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/mfd/lp3943.h>
  12 #include <linux/module.h>
  13 #include <linux/of.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 lp3943 *lp3943;
  24         struct lp3943_platform_data *pdata;
  25         struct lp3943_pwm_map pwm_map[LP3943_NUM_PWMS];
  26 };
  27
  28 static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *chip)
  29 {
  30         return pwmchip_get_drvdata(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 = &lp3943_pwm->pwm_map[hwpwm];
  39         int i, offset;
  40
  41         pwm_map->output = pdata->pwms[hwpwm]->output;
  42         pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs;
  43
  44         for (i = 0; i < pwm_map->num_outputs; i++) {
  45                 offset = pwm_map->output[i];
  46
  47                 /* Return an error if the pin is already assigned */
  48                 if (test_and_set_bit(offset, &lp3943->pin_used))
  49                         return ERR_PTR(-EBUSY);
  50         }
  51
  52         return pwm_map;
  53 }
  54
  55 static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  56 {
  57         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
  58         struct lp3943_pwm_map *pwm_map;
  59
  60         pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm);
  61         if (IS_ERR(pwm_map))
  62                 return PTR_ERR(pwm_map);
  63
  64         return 0;
  65 }
  66
  67 static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm,
  68                                 struct lp3943_pwm_map *pwm_map)
  69 {
  70         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
  71         int i, offset;
  72
  73         for (i = 0; i < pwm_map->num_outputs; i++) {
  74                 offset = pwm_map->output[i];
  75                 clear_bit(offset, &lp3943->pin_used);
  76         }
  77 }
  78
  79 static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  80 {
  81         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
  82         struct lp3943_pwm_map *pwm_map = &lp3943_pwm->pwm_map[pwm->hwpwm];
  83
  84         lp3943_pwm_free_map(lp3943_pwm, pwm_map);
  85 }
  86
  87 static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  88                              u64 duty_ns, u64 period_ns)
  89 {
  90         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
  91         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
  92         u8 val, reg_duty, reg_prescale;
  93         int err;
  94
  95         /*
  96          * How to configure the LP3943 PWMs
  97          *
  98          * 1) Period = 6250 ~ 1600000
  99          * 2) Prescale = period / 6250 -1
 100          * 3) Duty = input duty
 101          *
 102          * Prescale and duty are register values
 103          */
 104
 105         if (pwm->hwpwm == 0) {
 106                 reg_prescale = LP3943_REG_PRESCALE0;
 107                 reg_duty     = LP3943_REG_PWM0;
 108         } else {
 109                 reg_prescale = LP3943_REG_PRESCALE1;
 110                 reg_duty     = LP3943_REG_PWM1;
 111         }
 112
 113         /*
 114          * Note that after this clamping, period_ns fits into an int. This is
 115          * helpful because we can resort to integer division below instead of
 116          * the (more expensive) 64 bit division.
 117          */
 118         period_ns = clamp(period_ns, (u64)LP3943_MIN_PERIOD, (u64)LP3943_MAX_PERIOD);
 119         val       = (u8)((int)period_ns / LP3943_MIN_PERIOD - 1);
 120
 121         err = lp3943_write_byte(lp3943, reg_prescale, val);
 122         if (err)
 123                 return err;
 124
 125         duty_ns = min(duty_ns, period_ns);
 126         val = (u8)((int)duty_ns * LP3943_MAX_DUTY / (int)period_ns);
 127
 128         return lp3943_write_byte(lp3943, reg_duty, val);
 129 }
 130
 131 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
 132                                struct lp3943_pwm_map *pwm_map,
 133                                u8 val)
 134 {
 135         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
 136         const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
 137         int i, index, err;
 138
 139         for (i = 0; i < pwm_map->num_outputs; i++) {
 140                 index = pwm_map->output[i];
 141                 err = lp3943_update_bits(lp3943, mux[index].reg,
 142                                          mux[index].mask,
 143                                          val << mux[index].shift);
 144                 if (err)
 145                         return err;
 146         }
 147
 148         return 0;
 149 }
 150
 151 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 152 {
 153         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 154         struct lp3943_pwm_map *pwm_map = &lp3943_pwm->pwm_map[pwm->hwpwm];
 155         u8 val;
 156
 157         if (pwm->hwpwm == 0)
 158                 val = LP3943_DIM_PWM0;
 159         else
 160                 val = LP3943_DIM_PWM1;
 161
 162         /*
 163          * Each PWM generator is set to control any of outputs of LP3943.
 164          * To enable/disable the PWM, these output pins should be configured.
