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_MHZ 6 /* 6 MHz */ 25 #define PWM_MAX_PERIOD_NS 5461334 /* 183 Hz */ 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_calc_clk_div(int period_ns) 43 { 44 int clk_div; 45 46 clk_div = PWM_BASE_CLK_MHZ * period_ns / (256 * NSEC_PER_USEC); 47 /* clk_div 1 - 128, maps to register values 0-127 */ 48 if (clk_div > 0) 49 clk_div--; 50 51 return clk_div; 52 } 53 54 static int crc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 55 const struct pwm_state *state) 56 { 57 struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip); 58 struct device *dev = crc_pwm->chip.dev; 59 int err; 60 61 if (state->period > PWM_MAX_PERIOD_NS) { 62 dev_err(dev, "un-supported period_ns\n"); 63 return -EINVAL; 64 } 65 66 if (state->polarity != PWM_POLARITY_NORMAL) 67 return -EINVAL; 68 69 if (pwm_is_enabled(pwm) && !state->enabled) { 70 err = regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0); 71 if (err) { 72 dev_err(dev, "Error writing BACKLIGHT_EN %d\n", err); 73 return err; 74 } 75 } 76 77 if (pwm_get_duty_cycle(pwm) != state->duty_cycle || 78 pwm_get_period(pwm) != state->period) { 79 u64 level = state->duty_cycle * PWM_MAX_LEVEL; 80 81 do_div(level, state->period); 82 83 err = regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level); 84 if (err) { 85 dev_err(dev, "Error writing PWM0_DUTY_CYCLE %d\n", err); 86 return err; 87 } 88 } 89 90 if (pwm_is_enabled(pwm) && state->enabled && 91 pwm_get_period(pwm) != state->period) { 92 /* changing the clk divisor, clear PWM_OUTPUT_ENABLE first */ 93 err = regmap_write(crc_pwm->regmap, PWM0_CLK_DIV, 0); 94 if (err) { 95 dev_err(dev, "Error writing PWM0_CLK_DIV %d\n", err); 96 return err; 97 } 98 } 99 100 if (pwm_get_period(pwm) != state->period || 101 pwm_is_enabled(pwm) != state->enabled) { 102 int clk_div = crc_pwm_calc_clk_div(state->period); 103 int pwm_output_enable = state->enabled ? PWM_OUTPUT_ENABLE : 0; 104 105 err = regmap_write(crc_pwm->regmap, PWM0_CLK_DIV, 106 clk_div | pwm_output_enable); 107 if (err) { 108 dev_err(dev, "Error writing PWM0_CLK_DIV %d\n", err); 109 return err; 110 } 111 } 112 113 if (!pwm_is_enabled(pwm) && state->enabled) { 114 err = regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1); 115 if (err) { 116 dev_err(dev, "Error writing BACKLIGHT_EN %d\n", err); 117 return err; 118 } 119 } 120 121 return 0; 122 } 123 124 static void crc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, 125 struct pwm_state *state) 126 { 127 struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip); 128 struct device *dev = crc_pwm->chip.dev; 129 unsigned int clk_div, clk_div_reg, duty_cycle_reg; 130 int error; 131 132 error = regmap_read(crc_pwm->regmap, PWM0_CLK_DIV, &clk_div_reg); 133 if (error) { 134 dev_err(dev, "Error reading PWM0_CLK_DIV %d\n", error); 135 return; 136 } 137 138 error = regmap_read(crc_pwm->regmap, PWM0_DUTY_CYCLE, &duty_cycle_reg); 139 if (error) { 140 dev_err(dev, "Error reading PWM0_DUTY_CYCLE %d\n", error); 141 return; 142 } 143 144 clk_div = (clk_div_reg & ~PWM_OUTPUT_ENABLE) + 1; 145 146 state->period = 147 DIV_ROUND_UP(clk_div * NSEC_PER_USEC * 256, PWM_BASE_CLK_MHZ); 148 state->duty_cycle = 149 DIV_ROUND_UP_ULL(duty_cycle_reg * state->period, PWM_MAX_LEVEL); 150 state->polarity = PWM_POLARITY_NORMAL; 151 state->enabled = !!(clk_div_reg & PWM_OUTPUT_ENABLE); 152 } 153 154 static const struct pwm_ops crc_pwm_ops = { 155 .apply = crc_pwm_apply, 156 .get_state = crc_pwm_get_state, 157 }; 158 159 static int crystalcove_pwm_probe(struct platform_device *pdev) 160 { 161 struct crystalcove_pwm *pwm; 162 struct device *dev = pdev->dev.parent; 163 struct intel_soc_pmic *pmic = dev_get_drvdata(dev); 164 165 pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); 166 if (!pwm) 167 return -ENOMEM; 168 169 pwm->chip.dev = &pdev->dev; 170 pwm->chip.ops = &crc_pwm_ops; 171 pwm->chip.base = -1; 172 pwm->chip.npwm = 1; 173 174 /* get the PMIC regmap */ 175 pwm->regmap = pmic->regmap; 176 177 platform_set_drvdata(pdev, pwm); 178 179 return pwmchip_add(&pwm->chip); 180 } 181 182 static int crystalcove_pwm_remove(struct platform_device *pdev) 183 { 184 struct crystalcove_pwm *pwm = platform_get_drvdata(pdev); 185 186 return pwmchip_remove(&pwm->chip); 187 } 188 189 static struct platform_driver crystalcove_pwm_driver = { 190 .probe = crystalcove_pwm_probe, 191 .remove = crystalcove_pwm_remove, 192 .driver = { 193 .name = "crystal_cove_pwm", 194 }, 195 }; 196 197 builtin_platform_driver(crystalcove_pwm_driver); 198