2 * Simple PWM driver for EP93XX
4 * (c) Copyright 2009 Matthieu Crapet <mcrapet@gmail.com>
5 * (c) Copyright 2009 H Hartley Sweeten <hsweeten@visionengravers.com>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
12 * EP9307 has only one channel:
15 * EP9301/02/12/15 have two channels:
17 * - PWMOUT1 (alternate function for EGPIO14)
20 #include <linux/module.h>
21 #include <linux/platform_device.h>
22 #include <linux/clk.h>
23 #include <linux/err.h>
26 #include <mach/platform.h>
28 #define EP93XX_PWMx_TERM_COUNT 0x00
29 #define EP93XX_PWMx_DUTY_CYCLE 0x04
30 #define EP93XX_PWMx_ENABLE 0x08
31 #define EP93XX_PWMx_INVERT 0x0C
33 #define EP93XX_PWM_MAX_COUNT 0xFFFF
36 void __iomem *mmio_base;
41 static inline void ep93xx_pwm_writel(struct ep93xx_pwm *pwm,
42 unsigned int val, unsigned int off)
44 __raw_writel(val, pwm->mmio_base + off);
47 static inline unsigned int ep93xx_pwm_readl(struct ep93xx_pwm *pwm,
50 return __raw_readl(pwm->mmio_base + off);
53 static inline void ep93xx_pwm_write_tc(struct ep93xx_pwm *pwm, u16 value)
55 ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_TERM_COUNT);
58 static inline u16 ep93xx_pwm_read_tc(struct ep93xx_pwm *pwm)
60 return ep93xx_pwm_readl(pwm, EP93XX_PWMx_TERM_COUNT);
63 static inline void ep93xx_pwm_write_dc(struct ep93xx_pwm *pwm, u16 value)
65 ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_DUTY_CYCLE);
68 static inline void ep93xx_pwm_enable(struct ep93xx_pwm *pwm)
70 ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_ENABLE);
73 static inline void ep93xx_pwm_disable(struct ep93xx_pwm *pwm)
75 ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_ENABLE);
78 static inline int ep93xx_pwm_is_enabled(struct ep93xx_pwm *pwm)
80 return ep93xx_pwm_readl(pwm, EP93XX_PWMx_ENABLE) & 0x1;
83 static inline void ep93xx_pwm_invert(struct ep93xx_pwm *pwm)
85 ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_INVERT);
88 static inline void ep93xx_pwm_normal(struct ep93xx_pwm *pwm)
90 ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_INVERT);
93 static inline int ep93xx_pwm_is_inverted(struct ep93xx_pwm *pwm)
95 return ep93xx_pwm_readl(pwm, EP93XX_PWMx_INVERT) & 0x1;
99 * /sys/devices/platform/ep93xx-pwm.N
100 * /min_freq read-only minimum pwm output frequency
101 * /max_req read-only maximum pwm output frequency
102 * /freq read-write pwm output frequency (0 = disable output)
103 * /duty_percent read-write pwm duty cycle percent (1..99)
104 * /invert read-write invert pwm output
107 static ssize_t ep93xx_pwm_get_min_freq(struct device *dev,
108 struct device_attribute *attr, char *buf)
110 struct platform_device *pdev = to_platform_device(dev);
111 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
112 unsigned long rate = clk_get_rate(pwm->clk);
114 return sprintf(buf, "%ld\n", rate / (EP93XX_PWM_MAX_COUNT + 1));
117 static ssize_t ep93xx_pwm_get_max_freq(struct device *dev,
118 struct device_attribute *attr, char *buf)
120 struct platform_device *pdev = to_platform_device(dev);
121 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
122 unsigned long rate = clk_get_rate(pwm->clk);
124 return sprintf(buf, "%ld\n", rate / 2);
127 static ssize_t ep93xx_pwm_get_freq(struct device *dev,
128 struct device_attribute *attr, char *buf)
130 struct platform_device *pdev = to_platform_device(dev);
131 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
133 if (ep93xx_pwm_is_enabled(pwm)) {
134 unsigned long rate = clk_get_rate(pwm->clk);
135 u16 term = ep93xx_pwm_read_tc(pwm);
137 return sprintf(buf, "%ld\n", rate / (term + 1));
139 return sprintf(buf, "disabled\n");
143 static ssize_t ep93xx_pwm_set_freq(struct device *dev,
144 struct device_attribute *attr, const char *buf, size_t count)
146 struct platform_device *pdev = to_platform_device(dev);
147 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
151 err = strict_strtol(buf, 10, &val);
156 ep93xx_pwm_disable(pwm);
157 } else if (val <= (clk_get_rate(pwm->clk) / 2)) {
160 val = (clk_get_rate(pwm->clk) / val) - 1;
161 if (val > EP93XX_PWM_MAX_COUNT)
162 val = EP93XX_PWM_MAX_COUNT;
166 term = ep93xx_pwm_read_tc(pwm);
167 duty = ((val + 1) * pwm->duty_percent / 100) - 1;
169 /* If pwm is running, order is important */
171 ep93xx_pwm_write_tc(pwm, val);
172 ep93xx_pwm_write_dc(pwm, duty);
174 ep93xx_pwm_write_dc(pwm, duty);
175 ep93xx_pwm_write_tc(pwm, val);
178 if (!ep93xx_pwm_is_enabled(pwm))
179 ep93xx_pwm_enable(pwm);
