2 * Nomadik clock implementation
3 * Copyright (C) 2013 ST-Ericsson AB
4 * License terms: GNU General Public License (GPL) version 2
5 * Author: Linus Walleij <linus.walleij@linaro.org>
8 #define pr_fmt(fmt) "Nomadik SRC clocks: " fmt
10 #include <linux/bitops.h>
11 #include <linux/slab.h>
12 #include <linux/err.h>
14 #include <linux/clk-provider.h>
16 #include <linux/of_address.h>
17 #include <linux/debugfs.h>
18 #include <linux/seq_file.h>
19 #include <linux/spinlock.h>
20 #include <linux/reboot.h>
23 * The Nomadik clock tree is described in the STN8815A12 DB V4.2
24 * reference manual for the chip, page 94 ff.
25 * Clock IDs are in the STn8815 Reference Manual table 3, page 27.
29 #define SRC_CR_T0_ENSEL BIT(15)
30 #define SRC_CR_T1_ENSEL BIT(17)
31 #define SRC_CR_T2_ENSEL BIT(19)
32 #define SRC_CR_T3_ENSEL BIT(21)
33 #define SRC_CR_T4_ENSEL BIT(23)
34 #define SRC_CR_T5_ENSEL BIT(25)
35 #define SRC_CR_T6_ENSEL BIT(27)
36 #define SRC_CR_T7_ENSEL BIT(29)
37 #define SRC_XTALCR 0x0CU
38 #define SRC_XTALCR_XTALTIMEN BIT(20)
39 #define SRC_XTALCR_SXTALDIS BIT(19)
40 #define SRC_XTALCR_MXTALSTAT BIT(2)
41 #define SRC_XTALCR_MXTALEN BIT(1)
42 #define SRC_XTALCR_MXTALOVER BIT(0)
43 #define SRC_PLLCR 0x10U
44 #define SRC_PLLCR_PLLTIMEN BIT(29)
45 #define SRC_PLLCR_PLL2EN BIT(28)
46 #define SRC_PLLCR_PLL1STAT BIT(2)
47 #define SRC_PLLCR_PLL1EN BIT(1)
48 #define SRC_PLLCR_PLL1OVER BIT(0)
49 #define SRC_PLLFR 0x14U
50 #define SRC_PCKEN0 0x24U
51 #define SRC_PCKDIS0 0x28U
52 #define SRC_PCKENSR0 0x2CU
53 #define SRC_PCKSR0 0x30U
54 #define SRC_PCKEN1 0x34U
55 #define SRC_PCKDIS1 0x38U
56 #define SRC_PCKENSR1 0x3CU
57 #define SRC_PCKSR1 0x40U
59 /* Lock protecting the SRC_CR register */
60 static DEFINE_SPINLOCK(src_lock
);
61 /* Base address of the SRC */
62 static void __iomem
*src_base
;
64 static int nomadik_clk_reboot_handler(struct notifier_block
*this,
70 /* The main chrystal need to be enabled for reboot to work */
71 val
= readl(src_base
+ SRC_XTALCR
);
72 val
&= ~SRC_XTALCR_MXTALOVER
;
73 val
|= SRC_XTALCR_MXTALEN
;
74 pr_crit("force-enabling MXTALO\n");
75 writel(val
, src_base
+ SRC_XTALCR
);
79 static struct notifier_block nomadik_clk_reboot_notifier
= {
80 .notifier_call
= nomadik_clk_reboot_handler
,
83 static const struct of_device_id nomadik_src_match
[] __initconst
= {
84 { .compatible
= "stericsson,nomadik-src" },
88 static void __init
nomadik_src_init(void)
90 struct device_node
*np
;
93 np
= of_find_matching_node(NULL
, nomadik_src_match
);
95 pr_crit("no matching node for SRC, aborting clock init\n");
98 src_base
= of_iomap(np
, 0);
100 pr_err("%s: must have src parent node with REGS (%pOFn)\n",
105 /* Set all timers to use the 2.4 MHz TIMCLK */
106 val
= readl(src_base
+ SRC_CR
);
107 val
|= SRC_CR_T0_ENSEL
;
108 val
|= SRC_CR_T1_ENSEL
;
109 val
|= SRC_CR_T2_ENSEL
;
110 val
|= SRC_CR_T3_ENSEL
;
111 val
|= SRC_CR_T4_ENSEL
;
112 val
|= SRC_CR_T5_ENSEL
