pwm-pca9685.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for PCA9685 16-channel 12-bit PWM LED controller
*
* Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
* Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
*
* based on the pwm-twl-led.c driver
*/
#include <linux/acpi.h>
#include <linux/gpio/driver.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/pwm.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/pm_runtime.h>
#include <linux/bitmap.h>
/*
* Because the PCA9685 has only one prescaler per chip, changing the period of
* one channel affects the period of all 16 PWM outputs!
* However, the ratio between each configured duty cycle and the chip-wide
* period remains constant, because the OFF time is set in proportion to the
* counter range.
*/
#define PCA9685_MODE1 0x00
#define PCA9685_MODE2 0x01
#define PCA9685_SUBADDR1 0x02
#define PCA9685_SUBADDR2 0x03
#define PCA9685_SUBADDR3 0x04
#define PCA9685_ALLCALLADDR 0x05
#define PCA9685_LEDX_ON_L 0x06
#define PCA9685_LEDX_ON_H 0x07
#define PCA9685_LEDX_OFF_L 0x08
#define PCA9685_LEDX_OFF_H 0x09
#define PCA9685_ALL_LED_ON_L 0xFA
#define PCA9685_ALL_LED_ON_H 0xFB
#define PCA9685_ALL_LED_OFF_L 0xFC
#define PCA9685_ALL_LED_OFF_H 0xFD
#define PCA9685_PRESCALE 0xFE
#define PCA9685_PRESCALE_MIN 0x03 /* => max. frequency of 1526 Hz */
#define PCA9685_PRESCALE_MAX 0xFF /* => min. frequency of 24 Hz */
#define PCA9685_COUNTER_RANGE 4096
#define PCA9685_OSC_CLOCK_MHZ 25 /* Internal oscillator with 25 MHz */
#define PCA9685_NUMREGS 0xFF
#define PCA9685_MAXCHAN 0x10
#define LED_FULL BIT(4)
#define MODE1_ALLCALL BIT(0)
#define MODE1_SUB3 BIT(1)
#define MODE1_SUB2 BIT(2)
#define MODE1_SUB1 BIT(3)
#define MODE1_SLEEP BIT(4)
#define MODE2_INVRT BIT(4)
#define MODE2_OUTDRV BIT(2)
#define LED_N_ON_H(N) (PCA9685_LEDX_ON_H + (4 * (N)))
#define LED_N_ON_L(N) (PCA9685_LEDX_ON_L + (4 * (N)))
#define LED_N_OFF_H(N) (PCA9685_LEDX_OFF_H + (4 * (N)))
#define LED_N_OFF_L(N) (PCA9685_LEDX_OFF_L + (4 * (N)))
#define REG_ON_H(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_ON_H : LED_N_ON_H((C)))
#define REG_ON_L(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_ON_L : LED_N_ON_L((C)))
#define REG_OFF_H(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_OFF_H : LED_N_OFF_H((C)))
#define REG_OFF_L(C) ((C) >= PCA9685_MAXCHAN ? PCA9685_ALL_LED_OFF_L : LED_N_OFF_L((C)))
struct pca9685 {
struct pwm_chip chip;
struct regmap *regmap;
#if IS_ENABLED(CONFIG_GPIOLIB)
struct mutex lock;
struct gpio_chip gpio;
DECLARE_BITMAP(pwms_inuse, PCA9685_MAXCHAN + 1);
#endif
};
static inline struct pca9685 *to_pca(struct pwm_chip *chip)
{
return container_of(chip, struct pca9685, chip);
}
/* Helper function to set the duty cycle ratio to duty/4096 (e.g. duty=2048 -> 50%) */
static void pca9685_pwm_set_duty(struct pca9685 *pca, int channel, unsigned int duty)
{
if (duty == 0) {
/* Set the full OFF bit, which has the highest precedence */
regmap_write(pca->regmap, REG_OFF_H(channel), LED_FULL);
} else if (duty >= PCA9685_COUNTER_RANGE) {
/* Set the full ON bit and clear the full OFF bit */
