16is7xx_one, e)))
345
346 static int sc16is7xx_line(struct uart_port *port)
347 {
348 struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
349
350 return one->line;
351 }
352
353 static u8 sc16is7xx_port_read(struct uart_port *port, u8 reg)
354 {
355 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
356 unsigned int val = 0;
357 const u8 line = sc16is7xx_line(port);
358
359 regmap_read(s->regmap, (reg << SC16IS7XX_REG_SHIFT) | line, &val);
360
361 return val;
362 }
363
364 static void sc16is7xx_port_write(struct uart_port *port, u8 reg, u8 val)
365 {
366 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
367 const u8 line = sc16is7xx_line(port);
368
369 regmap_write(s->regmap, (reg << SC16IS7XX_REG_SHIFT) | line, val);
370 }
371
372 static void sc16is7xx_fifo_read(struct uart_port *port, unsigned int rxlen)
373 {
374 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
375 const u8 line = sc16is7xx_line(port);
376 u8 addr = (SC16IS7XX_RHR_REG << SC16IS7XX_REG_SHIFT) | line;
377
378 regcache_cache_bypass(s->regmap, true);
379 regmap_raw_read(s->regmap, addr, s->buf, rxlen);
380 regcache_cache_bypass(s->regmap, false);
381 }
382
383 static void sc16is7xx_fifo_write(struct uart_port *port, u8 to_send)
384 {
385 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
386 const u8 line = sc16is7xx_line(port);
387 u8 addr = (SC16IS7XX_THR_REG << SC16IS7XX_REG_SHIFT) | line;
388
389 /*
390 * Don't send zero-length data, at least on SPI it confuses the chip
391 * delivering wrong TXLVL data.
392 */
393 if (unlikely(!to_send))
394 return;
395
396 regcache_cache_bypass(s->regmap, true);
397 regmap_raw_write(s->regmap, addr, s->buf, to_send);
398 regcache_cache_bypass(s->regmap, false);
399 }
400
401 static void sc16is7xx_port_update(struct uart_port *port, u8 reg,
402 u8 mask, u8 val)
403 {
404 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
405 const u8 line = sc16is7xx_line(port);
406
407 regmap_update_bits(s->regmap, (reg << SC16IS7XX_REG_SHIFT) | line,
408 mask, val);
409 }
410
411 static int sc16is7xx_alloc_line(void)
412 {
413 int i;
414
415 BUILD_BUG_ON(SC16IS7XX_MAX_DEVS > BITS_PER_LONG);
416
417 for (i = 0; i < SC16IS7XX_MAX_DEVS; i++)
418 if (!test_and_set_bit(i, &sc16is7xx_lines))
419 break;
420
421 return i;
422 }
423
424 static void sc16is7xx_power(struct uart_port *port, int on)
425 {
426 sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
427 SC16IS7XX_IER_SLEEP_BIT,
428 on ? 0 : SC16IS7XX_IER_SLEEP_BIT);
429 }
430
431 static const struct sc16is7xx_devtype sc16is74x_devtype = {
432 .name = "SC16IS74X",
433 .nr_gpio = 0,
434 .nr_uart = 1,
435 };
436
437 static const struct sc16is7xx_devtype sc16is750_devtype = {
438 .name = "SC16IS750",
439 .nr_gpio = 8,
440 .nr_uart = 1,
441 };
442
443 static const struct sc16is7xx_devtype sc16is752_devtype = {
444 .name = "SC16IS752",
445 .nr_gpio = 8,
446 .nr_uart = 2,
447 };
448
449 static const struct sc16is7xx_devtype sc16is760_devtype = {
450 .name = "SC16IS760",
451 .nr_gpio = 8,
452 .nr_uart = 1,
453 };
454
455 static const struct sc16is7xx_devtype sc16is762_devtype = {
456 .name = "SC16IS762",
457 .nr_gpio = 8,
458 .nr_uart = 2,
459 };
460
461 static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
462 {
463 switch (reg >> SC16IS7XX_REG_SHIFT) {
464 case SC16IS7XX_RHR_REG:
465 case SC16IS7XX_IIR_REG:
466 case SC16IS7XX_LSR_REG:
467 case SC16IS7XX_MSR_REG:
468 case SC16IS7XX_TXLVL_REG:
469 case SC16IS7XX_RXLVL_REG:
470 case SC16IS7XX_IOSTATE_REG:
471 return true;
472 default:
473 break;
474 }
475
476 return false;
477 }
478
479 static bool sc16is7xx_regmap_precious(struct device *dev, unsigned int reg)
480 {
481 switch (reg >> SC16IS7XX_REG_SHIFT) {
482 case SC16IS7XX_RHR_REG:
483 return true;
484 default:
485 break;
486 }
487
488 return false;
489 }
490
491 static int sc16is7xx_set_baud(struct uart_port *port, int baud)
492 {
493 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
494 u8 lcr;
495 u8 prescaler = 0;
496 unsigned long clk = port->uartclk, div = clk / 16 / baud;
497
498 if (div > 0xffff) {
499 prescaler = SC16IS7XX_MCR_CLKSEL_BIT;
500 div /= 4;
501 }
502
503 /* In an amazing feat of design, the Enhanced Features Register shares
504 * the address of the Interrupt Identification Register, and is
505 * switched in by writing a magic value (0xbf) to the Line Control
506 * Register. Any interrupt firing during this time will see the EFR
507 * where it expects the IIR to be, leading to "Unexpected interrupt"
508 * messages.
509 *
510 * Prevent this possibility by claiming a mutex while accessing the
511 * EFR, and claiming the same mutex from within the interrupt handler.
512 * This is similar to disabling the interrupt, but that doesn't work
513 * because the bulk of the interrupt processing is run as a workqueue
514 * job in thread context.
