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