;
113 val
|= SRC_CR_T6_ENSEL
;
114 val
|= SRC_CR_T7_ENSEL
;
115 writel(val
, src_base
+ SRC_CR
);
117 val
= readl(src_base
+ SRC_XTALCR
);
118 pr_info("SXTALO is %s\n",
119 (val
& SRC_XTALCR_SXTALDIS
) ? "disabled" : "enabled");
120 pr_info("MXTAL is %s\n",
121 (val
& SRC_XTALCR_MXTALSTAT
) ? "enabled" : "disabled");
122 if (of_property_read_bool(np
, "disable-sxtalo")) {
123 /* The machine uses an external oscillator circuit */
124 val
|= SRC_XTALCR_SXTALDIS
;
125 pr_info("disabling SXTALO\n");
127 if (of_property_read_bool(np
, "disable-mxtalo")) {
128 /* Disable this too: also run by external oscillator */
129 val
|= SRC_XTALCR_MXTALOVER
;
130 val
&= ~SRC_XTALCR_MXTALEN
;
131 pr_info("disabling MXTALO\n");
133 writel(val
, src_base
+ SRC_XTALCR
);
134 register_reboot_notifier(&nomadik_clk_reboot_notifier
);
138 * struct clk_pll1 - Nomadik PLL1 clock
139 * @hw: corresponding clock hardware entry
140 * @id: PLL instance: 1 or 2
148 * struct clk_src - Nomadik src clock
149 * @hw: corresponding clock hardware entry
151 * @group1: true if the clock is in group1, else it is in group0
152 * @clkbit: bit 0...31 corresponding to the clock in each clock register
161 #define to_pll(_hw) container_of(_hw, struct clk_pll, hw)
162 #define to_src(_hw) container_of(_hw, struct clk_src, hw)
164 static int pll_clk_enable(struct clk_hw
*hw
)
166 struct clk_pll
*pll
= to_pll(hw
);
169 spin_lock(&src_lock
);
170 val
= readl(src_base
+ SRC_PLLCR
);
172 if (val
& SRC_PLLCR_PLL1OVER
) {
173 val
|= SRC_PLLCR_PLL1EN
;
174 writel(val
, src_base
+ SRC_PLLCR
);
176 } else if (pll
->id
== 2) {
177 val
|= SRC_PLLCR_PLL2EN
;
178 writel(val
, src_base
+ SRC_PLLCR
);
180 spin_unlock(&src_lock
);
184 static void pll_clk_disable(struct clk_hw
*hw
)
186 struct clk_pll
*pll
= to_pll(hw
);
189 spin_lock(&src_lock
);
190 val
= readl(src_base
+ SRC_PLLCR
);
192 if (val
& SRC_PLLCR_PLL1OVER
) {
193 val
&= ~SRC_PLLCR_PLL1EN
;
194 writel(val
, src_base
+ SRC_PLLCR
);
196 } else if (pll
->id
== 2) {
197 val
&= ~SRC_PLLCR_PLL2EN
;
198 writel(val
, src_base
+ SRC_PLLCR
);
200 spin_unlock(&src_lock
);
203 static int pll_clk_is_enabled(struct clk_hw
*hw
)
205 struct clk_pll
*pll
= to_pll(hw
);
208 val
= readl(src_base
+ SRC_PLLCR
);
210 if (val
& SRC_PLLCR_PLL1OVER
)
211 return !!(val
& SRC_PLLCR_PLL1EN
);
212 } else if (pll
->id
== 2) {
213 return !!(val
& SRC_PLLCR_PLL2EN
);
218 static unsigned long pll_clk_recalc_rate(struct clk_hw
*hw
,
219 unsigned long parent_rate
)
221 struct clk_pll
*pll
= to_pll(hw
);
224 val
= readl(src_base
+ SRC_PLLFR
);
230 mul
= (val
>> 8) & 0x3FU
;
233 return (parent_rate
* mul
) >> div
;
239 mul
= (val
>> 24) & 0x3FU
;
241 return (parent_rate
* mul
);
249 static const struct clk_ops pll_clk_ops
= {
250 .enable
= pll_clk_enable
,
251 .disable
= pll_clk_disable
,
252 .is_enabled
= pll_clk_is_enabled
,
253 .recalc_rate
= pll_clk_recalc_rate
,
256 static struct clk_hw