515 */
516 mutex_lock(&s->efr_lock);
517
518 lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG);
519
520 /* Open the LCR divisors for configuration */
521 sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
522 SC16IS7XX_LCR_CONF_MODE_B);
523
524 /* Enable enhanced features */
525 regcache_cache_bypass(s->regmap, true);
526 sc16is7xx_port_write(port, SC16IS7XX_EFR_REG,
527 SC16IS7XX_EFR_ENABLE_BIT);
528 regcache_cache_bypass(s->regmap, false);
529
530 /* Put LCR back to the normal mode */
531 sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
532
533 mutex_unlock(&s->efr_lock);
534
535 sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
536 SC16IS7XX_MCR_CLKSEL_BIT,
537 prescaler);
538
539 /* Open the LCR divisors for configuration */
540 sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
541 SC16IS7XX_LCR_CONF_MODE_A);
542
543 /* Write the new divisor */
544 regcache_cache_bypass(s->regmap, true);
545 sc16is7xx_port_write(port, SC16IS7XX_DLH_REG, div / 256);
546 sc16is7xx_port_write(port, SC16IS7XX_DLL_REG, div % 256);
547 regcache_cache_bypass(s->regmap, false);
548
549 /* Put LCR back to the normal mode */
550 sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
551
552 return DIV_ROUND_CLOSEST(clk / 16, div);
553 }
554
555 static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
556 unsigned int iir)
557 {
558 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
559 unsigned int lsr = 0, ch, flag, bytes_read, i;
560 bool read_lsr = (iir == SC16IS7XX_IIR_RLSE_SRC) ? true : false;
561
562 if (unlikely(rxlen >= sizeof(s->buf))) {
563 dev_warn_ratelimited(port->dev,
564 "ttySC%i: Possible RX FIFO overrun: %d\n",
565 port->line, rxlen);
566 port->icount.buf_overrun++;
567 /* Ensure sanity of RX level */
568 rxlen = sizeof(s->buf);
569 }
570
571 while (rxlen) {
572 /* Only read lsr if there are possible errors in FIFO */
573 if (read_lsr) {
574 lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
575 if (!(lsr & SC16IS7XX_LSR_FIFOE_BIT))
576 read_lsr = false; /* No errors left in FIFO */
577 } else
578 lsr = 0;
579
580 if (read_lsr) {
581 s->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG);
582 bytes_read = 1;
583 } else {
584 sc16is7xx_fifo_read(port, rxlen);
585 bytes_read = rxlen;
586 }
587
588 lsr &= SC16IS7XX_LSR_BRK_ERROR_MASK;
589
590 port->icount.rx++;
591 flag = TTY_NORMAL;
592
593 if (unlikely(lsr)) {
594 if (lsr & SC16IS7XX_LSR_BI_BIT) {
595 port->icount.brk++;
596 if (uart_handle_break(port))
597 continue;
598 } else if (lsr & SC16IS7XX_LSR_PE_BIT)
599 port->icount.parity++;
600 else if (lsr & SC16IS7XX_LSR_FE_BIT)
601 port->icount.frame++;
602 else if (lsr & SC16IS7XX_LSR_OE_BIT)
603 port->icount.overrun++;
604
605 lsr &= port->read_status_mask;
606 if (lsr & SC16IS7XX_LSR_BI_BIT)
607 flag = TTY_BREAK;
608 else if (lsr & SC16IS7XX_LSR_PE_BIT)
609 flag = TTY_PARITY;
610 else if (lsr & SC16IS7XX_LSR_FE_BIT)
611 flag = TTY_FRAME;
612 else if (lsr & SC16IS7XX_LSR_OE_BIT)
613 flag = TTY_OVERRUN;
614 }
615
616 for (i = 0; i < bytes_read; ++i) {
617 ch = s->buf[i];
618 if (uart_handle_sysrq_char(port, ch))
619 continue;
620
621 if (lsr & port->ignore_status_mask)
622 continue;
623
624 uart_insert_char(port, lsr, SC16IS7XX_LSR_OE_BIT, ch,
625 flag);
626 }
627 rxlen -= bytes_read;
628 }
629
630 tty_flip_buffer_push(&port->state->port);
631 }
632
633 static void sc16is7xx_handle_tx(struct uart_port *port)
634 {
635 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
636 struct circ_buf *xmit = &port->state->xmit;
637 unsigned int txlen, to_send, i;
638
639 if (unlikely(port->x_char)) {
640 sc16is7xx_port_write(port, SC16IS7XX_THR_REG, port->x_char);
641 port->icount.tx++;
642 port->x_char = 0;
643 return;
644 }
645
646 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
647 return;
648
649 /* Get length of data pending in circular buffer */
650 to_send = uart_circ_chars_pending(xmit);
651 if (likely(to_send)) {
652 /* Limit to size of TX FIFO */
653 txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
654 if (txlen > SC16IS7XX_FIFO_SIZE) {
655 dev_err_ratelimited(port->dev,
656 "chip reports %d free bytes in TX fifo, but it only has %d",
657 txlen, SC16IS7XX_FIFO_SIZE);
658 txlen = 0;
659 }
660 to_send = (to_send > txlen) ? txlen : to_send;
661
662 /* Add data to send */
663 port->icount.tx += to_send;
664
665 /* Convert to linear buffer */
666 for (i = 0; i < to_send; ++i) {
667 s->buf[i] = xmit->buf[xmit->tail];
668 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
669 }
670
671 sc16is7xx_fifo_write(port, to_send);