regmap_write(pca->regmap, REG_ON_H(channel), LED_FULL);
regmap_write(pca->regmap, REG_OFF_H(channel), 0);
} else {
/* Set OFF time (clears the full OFF bit) */
regmap_write(pca->regmap, REG_OFF_L(channel), duty & 0xff);
regmap_write(pca->regmap, REG_OFF_H(channel), (duty >> 8) & 0xf);
/* Clear the full ON bit */
regmap_write(pca->regmap, REG_ON_H(channel), 0);
}
}
static unsigned int pca9685_pwm_get_duty(struct pca9685 *pca, int channel)
{
unsigned int off_h = 0, val = 0;
if (WARN_ON(channel >= PCA9685_MAXCHAN)) {
/* HW does not support reading state of "all LEDs" channel */
return 0;
}
regmap_read(pca->regmap, LED_N_OFF_H(channel), &off_h);
if (off_h & LED_FULL) {
/* Full OFF bit is set */
return 0;
}
regmap_read(pca->regmap, LED_N_ON_H(channel), &val);
if (val & LED_FULL) {
/* Full ON bit is set */
return PCA9685_COUNTER_RANGE;
}
if (regmap_read(pca->regmap, LED_N_OFF_L(channel), &val)) {
/* Reset val to 0 in case reading LED_N_OFF_L failed */
val = 0;
}
return ((off_h & 0xf) << 8) | (val & 0xff);
}
#if IS_ENABLED(CONFIG_GPIOLIB)
static bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca, int pwm_idx)
{
bool is_inuse;
mutex_lock(&pca->lock);
if (pwm_idx >= PCA9685_MAXCHAN) {
/*
* "All LEDs" channel:
* pretend already in use if any of the PWMs are requested
*/
if (!bitmap_empty(pca->pwms_inuse, PCA9685_MAXCHAN)) {
is_inuse = true;
goto out;
}
} else {
/*
* Regular channel:
* pretend already in use if the "all LEDs" channel is requested
*/
if (test_bit(PCA9685_MAXCHAN, pca->pwms_inuse)) {
is_inuse = true;
goto out;
}
}
is_inuse = test_and_set_bit(pwm_idx, pca->pwms_inuse);
out:
mutex_unlock(&pca->lock);
return is_inuse;
}
static void pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
{
mutex_lock(&pca->lock);
clear_bit(pwm_idx, pca->pwms_inuse);
mutex_unlock(&pca->lock);
}
static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
if (pca9685_pwm_test_and_set_inuse(pca, offset))
return -EBUSY;
pm_runtime_get_sync(pca->chip.dev);
return 0;
}
static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
return pca9685_pwm_get_duty(pca, offset) != 0;
}
static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
int value)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
pca9685_pwm_set_duty(pca, offset, value ? PCA9685_COUNTER_RANGE : 0);
}
static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
pca9685_pwm_set_duty(pca, offset, 0);
pm_runtime_put(pca->chip.dev);
pca9685_pwm_clear_inuse(pca, offset);
}
static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
unsigned int offset)
{
/* Always out */
return GPIO_LINE_DIRECTION_OUT;
}
static int pca9685_pwm_gpio_direction_input(struct gpio_chip *gpio,
unsigned int offset)
{
return -EINVAL;
}
static int pca9685_pwm_gpio_direction_output(struct gpio_chip *gpio,
unsigned int offset, int value)
{
pca9685_pwm_gpio_set(gpio, offset, value);
return 0;
}
/*
* The PCA9685 has a bit for turning the PWM output full off or on. Some
* boards like Intel Galileo actually uses these as normal GPIOs so we
* expose a GPIO chip here which can exclusively take over the underlying
* PWM channel.
