drivers/pwm/pwm-lp3943.c

   1 /*
   2  * TI/National Semiconductor LP3943 PWM driver
   3  *
   4  * Copyright 2013 Texas Instruments
   5  *
   6  * Author: Milo Kim <milo.kim@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; version 2.
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/i2c.h>
  15 #include <linux/mfd/lp3943.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/pwm.h>
  19 #include <linux/slab.h>
  20
  21 #define LP3943_MAX_DUTY                 255
  22 #define LP3943_MIN_PERIOD               6250
  23 #define LP3943_MAX_PERIOD               1600000
  24
  25 struct lp3943_pwm {
  26         struct pwm_chip chip;
  27         struct lp3943 *lp3943;
  28         struct lp3943_platform_data *pdata;
  29 };
  30
  31 static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *_chip)
  32 {
  33         return container_of(_chip, struct lp3943_pwm, chip);
  34 }
  35
  36 static struct lp3943_pwm_map *
  37 lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm)
  38 {
  39         struct lp3943_platform_data *pdata = lp3943_pwm->pdata;
  40         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
  41         struct lp3943_pwm_map *pwm_map;
  42         int i, offset;
  43
  44         pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL);
  45         if (!pwm_map)
  46                 return ERR_PTR(-ENOMEM);
  47
  48         pwm_map->output = pdata->pwms[hwpwm]->output;
  49         pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs;
  50
  51         for (i = 0; i < pwm_map->num_outputs; i++) {
  52                 offset = pwm_map->output[i];
  53
  54                 /* Return an error if the pin is already assigned */
  55                 if (test_and_set_bit(offset, &lp3943->pin_used)) {
  56                         kfree(pwm_map);
  57                         return ERR_PTR(-EBUSY);
  58                 }
  59         }
  60
  61         return pwm_map;
  62 }
  63
  64 static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  65 {
  66         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
  67         struct lp3943_pwm_map *pwm_map;
  68
  69         pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm);
  70         if (IS_ERR(pwm_map))
  71                 return PTR_ERR(pwm_map);
  72
  73         return pwm_set_chip_data(pwm, pwm_map);
  74 }
  75
  76 static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm,
  77                                 struct lp3943_pwm_map *pwm_map)
  78 {
  79         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
  80         int i, offset;
  81
  82         for (i = 0; i < pwm_map->num_outputs; i++) {
  83                 offset = pwm_map->output[i];
  84                 clear_bit(offset, &lp3943->pin_used);
  85         }
  86
  87         kfree(pwm_map);
  88 }
  89
  90 static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  91 {
  92         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
  93         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
  94
  95         lp3943_pwm_free_map(lp3943_pwm, pwm_map);
  96 }
  97
  98 static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  99                              int duty_ns, int period_ns)
 100 {
 101         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 102         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
 103         u8 val, reg_duty, reg_prescale;
 104         int err;
 105
 106         /*
 107          * How to configure the LP3943 PWMs
 108          *
 109          * 1) Period = 6250 ~ 1600000
 110          * 2) Prescale = period / 6250 -1
 111          * 3) Duty = input duty
 112          *
 113          * Prescale and duty are register values
 114          */
 115
 116         if (pwm->hwpwm == 0) {
 117                 reg_prescale = LP3943_REG_PRESCALE0;
 118                 reg_duty     = LP3943_REG_PWM0;
 119         } else {
 120                 reg_prescale = LP3943_REG_PRESCALE1;
 121                 reg_duty     = LP3943_REG_PWM1;
 122         }
 123
 124         period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD);
 125         val       = (u8)(period_ns / LP3943_MIN_PERIOD - 1);
 126
 127         err = lp3943_write_byte(lp3943, reg_prescale, val);
 128         if (err)
 129                 return err;
 130
 131         val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
 132
 133         return lp3943_write_byte(lp3943, reg_duty, val);
 134 }
 135
 136 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
 137                                struct lp3943_pwm_map *pwm_map,
 138                                u8 val)
 139 {
 140         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
 141         const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
 142         int i, index, err;
 143
 144         for (i = 0; i < pwm_map->num_outputs; i++) {
 145                 index = pwm_map->output[i];
 146                 err = lp3943_update_bits(lp3943, mux[index].reg,
 147                                          mux[index].mask,
 148                                          val << mux[index].shift);
 149                 if (err)
 150                         return err;
 151         }
 152
 153         return 0;
 154 }
 155
 156 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 157 {
 158         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 159         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
 160         u8 val;
 161
 162         if (pwm->hwpwm == 0)
 163                 val = LP3943_DIM_PWM0;
 164         else
 165                 val = LP3943_DIM_PWM1;
 166
 167         /*
 168          * Each PWM generator is set to control any of outputs of LP3943.
