diff options
Diffstat (limited to 'kernel/drivers/pwm/pwm-lp3943.c')
| -rw-r--r-- | kernel/drivers/pwm/pwm-lp3943.c | 316 |
1 files changed, 316 insertions, 0 deletions
diff --git a/kernel/drivers/pwm/pwm-lp3943.c b/kernel/drivers/pwm/pwm-lp3943.c new file mode 100644 index 000000000..872ea76a4 --- /dev/null +++ b/kernel/drivers/pwm/pwm-lp3943.c @@ -0,0 +1,316 @@ +/* + * TI/National Semiconductor LP3943 PWM driver + * + * Copyright 2013 Texas Instruments + * + * Author: Milo Kim <milo.kim@ti.com> + * + * 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 <linux/err.h> +#include <linux/i2c.h> +#include <linux/mfd/lp3943.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/slab.h> + +#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; + + 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"); |