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                              int duty_ns, int 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         period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD);
 122         val       = (u8)(period_ns / LP3943_MIN_PERIOD - 1);
 123
 124         err = lp3943_write_byte(lp3943, reg_prescale, val);
 125         if (err)
 126                 return err;
 127
 128         val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
 129
 130         return lp3943_write_byte(lp3943, reg_duty, val);
 131 }
 132
 133 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
 134                                struct lp3943_pwm_map *pwm_map,
 135                                u8 val)
 136 {
 137         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
 138         const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
 139         int i, index, err;
 140
 141         for (i = 0; i < pwm_map->num_outputs; i++) {
 142                 index = pwm_map->output[i];
 143                 err = lp3943_update_bits(lp3943, mux[index].reg,
 144                                          mux[index].mask,
 145                                          val << mux[index].shift);
 146                 if (err)
 147                         return err;
 148         }
 149
 150         return 0;
 151 }
 152
 153 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 154 {
 155         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 156         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
 157         u8 val;
 158
 159         if (pwm->hwpwm == 0)
 160                 val = LP3943_DIM_PWM0;
 161         else
 162                 val = LP3943_DIM_PWM1;
 163
 164         /*
 165          * Each PWM generator is set to control any of outputs of LP3943.
 166          * To enable/disable the PWM, these output pins should be configured.
 167          */
 168
 169         return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
 170 }
 171
 172 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 173 {
 174         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 175         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
 176
 177         /*
 178          * LP3943 outputs are open-drain, so the pin should be configured
 179          * when the PWM is disabled.
 180          */
 181
 182         lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
 183 }
 184
 185 static const struct pwm_ops lp3943_pwm_ops = {
 186         .request        = lp3943_pwm_request,
 187         .free           = lp3943_pwm_free,
 188         .config         = lp3943_pwm_config,
 189         .enable         = lp3943_pwm_enable,
 190         .disable        = lp3943_pwm_disable,
 191         .owner          = THIS_MODULE,
 192 };
 193
 194 static int lp3943_pwm_parse_dt(struct device *dev,
 195                                struct lp3943_pwm *lp3943_pwm)
 196 {
 197         static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
 198         struct device_node *node = dev->of_node;
 199         struct lp3943_platform_data *pdata;
 200         struct lp3943_pwm_map *pwm_map;
 201         enum lp3943_pwm_output *output;
 202         int i, err, proplen, count = 0;
 203         u32 num_outputs;
 204
 205         if (!node)
 206                 return -EINVAL;
 207
 208         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 209         if (!pdata)
 210                 return -ENOMEM;
 211
 212         /*
 213          * Read the output map configuration from the device tree.
 214          * Each of the two PWM generators can drive zero or more outputs.
 215          */
 216
 217         for (i = 0; i < LP3943_NUM_PWMS; i++) {
 218                 if (!of_get_property(node, name[i], &proplen))
 219                         continue;
 220
 221                 num_outputs = proplen / sizeof(u32);
 222                 if (num_outputs == 0)
 223                         continue;
 224
 225                 output = devm_kcalloc(dev, num_outputs, sizeof(*output),
 226                                       GFP_KERNEL);
 227                 if (!output)
 228                         return -ENOMEM;
 229
 230                 err = of_property_read_u32_array(node, name[i], output,
 231                                                  num_outputs);
 232                 if (err)
 233                         return err;
 234
 235                 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
 236                 if (!pwm_map)
 237                         return -ENOMEM;
 238
 239                 pwm_map->output = output;
 240                 pwm_map->num_outputs = num_outputs;
 241                 pdata->pwms[i] = pwm_map;
 242
 243                 count++;
 244         }
 245
 246         if (count == 0)
 247                 return -ENODATA;
 248
 249         lp3943_pwm->pdata = pdata;
 250         return 0;
 251 }
 252
 253 static int lp3943_pwm_probe(struct platform_device *pdev)
 254 {
 255         struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
 256         struct lp3943_pwm *lp3943_pwm;
 257         int ret;
 258
 259         lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
 260         if (!lp3943_pwm)
 261                 return -ENOMEM;
 262
 263         lp3943_pwm->pdata = lp3943->pdata;
 264         if (!lp3943_pwm->pdata) {
 265                 if (IS_ENABLED(CONFIG_OF))
 266                         ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
 267                 else
 268                         ret = -ENODEV;
 269
 270                 if (ret)
 271                         return ret;
 272         }
 273
 274         lp3943_pwm->lp3943 = lp3943;
 275         lp3943_pwm->chip.dev = &pdev->dev;
 276         lp3943_pwm->chip.ops = &lp3943_pwm_ops;
 277         lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
 278
 279         return devm_pwmchip_add(&pdev->dev, &lp3943_pwm->chip);
 280 }
 281
 282 #ifdef CONFIG_OF
 283 static const struct of_device_id lp3943_pwm_of_match[] = {
 284         { .compatible = "ti,lp3943-pwm", },
 285         { }
 286 };
 287 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
 288 #endif
 289
 290 static struct platform_driver lp3943_pwm_driver = {
 291         .probe = lp3943_pwm_probe,
 292         .driver = {
 293                 .name = "lp3943-pwm",
 294                 .of_match_table = of_match_ptr(lp3943_pwm_of_match),
 295         },
 296 };
 297 module_platform_driver(lp3943_pwm_driver);
 298
 299 MODULE_DESCRIPTION("LP3943 PWM driver");
 300 MODULE_ALIAS("platform:lp3943-pwm");
 301 MODULE_AUTHOR("Milo Kim");
 302 MODULE_LICENSE("GPL");