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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * TI/National Semiconductor LP3943 PWM driver4 *5 * Copyright 2013 Texas Instruments6 *7 * Author: Milo Kim <milo.kim@ti.com>8 */9 10#include <linux/err.h>11#include <linux/mfd/lp3943.h>12#include <linux/module.h>13#include <linux/of.h>14#include <linux/platform_device.h>15#include <linux/pwm.h>16#include <linux/slab.h>17 18#define LP3943_MAX_DUTY 25519#define LP3943_MIN_PERIOD 625020#define LP3943_MAX_PERIOD 160000021 22struct lp3943_pwm {23 struct lp3943 *lp3943;24 struct lp3943_platform_data *pdata;25 struct lp3943_pwm_map pwm_map[LP3943_NUM_PWMS];26};27 28static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *chip)29{30 return pwmchip_get_drvdata(chip);31}32 33static struct lp3943_pwm_map *34lp3943_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 = &lp3943_pwm->pwm_map[hwpwm];39 int i, offset;40 41 pwm_map->output = pdata->pwms[hwpwm]->output;42 pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs;43 44 for (i = 0; i < pwm_map->num_outputs; i++) {45 offset = pwm_map->output[i];46 47 /* Return an error if the pin is already assigned */48 if (test_and_set_bit(offset, &lp3943->pin_used))49 return ERR_PTR(-EBUSY);50 }51 52 return pwm_map;53}54 55static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)56{57 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);58 struct lp3943_pwm_map *pwm_map;59 60 pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm);61 if (IS_ERR(pwm_map))62 return PTR_ERR(pwm_map);63 64 return 0;65}66 67static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm,68 struct lp3943_pwm_map *pwm_map)69{70 struct lp3943 *lp3943 = lp3943_pwm->lp3943;71 int i, offset;72 73 for (i = 0; i < pwm_map->num_outputs; i++) {74 offset = pwm_map->output[i];75 clear_bit(offset, &lp3943->pin_used);76 }77}78 79static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)80{81 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);82 struct lp3943_pwm_map *pwm_map = &lp3943_pwm->pwm_map[pwm->hwpwm];83 84 lp3943_pwm_free_map(lp3943_pwm, pwm_map);85}86 87static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,88 u64 duty_ns, u64 period_ns)89{90 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);91 struct lp3943 *lp3943 = lp3943_pwm->lp3943;92 u8 val, reg_duty, reg_prescale;93 int err;94 95 /*96 * How to configure the LP3943 PWMs97 *98 * 1) Period = 6250 ~ 160000099 * 2) Prescale = period / 6250 -1100 * 3) Duty = input duty101 *102 * Prescale and duty are register values103 */104 105 if (pwm->hwpwm == 0) {106 reg_prescale = LP3943_REG_PRESCALE0;107 reg_duty = LP3943_REG_PWM0;108 } else {109 reg_prescale = LP3943_REG_PRESCALE1;110 reg_duty = LP3943_REG_PWM1;111 }112 113 /*114 * Note that after this clamping, period_ns fits into an int. This is115 * helpful because we can resort to integer division below instead of116 * the (more expensive) 64 bit division.117 */118 period_ns = clamp(period_ns, (u64)LP3943_MIN_PERIOD, (u64)LP3943_MAX_PERIOD);119 val = (u8)((int)period_ns / LP3943_MIN_PERIOD - 1);120 121 err = lp3943_write_byte(lp3943, reg_prescale, val);122 if (err)123 return err;124 125 duty_ns = min(duty_ns, period_ns);126 val = (u8)((int)duty_ns * LP3943_MAX_DUTY / (int)period_ns);127 128 return lp3943_write_byte(lp3943, reg_duty, val);129}130 131static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm,132 struct lp3943_pwm_map *pwm_map,133 u8 val)134{135 struct lp3943 *lp3943 = lp3943_pwm->lp3943;136 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;137 int i, index, err;138 139 for (i = 0; i < pwm_map->num_outputs; i++) {140 index = pwm_map->output[i];141 err = lp3943_update_bits(lp3943, mux[index].reg,142 mux[index].mask,143 val << mux[index].shift);144 if (err)145 return err;146 }147 148 return 0;149}150 151static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)152{153 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);154 struct lp3943_pwm_map *pwm_map = &lp3943_pwm->pwm_map[pwm->hwpwm];155 