drivers/pwm/pwm-crc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2015 Intel Corporation. All rights reserved.
   4  *
   5  * Author: Shobhit Kumar <shobhit.kumar@intel.com>
   6  */
   7
   8 #include <linux/platform_device.h>
   9 #include <linux/regmap.h>
  10 #include <linux/mfd/intel_soc_pmic.h>
  11 #include <linux/pwm.h>
  12
  13 #define PWM0_CLK_DIV            0x4B
  14 #define  PWM_OUTPUT_ENABLE      BIT(7)
  15 #define  PWM_DIV_CLK_0          0x00 /* DIVIDECLK = BASECLK */
  16 #define  PWM_DIV_CLK_100        0x63 /* DIVIDECLK = BASECLK/100 */
  17 #define  PWM_DIV_CLK_128        0x7F /* DIVIDECLK = BASECLK/128 */
  18
  19 #define PWM0_DUTY_CYCLE         0x4E
  20 #define BACKLIGHT_EN            0x51
  21
  22 #define PWM_MAX_LEVEL           0xFF
  23
  24 #define PWM_BASE_CLK            6000000  /* 6 MHz */
  25 #define PWM_MAX_PERIOD_NS       21333    /* 46.875KHz */
  26
  27 /**
  28  * struct crystalcove_pwm - Crystal Cove PWM controller
  29  * @chip: the abstract pwm_chip structure.
  30  * @regmap: the regmap from the parent device.
  31  */
  32 struct crystalcove_pwm {
  33         struct pwm_chip chip;
  34         struct regmap *regmap;
  35 };
  36
  37 static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *pc)
  38 {
  39         return container_of(pc, struct crystalcove_pwm, chip);
  40 }
  41
  42 static int crc_pwm_enable(struct pwm_chip *c, struct pwm_device *pwm)
  43 {
  44         struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
  45
  46         regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1);
  47
  48         return 0;
  49 }
  50
  51 static void crc_pwm_disable(struct pwm_chip *c, struct pwm_device *pwm)
  52 {
  53         struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
  54
  55         regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0);
  56 }
  57
  58 static int crc_pwm_config(struct pwm_chip *c, struct pwm_device *pwm,
  59                           int duty_ns, int period_ns)
  60 {
  61         struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
  62         struct device *dev = crc_pwm->chip.dev;
  63         int level;
  64
  65         if (period_ns > PWM_MAX_PERIOD_NS) {
  66                 dev_err(dev, "un-supported period_ns\n");
  67                 return -EINVAL;
  68         }
  69
  70         if (pwm_get_period(pwm) != period_ns) {
  71                 int clk_div;
  72
  73                 /* changing the clk divisor, need to disable fisrt */
  74                 crc_pwm_disable(c, pwm);
  75                 clk_div = PWM_BASE_CLK * period_ns / NSEC_PER_SEC;
  76
  77                 regmap_write(crc_pwm->regmap, PWM0_CLK_DIV,
  78                                         clk_div | PWM_OUTPUT_ENABLE);
  79
  80                 /* enable back */
  81                 crc_pwm_enable(c, pwm);
  82         }
  83
  84         /* change the pwm duty cycle */
  85         level = duty_ns * PWM_MAX_LEVEL / period_ns;
  86         regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level);
  87
  88         return 0;
  89 }
  90
  91 static const struct pwm_ops crc_pwm_ops = {
  92         .config = crc_pwm_config,
  93         .enable = crc_pwm_enable,
  94         .disable = crc_pwm_disable,
  95 };
  96
  97 static int crystalcove_pwm_probe(struct platform_device *pdev)
  98 {
  99         struct crystalcove_pwm *pwm;
 100         struct device *dev = pdev->dev.parent;
 101         struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
 102
 103         pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
 104         if (!pwm)
 105                 return -ENOMEM;
 106
 107         pwm->chip.dev = &pdev->dev;
 108         pwm->chip.ops = &crc_pwm_ops;
 109         pwm->chip.base = -1;
 110         pwm->chip.npwm = 1;
 111
 112         /* get the PMIC regmap */
 113         pwm->regmap = pmic->regmap;
 114
 115         platform_set_drvdata(pdev, pwm);
 116
 117         return pwmchip_add(&pwm->chip);
 118 }
 119
 120 static int crystalcove_pwm_remove(struct platform_device *pdev)
 121 {
 122         struct crystalcove_pwm *pwm = platform_get_drvdata(pdev);
 123
 124         return pwmchip_remove(&pwm->chip);
 125 }
 126
 127 static struct platform_driver crystalcove_pwm_driver = {
 128         .probe = crystalcove_pwm_probe,
 129         .remove = crystalcove_pwm_remove,
 130         .driver = {
 131                 .name = "crystal_cove_pwm",
 132         },
 133 };
 134
 135 builtin_platform_driver(crystalcove_pwm_driver);