* __init
257 pll_clk_register(struct device
*dev
, const char *name
,
258 const char *parent_name
, u32 id
)
262 struct clk_init_data init
;
264 if (id
!= 1 && id
!= 2) {
265 pr_err("%s: the Nomadik has only PLL 1 & 2\n", __func__
);
266 return ERR_PTR(-EINVAL
);
269 pll
= kzalloc(sizeof(*pll
), GFP_KERNEL
);
271 return ERR_PTR(-ENOMEM
);
274 init
.ops
= &pll_clk_ops
;
275 init
.parent_names
= (parent_name
? &parent_name
: NULL
);
276 init
.num_parents
= (parent_name
? 1 : 0);
277 pll
->hw
.init
= &init
;
280 pr_debug("register PLL1 clock \"%s\"\n", name
);
282 ret
= clk_hw_register(dev
, &pll
->hw
);
292 * The Nomadik SRC clocks are gated, but not in the sense that
293 * you read-modify-write a register. Instead there are separate
294 * clock enable and clock disable registers. Writing a '1' bit in
295 * the enable register for a certain clock ungates that clock without
296 * affecting the other clocks. The disable register works the opposite
300 static int src_clk_enable(struct clk_hw
*hw
)
302 struct clk_src
*sclk
= to_src(hw
);
303 u32 enreg
= sclk
->group1
? SRC_PCKEN1
: SRC_PCKEN0
;
304 u32 sreg
= sclk
->group1
? SRC_PCKSR1
: SRC_PCKSR0
;
306 writel(sclk
->clkbit
, src_base
+ enreg
);
307 /* spin until enabled */
308 while (!(readl(src_base
+ sreg
) & sclk
->clkbit
))
313 static void src_clk_disable(struct clk_hw
*hw
)
315 struct clk_src
*sclk
= to_src(hw
);
316 u32 disreg
= sclk
->group1
? SRC_PCKDIS1
: SRC_PCKDIS0
;
317 u32 sreg
= sclk
->group1
? SRC_PCKSR1
: SRC_PCKSR0
;
319 writel(sclk
->clkbit
, src_base
+ disreg
);
320 /* spin until disabled */
321 while (readl(src_base
+ sreg
) & sclk
->clkbit
)
325 static int src_clk_is_enabled(struct clk_hw
*hw
)
327 struct clk_src
*sclk
= to_src(hw
);
328 u32 sreg
= sclk
->group1
? SRC_PCKSR1
: SRC_PCKSR0
;
329 u32 val
= readl(src_base
+ sreg
);
331 return !!(val
& sclk
->clkbit
);
335 src_clk_recalc_rate(struct clk_hw
*hw
,
336 unsigned long parent_rate
)
341 static const struct clk_ops src_clk_ops
= {
342 .enable
= src_clk_enable
,
343 .disable
= src_clk_disable
,
344 .is_enabled
= src_clk_is_enabled
,
345 .recalc_rate
= src_clk_recalc_rate
,
348 static struct clk_hw
* __init
349 src_clk_register(struct device
*dev
, const char *name
,
350 const char *parent_name
, u8 id
)
353 struct clk_src
*sclk
;
354 struct clk_init_data init
;
356 sclk
= kzalloc(sizeof(*sclk
), GFP_KERNEL
);
358 return ERR_PTR(-ENOMEM
);
361 init
.ops
= &src_clk_ops
;
362 /* Do not force-disable the static SDRAM controller */
364 init
.flags
= CLK_IGNORE_UNUSED
;
367 init
.parent_names
= (parent_name
? &parent_name
: NULL
);
368 init
.num_parents
= (parent_name
? 1 : 0);
369 sclk
->hw
.init
= &init
;
371 sclk
->group1
= (id
> 31);
372 sclk
->clkbit
= BIT(id
& 0x1f);
374 pr_debug("register clock \"%s\" ID: %d group: %d bits: %08x\n",
375 name
, id
, sclk
->group1
, sclk
->clkbit
);
377 ret
= clk_hw_register(dev
, &sclk
->hw
);
386 #ifdef CONFIG_DEBUG_FS
