mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Uwe Kleine-König](/assets/img/avatar_default.png)
I found these just from reading the reference manual and the driver source. It's unclear to me if there are glitches when updating the ON and OFF registers. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
392 lines
9.7 KiB
C
392 lines
9.7 KiB
C
// 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");
|