2 * drivers/sbus/char/vfc_i2c.c
4 * Driver for the Videopix Frame Grabber.
6 * Functions that support the Phillips i2c(I squared C) bus on the vfc
7 * Documentation for the Phillips I2C bus can be found on the
10 * Copyright (C) 1996 Manish Vachharajani (mvachhar@noc.rutgers.edu)
14 /* NOTE: It seems to me that the documentation regarding the
15 pcd8584t/pcf8584 does not show the correct way to address the i2c bus.
16 Based on the information on the I2C bus itself and the remainder of
17 the Phillips docs the following algorithms appear to be correct. I am
18 fairly certain that the flowcharts in the phillips docs are wrong. */
21 #include <linux/kernel.h>
22 #include <linux/string.h>
23 #include <linux/slab.h>
24 #include <linux/errno.h>
25 #include <linux/sched.h>
26 #include <linux/wait.h>
27 #include <linux/delay.h>
28 #include <asm/openprom.h>
29 #include <asm/oplib.h>
31 #include <asm/system.h>
41 #define WRITE_S1(__val) \
42 sbus_writel(__val, &dev->regs->i2c_s1)
43 #define WRITE_REG(__val) \
44 sbus_writel(__val, &dev->regs->i2c_reg)
46 #define VFC_I2C_READ (0x1)
47 #define VFC_I2C_WRITE (0x0)
50 The i2c bus controller chip on the VFC is a pcd8584t, but
51 phillips claims it doesn't exist. As far as I can tell it is
52 identical to the PCF8584 so I treat it like it is the pcf8584.
54 NOTE: The pcf8584 only cares
55 about the msb of the word you feed it
58 int vfc_pcf8584_init(struct vfc_dev
*dev
)
60 /* This will also choose register S0_OWN so we can set it. */
63 /* The pcf8584 shifts this value left one bit and uses
64 * it as its i2c bus address.
66 WRITE_REG(0x55000000);
68 /* This will set the i2c bus at the same speed sun uses,
69 * and set another magic bit.
72 WRITE_REG(0x14000000);
74 /* Enable the serial port, idle the i2c bus and set
77 WRITE_S1(CLEAR_I2C_BUS
);
82 void vfc_i2c_delay_no_busy(struct vfc_dev
*dev
, unsigned long usecs
)
84 schedule_timeout_uninterruptible(usecs_to_jiffies(usecs
));
87 void inline vfc_i2c_delay(struct vfc_dev
*dev
)
89 vfc_i2c_delay_no_busy(dev
, 100);
92 int vfc_init_i2c_bus(struct vfc_dev
*dev
)
94 WRITE_S1(ENABLE_SERIAL
| SELECT(S0
) | ACK
);
95 vfc_i2c_reset_bus(dev
);
99 int vfc_i2c_reset_bus(struct vfc_dev
*dev
)
101 VFC_I2C_DEBUG_PRINTK((KERN_DEBUG
"vfc%d: Resetting the i2c bus\n",
105 if(dev
->regs
== NULL
)
107 WRITE_S1(SEND_I2C_STOP
);
108 WRITE_S1(SEND_I2C_STOP
| ACK
);
110 WRITE_S1(CLEAR_I2C_BUS
);
111 VFC_I2C_DEBUG_PRINTK((KERN_DEBUG
"vfc%d: I2C status %x\n",
113 sbus_readl(&dev
->regs
->i2c_s1
)));
117 int vfc_i2c_wait_for_bus(struct vfc_dev
*dev
)
121 while(!(sbus_readl(&dev
->regs
->i2c_s1
) & BB
)) {
129 int vfc_i2c_wait_for_pin(struct vfc_dev
*dev
, int ack
)
134 while ((s1
= sbus_readl(&dev