*/
static int pca9685_pwm_gpio_probe(struct pca9685 *pca)
{
struct device *dev = pca->chip.dev;
mutex_init(&pca->lock);
pca->gpio.label = dev_name(dev);
pca->gpio.parent = dev;
pca->gpio.request = pca9685_pwm_gpio_request;
pca->gpio.free = pca9685_pwm_gpio_free;
pca->gpio.get_direction = pca9685_pwm_gpio_get_direction;
pca->gpio.direction_input = pca9685_pwm_gpio_direction_input;
pca->gpio.direction_output = pca9685_pwm_gpio_direction_output;
pca->gpio.get = pca9685_pwm_gpio_get;
pca->gpio.set = pca9685_pwm_gpio_set;
pca->gpio.base = -1;
pca->gpio.ngpio = PCA9685_MAXCHAN;
pca->gpio.can_sleep = true;
return devm_gpiochip_add_data(dev, &pca->gpio, pca);
}
#else
static inline bool pca9685_pwm_test_and_set_inuse(struct pca9685 *pca,
int pwm_idx)
{
return false;
}
static inline void
pca9685_pwm_clear_inuse(struct pca9685 *pca, int pwm_idx)
{
}
static inline int pca9685_pwm_gpio_probe(struct pca9685 *pca)
{
return 0;
}
#endif
static void pca9685_set_sleep_mode(struct pca9685 *pca, bool enable)
{
regmap_update_bits(pca->regmap, PCA9685_MODE1,
MODE1_SLEEP, enable ? MODE1_SLEEP : 0);
if (!enable) {
/* Wait 500us for the oscillator to be back up */
udelay(500);
}
}
static int pca9685_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct pca9685 *pca = to_pca(chip);
unsigned long long duty, prescale;
unsigned int val = 0;
if (state->polarity != PWM_POLARITY_NORMAL)
return -EINVAL;
prescale = DIV_ROUND_CLOSEST_ULL(PCA9685_OSC_CLOCK_MHZ * state->period,
PCA9685_COUNTER_RANGE * 1000) - 1;
if (prescale < PCA9685_PRESCALE_MIN || prescale > PCA9685_PRESCALE_MAX) {
dev_err(chip->dev, "pwm not changed: period out of bounds!\n");
return -EINVAL;
}
if (!state->enabled) {
pca9685_pwm_set_duty(pca, pwm->hwpwm, 0);
return 0;
}
regmap_read(pca->regmap, PCA9685_PRESCALE, &val);
if (prescale != val) {
/*
* Putting the chip briefly into SLEEP mode
* at this point won't interfere with the
* pm_runtime framework, because the pm_runtime
* state is guaranteed active here.
*/
/* Put chip into sleep mode */
pca9685_set_sleep_mode(pca, true);
/* Change the chip-wide output frequency */
regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
/* Wake the chip up */
pca9685_set_sleep_mode(pca, false);
}
duty = PCA9685_COUNTER_RANGE * state->duty_cycle;
duty = DIV_ROUND_UP_ULL(duty, state->period);
pca9685_pwm_set_duty(pca, pwm->hwpwm, duty);
return 0;
}
static void pca9685_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct pca9685 *pca = to_pca(chip);
unsigned long long duty;
unsigned int val = 0;
/* Calculate (chip-wide) period from prescale value */
regmap_read(pca->regmap, PCA9685_PRESCALE, &val);
/*
* PCA9685_OSC_CLOCK_MHZ is 25, i.e. an integer divider of 1000.
* The following calculation is therefore only a multiplication
* and we are not losing precision.
*/
state->period = (PCA9685_COUNTER_RANGE * 1000 / PCA9685_OSC_CLOCK_MHZ) *
(val + 1);
/* The (per-channel) polarity is fixed */
state->polarity = PWM_POLARITY_NORMAL;
if (pwm->hwpwm >= PCA9685_MAXCHAN) {
/*
* The "all LEDs" channel does not support HW readout
* Return 0 and disabled for backwards compatibility
*/
state->duty_cycle = 0;
state->enabled = false;
return;
}
state->enabled = true;
duty = pca9685_pwm_get_duty(pca, pwm->hwpwm);
state->duty_cycle = DIV_ROUND_DOWN_ULL(duty * state->period, PCA9685_COUNTER_RANGE);
}
static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct pca9685 *pca = to_pca(chip);
if (pca9685_pwm_test_and_set_inuse(pca, pwm->hwpwm))
return -EBUSY;
pm_runtime_get_sync(chip->dev);
return 0;
}
static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct pca9685 *pca = to_pca(chip);
pca9685_pwm_set_duty(pca, pwm->hwpwm, 0);
pm_runtime_put(chip->dev);