187 static ssize_t ep93xx_pwm_get_duty_percent(struct device *dev,
188 struct device_attribute *attr, char *buf)
190 struct platform_device *pdev = to_platform_device(dev);
191 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
193 return sprintf(buf, "%d\n", pwm->duty_percent);
196 static ssize_t ep93xx_pwm_set_duty_percent(struct device *dev,
197 struct device_attribute *attr, const char *buf, size_t count)
199 struct platform_device *pdev = to_platform_device(dev);
200 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
204 err = strict_strtol(buf, 10, &val);
208 if (val > 0 && val < 100) {
209 u32 term = ep93xx_pwm_read_tc(pwm);
210 ep93xx_pwm_write_dc(pwm, ((term + 1) * val / 100) - 1);
211 pwm->duty_percent = val;
218 static ssize_t ep93xx_pwm_get_invert(struct device *dev,
219 struct device_attribute *attr, char *buf)
221 struct platform_device *pdev = to_platform_device(dev);
222 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
224 return sprintf(buf, "%d\n", ep93xx_pwm_is_inverted(pwm));
227 static ssize_t ep93xx_pwm_set_invert(struct device *dev,
228 struct device_attribute *attr, const char *buf, size_t count)
230 struct platform_device *pdev = to_platform_device(dev);
231 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
235 err = strict_strtol(buf, 10, &val);
240 ep93xx_pwm_normal(pwm);
242 ep93xx_pwm_invert(pwm);
249 static DEVICE_ATTR(min_freq, S_IRUGO, ep93xx_pwm_get_min_freq, NULL);
250 static DEVICE_ATTR(max_freq, S_IRUGO, ep93xx_pwm_get_max_freq, NULL);
251 static DEVICE_ATTR(freq, S_IWUGO | S_IRUGO,
252 ep93xx_pwm_get_freq, ep93xx_pwm_set_freq);
253 static DEVICE_ATTR(duty_percent, S_IWUGO | S_IRUGO,
254 ep93xx_pwm_get_duty_percent, ep93xx_pwm_set_duty_percent);
255 static DEVICE_ATTR(invert, S_IWUGO | S_IRUGO,
256 ep93xx_pwm_get_invert, ep93xx_pwm_set_invert);
258 static struct attribute *ep93xx_pwm_attrs[] = {
259 &dev_attr_min_freq.attr,
260 &dev_attr_max_freq.attr,
262 &dev_attr_duty_percent.attr,
263 &dev_attr_invert.attr,
267 static const struct attribute_group ep93xx_pwm_sysfs_files = {
268 .attrs = ep93xx_pwm_attrs,
271 static int __init ep93xx_pwm_probe(struct platform_device *pdev)
273 struct ep93xx_pwm *pwm;
274 struct resource *res;
277 err = ep93xx_pwm_acquire_gpio(pdev);
281 pwm = kzalloc(sizeof(struct ep93xx_pwm), GFP_KERNEL);
287 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
290 goto fail_no_mem_resource;
293 res = request_mem_region(res->start, resource_size(res), pdev->name);
296 goto fail_no_mem_resource;
299 pwm->mmio_base = ioremap(res->start, resource_size(res));
300 if (pwm->mmio_base == NULL) {
302 goto fail_no_ioremap;
305 err = sysfs_create_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
309 pwm->clk = clk_get(&pdev->dev, "pwm_clk");
310 if (IS_ERR(pwm->clk)) {
311 err = PTR_ERR(pwm->clk);
315 pwm->duty_percent = 50;
317 platform_set_drvdata(pdev, pwm);
319 /* disable pwm at startup. Avoids zero value. */
320 ep93xx_pwm_disable(pwm);
321 ep93xx_pwm_write_tc(pwm, EP93XX_PWM_MAX_COUNT);
322 ep93xx_pwm_write_dc(pwm, EP93XX_PWM_MAX_COUNT / 2);
324 clk_enable(pwm->clk);
329 sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
331 iounmap(pwm->mmio_base);
333 release_mem_region(res->start, resource_size(res));
334 fail_no_mem_resource:
337 ep93xx_pwm_release_gpio(pdev);
341 static int __exit ep93xx_pwm_remove(struct platform_device *pdev)
343 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
344 struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
346 ep93xx_pwm_disable(pwm);
347 clk_disable(pwm->clk);
349 platform_set_drvdata(pdev, NULL);
350 sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
351 iounmap(pwm->mmio_base);
352 release_mem_region(res->start, resource_size(res));
354 ep93xx_pwm_release_gpio(pdev);
359 static struct platform_driver ep93xx_pwm_driver = {
361 .name = "ep93xx-pwm",
362 .owner = THIS_MODULE,
364 .remove = __exit_p(ep93xx_pwm_remove),
367 static int __init ep93xx_pwm_init(void)
369 return platform_driver_probe(&ep93xx_pwm_driver, ep93xx_pwm_probe);
372 static void __exit ep93xx_pwm_exit(void)
374 platform_driver_unregister(&ep93xx_pwm_driver);
377 module_init(ep93xx_pwm_init);
378 module_exit(ep93xx_pwm_exit);
380 MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>, "
381 "H Hartley Sweeten <hsweeten@visionengravers.com>");
382 MODULE_DESCRIPTION("EP93xx PWM driver");
383 MODULE_LICENSE("GPL");
384 MODULE_ALIAS("platform:ep93xx-pwm");