672 }
673
674 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
675 uart_write_wakeup(port);
676 }
677
678 static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
679 {
680 struct uart_port *port = &s->p[portno].port;
681
682 do {
683 unsigned int iir, rxlen;
684
685 iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
686 if (iir & SC16IS7XX_IIR_NO_INT_BIT)
687 return false;
688
689 iir &= SC16IS7XX_IIR_ID_MASK;
690
691 switch (iir) {
692 case SC16IS7XX_IIR_RDI_SRC:
693 case SC16IS7XX_IIR_RLSE_SRC:
694 case SC16IS7XX_IIR_RTOI_SRC:
695 case SC16IS7XX_IIR_XOFFI_SRC:
696 rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG);
697 if (rxlen)
698 sc16is7xx_handle_rx(port, rxlen, iir);
699 break;
700 case SC16IS7XX_IIR_THRI_SRC:
701 sc16is7xx_handle_tx(port);
702 break;
703 default:
704 dev_err_ratelimited(port->dev,
705 "ttySC%i: Unexpected interrupt: %x",
706 port->line, iir);
707 break;
708 }
709 } while (0);
710 return true;
711 }
712
713 static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
714 {
715 struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
716
717 mutex_lock(&s->efr_lock);
718
719 while (1) {
720 bool keep_polling = false;
721 int i;
722
723 for (i = 0; i < s->devtype->nr_uart; ++i)
724 keep_polling |= sc16is7xx_port_irq(s, i);
725 if (!keep_polling)
726 break;
727 }
728
729 mutex_unlock(&s->efr_lock);
730
731 return IRQ_HANDLED;
732 }
733
734 static void sc16is7xx_tx_proc(struct kthread_work *ws)
735 {
736 struct uart_port *port = &(to_sc16is7xx_one(ws, tx_work)->port);
737
738 if ((port->rs485.flags & SER_RS485_ENABLED) &&
739 (port->rs485.delay_rts_before_send > 0))
740 msleep(port->rs485.delay_rts_before_send);
741
742 sc16is7xx_handle_tx(port);
743 }
744
745 static void sc16is7xx_reconf_rs485(struct uart_port *port)
746 {
747 const u32 mask = SC16IS7XX_EFCR_AUTO_RS485_BIT |
748 SC16IS7XX_EFCR_RTS_INVERT_BIT;
749 u32 efcr = 0;
750 struct serial_rs485 *rs485 = &port->rs485;
751 unsigned long irqflags;
752
753 spin_lock_irqsave(&port->lock, irqflags);
754 if (rs485->flags & SER_RS485_ENABLED) {
755 efcr |= SC16IS7XX_EFCR_AUTO_RS485_BIT;
756
757 if (rs485->flags & SER_RS485_RTS_AFTER_SEND)
758 efcr |= SC16IS7XX_EFCR_RTS_INVERT_BIT;
759 }
760 spin_unlock_irqrestore(&port->lock, irqflags);
761
762 sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr);
763 }
764
765 static void sc16is7xx_reg_proc(struct kthread_work *ws)
766 {
767 struct sc16is7xx_one *one = to_sc16is7xx_one(ws, reg_work);
768 struct sc16is7xx_one_config config;
769 unsigned long irqflags;
770
771 spin_lock_irqsave(&one->port.lock, irqflags);
772 config = one->config;
773 memset(&one->config, 0, sizeof(one->config));
774 spin_unlock_irqrestore(&one->port.lock, irqflags);
775
776 if (config.flags & SC16IS7XX_RECONF_MD) {
777 sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
778 SC16IS7XX_MCR_LOOP_BIT,
779 (one->port.mctrl & TIOCM_LOOP) ?
780 SC16IS7XX_MCR_LOOP_BIT : 0);
781 sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
782 SC16IS7XX_MCR_RTS_BIT,
783 (one->port.mctrl & TIOCM_RTS) ?
784 SC16IS7XX_MCR_RTS_BIT : 0);
785 sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
786 SC16IS7XX_MCR_DTR_BIT,
787 (one->port.mctrl & TIOCM_DTR) ?
788 SC16IS7XX_MCR_DTR_BIT : 0);
789 }
790 if (config.flags & SC16IS7XX_RECONF_IER)
791 sc16is7xx_port_update(&one->port, SC16IS7XX_IER_REG,
792 config.ier_clear, 0);
793
794 if (config.flags & SC16IS7XX_RECONF_RS485)
795 sc16is7xx_reconf_rs485(&one->port);
796 }
797
798 static void sc16is7xx_ier_clear(struct uart_port *port, u8 bit)
799 {
800 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
801 struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
802
803 one->config.flags |= SC16IS7XX_RECONF_IER;
804 one->config.ier_clear |= bit;
805 kthread_queue_work(&s->kworker, &one->reg_work);
806 }
807
808 static void sc16is7xx_stop_tx(struct uart_port *port)
809 {
810 sc16is7xx_ier_clear(port, SC16IS7XX_IER_THRI_BIT);
811 }
812
813 static void sc16is7xx_stop_rx(struct uart_port *port)
814 {
815 sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT);
816 }
817
818 static void sc16is7xx_start_tx(struct uart_port *port)
819 {
820 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
821 struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
822
823 kthread_queue_work(&s->kworker, &one->tx_work);
824 }
825
826 static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
827 {
828 unsigned int lsr;
829
830 lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
831
