LXR linux/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 */
  32struct crystalcove_pwm {
  33        struct pwm_chip chip;
  34        struct regmap *regmap;
  35};
  36
  37static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *pc)
  38{
  39        return container_of(pc, struct crystalcove_pwm, chip);
  40}
  41
  42static 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
  51static 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
  58static 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
  91static const struct pwm_ops crc_pwm_ops = {
  92        .config = crc_pwm_config,
  93        .enable = crc_pwm_enable,
  94        .disable = crc_pwm_disable,
  95};
  96
  97static 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
 120static 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
 127static 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
 135builtin_platform_driver(crystalcove_pwm_driver);
 136