drivers/misc/ep93xx_pwm.c

   1 /*
   2  *  Simple PWM driver for EP93XX
   3  *
   4  *      (c) Copyright 2009  Matthieu Crapet <mcrapet@gmail.com>
   5  *      (c) Copyright 2009  H Hartley Sweeten <hsweeten@visionengravers.com>
   6  *
   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.
  11  *
  12  *  EP9307 has only one channel:
  13  *    - PWMOUT
  14  *
  15  *  EP9301/02/12/15 have two channels:
  16  *    - PWMOUT
  17  *    - PWMOUT1 (alternate function for EGPIO14)
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/slab.h>
  23 #include <linux/clk.h>
  24 #include <linux/err.h>
  25 #include <linux/io.h>
  26
  27 #include <mach/platform.h>
  28
  29 #define EP93XX_PWMx_TERM_COUNT  0x00
  30 #define EP93XX_PWMx_DUTY_CYCLE  0x04
  31 #define EP93XX_PWMx_ENABLE      0x08
  32 #define EP93XX_PWMx_INVERT      0x0C
  33
  34 #define EP93XX_PWM_MAX_COUNT    0xFFFF
  35
  36 struct ep93xx_pwm {
  37         void __iomem    *mmio_base;
  38         struct clk      *clk;
  39         u32             duty_percent;
  40 };
  41
  42 static inline void ep93xx_pwm_writel(struct ep93xx_pwm *pwm,
  43                 unsigned int val, unsigned int off)
  44 {
  45         __raw_writel(val, pwm->mmio_base + off);
  46 }
  47
  48 static inline unsigned int ep93xx_pwm_readl(struct ep93xx_pwm *pwm,
  49                 unsigned int off)
  50 {
  51         return __raw_readl(pwm->mmio_base + off);
  52 }
  53
  54 static inline void ep93xx_pwm_write_tc(struct ep93xx_pwm *pwm, u16 value)
  55 {
  56         ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_TERM_COUNT);
  57 }
  58
  59 static inline u16 ep93xx_pwm_read_tc(struct ep93xx_pwm *pwm)
  60 {
  61         return ep93xx_pwm_readl(pwm, EP93XX_PWMx_TERM_COUNT);
  62 }
  63
  64 static inline void ep93xx_pwm_write_dc(struct ep93xx_pwm *pwm, u16 value)
  65 {
  66         ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_DUTY_CYCLE);
  67 }
  68
  69 static inline void ep93xx_pwm_enable(struct ep93xx_pwm *pwm)
  70 {
  71         ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_ENABLE);
  72 }
  73
  74 static inline void ep93xx_pwm_disable(struct ep93xx_pwm *pwm)
  75 {
  76         ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_ENABLE);
  77 }
  78
  79 static inline int ep93xx_pwm_is_enabled(struct ep93xx_pwm *pwm)
  80 {
  81         return ep93xx_pwm_readl(pwm, EP93XX_PWMx_ENABLE) & 0x1;
  82 }
  83
  84 static inline void ep93xx_pwm_invert(struct ep93xx_pwm *pwm)
  85 {
  86         ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_INVERT);
  87 }
  88
  89 static inline void ep93xx_pwm_normal(struct ep93xx_pwm *pwm)
  90 {
  91         ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_INVERT);
  92 }
  93
  94 static inline int ep93xx_pwm_is_inverted(struct ep93xx_pwm *pwm)
  95 {
  96         return ep93xx_pwm_readl(pwm, EP93XX_PWMx_INVERT) & 0x1;
  97 }
  98
  99 /*
 100  * /sys/devices/platform/ep93xx-pwm.N
 101  *   /min_freq      read-only   minimum pwm output frequency
 102  *   /max_req       read-only   maximum pwm output frequency
 103  *   /freq          read-write  pwm output frequency (0 = disable output)
 104  *   /duty_percent  read-write  pwm duty cycle percent (1..99)
 105  *   /invert        read-write  invert pwm output
 106  */
 107
 108 static ssize_t ep93xx_pwm_get_min_freq(struct device *dev,
 109                 struct device_attribute *attr, char *buf)
 110 {
 111         struct platform_device *pdev = to_platform_device(dev);
 112         struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
 113         unsigned long rate = clk_get_rate(pwm->clk);
 114
 115         return sprintf(buf, "%ld\n", rate / (EP93XX_PWM_MAX_COUNT + 1));
 116 }
 117
 118 static ssize_t ep93xx_pwm_get_max_freq(struct device *dev,
 119                 struct device_attribute *attr, char *buf)
 120 {
 121         struct platform_device *pdev = to_platform_device(dev);
 122         struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
 123         unsigned long rate = clk_get_rate(pwm->clk);
 124
 125         return sprintf(buf, "%ld\n", rate / 2);
 126 }
 127
 128 static ssize_t ep93xx_pwm_get_freq(struct device *dev,
 129                 struct device_attribute *attr, char *buf)
 130 {
 131         struct platform_device *pdev = to_platform_device(dev);
 132         struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
 133