832 return (lsr & SC16IS7XX_LSR_TEMT_BIT) ? TIOCSER_TEMT : 0;
833 }
834
835 static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
836 {
837 /* DCD and DSR are not wired and CTS/RTS is handled automatically
838 * so just indicate DSR and CAR asserted
839 */
840 return TIOCM_DSR | TIOCM_CAR;
841 }
842
843 static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
844 {
845 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
846 struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
847
848 one->config.flags |= SC16IS7XX_RECONF_MD;
849 kthread_queue_work(&s->kworker, &one->reg_work);
850 }
851
852 static void sc16is7xx_break_ctl(struct uart_port *port, int break_state)
853 {
854 sc16is7xx_port_update(port, SC16IS7XX_LCR_REG,
855 SC16IS7XX_LCR_TXBREAK_BIT,
856 break_state ? SC16IS7XX_LCR_TXBREAK_BIT : 0);
857 }
858
859 static void sc16is7xx_set_termios(struct uart_port *port,
860 struct ktermios *termios,
861 struct ktermios *old)
862 {
863 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
864 unsigned int lcr, flow = 0;
865 int baud;
866
867 /* Mask termios capabilities we don't support */
868 termios->c_cflag &= ~CMSPAR;
869
870 /* Word size */
871 switch (termios->c_cflag & CSIZE) {
872 case CS5:
873 lcr = SC16IS7XX_LCR_WORD_LEN_5;
874 break;
875 case CS6:
876 lcr = SC16IS7XX_LCR_WORD_LEN_6;
877 break;
878 case CS7:
879 lcr = SC16IS7XX_LCR_WORD_LEN_7;
880 break;
881 case CS8:
882 lcr = SC16IS7XX_LCR_WORD_LEN_8;
883 break;
884 default:
885 lcr = SC16IS7XX_LCR_WORD_LEN_8;
886 termios->c_cflag &= ~CSIZE;
887 termios->c_cflag |= CS8;
888 break;
889 }
890
891 /* Parity */
892 if (termios->c_cflag & PARENB) {
893 lcr |= SC16IS7XX_LCR_PARITY_BIT;
894 if (!(termios->c_cflag & PARODD))
895 lcr |= SC16IS7XX_LCR_EVENPARITY_BIT;
896 }
897
898 /* Stop bits */
899 if (termios->c_cflag & CSTOPB)
900 lcr |= SC16IS7XX_LCR_STOPLEN_BIT; /* 2 stops */
901
902 /* Set read status mask */
903 port->read_status_mask = SC16IS7XX_LSR_OE_BIT;
904 if (termios->c_iflag & INPCK)
905 port->read_status_mask |= SC16IS7XX_LSR_PE_BIT |
906 SC16IS7XX_LSR_FE_BIT;
907 if (termios->c_iflag & (BRKINT | PARMRK))
908 port->read_status_mask |= SC16IS7XX_LSR_BI_BIT;
909
910 /* Set status ignore mask */
911 port->ignore_status_mask = 0;
912 if (termios->c_iflag & IGNBRK)
913 port->ignore_status_mask |= SC16IS7XX_LSR_BI_BIT;
914 if (!(termios->c_cflag & CREAD))
915 port->ignore_status_mask |= SC16IS7XX_LSR_BRK_ERROR_MASK;
916
917 /* As above, claim the mutex while accessing the EFR. */
918 mutex_lock(&s->efr_lock);
919
920 sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
921 SC16IS7XX_LCR_CONF_MODE_B);
922
923 /* Configure flow control */
924 regcache_cache_bypass(s->regmap, true);
925 sc16is7xx_port_write(port, SC16IS7XX_XON1_REG, termios->c_cc[VSTART]);
926 sc16is7xx_port_write(port, SC16IS7XX_XOFF1_REG, termios->c_cc[VSTOP]);
927 if (termios->c_cflag & CRTSCTS)
928 flow |= SC16IS7XX_EFR_AUTOCTS_BIT |
929 SC16IS7XX_EFR_AUTORTS_BIT;
930 if (termios->c_iflag & IXON)
931 flow |= SC16IS7XX_EFR_SWFLOW3_BIT;
932 if (termios->c_iflag & IXOFF)
933 flow |= SC16IS7XX_EFR_SWFLOW1_BIT;
934
935 sc16is7xx_port_write(port, SC16IS7XX_EFR_REG, flow);
936 regcache_cache_bypass(s->regmap, false);
937
938 /* Update LCR register */
939 sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
940
941 mutex_unlock(&s->efr_lock);
942
943 /* Get baud rate generator configuration */
944 baud = uart_get_baud_rate(port, termios, old,
945 port->uartclk / 16 / 4 / 0xffff,
946 port->uartclk / 16);
947
948 /* Setup baudrate generator */
949 baud = sc16is7xx_set_baud(port, baud);
950
951 /* Update timeout according to new baud rate */
952 uart_update_timeout(port, termios->c_cflag, baud);
953 }
954
955 static int sc16is7xx_config_rs485(struct uart_port *port,
956 struct serial_rs485 *rs485)
957 {
958 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
959 struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
960
961 if (rs485->flags & SER_RS485_ENABLED) {
962 bool rts_during_rx, rts_during_tx;
963
964 rts_during_rx = rs485->flags & SER_RS485_RTS_AFTER_SEND;
965 rts_during_tx = rs485->flags & SER_RS485_RTS_ON_SEND;
966
967 if (rts_during_rx == rts_during_tx)
968 dev_err(port->dev,
969 "unsupported RTS signalling on_send:%d after_send:%d - exactly one of RS485 RTS flags should be set\n",
970 rts_during_tx, rts_during_rx);
971
972 /*
973 * RTS signal is handled by HW, it's timing can't be influenced.
974 * However, it's sometimes useful to delay TX even without RTS
975 * control therefore we try to handle .delay_rts_before_send.
