drivers/pwm/pwm-lp3943.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * TI/National Semiconductor LP3943 PWM driver
   4  *
   5  * Copyright 2013 Texas Instruments
   6  *
   7  * Author: Milo Kim <milo.kim@ti.com>
   8  */
   9
  10 #include <linux/err.h>
  11 #include <linux/i2c.h>
  12 #include <linux/mfd/lp3943.h>
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/pwm.h>
  16 #include <linux/slab.h>
  17
  18 #define LP3943_MAX_DUTY                 255
  19 #define LP3943_MIN_PERIOD               6250
  20 #define LP3943_MAX_PERIOD               1600000
  21
  22 struct lp3943_pwm {
  23         struct pwm_chip chip;
  24         struct lp3943 *lp3943;
  25         struct lp3943_platform_data *pdata;
  26 };
  27
  28 static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *_chip)
  29 {
  30         return container_of(_chip, struct lp3943_pwm, chip);
  31 }
  32
  33 static struct lp3943_pwm_map *
  34 lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm)
  35 {
  36         struct lp3943_platform_data *pdata = lp3943_pwm->pdata;
  37         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
  38         struct lp3943_pwm_map *pwm_map;
  39         int i, offset;
  40
  41         pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL);
  42         if (!pwm_map)
  43                 return ERR_PTR(-ENOMEM);
  44
  45         pwm_map->output = pdata->pwms[hwpwm]->output;
  46         pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs;
  47
  48         for (i = 0; i < pwm_map->num_outputs; i++) {
  49                 offset = pwm_map->output[i];
  50
  51                 /* Return an error if the pin is already assigned */
  52                 if (test_and_set_bit(offset, &lp3943->pin_used)) {
  53                         kfree(pwm_map);
  54                         return ERR_PTR(-EBUSY);
  55                 }
  56         }
  57
  58         return pwm_map;
  59 }
  60
  61 static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  62 {
  63         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
  64         struct lp3943_pwm_map *pwm_map;
  65
  66         pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm);
  67         if (IS_ERR(pwm_map))
  68                 return PTR_ERR(pwm_map);
  69
  70         return pwm_set_chip_data(pwm, pwm_map);
  71 }
  72
  73 static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm,
  74                                 struct lp3943_pwm_map *pwm_map)
  75 {
  76         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
  77         int i, offset;
  78
  79         for (i = 0; i < pwm_map->num_outputs; i++) {
  80                 offset = pwm_map->output[i];
  81                 clear_bit(offset, &lp3943->pin_used);
  82         }
  83
  84         kfree(pwm_map);
  85 }
  86
  87 static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  88 {
  89         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
  90         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
  91
  92         lp3943_pwm_free_map(lp3943_pwm, pwm_map);
  93 }
  94
  95 static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  96                              u64 duty_ns, u64 period_ns)
  97 {
  98         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
  99         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
 100         u8 val, reg_duty, reg_prescale;
 101         int err;
 102
 103         /*
 104          * How to configure the LP3943 PWMs
 105          *
 106          * 1) Period = 6250 ~ 1600000
 107          * 2) Prescale = period / 6250 -1
 108          * 3) Duty = input duty
 109          *
 110          * Prescale and duty are register values
 111          */
 112
 113         if (pwm->hwpwm == 0) {
 114                 reg_prescale = LP3943_REG_PRESCALE0;
 115                 reg_duty     = LP3943_REG_PWM0;
 116         } else {
 117                 reg_prescale = LP3943_REG_PRESCALE1;
 118                 reg_duty     = LP3943_REG_PWM1;
 119         }
 120
 121         /*
 122          * Note that after this clamping, period_ns fits into an int. This is
 123          * helpful because we can resort to integer division below instead of
 124          * the (more expensive) 64 bit division.
 125          */
 126         period_ns = clamp(period_ns, (u64)LP3943_MIN_PERIOD, (u64)LP3943_MAX_PERIOD);
 127         val       = (u8)((int)period_ns / LP3943_MIN_PERIOD - 1);
 128
 129         err = lp3943_write_byte(lp3943, reg_prescale, val);
 130         if (err)
 131                 return err;
 132
 133         duty_ns = min(duty_ns, period_ns);
 134         val = (u8)((int)duty_ns * LP3943_MAX_DUTY / (int)period_ns);
 135
 136         return lp3943_write_byte(lp3943, reg_duty, val);
 137 }
 138
 139 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
 140                                struct lp3943_pwm_map *pwm_map,
 141                                u8 val)
 142 {
 143         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
 144         const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
 145         int i, index, err;
 146
 147         for (i = 0; i < pwm_map->num_outputs; i++) {
 148                 index = pwm_map->output[i];
 149                 err = lp3943_update_bits(lp3943, mux[index].reg,
 150                                          mux[index].mask,
 151                                          val << mux[index].shift);
 152                 if (err)
 153                         return err;
 154         }
 155
 156         return 0;
 157 }
 158
 159 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 160 {
 161         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 162         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
 163         u8 val;
 164
 165         if (pwm->hwpwm == 0)
 166                 val = LP3943_DIM_PWM0;
 167         else
 168                 val = LP3943_DIM_PWM1;
 169
 170         /*
 171          * Each PWM generator is set to control any of outputs of LP3943.
