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         duty_ns = min(duty_ns, period_ns);
 132         val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
 133
 134         return lp3943_write_byte(lp3943, reg_duty, val);
 135 }
 136
 137 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
 138                                struct lp3943_pwm_map *pwm_map,
 139                                u8 val)
 140 {
 141         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
 142         const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
 143         int i, index, err;
 144
 145         for (i = 0; i < pwm_map->num_outputs; i++) {
 146                 index = pwm_map->output[i];
 147                 err = lp3943_update_bits(lp3943, mux[index].reg,
 148                                          mux[index].mask,
 149                                          val << mux[index].shift);
 150                 if (err)
 151                         return err;
 152         }
 153
 154         return 0;
 155 }
 156
 157 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 158 {
 159         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 160         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
 161         u8 val;
 162
 163         if (pwm->hwpwm == 0)
 164                 val = LP3943_DIM_PWM0;
 165         else
 166                 val = LP3943_DIM_PWM1;
 167
 168         /*
 169          * Each PWM generator is set to control any of outputs of LP3943.
 170          * To enable/disable the PWM, these output pins should be configured.
 171          */
 172
 173         return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
 174 }
 175
 176 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 177 {
 178         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 179         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
 180
 181         /*
 182          * LP3943 outputs are open-drain, so the pin should be configured
 183          * when the PWM is disabled.
 184          */
 185
 186         lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
 187 }
 188
 189 static const struct pwm_ops lp3943_pwm_ops = {
 190         .request        = lp3943_pwm_request,
 191         .free           = lp3943_pwm_free,
 192         .config         = lp3943_pwm_config,
 193         .enable         = lp3943_pwm_enable,
 194         .disable        = lp3943_pwm_disable,
 195         .owner          = THIS_MODULE,
 196 };
 197
 198 static int lp3943_pwm_parse_dt(struct device *dev,
 199                                struct lp3943_pwm *lp3943_pwm)
 200 {
 201         static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
 202         struct device_node *node = dev->of_node;
 203         struct lp3943_platform_data *pdata;
 204         struct lp3943_pwm_map *pwm_map;
 205         enum lp3943_pwm_output *output;
 206         int i, err, proplen, count = 0;
 207         u32 num_outputs;
 208
 209         if (!node)
 210                 return -EINVAL;
 211
 212         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 213         if (!pdata)
 214                 return -ENOMEM;
 215
 216         /*
 217          * Read the output map configuration from the device tree.
 218          * Each of the two PWM generators can drive zero or more outputs.
 219          */
 220
 221         for (i = 0; i < LP3943_NUM_PWMS; i++) {
 222                 if (!of_get_property(node, name[i], &proplen))
 223                         continue;
 224
 225                 num_outputs = proplen / sizeof(u32);
 226                 if (num_outputs == 0)
 227                         continue;
 228
 229                 output = devm_kzalloc(dev, sizeof(*output) * num_outputs,
 230                                       GFP_KERNEL);
 231                 if (!output)
 232                         return -ENOMEM;
 233
 234                 err = of_property_read_u32_array(node, name[i], output,
 235                                                  num_outputs);
 236                 if (err)
 237                         return err;
 238
 239                 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
 240                 if (!pwm_map)
 241                         return -ENOMEM;
 242
 243                 pwm_map->output = output;
 244                 pwm_map->num_outputs = num_outputs;
 245                 pdata->pwms[i] = pwm_map;
 246
 247                 count++;
 248         }
 249
 250         if (count == 0)
 251                 return -ENODATA;
 252
 253         lp3943_pwm->pdata = pdata;
 254         return 0;
 255 }
 256
 257 static int lp3943_pwm_probe(struct platform_device *pdev)
 258 {
 259         struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
 260         struct lp3943_pwm *lp3943_pwm;
 261         int ret;
 262
 263         lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
 264         if (!lp3943_pwm)
 265                 return -ENOMEM;
 266
 267         lp3943_pwm->pdata = lp3943->pdata;
 268         if (!lp3943_pwm->pdata) {
 269                 if (IS_ENABLED(CONFIG_OF))
 270                         ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
 271                 else
 272                         ret = -ENODEV;
 273
 274                 if (ret)
 275                         return ret;
 276         }
 277
 278         lp3943_pwm->lp3943 = lp3943;
 279         lp3943_pwm->chip.dev = &pdev->dev;
 280         lp3943_pwm->chip.ops = &lp3943_pwm_ops;
 281         lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
 282         lp3943_pwm->chip.can_sleep = true;
 283
 284         platform_set_drvdata(pdev, lp3943_pwm);
 285
 286         return pwmchip_add(&lp3943_pwm->chip);
 287 }
 288
 289 static int lp3943_pwm_remove(struct platform_device *pdev)
 290 {
 291         struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev);
 292
 293         return pwmchip_remove(&lp3943_pwm->chip);
 294 }
 295
 296 #ifdef CONFIG_OF
 297 static const struct of_device_id lp3943_pwm_of_match[] = {
 298         { .compatible = "ti,lp3943-pwm", },
 299         { }
 300 };
 301 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
 302 #endif
 303
 304 static struct platform_driver lp3943_pwm_driver = {
 305         .probe = lp3943_pwm_probe,
 306         .remove = lp3943_pwm_remove,
 307         .driver = {
 308                 .name = "lp3943-pwm",
 309                 .of_match_table = of_match_ptr(lp3943_pwm_of_match),
 310         },
 311 };
 312 module_platform_driver(lp3943_pwm_driver);
 313
 314 MODULE_DESCRIPTION("LP3943 PWM driver");
 315 MODULE_ALIAS("platform:lp3943-pwm");
 316 MODULE_AUTHOR("Milo Kim");
 317 MODULE_LICENSE("GPL");