976 */
977 if (rs485->delay_rts_after_send)
978 return -EINVAL;
979 }
980
981 port->rs485 = *rs485;
982 one->config.flags |= SC16IS7XX_RECONF_RS485;
983 kthread_queue_work(&s->kworker, &one->reg_work);
984
985 return 0;
986 }
987
988 static int sc16is7xx_startup(struct uart_port *port)
989 {
990 struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
991 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
992 unsigned int val;
993
994 sc16is7xx_power(port, 1);
995
996 /* Reset FIFOs*/
997 val = SC16IS7XX_FCR_RXRESET_BIT | SC16IS7XX_FCR_TXRESET_BIT;
998 sc16is7xx_port_write(port, SC16IS7XX_FCR_REG, val);
999 udelay(5);
1000 sc16is7xx_port_write(port, SC16IS7XX_FCR_REG,
1001 SC16IS7XX_FCR_FIFO_BIT);
1002
1003 /* Enable EFR */
1004 sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
1005 SC16IS7XX_LCR_CONF_MODE_B);
1006
1007 regcache_cache_bypass(s->regmap, true);
1008
1009 /* Enable write access to enhanced features and internal clock div */
1010 sc16is7xx_port_write(port, SC16IS7XX_EFR_REG,
1011 SC16IS7XX_EFR_ENABLE_BIT);
1012
1013 /* Enable TCR/TLR */
1014 sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
1015 SC16IS7XX_MCR_TCRTLR_BIT,
1016 SC16IS7XX_MCR_TCRTLR_BIT);
1017
1018 /* Configure flow control levels */
1019 /* Flow control halt level 48, resume level 24 */
1020 sc16is7xx_port_write(port, SC16IS7XX_TCR_REG,
1021 SC16IS7XX_TCR_RX_RESUME(24) |
1022 SC16IS7XX_TCR_RX_HALT(48));
1023
1024 regcache_cache_bypass(s->regmap, false);
1025
1026 /* Now, initialize the UART */
1027 sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8);
1028
1029 /* Enable IrDA mode if requested in DT */
1030 /* This bit must be written with LCR[7] = 0 */
1031 sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
1032 SC16IS7XX_MCR_IRDA_BIT,
1033 one->irda_mode ?
1034 SC16IS7XX_MCR_IRDA_BIT : 0);
1035
1036 /* Enable the Rx and Tx FIFO */
1037 sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
1038 SC16IS7XX_EFCR_RXDISABLE_BIT |
1039 SC16IS7XX_EFCR_TXDISABLE_BIT,
1040 0);
1041
1042 /* Enable RX, TX interrupts */
1043 val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_THRI_BIT;
1044 sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
1045
1046 return 0;
1047 }
1048
1049 static void sc16is7xx_shutdown(struct uart_port *port)
1050 {
1051 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
1052
1053 /* Disable all interrupts */
1054 sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
1055 /* Disable TX/RX */
1056 sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
1057 SC16IS7XX_EFCR_RXDISABLE_BIT |
1058 SC16IS7XX_EFCR_TXDISABLE_BIT,
1059 SC16IS7XX_EFCR_RXDISABLE_BIT |
1060 SC16IS7XX_EFCR_TXDISABLE_BIT);
1061
1062 sc16is7xx_power(port, 0);
1063
1064 kthread_flush_worker(&s->kworker);
1065 }
1066
1067 static const char *sc16is7xx_type(struct uart_port *port)
1068 {
1069 struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
1070
1071 return (port->type == PORT_SC16IS7XX) ? s->devtype->name : NULL;
1072 }
1073
1074 static int sc16is7xx_request_port(struct uart_port *port)
1075 {
1076 /* Do nothing */
1077 return 0;
1078 }
1079
1080 static void sc16is7xx_config_port(struct uart_port *port, int flags)
1081 {
1082 if (flags & UART_CONFIG_TYPE)
1083 port->type = PORT_SC16IS7XX;
1084 }
1085
1086 static int sc16is7xx_verify_port(struct uart_port *port,
1087 struct serial_struct *s)
1088 {
1089 if ((s->type != PORT_UNKNOWN) && (s->type != PORT_SC16IS7XX))
1090 return -EINVAL;
1091 if (s->irq != port->irq)
1092 return -EINVAL;
1093
1094 return 0;
1095 }
1096
1097 static void sc16is7xx_pm(struct uart_port *port, unsigned int state,
1098 unsigned int oldstate)
1099 {
1100 sc16is7xx_power(port, (state == UART_PM_STATE_ON) ? 1 : 0);
1101 }
1102
1103 static void sc16is7xx_null_void(struct uart_port *port)
1104 {
1105 /* Do nothing */
1106 }
1107
1108 static const struct uart_ops sc16is7xx_ops = {
1109 .tx_empty = sc16is7xx_tx_empty,
1110 .set_mctrl = sc16is7xx_set_mctrl,
1111 .get_mctrl = sc16is7xx_get_mctrl,
1112 .stop_tx = sc16is7xx_stop_tx,
1113 .start_tx = sc16is7xx_start_tx,
1114 .stop_rx = sc16is7xx_stop_rx,
1115 .break_ctl = sc16is7xx_break_ctl,
1116 .startup = sc16is7xx_startup,
1117 .shutdown = sc16is7xx_shutdown,
1118 .set_termios = sc16is7xx_set_termios,
1119 .type = sc16is7xx_type,
1120 .request_port = sc16is7xx_request_port,
1121 .release_port = sc16is7xx_null_void,
1122 .config_port = sc16is7xx_config_port,
1123 .verify_port = sc16is7xx_verify_port,
1124 .pm = sc16is7xx_pm,
1125 };
1126
1127 #ifdef CONFIG_GPIOLIB
1128 static int sc16is7xx_gpio_get(struct gpio_chip *chip, unsigned offset)
1129 {
1130 unsigned int val;
1131 struct sc16is7xx_port *s = gpiochip_get_data(chip);
1132 struct uart_port *port = &s->p[0].port;
1133
1134 val = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG);
1135
1136 return !!(val & BIT(offset));
1137 }
1138
1139 static void sc16is7xx_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
1140 {
1141 struct sc16is7xx_port *s = gpiochip_get_data(chip);
1142 struct uart_port *port = &s->p[0].port;
1143
1144 sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset),
1145 val ? BIT(offset) : 0);
1146 }
1147
1148 static int sc16is7xx_gpio_direction_input(struct gpio_chip *chip,
1149 unsigned offset)
1150 {
1151 struct sc16is7xx_port *s = gpiochip_get_data(chip);
1152 struct uart_port *port = &s->p[0].port;
1153
1154 sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset), 0);
1155
1156 return 0;
1157 }
1158
1159 static int sc16is7xx_gpio_direction_output(struct gpio_chip *chip,
1160 unsigned offset, int val)
1161 {
1162 struct sc16is7xx_port *s = gpiochip_get_data(chip);
1163 struct uart_port *port = &s->p[0].port;
1164 u8 state = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG);
1165
1166 if (val)
1167 state |= BIT(offset);
1168 else
1169 state &= ~BIT(offset);
1170 sc16is7xx_port_write(port, SC16IS7XX_IOSTATE_REG, state);
1171 sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset),
1172 BIT(offset));
1173
1174 return 0;
1175 }
1176 #endif
1177
1178 static int sc16is7xx_probe(struct device *dev,
1179 const struct sc16is7xx_devtype *devtype,
1180 struct regmap *regmap, int irq)
1181 {
1182 unsigned long freq = 0, *pfreq = dev_get_platdata(dev);
1183 unsigned int val;
1184 u32 uartclk = 0;
1185 int i, ret;
1186 struct sc16is7xx_port *s;
1187
1188 if (IS_ERR(regmap))
1189 return PTR_ERR(regmap);
1190
1191 /*
1192 * This device does not have an identification register that would
1193 * tell us if we are really connected to the correct device.
