/* * TI/National Semiconductor LP3943 PWM driver * * Copyright 2013 Texas Instruments * * Author: Milo Kim * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2. */ #include #include #include #include #include #include #include #define LP3943_MAX_DUTY 255 #define LP3943_MIN_PERIOD 6250 #define LP3943_MAX_PERIOD 1600000 struct lp3943_pwm { struct pwm_chip chip; struct lp3943 *lp3943; struct lp3943_platform_data *pdata; }; static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *_chip) { return container_of(_chip, struct lp3943_pwm, chip); } static struct lp3943_pwm_map * lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm) { struct lp3943_platform_data *pdata = lp3943_pwm->pdata; struct lp3943 *lp3943 = lp3943_pwm->lp3943; struct lp3943_pwm_map *pwm_map; int i, offset; pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL); if (!pwm_map) return ERR_PTR(-ENOMEM); pwm_map->output = pdata->pwms[hwpwm]->output; pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs; for (i = 0; i < pwm_map->num_outputs; i++) { offset = pwm_map->output[i]; /* Return an error if the pin is already assigned */ if (test_and_set_bit(offset, &lp3943->pin_used)) { kfree(pwm_map); return ERR_PTR(-EBUSY); } } return pwm_map; } static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) { struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); struct lp3943_pwm_map *pwm_map; pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm); if (IS_ERR(pwm_map)) return PTR_ERR(pwm_map); return pwm_set_chip_data(pwm, pwm_map); } static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm, struct lp3943_pwm_map *pwm_map) { struct lp3943 *lp3943 = lp3943_pwm->lp3943; int i, offset; for (i = 0; i < pwm_map->num_outputs; i++) { offset = pwm_map->output[i]; clear_bit(offset, &lp3943->pin_used); } kfree(pwm_map); } static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); lp3943_pwm_free_map(lp3943_pwm, pwm_map); } static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); struct lp3943 *lp3943 = lp3943_pwm->lp3943; u8 val, reg_duty, reg_prescale; int err; /* * How to configure the LP3943 PWMs * * 1) Period = 6250 ~ 1600000 * 2) Prescale = period / 6250 -1 * 3) Duty = input duty * * Prescale and duty are register values */ if (pwm->hwpwm == 0) { reg_prescale = LP3943_REG_PRESCALE0; reg_duty = LP3943_REG_PWM0; } else { reg_prescale = LP3943_REG_PRESCALE1; reg_duty = LP3943_REG_PWM1; } period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD); val = (u8)(period_ns / LP3943_MIN_PERIOD - 1); err = lp3943_write_byte(lp3943, reg_prescale, val); if (err) return err; duty_ns = min(duty_ns, period_ns); val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns); return lp3943_write_byte(lp3943, reg_duty, val); } static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm, struct lp3943_pwm_map *pwm_map, u8 val) { struct lp3943 *lp3943 = lp3943_pwm->lp3943; const struct lp3943_reg_cfg *mux = lp3943->mux_cfg; int i, index, err; for (i = 0; i < pwm_map->num_outputs; i++) { index = pwm_map->output[i]; err = lp3943_update_bits(lp3943, mux[index].reg, mux[index].mask, val << mux[index].shift); if (err) return err; } return 0; } static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) { struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); u8 val; if (pwm->hwpwm == 0) val = LP3943_DIM_PWM0; else val = LP3943_DIM_PWM1; /* * Each PWM generator is set to control any of outputs of LP3943. * To enable/disable the PWM, these output pins should be configured. */ return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val); } static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); /* * LP3943 outputs are open-drain, so the pin should be configured * when the PWM is disabled. */ lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH); } static const struct pwm_ops lp3943_pwm_ops = { .request = lp3943_pwm_request, .free = lp3943_pwm_free, .config = lp3943_pwm_config, .enable = lp3943_pwm_enable, .disable = lp3943_pwm_disable, .owner = THIS_MODULE, }; static int lp3943_pwm_parse_dt(struct device *dev, struct lp3943_pwm *lp3943_pwm) { static const char * const name[] = { "ti,pwm0", "ti,pwm1", }; struct device_node *node = dev->of_node; struct lp3943_platform_data *pdata; struct lp3943_pwm_map *pwm_map; enum lp3943_pwm_output *output; int i, err, proplen, count = 0; u32 num_outputs; if (!node) return -EINVAL; pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); if (!pdata) return -ENOMEM; /* * Read the output map configuration from the device tree. * Each of the two PWM generators can drive zero or more outputs. */ for (i = 0; i < LP3943_NUM_PWMS; i++) { if (!of_get_property(node, name[i], &proplen)) continue; num_outputs = proplen / sizeof(u32); if (num_outputs == 0) continue; output = devm_kzalloc(dev, sizeof(*output) * num_outputs, GFP_KERNEL); if (!output) return -ENOMEM; err = of_property_read_u32_array(node, name[i], output, num_outputs); if (err) return err; pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL); if (!pwm_map) return -ENOMEM; pwm_map->output = output; pwm_map->num_outputs = num_outputs; pdata->pwms[i] = pwm_map; count++; } if (count == 0) return -ENODATA; lp3943_pwm->pdata = pdata; return 0; } static int lp3943_pwm_probe(struct platform_device *pdev) { struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent); struct lp3943_pwm *lp3943_pwm; int ret; lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL); if (!lp3943_pwm) return -ENOMEM; lp3943_pwm->pdata = lp3943->pdata; if (!lp3943_pwm->pdata) { if (IS_ENABLED(CONFIG_OF)) ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm); else ret = -ENODEV; if (ret) return ret; } lp3943_pwm->lp3943 = lp3943; lp3943_pwm->chip.dev = &pdev->dev; lp3943_pwm->chip.ops = &lp3943_pwm_ops; lp3943_pwm->chip.npwm = LP3943_NUM_PWMS; lp3943_pwm->chip.can_sleep = true; platform_set_drvdata(pdev, lp3943_pwm); return pwmchip_add(&lp3943_pwm->chip); } static int lp3943_pwm_remove(struct platform_device *pdev) { struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev); return pwmchip_remove(&lp3943_pwm->chip); } #ifdef CONFIG_OF static const struct of_device_id lp3943_pwm_of_match[] = { { .compatible = "ti,lp3943-pwm", }, { } }; MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match); #endif static struct platform_driver lp3943_pwm_driver = { .probe = lp3943_pwm_probe, .remove = lp3943_pwm_remove, .driver = { .name = "lp3943-pwm", .of_match_table = of_match_ptr(lp3943_pwm_of_match), }, }; module_platform_driver(lp3943_pwm_driver); MODULE_DESCRIPTION("LP3943 PWM driver"); MODULE_ALIAS("platform:lp3943-pwm"); MODULE_AUTHOR("Milo Kim"); MODULE_LICENSE("GPL");