drivers/pwm/pwm-lp3943.c

   1 /*
   2  * TI/National Semiconductor LP3943 PWM driver
   3  *
   4  * Copyright 2013 Texas Instruments
   5  *
   6  * Author: Milo Kim <milo.kim@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; version 2.
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/i2c.h>
  15 #include <linux/mfd/lp3943.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/pwm.h>
  19 #include <linux/slab.h>
  20
  21 #define LP3943_MAX_DUTY                 255
  22 #define LP3943_MIN_PERIOD               6250
  23 #define LP3943_MAX_PERIOD               1600000
  24
  25 struct lp3943_pwm {
  26         struct pwm_chip chip;
  27         struct lp3943 *lp3943;
  28         struct lp3943_platform_data *pdata;
  29 };
  30
  31 static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *_chip)
  32 {
  33         return container_of(_chip, struct lp3943_pwm, chip);
  34 }
  35
  36 static struct lp3943_pwm_map *
  37 lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm)
  38 {
  39         struct lp3943_platform_data *pdata = lp3943_pwm->pdata;
  40         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
  41         struct lp3943_pwm_map *pwm_map;
  42         int i, offset;
  43
  44         pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL);
  45         if (!pwm_map)
  46                 return ERR_PTR(-ENOMEM);
  47
  48         pwm_map->output = pdata->pwms[hwpwm]->output;
  49         pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs;
  50
  51         for (i = 0; i < pwm_map->num_outputs; i++) {
  52                 offset = pwm_map->output[i];
  53
  54                 /* Return an error if the pin is already assigned */
  55                 if (test_and_set_bit(offset, &lp3943->pin_used))
  56                         return ERR_PTR(-EBUSY);
  57         }
  58
  59         return pwm_map;
  60 }
  61
  62 static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  63 {
  64         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
  65         struct lp3943_pwm_map *pwm_map;
  66
  67         pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm);
  68         if (IS_ERR(pwm_map))
  69                 return PTR_ERR(pwm_map);
  70
  71         return pwm_set_chip_data(pwm, pwm_map);
  72 }
  73
  74 static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm,
  75                                 struct lp3943_pwm_map *pwm_map)
  76 {
  77         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
  78         int i, offset;
  79
  80         for (i = 0; i < pwm_map->num_outputs; i++) {
  81                 offset = pwm_map->output[i];
  82                 clear_bit(offset, &lp3943->pin_used);
  83         }
  84
  85         kfree(pwm_map);
  86 }
  87
  88 static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  89 {
  90         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
  91         struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm);
  92
  93         lp3943_pwm_free_map(lp3943_pwm, pwm_map);
  94 }
  95
  96 static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  97                              int duty_ns, int period_ns)
  98 {
  99         struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);
 100         struct lp3943 *lp3943 = lp3943_pwm->lp3943;
 101         u8 val, reg_duty, reg_prescale;
 102         int err;
 103
 104         /*
 105          * How to configure the LP3943 PWMs
 106          *
 107          * 1) Period = 6250 ~ 1600000
 108          * 2) Prescale = period / 6250 -1
 109          * 3) Duty = input duty
 110          *
 111          * Prescale and duty are register values
 112          */
 113
 114         if (pwm->hwpwm == 0) {
 115                 reg_prescale = LP3943_REG_PRESCALE0;
 116                 reg_duty     = LP3943_REG_PWM0;
 117         } else {
 118                 reg_prescale = LP3943_REG_PRESCALE1;
 119                 reg_duty     = LP3943_REG_PWM1;
 120         }
 121
 122         period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD);
 123         val       = (u8)(period_ns / LP3943_MIN_PERIOD - 1);
 124
 125         err = lp3943_write_byte(lp3943, reg_prescale, val);
 126         if (err)
 127                 return err;
 128
 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_kzalloc(dev, sizeof(*output) * num_outputs,
 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
 280         platform_set_drvdata(pdev, lp3943_pwm);
 281
 282         return pwmchip_add(&lp3943_pwm->chip);
 283 }
 284
 285 static int lp3943_pwm_remove(struct platform_device *pdev)
 286 {
 287         struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev);
 288
 289         return pwmchip_remove(&lp3943_pwm->chip);
 290 }
 291
 292 #ifdef CONFIG_OF
 293 static const struct of_device_id lp3943_pwm_of_match[] = {
 294         { .compatible = "ti,lp3943-pwm", },
 295         { }
 296 };
 297 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);
 298 #endif
 299
 300 static struct platform_driver lp3943_pwm_driver = {
 301         .probe = lp3943_pwm_probe,
 302         .remove = lp3943_pwm_remove,
 303         .driver = {
 304                 .name = "lp3943-pwm",
 305                 .owner = THIS_MODULE,
 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");