1194 * The best we can do is to check if communication is at all possible.
1195 */
1196 ret = regmap_read(regmap,
1197 SC16IS7XX_LSR_REG << SC16IS7XX_REG_SHIFT, &val);
1198 if (ret < 0)
1199 return ret;
1200
1201 /* Alloc port structure */
1202 s = devm_kzalloc(dev, struct_size(s, p, devtype->nr_uart), GFP_KERNEL);
1203 if (!s) {
1204 dev_err(dev, "Error allocating port structure\n");
1205 return -ENOMEM;
1206 }
1207
1208 /* Always ask for fixed clock rate from a property. */
1209 device_property_read_u32(dev, "clock-frequency", &uartclk);
1210
1211 s->clk = devm_clk_get(dev, NULL);
1212 if (IS_ERR(s->clk)) {
1213 if (uartclk)
1214 freq = uartclk;
1215 if (pfreq)
1216 freq = *pfreq;
1217 if (freq)
1218 dev_dbg(dev, "Clock frequency: %luHz\n", freq);
1219 else
1220 return PTR_ERR(s->clk);
1221 } else {
1222 ret = clk_prepare_enable(s->clk);
1223 if (ret)
1224 return ret;
1225
1226 freq = clk_get_rate(s->clk);
1227 }
1228
1229 s->regmap = regmap;
1230 s->devtype = devtype;
1231 dev_set_drvdata(dev, s);
1232 mutex_init(&s->efr_lock);
1233
1234 kthread_init_worker(&s->kworker);
1235 s->kworker_task = kthread_run(kthread_worker_fn, &s->kworker,
1236 "sc16is7xx");
1237 if (IS_ERR(s->kworker_task)) {
1238 ret = PTR_ERR(s->kworker_task);
1239 goto out_clk;
1240 }
1241 sched_set_fifo(s->kworker_task);
1242
1243 #ifdef CONFIG_GPIOLIB
1244 if (devtype->nr_gpio) {
1245 /* Setup GPIO cotroller */
1246 s->gpio.owner = THIS_MODULE;
1247 s->gpio.parent = dev;
1248 s->gpio.label = dev_name(dev);
1249 s->gpio.direction_input = sc16is7xx_gpio_direction_input;
1250 s->gpio.get = sc16is7xx_gpio_get;
1251 s->gpio.direction_output = sc16is7xx_gpio_direction_output;
1252 s->gpio.set = sc16is7xx_gpio_set;
1253 s->gpio.base = -1;
1254 s->gpio.ngpio = devtype->nr_gpio;
1255 s->gpio.can_sleep = 1;
1256 ret = gpiochip_add_data(&s->gpio, s);
1257 if (ret)
1258 goto out_thread;
1259 }
1260 #endif
1261
1262 /* reset device, purging any pending irq / data */
1263 regmap_write(s->regmap, SC16IS7XX_IOCONTROL_REG << SC16IS7XX_REG_SHIFT,
1264 SC16IS7XX_IOCONTROL_SRESET_BIT);
1265
1266 for (i = 0; i < devtype->nr_uart; ++i) {
1267 s->p[i].line = i;
1268 /* Initialize port data */
1269 s->p[i].port.dev = dev;
1270 s->p[i].port.irq = irq;
1271 s->p[i].port.type = PORT_SC16IS7XX;
1272 s->p[i].port.fifosize = SC16IS7XX_FIFO_SIZE;
1273 s->p[i].port.flags = UPF_FIXED_TYPE | UPF_LOW_LATENCY;
1274 s->p[i].port.iobase = i;
1275 s->p[i].port.iotype = UPIO_PORT;
1276 s->p[i].port.uartclk = freq;
1277 s->p[i].port.rs485_config = sc16is7xx_config_rs485;
1278 s->p[i].port.ops = &sc16is7xx_ops;
1279 s->p[i].port.line = sc16is7xx_alloc_line();
1280 if (s->p[i].port.line >= SC16IS7XX_MAX_DEVS) {
1281 ret = -ENOMEM;
1282 goto out_ports;
1283 }
1284
1285 /* Disable all interrupts */
1286 sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_IER_REG, 0);
1287 /* Disable TX/RX */
1288 sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFCR_REG,
1289 SC16IS7XX_EFCR_RXDISABLE_BIT |
1290 SC16IS7XX_EFCR_TXDISABLE_BIT);
1291 /* Initialize kthread work structs */
1292 kthread_init_work(&s->p[i].tx_work, sc16is7xx_tx_proc);
1293 kthread_init_work(&s->p[i].reg_work, sc16is7xx_reg_proc);
1294 /* Register port */
1295 uart_add_one_port(&sc16is7xx_uart, &s->p[i].port);
1296
1297 /* Enable EFR */
1298 sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG,
1299 SC16IS7XX_LCR_CONF_MODE_B);
1300
1301 regcache_cache_bypass(s->regmap, true);
1302
1303 /* Enable write access to enhanced features */
1304 sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFR_REG,
1305 SC16IS7XX_EFR_ENABLE_BIT);
1306
1307 regcache_cache_bypass(s->regmap, false);
1308
1309 /* Restore access to general registers */
1310 sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG, 0x00);
1311
1312 /* Go to suspend mode */
1313 sc16is7xx_power(&s->p[i].port, 0);
1314 }
1315
1316 if (dev->of_node) {
1317 struct property *prop;
1318 const __be32 *p;
1319 u32 u;
1320
1321 of_property_for_each_u32(dev->of_node, "irda-mode-ports",
1322 prop, p, u)
1323 if (u < devtype->nr_uart)
1324 s->p[u].irda_mode = true;
1325 }
1326
1327 /*
1328 * Setup interrupt. We first try to acquire the IRQ line as level IRQ.
