diff options
Diffstat (limited to 'drivers/pwm/pwm-twl-led.c')
| -rw-r--r-- | drivers/pwm/pwm-twl-led.c | 392 |
1 files changed, 392 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-twl-led.c b/drivers/pwm/pwm-twl-led.c new file mode 100644 index 000000000..8fb84b441 --- /dev/null +++ b/drivers/pwm/pwm-twl-led.c @@ -0,0 +1,392 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Driver for TWL4030/6030 Pulse Width Modulator used as LED driver + * + * Copyright (C) 2012 Texas Instruments + * Author: Peter Ujfalusi <peter.ujfalusi@ti.com> + * + * This driver is a complete rewrite of the former pwm-twl6030.c authorded by: + * Hemanth V <hemanthv@ti.com> + * + * Reference manual for the twl6030 is available at: + * https://www.ti.com/lit/ds/symlink/twl6030.pdf + * + * Limitations: + * - The twl6030 hardware only supports two period lengths (128 clock ticks and + * 64 clock ticks), the driver only uses 128 ticks + * - The hardware doesn't support ON = 0, so the active part of a period doesn't + * start at its beginning. + * - The hardware could support inverted polarity (with a similar limitation as + * for normal: the last clock tick is always inactive). + * - The hardware emits a constant low output when disabled. + * - A request for .duty_cycle = 0 results in an output wave with one active + * clock tick per period. This should better use the disabled state. + * - The driver only implements setting the relative duty cycle. + * - The driver doesn't implement .get_state(). + */ + +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/mfd/twl.h> +#include <linux/slab.h> + +/* + * This driver handles the PWM driven LED terminals of TWL4030 and TWL6030. + * To generate the signal on TWL4030: + * - LEDA uses PWMA + * - LEDB uses PWMB + * TWL6030 has one LED pin with dedicated LEDPWM + */ + +#define TWL4030_LED_MAX 0x7f +#define TWL6030_LED_MAX 0xff + +/* Registers, bits and macro for TWL4030 */ +#define TWL4030_LEDEN_REG 0x00 +#define TWL4030_PWMA_REG 0x01 + +#define TWL4030_LEDXON (1 << 0) +#define TWL4030_LEDXPWM (1 << 4) +#define TWL4030_LED_PINS (TWL4030_LEDXON | TWL4030_LEDXPWM) +#define TWL4030_LED_TOGGLE(led, x) ((x) << (led)) + +/* Register, bits and macro for TWL6030 */ +#define TWL6030_LED_PWM_CTRL1 0xf4 +#define TWL6030_LED_PWM_CTRL2 0xf5 + +#define TWL6040_LED_MODE_HW 0x00 +#define TWL6040_LED_MODE_ON 0x01 +#define TWL6040_LED_MODE_OFF 0x02 +#define TWL6040_LED_MODE_MASK 0x03 + +struct twl_pwmled_chip { + struct pwm_chip chip; + struct mutex mutex; +}; + +static inline struct twl_pwmled_chip *to_twl(struct pwm_chip *chip) +{ + return container_of(chip, struct twl_pwmled_chip, chip); +} + +static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + int duty_cycle = DIV_ROUND_UP(duty_ns * TWL4030_LED_MAX, period_ns) + 1; + u8 pwm_config[2] = { 1, 0 }; + int base, ret; + + /* + * To configure the duty period: + * On-cycle is set to 1 (the minimum allowed value) + * The off time of 0 is not configurable, so the mapping is: + * 0 -> off cycle = 2, + * 1 -> off cycle = 2, + * 2 -> off cycle = 3, + * 126 - > off cycle 127, + * 127 - > off cycle 1 + * When on cycle == off cycle the PWM will be always on + */ + if (duty_cycle == 1) + duty_cycle = 2; + else if (duty_cycle > TWL4030_LED_MAX) + duty_cycle = 1; + + base = pwm->hwpwm * 2 + TWL4030_PWMA_REG; + + pwm_config[1] = duty_cycle; + + ret = twl_i2c_write(TWL4030_MODULE_LED, pwm_config, base, 2); + if (ret < 0) + dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label); + + return ret; +} + +static int twl4030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct twl_pwmled_chip *twl = to_twl(chip); + int ret; + u8 val; + + mutex_lock(&twl->mutex); + ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG); + if (ret < 0) { + dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label); + goto out; + } + + val |= TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS); + + ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG); + if (ret < 0) + dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label); + +out: + mutex_unlock(&twl->mutex); + return ret; +} + +static void twl4030_pwmled_disable(struct pwm_chip *chip, + struct pwm_device *pwm) +{ + struct twl_pwmled_chip *twl = to_twl(chip); + int ret; + u8 val; + + mutex_lock(&twl->mutex); + ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG); + if (ret < 0) { + dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label); + goto out; + } + + val &= ~TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS); + + ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG); + if (ret < 0) + dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label); + +out: + mutex_unlock(&twl->mutex); +} + +static int twl4030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + int ret; + + if (state->polarity != PWM_POLARITY_NORMAL) + return -EINVAL; + + if (!state->enabled) { + if (pwm->state.enabled) + twl4030_pwmled_disable(chip, pwm); + + return 0; + } + + /* + * We cannot skip calling ->config even if state->period == + * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle + * because we might have exited early in the last call to + * pwm_apply_state because of !state->enabled and so the two values in + * pwm->state might not be configured in hardware. + */ + ret = twl4030_pwmled_config(pwm->chip, pwm, + state->duty_cycle, state->period); + if (ret) + return ret; + + if (!pwm->state.enabled) + ret = twl4030_pwmled_enable(chip, pwm); + + return ret; +} + + +static const struct pwm_ops twl4030_pwmled_ops = { + .apply = twl4030_pwmled_apply, + .owner = THIS_MODULE, +}; + +static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + int duty_cycle = (duty_ns * TWL6030_LED_MAX) / period_ns; + u8 on_time; + int ret; + + on_time = duty_cycle & 0xff; + + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time, + TWL6030_LED_PWM_CTRL1); + if (ret < 0) + dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label); + + return ret; +} + +static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct twl_pwmled_chip *twl = to_twl(chip); + int ret; + u8 val; + + mutex_lock(&twl->mutex); + ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2); + if (ret < 0) { + dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n", + pwm->label); + goto out; + } + + val &= ~TWL6040_LED_MODE_MASK; + val |= TWL6040_LED_MODE_ON; + + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2); + if (ret < 0) + dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label); + +out: + mutex_unlock(&twl->mutex); + return ret; +} + +static void twl6030_pwmled_disable(struct pwm_chip *chip, + struct pwm_device *pwm) +{ + struct twl_pwmled_chip *twl = to_twl(chip); + int ret; + u8 val; + + mutex_lock(&twl->mutex); + ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2); + if (ret < 0) { + dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n", + pwm->label); + goto out; + } + + val &= ~TWL6040_LED_MODE_MASK; + val |= TWL6040_LED_MODE_OFF; + + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2); + if (ret < 0) + dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label); + +out: + mutex_unlock(&twl->mutex); +} + +static int twl6030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + int err; + + if (state->polarity != pwm->state.polarity) + return -EINVAL; + + if (!state->enabled) { + if (pwm->state.enabled) + twl6030_pwmled_disable(chip, pwm); + + return 0; + } + + err = twl6030_pwmled_config(pwm->chip, pwm, + state->duty_cycle, state->period); + if (err) + return err; + + if (!pwm->state.enabled) + err = twl6030_pwmled_enable(chip, pwm); + + return err; +} + +static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct twl_pwmled_chip *twl = to_twl(chip); + int ret; + u8 val; + + mutex_lock(&twl->mutex); + ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2); + if (ret < 0) { + dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n", + pwm->label); + goto out; + } + + val &= ~TWL6040_LED_MODE_MASK; + val |= TWL6040_LED_MODE_OFF; + + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2); + if (ret < 0) + dev_err(chip->dev, "%s: Failed to request PWM\n", pwm->label); + +out: + mutex_unlock(&twl->mutex); + return ret; +} + +static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct twl_pwmled_chip *twl = to_twl(chip); + int ret; + u8 val; + + mutex_lock(&twl->mutex); + ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2); + if (ret < 0) { + dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n", + pwm->label); + goto out; + } + + val &= ~TWL6040_LED_MODE_MASK; + val |= TWL6040_LED_MODE_HW; + + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2); + if (ret < 0) + dev_err(chip->dev, "%s: Failed to free PWM\n", pwm->label); + +out: + mutex_unlock(&twl->mutex); +} + +static const struct pwm_ops twl6030_pwmled_ops = { + .apply = twl6030_pwmled_apply, + .request = twl6030_pwmled_request, + .free = twl6030_pwmled_free, + .owner = THIS_MODULE, +}; + +static int twl_pwmled_probe(struct platform_device *pdev) +{ + struct twl_pwmled_chip *twl; + + twl = devm_kzalloc(&pdev->dev, sizeof(*twl), GFP_KERNEL); + if (!twl) + return -ENOMEM; + + if (twl_class_is_4030()) { + twl->chip.ops = &twl4030_pwmled_ops; + twl->chip.npwm = 2; + } else { + twl->chip.ops = &twl6030_pwmled_ops; + twl->chip.npwm = 1; + } + + twl->chip.dev = &pdev->dev; + + mutex_init(&twl->mutex); + + return devm_pwmchip_add(&pdev->dev, &twl->chip); +} + +#ifdef CONFIG_OF +static const struct of_device_id twl_pwmled_of_match[] = { + { .compatible = "ti,twl4030-pwmled" }, + { .compatible = "ti,twl6030-pwmled" }, + { }, +}; +MODULE_DEVICE_TABLE(of, twl_pwmled_of_match); +#endif + +static struct platform_driver twl_pwmled_driver = { + .driver = { + .name = "twl-pwmled", + .of_match_table = of_match_ptr(twl_pwmled_of_match), + }, + .probe = twl_pwmled_probe, +}; +module_platform_driver(twl_pwmled_driver); + +MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>"); +MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030 LED outputs"); +MODULE_ALIAS("platform:twl-pwmled"); +MODULE_LICENSE("GPL"); |