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