 134         if (ep93xx_pwm_is_enabled(pwm)) {
 135                 unsigned long rate = clk_get_rate(pwm->clk);
 136                 u16 term = ep93xx_pwm_read_tc(pwm);
 137
 138                 return sprintf(buf, "%ld\n", rate / (term + 1));
 139         } else {
 140                 return sprintf(buf, "disabled\n");
 141         }
 142 }
 143
 144 static ssize_t ep93xx_pwm_set_freq(struct device *dev,
 145                 struct device_attribute *attr, const char *buf, size_t count)
 146 {
 147         struct platform_device *pdev = to_platform_device(dev);
 148         struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
 149         long val;
 150         int err;
 151
 152         err = strict_strtol(buf, 10, &val);
 153         if (err)
 154                 return -EINVAL;
 155
 156         if (val == 0) {
 157                 ep93xx_pwm_disable(pwm);
 158         } else if (val <= (clk_get_rate(pwm->clk) / 2)) {
 159                 u32 term, duty;
 160
 161                 val = (clk_get_rate(pwm->clk) / val) - 1;
 162                 if (val > EP93XX_PWM_MAX_COUNT)
 163                         val = EP93XX_PWM_MAX_COUNT;
 164                 if (val < 1)
 165                         val = 1;
 166
 167                 term = ep93xx_pwm_read_tc(pwm);
 168                 duty = ((val + 1) * pwm->duty_percent / 100) - 1;
 169
 170                 /* If pwm is running, order is important */
 171                 if (val > term) {
 172                         ep93xx_pwm_write_tc(pwm, val);
 173                         ep93xx_pwm_write_dc(pwm, duty);
 174                 } else {
 175                         ep93xx_pwm_write_dc(pwm, duty);
 176                         ep93xx_pwm_write_tc(pwm, val);
 177                 }
 178
 179                 if (!ep93xx_pwm_is_enabled(pwm))
 180                         ep93xx_pwm_enable(pwm);
 181         } else {
 182                 return -EINVAL;
 183         }
 184
 185         return count;
 186 }
 187
 188 static ssize_t ep93xx_pwm_get_duty_percent(struct device *dev,
 189                 struct device_attribute *attr, char *buf)
 190 {
 191         struct platform_device *pdev = to_platform_device(dev);
 192         struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
 193
 194         return sprintf(buf, "%d\n", pwm->duty_percent);
 195 }
 196
 197 static ssize_t ep93xx_pwm_set_duty_percent(struct device *dev,
 198                 struct device_attribute *attr, const char *buf, size_t count)
 199 {
 200         struct platform_device *pdev = to_platform_device(dev);
 201         struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
 202         long val;
 203         int err;
 204
 205         err = strict_strtol(buf, 10, &val);
 206         if (err)
 207                 return -EINVAL;
 208
 209         if (val > 0 && val < 100) {
 210                 u32 term = ep93xx_pwm_read_tc(pwm);
 211                 ep93xx_pwm_write_dc(pwm, ((term + 1) * val / 100) - 1);
 212                 pwm->duty_percent = val;
 213                 return count;
 214         }
 215
 216         return -EINVAL;
 217 }
 218
 219 static ssize_t ep93xx_pwm_get_invert(struct device *dev,
 220                 struct device_attribute *attr, char *buf)
 221 {
 222         struct platform_device *pdev = to_platform_device(dev);
 223         struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
 224
 225         return sprintf(buf, "%d\n", ep93xx_pwm_is_inverted(pwm));
 226 }
 227
 228 static ssize_t ep93xx_pwm_set_invert(struct device *dev,
 229                 struct device_attribute *attr, const char *buf, size_t count)
 230 {
 231         struct platform_device *pdev = to_platform_device(dev);
 232         struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
 233         long val;
 234         int err;
 235
 236         err = strict_strtol(buf, 10, &val);
 237         if (err)
 238                 return -EINVAL;
 239
 240         if (val == 0)
 241                 ep93xx_pwm_normal(pwm);
 242         else if (val == 1)
 243                 ep93xx_pwm_invert(pwm);
 244         else
 245                 return -EINVAL;
 246
 247         return count;
 248 }
 249
 250 static DEVICE_ATTR(min_freq, S_IRUGO, ep93xx_pwm_get_min_freq, NULL);
 251 static DEVICE_ATTR(max_freq, S_IRUGO, ep93xx_pwm_get_max_freq, NULL);
 252 static DEVICE_ATTR(freq, S_IWUGO | S_IRUGO,
 253                    ep93xx_pwm_get_freq, ep93xx_pwm_set_freq);