 172          * To enable/disable the PWM, these output pins should be configured.
 173          */
 174
 175         return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
 176 }
 177
 178 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 179 {
 180         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 181         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
 182
 183         /*
 184          * LP3943 outputs are open-drain, so the pin should be configured
 185          * when the PWM is disabled.
 186          */
 187
 188         lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
 189 }
 190
 191 static int lp3943_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 192                             const struct pwm_state *state)
 193 {
 194         int err;
 195
 196         if (state->polarity != PWM_POLARITY_NORMAL)
 197                 return -EINVAL;
 198
 199         if (!state->enabled) {
 200                 if (pwm->state.enabled)
 201                         lp3943_pwm_disable(chip, pwm);
 202                 return 0;
 203         }
 204
 205         err = lp3943_pwm_config(chip, pwm, state->duty_cycle, state->period);
 206         if (err)
 207                 return err;
 208
 209         if (!pwm->state.enabled)
 210                 err = lp3943_pwm_enable(chip, pwm);
 211
 212         return err;
 213 }
 214
 215 static const struct pwm_ops lp3943_pwm_ops = {
 216         .request        = lp3943_pwm_request,
 217         .free           = lp3943_pwm_free,
 218         .apply          = lp3943_pwm_apply,
 219         .owner          = THIS_MODULE,
 220 };
 221
 222 static int lp3943_pwm_parse_dt(struct device *dev,
 223                                struct lp3943_pwm *lp3943_pwm)
 224 {
 225         static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
 226         struct device_node *node = dev->of_node;
 227         struct lp3943_platform_data *pdata;
 228         struct lp3943_pwm_map *pwm_map;
 229         enum lp3943_pwm_output *output;
 230         int i, err, proplen, count = 0;
 231         u32 num_outputs;
 232
 233         if (!node)
 234                 return -EINVAL;
 235
 236         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 237         if (!pdata)
 238                 return -ENOMEM;
 239
 240         /*
 241          * Read the output map configuration from the device tree.
 242          * Each of the two PWM generators can drive zero or more outputs.
 243          */
 244
 245         for (i = 0; i < LP3943_NUM_PWMS; i++) {
 246                 if (!of_get_property(node, name[i], &proplen))
 247                         continue;
 248
 249                 num_outputs = proplen / sizeof(u32);
 250                 if (num_outputs == 0)
 251                         continue;
 252
 253                 output = devm_kcalloc(dev, num_outputs, sizeof(*output),
 254                                       GFP_KERNEL);
 255                 if (!output)
 256                         return -ENOMEM;
 257
 258                 err = of_property_read_u32_array(node, name[i], output,
 259                                                  num_outputs);
 260                 if (err)
 261                         return err;
 262
 263                 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
 264                 if (!pwm_map)
 265                         return -ENOMEM;
 266
 267                 pwm_map->output = output;
 268                 pwm_map->num_outputs = num_outputs;
 269                 pdata->pwms[i] = pwm_map;
 270
 271                 count++;
 272         }
 273
 274         if (count == 0)
 275                 return -ENODATA;
 276
 277         lp3943_pwm->pdata = pdata;
 278         return 0;
 279 }
 280
 281 static int lp3943_pwm_probe(struct platform_device *pdev)
 282 {
 283         struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
 284         struct lp3943_pwm *lp3943_pwm;
 285         int ret;
 286
 287         lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
 288         if (!lp3943_pwm)
 289                 return -ENOMEM;
 290
 291         lp3943_pwm->pdata = lp3943->pdata;
 292         if (!lp3943_pwm->pdata) {
 293                 if (IS_ENABLED(CONFIG_OF))
 294                         ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
 295                 else
 296                         ret = -ENODEV;
 297
 298                 if (ret)
 299                         return ret;
 300         }
 301
 302         lp3943_pwm->lp3943 = lp3943;
 303         lp3943_pwm->chip.dev = &pdev->dev;
 304         lp3943_pwm->chip.ops = &lp3943_pwm_ops;
 305         lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
 306
 307         return devm_pwmchip_add(&pdev->dev, &lp3943_pwm->chip);
 308 }
 309
 310 #ifdef CONFIG_OF
 311 static const struct of_device_id lp3943_pwm_of_match[] = {
 312         { .compatible = "ti,lp3943-pwm", },
 313         { }
 314 };
 315 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
 316 #endif
 317
 318 static struct platform_driver lp3943_pwm_driver = {
 319         .probe = lp3943_pwm_probe,
 320         .driver = {
 321                 .name = "lp3943-pwm",
 322                 .of_match_table = of_match_ptr(lp3943_pwm_of_match),
 323         },
 324 };
 325 module_platform_driver(lp3943_pwm_driver);
 326
 327 MODULE_DESCRIPTION("LP3943 PWM driver");
 328 MODULE_ALIAS("platform:lp3943-pwm");
 329 MODULE_AUTHOR("Milo Kim");
 330 MODULE_LICENSE("GPL");