 165          */
 166
 167         return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
 168 }
 169
 170 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 171 {
 172         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 173         struct lp3943_pwm_map *pwm_map = &lp3943_pwm->pwm_map[pwm->hwpwm];
 174
 175         /*
 176          * LP3943 outputs are open-drain, so the pin should be configured
 177          * when the PWM is disabled.
 178          */
 179
 180         lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
 181 }
 182
 183 static int lp3943_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 184                             const struct pwm_state *state)
 185 {
 186         int err;
 187
 188         if (state->polarity != PWM_POLARITY_NORMAL)
 189                 return -EINVAL;
 190
 191         if (!state->enabled) {
 192                 if (pwm->state.enabled)
 193                         lp3943_pwm_disable(chip, pwm);
 194                 return 0;
 195         }
 196
 197         err = lp3943_pwm_config(chip, pwm, state->duty_cycle, state->period);
 198         if (err)
 199                 return err;
 200
 201         if (!pwm->state.enabled)
 202                 err = lp3943_pwm_enable(chip, pwm);
 203
 204         return err;
 205 }
 206
 207 static const struct pwm_ops lp3943_pwm_ops = {
 208         .request        = lp3943_pwm_request,
 209         .free           = lp3943_pwm_free,
 210         .apply          = lp3943_pwm_apply,
 211 };
 212
 213 static int lp3943_pwm_parse_dt(struct device *dev,
 214                                struct lp3943_pwm *lp3943_pwm)
 215 {
 216         static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
 217         struct device_node *node = dev->of_node;
 218         struct lp3943_platform_data *pdata;
 219         struct lp3943_pwm_map *pwm_map;
 220         enum lp3943_pwm_output *output;
 221         int i, err, num_outputs, count = 0;
 222
 223         if (!node)
 224                 return -EINVAL;
 225
 226         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 227         if (!pdata)
 228                 return -ENOMEM;
 229
 230         /*
 231          * Read the output map configuration from the device tree.
 232          * Each of the two PWM generators can drive zero or more outputs.
 233          */
 234
 235         for (i = 0; i < LP3943_NUM_PWMS; i++) {
 236                 num_outputs = of_property_count_u32_elems(node, name[i]);
 237                 if (num_outputs <= 0)
 238                         continue;
 239
 240                 output = devm_kcalloc(dev, num_outputs, sizeof(*output),
 241                                       GFP_KERNEL);
 242                 if (!output)
 243                         return -ENOMEM;
 244
 245                 err = of_property_read_u32_array(node, name[i], output,
 246                                                  num_outputs);
 247                 if (err)
 248                         return err;
 249
 250                 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
 251                 if (!pwm_map)
 252                         return -ENOMEM;
 253
 254                 pwm_map->output = output;
 255                 pwm_map->num_outputs = num_outputs;
 256                 pdata->pwms[i] = pwm_map;
 257
 258                 count++;
 259         }
 260
 261         if (count == 0)
 262                 return -ENODATA;
 263
 264         lp3943_pwm->pdata = pdata;
 265         return 0;
 266 }
 267
 268 static int lp3943_pwm_probe(struct platform_device *pdev)
 269 {
 270         struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
 271         struct pwm_chip *chip;
 272         struct lp3943_pwm *lp3943_pwm;
 273         int ret;
 274
 275         chip = devm_pwmchip_alloc(&pdev->dev, LP3943_NUM_PWMS, sizeof(*lp3943_pwm));
 276         if (IS_ERR(chip))
 277                 return PTR_ERR(chip);
 278         lp3943_pwm = to_lp3943_pwm(chip);
 279
 280         lp3943_pwm->pdata = lp3943->pdata;
 281         if (!lp3943_pwm->pdata) {
 282                 if (IS_ENABLED(CONFIG_OF))
 283                         ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
 284                 else
 285                         ret = -ENODEV;
 286
 287                 if (ret)
 288                         return ret;
 289         }
 290
 291         lp3943_pwm->lp3943 = lp3943;
 292         chip->ops = &lp3943_pwm_ops;
 293
 294         return devm_pwmchip_add(&pdev->dev, chip);
 295 }
 296
 297 #ifdef CONFIG_OF
 298 static const struct of_device_id lp3943_pwm_of_match[] = {
 299         { .compatible = "ti,lp3943-pwm", },
 300         { }
 301 };
 302 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
 303 #endif
 304
 305 static struct platform_driver lp3943_pwm_driver = {
 306         .probe = lp3943_pwm_probe,
 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");