1 /* drivers/pwm/pwm-samsung.c
3 * Copyright (c) 2007 Ben Dooks
4 * Copyright (c) 2008 Simtec Electronics
5 * Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
7 * S3C series PWM device core
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License.
14 #define pr_fmt(fmt) "pwm-samsung: " fmt
16 #include <linux/export.h>
17 #include <linux/kernel.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/err.h>
21 #include <linux/clk.h>
23 #include <linux/pwm.h>
27 #include <plat/regs-timer.h>
30 struct platform_device
*pdev
;
36 unsigned int period_ns
;
39 unsigned char tcon_base
;
44 #define to_s3c_chip(chip) container_of(chip, struct s3c_chip, chip)
46 #define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg)
48 static struct clk
*clk_scaler
[2];
50 static inline int pwm_is_tdiv(struct s3c_chip
*chip
)
52 return clk_get_parent(chip
->clk
) == chip
->clk_div
;
55 #define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0))
56 #define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2))
57 #define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3))
58 #define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1))
60 static int s3c_pwm_enable(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
62 struct s3c_chip
*s3c
= to_s3c_chip(chip
);
66 local_irq_save(flags
);
68 tcon
= __raw_readl(S3C2410_TCON
);
69 tcon
|= pwm_tcon_start(s3c
);
70 __raw_writel(tcon
, S3C2410_TCON
);
72 local_irq_restore(flags
);
77 static void s3c_pwm_disable(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
79 struct s3c_chip
*s3c
= to_s3c_chip(chip
);
83 local_irq_save(flags
);
85 tcon
= __raw_readl(S3C2410_TCON
);
86 tcon
&= ~pwm_tcon_start(s3c
);
87 __raw_writel(tcon
, S3C2410_TCON
);
89 local_irq_restore(flags
);
92 static unsigned long pwm_calc_tin(struct s3c_chip
*s3c
, unsigned long freq
)
94 unsigned long tin_parent_rate
;
97 tin_parent_rate
= clk_get_rate(clk_get_parent(s3c
->clk_div
));
98 pwm_dbg(s3c
, "tin parent at %lu\n", tin_parent_rate
);
100 for (div
= 2; div
<= 16; div
*= 2) {
101 if ((tin_parent_rate
/ (div
<< 16)) < freq
)
102 return tin_parent_rate
/ div
;
105 return tin_parent_rate
/ 16;
108 #define NS_IN_HZ (1000000000UL)
110 static int s3c_pwm_config(struct pwm_chip
*chip
, struct pwm_device
*pwm
,
111 int duty_ns
, int period_ns
)
113 struct s3c_chip
*s3c
= to_s3c_chip(chip
);
114 unsigned long tin_rate
;
115 unsigned long tin_ns
;
116 unsigned long period
;
122 /* We currently avoid using 64bit arithmetic by using the
123 * fact that anything faster than 1Hz is easily representable
126 if (period_ns
> NS_IN_HZ
|| duty_ns
> NS_IN_HZ
)
129 if (duty_ns
> period_ns
)
132 if (period_ns
== s3c
->period_ns
&&
133 duty_ns
== s3c
->duty_ns
)
136 /* The TCMP and TCNT can be read without a lock, they're not
137 * shared between the timers. */
139 tcmp
= __raw_readl(S3C2410_TCMPB(s3c
->pwm_id
));
140 tcnt
= __raw_readl(S3C2410_TCNTB(s3c
->pwm_id
));
142 period
= NS_IN_HZ
/ period_ns
;
144 pwm_dbg(s3c
, "duty_ns=%d, period_ns=%d (%lu)\n",
145 duty_ns
, period_ns
, period
);
147 /* Check to see if we are changing the clock rate of the PWM */
149 if (s3c
->period_ns
!= period_ns
) {
150 if (pwm_is_tdiv(s3c
)) {
151 tin_rate
= pwm_calc_tin(s3c
, period
);
152 clk_set_rate(s3c
->clk_div
, tin_rate
);
154 tin_rate
= clk_get_rate(s3c
->clk
);
156 s3c
->period_ns
= period_ns
;
158 pwm_dbg(s3c
, "tin_rate=%lu\n", tin_rate
);
160 tin_ns
= NS_IN_HZ
/ tin_rate
;
161 tcnt
= period_ns
/ tin_ns
;
163 tin_ns
= NS_IN_HZ
/ clk_get_rate(s3c
->clk
);
165 /* Note, counters count down */
167 tcmp
= duty_ns
/ tin_ns
;
169 /* the pwm hw only checks the compare register after a decrement,
170 so the pin never toggles if tcmp = tcnt */