1329 * If that succeeds, we can allow sharing the interrupt as well.
1330 * In case the interrupt controller doesn't support that, we fall
1331 * back to a non-shared falling-edge trigger.
1332 */
1333 ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq,
1334 IRQF_TRIGGER_LOW | IRQF_SHARED |
1335 IRQF_ONESHOT,
1336 dev_name(dev), s);
1337 if (!ret)
1338 return 0;
1339
1340 ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq,
1341 IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
1342 dev_name(dev), s);
1343 if (!ret)
1344 return 0;
1345
1346 out_ports:
1347 for (i--; i >= 0; i--) {
1348 uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
1349 clear_bit(s->p[i].port.line, &sc16is7xx_lines);
1350 }
1351
1352 #ifdef CONFIG_GPIOLIB
1353 if (devtype->nr_gpio)
1354 gpiochip_remove(&s->gpio);
1355
1356 out_thread:
1357 #endif
1358 kthread_stop(s->kworker_task);
1359
1360 out_clk:
1361 if (!IS_ERR(s->clk))
1362 clk_disable_unprepare(s->clk);
1363
1364 return ret;
1365 }
1366
1367 static int sc16is7xx_remove(struct device *dev)
1368 {
1369 struct sc16is7xx_port *s = dev_get_drvdata(dev);
1370 int i;
1371
1372 #ifdef CONFIG_GPIOLIB
1373 if (s->devtype->nr_gpio)
1374 gpiochip_remove(&s->gpio);
1375 #endif
1376
1377 for (i = 0; i < s->devtype->nr_uart; i++) {
1378 uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
1379 clear_bit(s->p[i].port.line, &sc16is7xx_lines);
1380 sc16is7xx_power(&s->p[i].port, 0);
1381 }
1382
1383 kthread_flush_worker(&s->kworker);
1384 kthread_stop(s->kworker_task);
1385
1386 if (!IS_ERR(s->clk))
1387 clk_disable_unprepare(s->clk);
1388
1389 return 0;
1390 }
1391
1392 static const struct of_device_id __maybe_unused sc16is7xx_dt_ids[] = {
1393 { .compatible = "nxp,sc16is740", .data = &sc16is74x_devtype, },
1394 { .compatible = "nxp,sc16is741", .data = &sc16is74x_devtype, },
1395 { .compatible = "nxp,sc16is750", .data = &sc16is750_devtype, },
1396 { .compatible = "nxp,sc16is752", .data = &sc16is752_devtype, },
1397 { .compatible = "nxp,sc16is760", .data = &sc16is760_devtype, },
1398 { .compatible = "nxp,sc16is762", .data = &sc16is762_devtype, },
1399 { }
1400 };
1401 MODULE_DEVICE_TABLE(of, sc16is7xx_dt_ids);
1402
1403 static struct regmap_config regcfg = {
1404 .reg_bits = 7,
1405 .pad_bits = 1,
1406 .val_bits = 8,
1407 .cache_type = REGCACHE_RBTREE,
1408 .volatile_reg = sc16is7xx_regmap_volatile,
1409 .precious_reg = sc16is7xx_regmap_precious,
1410 };
1411
1412 #ifdef CONFIG_SERIAL_SC16IS7XX_SPI
1413 static int sc16is7xx_spi_probe(struct spi_device *spi)
1414 {
1415 const struct sc16is7xx_devtype *devtype;
1416 struct regmap *regmap;
1417 int ret;
1418
1419 /* Setup SPI bus */
1420 spi->bits_per_word = 8;
1421 /* only supports mode 0 on SC16IS762 */
1422 spi->mode = spi->mode ? : SPI_MODE_0;
1423 spi->max_speed_hz = spi->max_speed_hz ? : 15000000;
1424 ret = spi_setup(spi);
1425 if (ret)
1426 return ret;
1427
1428 if (spi->dev.of_node) {
1429 devtype = device_get_match_data(&spi->dev);
1430 if (!devtype)
1431 return -ENODEV;
1432 } else {
1433 const struct spi_device_id *id_entry = spi_get_device_id(spi);
1434
1435 devtype = (struct sc16is7xx_devtype *)id_entry->driver_data;
1436 }
1437
1438 regcfg.max_register = (0xf << SC16IS7XX_REG_SHIFT) |
1439 (devtype->nr_uart - 1);
1440 regmap = devm_regmap_init_spi(spi, &regcfg);
1441
1442 return sc16is7xx_probe(&spi->dev, devtype, regmap, spi->irq);
1443 }
1444
1445 static int sc16is7xx_spi_remove(struct spi_device *spi)
1446 {
1447 return sc16is7xx_remove(&spi->dev);
1448 }
1449
1450 static const struct spi_device_id sc16is7xx_spi_id_table[] = {
1451 { "sc16is74x", (kernel_ulong_t)&sc16is74x_devtype, },
1452 { "sc16is740", (kernel_ulong_t)&sc16is74x_devtype, },
1453 { "sc16is741", (kernel_ulong_t)&sc16is74x_devtype, },