u8 val;156 157 if (pwm->hwpwm == 0)158 val = LP3943_DIM_PWM0;159 else160 val = LP3943_DIM_PWM1;161 162 /*163 * Each PWM generator is set to control any of outputs of LP3943.164 * To enable/disable the PWM, these output pins should be configured.165 */166 167 return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val);168}169 170static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)171{172 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip);173 struct lp3943_pwm_map *pwm_map = &lp3943_pwm->pwm_map[pwm->hwpwm];174 175 /*176 * LP3943 outputs are open-drain, so the pin should be configured177 * when the PWM is disabled.178 */179 180 lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH);181}182 183static int lp3943_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,184 const struct pwm_state *state)185{186 int err;187 188 if (state->polarity != PWM_POLARITY_NORMAL)189 return -EINVAL;190 191 if (!state->enabled) {192 if (pwm->state.enabled)193 lp3943_pwm_disable(chip, pwm);194 return 0;195 }196 197 err = lp3943_pwm_config(chip, pwm, state->duty_cycle, state->period);198 if (err)199 return err;200 201 if (!pwm->state.enabled)202 err = lp3943_pwm_enable(chip, pwm);203 204 return err;205}206 207static const struct pwm_ops lp3943_pwm_ops = {208 .request = lp3943_pwm_request,209 .free = lp3943_pwm_free,210 .apply = lp3943_pwm_apply,211};212 213static int lp3943_pwm_parse_dt(struct device *dev,214 struct lp3943_pwm *lp3943_pwm)215{216 static const char * const name[] = { "ti,pwm0", "ti,pwm1", };217 struct device_node *node = dev->of_node;218 struct lp3943_platform_data *pdata;219 struct lp3943_pwm_map *pwm_map;220 enum lp3943_pwm_output *output;221 int i, err, num_outputs, count = 0;222 223 if (!node)224 return -EINVAL;225 226 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);227 if (!pdata)228 return -ENOMEM;229 230 /*231 * Read the output map configuration from the device tree.232 * Each of the two PWM generators can drive zero or more outputs.233 */234 235 for (i = 0; i < LP3943_NUM_PWMS; i++) {236 num_outputs = of_property_count_u32_elems(node, name[i]);237 if (num_outputs <= 0)238 continue;239 240 output = devm_kcalloc(dev, num_outputs, sizeof(*output),241 GFP_KERNEL);242 if (!output)243 return -ENOMEM;244 245 err = of_property_read_u32_array(node, name[i], output,246 num_outputs);247 if (err)248 return err;249 250 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL);251 if (!pwm_map)252 return -ENOMEM;253 254 pwm_map->output = output;255 pwm_map->num_outputs = num_outputs;256 pdata->pwms[i] = pwm_map;257 258 count++;259 }260 261 if (count == 0)262 return -ENODATA;263 264 lp3943_pwm->pdata = pdata;265 return 0;266}267 268static int lp3943_pwm_probe(struct platform_device *pdev)269{270 struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);271 struct pwm_chip *chip;272 struct lp3943_pwm *lp3943_pwm;273 int ret;274 275 chip = devm_pwmchip_alloc(&pdev->dev, LP3943_NUM_PWMS, sizeof(*lp3943_pwm));276 if (IS_ERR(chip))277 return PTR_ERR(chip);278 lp3943_pwm = to_lp3943_pwm(chip);279 280 lp3943_pwm->pdata = lp3943->pdata;281 if (!lp3943_pwm->pdata) {282 if (IS_ENABLED(CONFIG_OF))283 ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm);284 else285 ret = -ENODEV;286 287 if (ret)288 return ret;289 }290 291 lp3943_pwm->lp3943 = lp3943;292 chip->ops = &lp3943_pwm_ops;293 294 return devm_pwmchip_add(&pdev->dev, chip);295}296 297#ifdef CONFIG_OF298static const struct of_device_id lp3943_pwm_of_match[] = {299 { .compatible = "ti,lp3943-pwm", },300 { }301};302MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match);303#endif304 305static struct platform_driver lp3943_pwm_driver = {306 .probe = lp3943_pwm_probe,307 .driver = {308 .name = "lp3943-pwm",309 .of_match_table = of_match_ptr(lp3943_pwm_of_match),310 },311};312module_platform_driver(lp3943_pwm_driver);313 314MODULE_DESCRIPTION("LP3943 PWM driver");315MODULE_ALIAS("platform:lp3943-pwm");316MODULE_AUTHOR("Milo Kim");317MODULE_LICENSE("GPL");318