 254 static DEVICE_ATTR(duty_percent, S_IWUGO | S_IRUGO,
 255                    ep93xx_pwm_get_duty_percent, ep93xx_pwm_set_duty_percent);
 256 static DEVICE_ATTR(invert, S_IWUGO | S_IRUGO,
 257                    ep93xx_pwm_get_invert, ep93xx_pwm_set_invert);
 258
 259 static struct attribute *ep93xx_pwm_attrs[] = {
 260         &dev_attr_min_freq.attr,
 261         &dev_attr_max_freq.attr,
 262         &dev_attr_freq.attr,
 263         &dev_attr_duty_percent.attr,
 264         &dev_attr_invert.attr,
 265         NULL
 266 };
 267
 268 static const struct attribute_group ep93xx_pwm_sysfs_files = {
 269         .attrs  = ep93xx_pwm_attrs,
 270 };
 271
 272 static int __init ep93xx_pwm_probe(struct platform_device *pdev)
 273 {
 274         struct ep93xx_pwm *pwm;
 275         struct resource *res;
 276         int err;
 277
 278         err = ep93xx_pwm_acquire_gpio(pdev);
 279         if (err)
 280                 return err;
 281
 282         pwm = kzalloc(sizeof(struct ep93xx_pwm), GFP_KERNEL);
 283         if (!pwm) {
 284                 err = -ENOMEM;
 285                 goto fail_no_mem;
 286         }
 287
 288         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 289         if (res == NULL) {
 290                 err = -ENXIO;
 291                 goto fail_no_mem_resource;
 292         }
 293
 294         res = request_mem_region(res->start, resource_size(res), pdev->name);
 295         if (res == NULL) {
 296                 err = -EBUSY;
 297                 goto fail_no_mem_resource;
 298         }
 299
 300         pwm->mmio_base = ioremap(res->start, resource_size(res));
 301         if (pwm->mmio_base == NULL) {
 302                 err = -ENXIO;
 303                 goto fail_no_ioremap;
 304         }
 305
 306         err = sysfs_create_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
 307         if (err)
 308                 goto fail_no_sysfs;
 309
 310         pwm->clk = clk_get(&pdev->dev, "pwm_clk");
 311         if (IS_ERR(pwm->clk)) {
 312                 err = PTR_ERR(pwm->clk);
 313                 goto fail_no_clk;
 314         }
 315
 316         pwm->duty_percent = 50;
 317
 318         platform_set_drvdata(pdev, pwm);
 319
 320         /* disable pwm at startup. Avoids zero value. */
 321         ep93xx_pwm_disable(pwm);
 322         ep93xx_pwm_write_tc(pwm, EP93XX_PWM_MAX_COUNT);
 323         ep93xx_pwm_write_dc(pwm, EP93XX_PWM_MAX_COUNT / 2);
 324
 325         clk_enable(pwm->clk);
 326
 327         return 0;
 328
 329 fail_no_clk:
 330         sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
 331 fail_no_sysfs:
 332         iounmap(pwm->mmio_base);
 333 fail_no_ioremap:
 334         release_mem_region(res->start, resource_size(res));
 335 fail_no_mem_resource:
 336         kfree(pwm);
 337 fail_no_mem:
 338         ep93xx_pwm_release_gpio(pdev);
 339         return err;
 340 }
 341
 342 static int __exit ep93xx_pwm_remove(struct platform_device *pdev)
 343 {
 344         struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
 345         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 346
 347         ep93xx_pwm_disable(pwm);
 348         clk_disable(pwm->clk);
 349         clk_put(pwm->clk);
 350         platform_set_drvdata(pdev, NULL);
 351         sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
 352         iounmap(pwm->mmio_base);
 353         release_mem_region(res->start, resource_size(res));
 354         kfree(pwm);
 355         ep93xx_pwm_release_gpio(pdev);
 356
 357         return 0;
 358 }
 359
 360 static struct platform_driver ep93xx_pwm_driver = {
 361         .driver         = {
 362                 .name   = "ep93xx-pwm",
 363                 .owner  = THIS_MODULE,
 364         },
 365         .remove         = __exit_p(ep93xx_pwm_remove),
 366 };
 367
 368 static int __init ep93xx_pwm_init(void)
 369 {
 370         return platform_driver_probe(&ep93xx_pwm_driver, ep93xx_pwm_probe);
 371 }
 372
 373 static void __exit ep93xx_pwm_exit(void)
 374 {
 375         platform_driver_unregister(&ep93xx_pwm_driver);
 376 }
 377
 378 module_init(ep93xx_pwm_init);
 379 module_exit(ep93xx_pwm_exit);
 380
 381 MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>, "
 382               "H Hartley Sweeten <hsweeten@visionengravers.com>");
 383 MODULE_DESCRIPTION("EP93xx PWM driver");
 384 MODULE_LICENSE("GPL");
 385 MODULE_ALIAS("platform:ep93xx-pwm");