1454 { "sc16is750", (kernel_ulong_t)&sc16is750_devtype, },
1455 { "sc16is752", (kernel_ulong_t)&sc16is752_devtype, },
1456 { "sc16is760", (kernel_ulong_t)&sc16is760_devtype, },
1457 { "sc16is762", (kernel_ulong_t)&sc16is762_devtype, },
1458 { }
1459 };
1460
1461 MODULE_DEVICE_TABLE(spi, sc16is7xx_spi_id_table);
1462
1463 static struct spi_driver sc16is7xx_spi_uart_driver = {
1464 .driver = {
1465 .name = SC16IS7XX_NAME,
1466 .of_match_table = sc16is7xx_dt_ids,
1467 },
1468 .probe = sc16is7xx_spi_probe,
1469 .remove = sc16is7xx_spi_remove,
1470 .id_table = sc16is7xx_spi_id_table,
1471 };
1472
1473 MODULE_ALIAS("spi:sc16is7xx");
1474 #endif
1475
1476 #ifdef CONFIG_SERIAL_SC16IS7XX_I2C
1477 static int sc16is7xx_i2c_probe(struct i2c_client *i2c,
1478 const struct i2c_device_id *id)
1479 {
1480 const struct sc16is7xx_devtype *devtype;
1481 struct regmap *regmap;
1482
1483 if (i2c->dev.of_node) {
1484 devtype = device_get_match_data(&i2c->dev);
1485 if (!devtype)
1486 return -ENODEV;
1487 } else {
1488 devtype = (struct sc16is7xx_devtype *)id->driver_data;
1489 }
1490
1491 regcfg.max_register = (0xf << SC16IS7XX_REG_SHIFT) |
1492 (devtype->nr_uart - 1);
1493 regmap = devm_regmap_init_i2c(i2c, &regcfg);
1494
1495 return sc16is7xx_probe(&i2c->dev, devtype, regmap, i2c->irq);
1496 }
1497
1498 static int sc16is7xx_i2c_remove(struct i2c_client *client)
1499 {
1500 return sc16is7xx_remove(&client->dev);
1501 }
1502
1503 static const struct i2c_device_id sc16is7xx_i2c_id_table[] = {
1504 { "sc16is74x", (kernel_ulong_t)&sc16is74x_devtype, },
1505 { "sc16is740", (kernel_ulong_t)&sc16is74x_devtype, },
1506 { "sc16is741", (kernel_ulong_t)&sc16is74x_devtype, },
1507 { "sc16is750", (kernel_ulong_t)&sc16is750_devtype, },
1508 { "sc16is752", (kernel_ulong_t)&sc16is752_devtype, },
1509 { "sc16is760", (kernel_ulong_t)&sc16is760_devtype, },
1510 { "sc16is762", (kernel_ulong_t)&sc16is762_devtype, },
1511 { }
1512 };
1513 MODULE_DEVICE_TABLE(i2c, sc16is7xx_i2c_id_table);
1514
1515 static struct i2c_driver sc16is7xx_i2c_uart_driver = {
1516 .driver = {
1517 .name = SC16IS7XX_NAME,
1518 .of_match_table = sc16is7xx_dt_ids,
1519 },
1520 .probe = sc16is7xx_i2c_probe,
1521 .remove = sc16is7xx_i2c_remove,
1522 .id_table = sc16is7xx_i2c_id_table,
1523 };
1524
1525 #endif
1526
1527 static int __init sc16is7xx_init(void)
1528 {
1529 int ret;
1530
1531 ret = uart_register_driver(&sc16is7xx_uart);
1532 if (ret) {
1533 pr_err("Registering UART driver failed\n");
1534 return ret;
1535 }
1536
1537 #ifdef CONFIG_SERIAL_SC16IS7XX_I2C
1538 ret = i2c_add_driver(&sc16is7xx_i2c_uart_driver);
1539 if (ret < 0) {
1540 pr_err("failed to init sc16is7xx i2c --> %d\n", ret);
1541 goto err_i2c;
1542 }
1543 #endif
1544
1545 #ifdef CONFIG_SERIAL_SC16IS7XX_SPI
1546 ret = spi_register_driver(&sc16is7xx_spi_uart_driver);
1547 if (ret < 0) {
1548 pr_err("failed to init sc16is7xx spi --> %d\n", ret);
1549 goto err_spi;
1550 }
1551 #endif
1552 return ret;
1553
1554 #ifdef CONFIG_SERIAL_SC16IS7XX_SPI
1555 err_spi:
1556 #endif
1557 #ifdef CONFIG_SERIAL_SC16IS7XX_I2C
1558 i2c_del_driver(&sc16is7xx_i2c_uart_driver);
1559 err_i2c:
1560 #endif
1561 uart_unregister_driver(&sc16is7xx_uart);
1562 return ret;
1563 }
1564 module_init(sc16is7xx_init);
1565
1566 static void __exit sc16is7xx_exit(void)
1567 {
1568 #ifdef CONFIG_SERIAL_SC16IS7XX_I2C
1569 i2c_del_driver(&sc16is7xx_i2c_uart_driver);
1570 #endif
1571
1572 #ifdef CONFIG_SERIAL_SC16IS7XX_SPI
1573 spi_unregister_driver(&sc16is7xx_spi_uart_driver);
1574 #endif
1575 uart_unregister_driver(&sc16is7xx_uart);
1576 }
1577 module_exit(sc16is7xx_exit);
1578
1579 MODULE_LICENSE("GPL");
1580 MODULE_AUTHOR("Jon Ringle <jringle@gridpoint.com>");
1581 MODULE_DESCRIPTION("SC16IS7XX serial driver");
Linux with added FPC-III support