->regs
->i2c_s1
)) & PIN
) {
139 if (ack
== VFC_I2C_ACK_CHECK
) {
146 #define SHIFT(a) ((a) << 24)
147 int vfc_i2c_xmit_addr(struct vfc_dev
*dev
, unsigned char addr
, char mode
)
151 WRITE_S1(SEND_I2C_STOP
| ACK
);
152 WRITE_S1(SELECT(S0
) | ENABLE_SERIAL
);
158 raddr
= SHIFT(((unsigned int)addr
| 0x1));
160 VFC_I2C_DEBUG_PRINTK(("vfc%d: receiving from i2c addr 0x%x\n",
161 dev
->instance
, addr
| 0x1));
164 raddr
= SHIFT((unsigned int)addr
& ~0x1);
166 VFC_I2C_DEBUG_PRINTK(("vfc%d: sending to i2c addr 0x%x\n",
167 dev
->instance
, addr
& ~0x1));
173 WRITE_S1(SEND_I2C_START
);
175 ret
= vfc_i2c_wait_for_pin(dev
,VFC_I2C_ACK_CHECK
); /* We wait
184 printk(KERN_ERR
"vfc%d: VFC xmit addr timed out or no ack\n",
187 } else if (mode
== VFC_I2C_READ
) {
188 if ((ret
= sbus_readl(&dev
->regs
->i2c_reg
) & 0xff000000) != raddr
) {
190 "vfc%d: returned slave address "
192 dev
->instance
, raddr
, ret
);
198 int vfc_i2c_xmit_byte(struct vfc_dev
*dev
,unsigned char *byte
)
201 u32 val
= SHIFT((unsigned int)*byte
);
205 ret
= vfc_i2c_wait_for_pin(dev
, VFC_I2C_ACK_CHECK
);
208 printk(KERN_ERR
"vfc%d: VFC xmit byte timed out or no ack\n",
212 ret
= XMIT_LAST_BYTE
;
221 int vfc_i2c_recv_byte(struct vfc_dev
*dev
, unsigned char *byte
, int last
)
226 WRITE_REG(NEGATIVE_ACK
);
227 VFC_I2C_DEBUG_PRINTK(("vfc%d: sending negative ack\n",
233 ret
= vfc_i2c_wait_for_pin(dev
, VFC_I2C_NO_ACK_CHECK
);
235 printk(KERN_ERR
"vfc%d: "
236 "VFC recv byte timed out\n",
239 *byte
= (sbus_readl(&dev
->regs
->i2c_reg
)) >> 24;
243 int vfc_i2c_recvbuf(struct vfc_dev
*dev
, unsigned char addr
,
244 char *buf
, int count
)
248 if(!(count
&& buf
&& dev
&& dev
->regs
) )
251 if ((ret
= vfc_i2c_wait_for_bus(dev
))) {
252 printk(KERN_ERR
"vfc%d: VFC I2C bus busy\n", dev
->instance
);
256 if ((ret
= vfc_i2c_xmit_addr(dev
, addr
, VFC_I2C_READ
))) {
257 WRITE_S1(SEND_I2C_STOP
);
266 if ((ret
= vfc_i2c_recv_byte(dev
, buf
, last
))) {
267 printk(KERN_ERR
"vfc%d: "
268 "VFC error while receiving byte\n",
270 WRITE_S1(SEND_I2C_STOP
);
275 WRITE_S1(SEND_I2C_STOP
| ACK
);
280 int vfc_i2c_sendbuf(struct vfc_dev
*dev
, unsigned char addr
,
281 char *buf
, int count
)
285 if (!(buf
&& dev
&& dev
->regs
))
288 if ((ret
= vfc_i2c_wait_for_bus(dev
))) {
289 printk(KERN_ERR
"vfc%d: VFC I2C bus busy\n", dev
->instance
);
293 if ((ret
= vfc_i2c_xmit_addr(dev
, addr
, VFC_I2C_WRITE
))) {
294 WRITE_S1(SEND_I2C_STOP
);
300 ret
= vfc_i2c_xmit_byte(dev
, buf
);
303 VFC_I2C_DEBUG_PRINTK(("vfc%d: "
304 "Receiver ended transmission with "
305 " %d bytes remaining\n",
306 dev
->instance
, count
));
313 printk(KERN_ERR
"vfc%d: "
314 "VFC error while sending byte\n", dev
->instance
);
321 WRITE_S1(SEND_I2C_STOP
| ACK
);