 169          * To enable/disable the PWM, these output pins should be configured.
 170          */
 171
 172         return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
 173 }
 174
 175 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 176 {
 177         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 178         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
 179
 180         /*
 181          * LP3943 outputs are open-drain, so the pin should be configured
 182          * when the PWM is disabled.
 183          */
 184
 185         lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
 186 }
 187
 188 static const struct pwm_ops lp3943_pwm_ops = {
 189         .request        = lp3943_pwm_request,
 190         .free           = lp3943_pwm_free,
 191         .config         = lp3943_pwm_config,
 192         .enable         = lp3943_pwm_enable,
 193         .disable        = lp3943_pwm_disable,
 194         .owner          = THIS_MODULE,
 195 };
 196
 197 static int lp3943_pwm_parse_dt(struct device *dev,
 198                                struct lp3943_pwm *lp3943_pwm)
 199 {
 200         static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
 201         struct device_node *node = dev->of_node;
 202         struct lp3943_platform_data *pdata;
 203         struct lp3943_pwm_map *pwm_map;
 204         enum lp3943_pwm_output *output;
 205         int i, err, proplen, count = 0;
 206         u32 num_outputs;
 207
 208         if (!node)
 209                 return -EINVAL;
 210
 211         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 212         if (!pdata)
 213                 return -ENOMEM;
 214
 215         /*
 216          * Read the output map configuration from the device tree.
 217          * Each of the two PWM generators can drive zero or more outputs.
 218          */
 219
 220         for (i = 0; i < LP3943_NUM_PWMS; i++) {
 221                 if (!of_get_property(node, name[i], &proplen))
 222                         continue;
 223
 224                 num_outputs = proplen / sizeof(u32);
 225                 if (num_outputs == 0)
 226                         continue;
 227
 228                 output = devm_kcalloc(dev, num_outputs, sizeof(*output),
 229                                       GFP_KERNEL);
 230                 if (!output)
 231                         return -ENOMEM;
 232
 233                 err = of_property_read_u32_array(node, name[i], output,
 234                                                  num_outputs);
 235                 if (err)
 236                         return err;
 237
 238                 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
 239                 if (!pwm_map)
 240                         return -ENOMEM;
 241
 242                 pwm_map->output = output;
 243                 pwm_map->num_outputs = num_outputs;
 244                 pdata->pwms[i] = pwm_map;
 245
 246                 count++;
 247         }
 248
 249         if (count == 0)
 250                 return -ENODATA;
 251
 252         lp3943_pwm->pdata = pdata;
 253         return 0;
 254 }
 255
 256 static int lp3943_pwm_probe(struct platform_device *pdev)
 257 {
 258         struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
 259         struct lp3943_pwm *lp3943_pwm;
 260         int ret;
 261
 262         lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
 263         if (!lp3943_pwm)
 264                 return -ENOMEM;
 265
 266         lp3943_pwm->pdata = lp3943->pdata;
 267         if (!lp3943_pwm->pdata) {
 268                 if (IS_ENABLED(CONFIG_OF))
 269                         ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
 270                 else
 271                         ret = -ENODEV;
 272
 273                 if (ret)
 274                         return ret;
 275         }
 276
 277         lp3943_pwm->lp3943 = lp3943;
 278         lp3943_pwm->chip.dev = &pdev->dev;
 279         lp3943_pwm->chip.ops = &lp3943_pwm_ops;
 280         lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
 281
 282         platform_set_drvdata(pdev, lp3943_pwm);
 283
 284         return pwmchip_add(&lp3943_pwm->chip);
 285 }
 286
 287 static int lp3943_pwm_remove(struct platform_device *pdev)
 288 {
 289         struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev);
 290
 291         return pwmchip_remove(&lp3943_pwm->chip);
 292 }
 293
 294 #ifdef CONFIG_OF
 295 static const struct of_device_id lp3943_pwm_of_match[] = {
 296         { .compatible = "ti,lp3943-pwm", },
 297         { }
 298 };
 299 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
 300 #endif
 301
 302 static struct platform_driver lp3943_pwm_driver = {
 303         .probe = lp3943_pwm_probe,
 304         .remove = lp3943_pwm_remove,
 305         .driver = {
 306                 .name = "lp3943-pwm",
 307                 .of_match_table = of_match_ptr(lp3943_pwm_of_match),
 308         },
 309 };
 310 module_platform_driver(lp3943_pwm_driver);
 311
 312 MODULE_DESCRIPTION("LP3943 PWM driver");
 313 MODULE_ALIAS("platform:lp3943-pwm");
 314 MODULE_AUTHOR("Milo Kim");
 315 MODULE_LICENSE("GPL");