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         duty_ns = min(duty_ns, period_ns);
 129         val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns);
 130
 131         return lp3943_write_byte(lp3943, reg_duty, val);
 132 }
 133
 134 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,
 135                                struct lp3943_pwm_map *pwm_map,
 136                                u8 val)
 137 {
 138         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
 139         const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;
 140         int i, index, err;
 141
 142         for (i = 0; i < pwm_map->num_outputs; i++) {
 143                 index = pwm_map->output[i];
 144                 err = lp3943_update_bits(lp3943, mux[index].reg,
 145                                          mux[index].mask,
 146                                          val << mux[index].shift);
 147                 if (err)
 148                         return err;
 149         }
 150
 151         return 0;
 152 }
 153
 154 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 155 {
 156         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 157         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
 158         u8 val;
 159
 160         if (pwm->hwpwm == 0)
 161                 val = LP3943_DIM_PWM0;
 162         else
 163                 val = LP3943_DIM_PWM1;
 164
 165         /*
 166          * Each PWM generator is set to control any of outputs of LP3943.
 167          * To enable/disable the PWM, these output pins should be configured.
 168          */
 169
 170         return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);
 171 }
 172
 173 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 174 {
 175         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 176         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
 177
 178         /*
 179          * LP3943 outputs are open-drain, so the pin should be configured
 180          * when the PWM is disabled.
 181          */
 182
 183         lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);
 184 }
 185
 186 static const struct pwm_ops lp3943_pwm_ops = {
 187         .request        = lp3943_pwm_request,
 188         .free           = lp3943_pwm_free,
 189         .config         = lp3943_pwm_config,
 190         .enable         = lp3943_pwm_enable,
 191         .disable        = lp3943_pwm_disable,
 192         .owner          = THIS_MODULE,
 193 };
 194
 195 static int lp3943_pwm_parse_dt(struct device *dev,
 196                                struct lp3943_pwm *lp3943_pwm)
 197 {
 198         static const char * const name[] = { "ti,pwm0", "ti,pwm1", };
 199         struct device_node *node = dev->of_node;
 200         struct lp3943_platform_data *pdata;
 201         struct lp3943_pwm_map *pwm_map;
 202         enum lp3943_pwm_output *output;
 203         int i, err, proplen, count = 0;
 204         u32 num_outputs;
 205
 206         if (!node)
 207                 return -EINVAL;
 208
 209         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 210         if (!pdata)
 211                 return -ENOMEM;
 212
 213         /*
 214          * Read the output map configuration from the device tree.
 215          * Each of the two PWM generators can drive zero or more outputs.
 216          */
 217
 218         for (i = 0; i < LP3943_NUM_PWMS; i++) {
 219                 if (!of_get_property(node, name[i], &proplen))
 220                         continue;
 221
 222                 num_outputs = proplen / sizeof(u32);
 223                 if (num_outputs == 0)
 224                         continue;
 225
 226                 output = devm_kcalloc(dev, num_outputs, sizeof(*output),
 227                                       GFP_KERNEL);
 228                 if (!output)
 229                         return -ENOMEM;
 230
 231                 err = of_property_read_u32_array(node, name[i], output,
 232                                                  num_outputs);
 233                 if (err)
 234                         return err;
 235
 236                 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);
 237                 if (!pwm_map)
 238                         return -ENOMEM;
 239
 240                 pwm_map->output = output;
 241                 pwm_map->num_outputs = num_outputs;
 242                 pdata->pwms[i] = pwm_map;
 243
 244                 count++;
 245         }
 246
 247         if (count == 0)
 248                 return -ENODATA;
 249
 250         lp3943_pwm->pdata = pdata;
 251         return 0;
 252 }
 253
 254 static int lp3943_pwm_probe(struct platform_device *pdev)
 255 {
 256         struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
 257         struct lp3943_pwm *lp3943_pwm;
 258         int ret;
 259
 260         lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
 261         if (!lp3943_pwm)
 262                 return -ENOMEM;
 263
 264         lp3943_pwm->pdata = lp3943->pdata;
 265         if (!lp3943_pwm->pdata) {
 266                 if (IS_ENABLED(CONFIG_OF))
 267                         ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);
 268                 else
 269                         ret = -ENODEV;
 270
 271                 if (ret)
 272                         return ret;
 273         }
 274
 275         lp3943_pwm->lp3943 = lp3943;
 276         lp3943_pwm->chip.dev = &pdev->dev;
 277         lp3943_pwm->chip.ops = &lp3943_pwm_ops;
 278         lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
 279         lp3943_pwm->chip.base = -1;
 280
 281         platform_set_drvdata(pdev, lp3943_pwm);
 282
 283         return pwmchip_add(&lp3943_pwm->chip);
 284 }
 285
 286 static int lp3943_pwm_remove(struct platform_device *pdev)
 287 {
 288         struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev);
 289
 290         return pwmchip_remove(&lp3943_pwm->chip);
 291 }
 292
 293 #ifdef CONFIG_OF
 294 static const struct of_device_id lp3943_pwm_of_match[] = {
 295         { .compatible = "ti,lp3943-pwm", },
 296         { }
 297 };
 298 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
 299 #endif
 300
 301 static struct platform_driver lp3943_pwm_driver = {
 302         .probe = lp3943_pwm_probe,
 303         .remove = lp3943_pwm_remove,
 304         .driver = {
 305                 .name = "lp3943-pwm",
 306                 .of_match_table = of_match_ptr(lp3943_pwm_of_match),
 307         },
 308 };
 309 module_platform_driver(lp3943_pwm_driver);
 310
 311 MODULE_DESCRIPTION("LP3943 PWM driver");
 312 MODULE_ALIAS("platform:lp3943-pwm");
 313 MODULE_AUTHOR("Milo Kim");
 314 MODULE_LICENSE("GPL");