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);