388 static u32 src_pcksr0_boot
;
389 static u32 src_pcksr1_boot
;
391 static const char * const src_clk_names
[] = {
458 static int nomadik_src_clk_debugfs_show(struct seq_file
*s
, void *what
)
461 u32 src_pcksr0
= readl(src_base
+ SRC_PCKSR0
);
462 u32 src_pcksr1
= readl(src_base
+ SRC_PCKSR1
);
463 u32 src_pckensr0
= readl(src_base
+ SRC_PCKENSR0
);
464 u32 src_pckensr1
= readl(src_base
+ SRC_PCKENSR1
);
466 seq_puts(s
, "Clock: Boot: Now: Request: ASKED:\n");
467 for (i
= 0; i
< ARRAY_SIZE(src_clk_names
); i
++) {
468 u32 pcksrb
= (i
< 0x20) ? src_pcksr0_boot
: src_pcksr1_boot
;
469 u32 pcksr
= (i
< 0x20) ? src_pcksr0
: src_pcksr1
;
470 u32 pckreq
= (i
< 0x20) ? src_pckensr0
: src_pckensr1
;
471 u32 mask
= BIT(i
& 0x1f);
473 seq_printf(s
, "%s %s %s %s\n",
475 (pcksrb
& mask
) ? "on " : "off",
476 (pcksr
& mask
) ? "on " : "off",
477 (pckreq
& mask
) ? "on " : "off");
482 DEFINE_SHOW_ATTRIBUTE(nomadik_src_clk_debugfs
);
484 static int __init
nomadik_src_clk_init_debugfs(void)
486 /* Vital for multiplatform */
489 src_pcksr0_boot
= readl(src_base
+ SRC_PCKSR0
);
490 src_pcksr1_boot
= readl(src_base
+ SRC_PCKSR1
);
491 debugfs_create_file("nomadik-src-clk", S_IFREG
| S_IRUGO
,
492 NULL
, NULL
, &nomadik_src_clk_debugfs_fops
);
495 device_initcall(nomadik_src_clk_init_debugfs
);
499 static void __init
of_nomadik_pll_setup(struct device_node
*np
)
502 const char *clk_name
= np
->name
;
503 const char *parent_name
;
509 if (of_property_read_u32(np
, "pll-id", &pll_id
)) {
510 pr_err("%s: PLL \"%s\" missing pll-id property\n",
514 parent_name
= of_clk_get_parent_name(np
, 0);
515 hw
= pll_clk_register(NULL
, clk_name
, parent_name
, pll_id
);
517 of_clk_add_hw_provider(np
, of_clk_hw_simple_get
, hw
);
519 CLK_OF_DECLARE(nomadik_pll_clk
,
520 "st,nomadik-pll-clock", of_nomadik_pll_setup
);
522 static void __init
of_nomadik_hclk_setup(struct device_node
*np
)
525 const char *clk_name
= np
->name
;
526 const char *parent_name
;
531 parent_name
= of_clk_get_parent_name(np
, 0);
533 * The HCLK divides PLL1 with 1 (passthru), 2, 3 or 4.
535 hw
= clk_hw_register_divider(NULL
, clk_name
, parent_name
,
536 0, src_base
+ SRC_CR
,
538 CLK_DIVIDER_ONE_BASED
| CLK_DIVIDER_ALLOW_ZERO
,
541 of_clk_add_hw_provider(np
, of_clk_hw_simple_get
, hw
);
543 CLK_OF_DECLARE(nomadik_hclk_clk
,
544 "st,nomadik-hclk-clock", of_nomadik_hclk_setup
);
546 static void __init
of_nomadik_src_clk_setup(struct device_node
*np
)
549 const char *clk_name
= np
->name
;
550 const char *parent_name
;
556 if (of_property_read_u32(np
, "clock-id", &clk_id
)) {
557 pr_err("%s: SRC clock \"%s\" missing clock-id property\n",
561 parent_name
= of_clk_get_parent_name(np
, 0);
562 hw
= src_clk_register(NULL
, clk_name
, parent_name
, clk_id
);
564 of_clk_add_hw_provider(np
, of_clk_hw_simple_get
, hw
);
566 CLK_OF_DECLARE(nomadik_src_clk
,
567 "st,nomadik-src-clock", of_nomadik_src_clk_setup
);