174 pwm_dbg(s3c
, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns
, tcmp
, tcnt
);
179 /* Update the PWM register block. */
181 local_irq_save(flags
);
183 __raw_writel(tcmp
, S3C2410_TCMPB(s3c
->pwm_id
));
184 __raw_writel(tcnt
, S3C2410_TCNTB(s3c
->pwm_id
));
186 tcon
= __raw_readl(S3C2410_TCON
);
187 tcon
|= pwm_tcon_manulupdate(s3c
);
188 tcon
|= pwm_tcon_autoreload(s3c
);
189 __raw_writel(tcon
, S3C2410_TCON
);
191 tcon
&= ~pwm_tcon_manulupdate(s3c
);
192 __raw_writel(tcon
, S3C2410_TCON
);
194 local_irq_restore(flags
);
199 static struct pwm_ops s3c_pwm_ops
= {
200 .enable
= s3c_pwm_enable
,
201 .disable
= s3c_pwm_disable
,
202 .config
= s3c_pwm_config
,
203 .owner
= THIS_MODULE
,
206 static int s3c_pwm_probe(struct platform_device
*pdev
)
208 struct device
*dev
= &pdev
->dev
;
209 struct s3c_chip
*s3c
;
212 unsigned int id
= pdev
->id
;
216 dev_err(dev
, "TIMER4 is currently not supported\n");
220 s3c
= devm_kzalloc(&pdev
->dev
, sizeof(*s3c
), GFP_KERNEL
);
222 dev_err(dev
, "failed to allocate pwm_device\n");
226 /* calculate base of control bits in TCON */
227 s3c
->tcon_base
= id
== 0 ? 0 : (id
* 4) + 4;
228 s3c
->chip
.ops
= &s3c_pwm_ops
;
232 s3c
->clk
= devm_clk_get(dev
, "pwm-tin");
233 if (IS_ERR(s3c
->clk
)) {
234 dev_err(dev
, "failed to get pwm tin clk\n");
235 return PTR_ERR(s3c
->clk
);
238 s3c
->clk_div
= devm_clk_get(dev
, "pwm-tdiv");
239 if (IS_ERR(s3c
->clk_div
)) {
240 dev_err(dev
, "failed to get pwm tdiv clk\n");
241 return PTR_ERR(s3c
->clk_div
);
244 clk_enable(s3c
->clk
);
245 clk_enable(s3c
->clk_div
);
247 local_irq_save(flags
);
249 tcon
= __raw_readl(S3C2410_TCON
);
250 tcon
|= pwm_tcon_invert(s3c
);
251 __raw_writel(tcon
, S3C2410_TCON
);
253 local_irq_restore(flags
);
255 ret
= pwmchip_add(&s3c
->chip
);
257 dev_err(dev
, "failed to register pwm\n");
261 pwm_dbg(s3c
, "config bits %02x\n",
262 (__raw_readl(S3C2410_TCON
) >> s3c
->tcon_base
) & 0x0f);
264 dev_info(dev
, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n",
265 clk_get_rate(s3c
->clk
),
266 clk_get_rate(s3c
->clk_div
),
267 pwm_is_tdiv(s3c
) ? "div" : "ext", s3c
->tcon_base
);
269 platform_set_drvdata(pdev
, s3c
);
273 clk_disable(s3c
->clk_div
);
274 clk_disable(s3c
->clk
);
278 static int __devexit
s3c_pwm_remove(struct platform_device
*pdev
)
280 struct s3c_chip
*s3c
= platform_get_drvdata(pdev
);
283 err
= pwmchip_remove(&s3c
->chip
);
287 clk_disable(s3c
->clk_div
);
288 clk_disable(s3c
->clk
);
294 static int s3c_pwm_suspend(struct platform_device
*pdev
, pm_message_t state
)
296 struct s3c_chip
*s3c
= platform_get_drvdata(pdev
);
298 /* No one preserve these values during suspend so reset them
299 * Otherwise driver leaves PWM unconfigured if same values
300 * passed to pwm_config
308 static int s3c_pwm_resume(struct platform_device
*pdev
)
310 struct s3c_chip
*s3c
= platform_get_drvdata(pdev
);
313 /* Restore invertion */
314 tcon
= __raw_readl(S3C2410_TCON
);
315 tcon
|= pwm_tcon_invert(s3c
);
316 __raw_writel(tcon
, S3C2410_TCON
);
322 #define s3c_pwm_suspend NULL
323 #define s3c_pwm_resume NULL
326 static struct platform_driver s3c_pwm_driver
= {
328 .name
= "s3c24xx-pwm",
329 .owner
= THIS_MODULE
,
331 .probe
= s3c_pwm_probe
,
332 .remove
= __devexit_p(s3c_pwm_remove
),
333 .suspend
= s3c_pwm_suspend
,
334 .resume
= s3c_pwm_resume
,
337 static int __init
pwm_init(void)
341 clk_scaler
[0] = clk_get(NULL
, "pwm-scaler0");
342 clk_scaler
[1] = clk_get(NULL
, "pwm-scaler1");
344 if (IS_ERR(clk_scaler
[0]) || IS_ERR(clk_scaler
[1])) {
345 pr_err("failed to get scaler clocks\n");
349 ret
= platform_driver_register(&s3c_pwm_driver
);
351 pr_err("failed to add pwm driver\n");
356 arch_initcall(pwm_init
);