pca9685_pwm_clear_inuse(pca, pwm->hwpwm);
}
static const struct pwm_ops pca9685_pwm_ops = {
.apply = pca9685_pwm_apply,
.get_state = pca9685_pwm_get_state,
.request = pca9685_pwm_request,
.free = pca9685_pwm_free,
.owner = THIS_MODULE,
};
static const struct regmap_config pca9685_regmap_i2c_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = PCA9685_NUMREGS,
.cache_type = REGCACHE_NONE,
};
static int pca9685_pwm_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pca9685 *pca;
unsigned int reg;
int ret;
pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
if (!pca)
return -ENOMEM;
pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
if (IS_ERR(pca->regmap)) {
ret = PTR_ERR(pca->regmap);
dev_err(&client->dev, "Failed to initialize register map: %d\n",
ret);
return ret;
}
i2c_set_clientdata(client, pca);
regmap_read(pca->regmap, PCA9685_MODE2, ®);
if (device_property_read_bool(&client->dev, "invert"))
reg |= MODE2_INVRT;
else
reg &= ~MODE2_INVRT;
if (device_property_read_bool(&client->dev, "open-drain"))
reg &= ~MODE2_OUTDRV;
else
reg |= MODE2_OUTDRV;
regmap_write(pca->regmap, PCA9685_MODE2, reg);
/* Disable all LED ALLCALL and SUBx addresses to avoid bus collisions */
regmap_read(pca->regmap, PCA9685_MODE1, ®);
reg &= ~(MODE1_ALLCALL | MODE1_SUB1 | MODE1_SUB2 | MODE1_SUB3);
regmap_write(pca->regmap, PCA9685_MODE1, reg);
/* Reset OFF registers to POR default */
regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, LED_FULL);
regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, LED_FULL);
pca->chip.ops = &pca9685_pwm_ops;
/* Add an extra channel for ALL_LED */
pca->chip.npwm = PCA9685_MAXCHAN + 1;
pca->chip.dev = &client->dev;
ret = pwmchip_add(&pca->chip);
if (ret < 0)
return ret;
ret = pca9685_pwm_gpio_probe(pca);
if (ret < 0) {
pwmchip_remove(&pca->chip);
return ret;
}
pm_runtime_enable(&client->dev);
if (pm_runtime_enabled(&client->dev)) {
/*
* Although the chip comes out of power-up in the sleep state,
* we force it to sleep in case it was woken up before
*/
pca9685_set_sleep_mode(pca, true);
pm_runtime_set_suspended(&client->dev);
} else {
/* Wake the chip up if runtime PM is disabled */
pca9685_set_sleep_mode(pca, false);
}
return 0;
}
static int pca9685_pwm_remove(struct i2c_client *client)
{
struct pca9685 *pca = i2c_get_clientdata(client);
int ret;
ret = pwmchip_remove(&pca->chip);
if (ret)
return ret;
if (!pm_runtime_enabled(&client->dev)) {
/* Put chip in sleep state if runtime PM is disabled */
pca9685_set_sleep_mode(pca, true);
}
pm_runtime_disable(&client->dev);
return 0;
}
static int __maybe_unused pca9685_pwm_runtime_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct pca9685 *pca = i2c_get_clientdata(client);
pca9685_set_sleep_mode(pca, true);
return 0;
}
static int __maybe_unused pca9685_pwm_runtime_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct pca9685 *pca = i2c_get_clientdata(client);
pca9685_set_sleep_mode(pca, false);
return 0;
}
static const struct i2c_device_id pca9685_id[] = {
{ "pca9685", 0 },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(i2c, pca9685_id);
#ifdef CONFIG_ACPI
static const struct acpi_device_id pca9685_acpi_ids[] = {
{ "INT3492", 0 },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
#endif
#ifdef CONFIG_OF
static const struct of_device_id pca9685_dt_ids[] = {
{ .compatible = "nxp,pca9685-pwm", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
#endif
static const struct dev_pm_ops pca9685_pwm_pm = {
SET_RUNTIME_PM_OPS(pca9685_pwm_runtime_suspend,
pca9685_pwm_runtime_resume, NULL)
};
static struct i2c_driver pca9685_i2c_driver = {
.driver = {
.name = "pca9685-pwm",
.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
.of_match_table = of_match_ptr(pca9685_dt_ids),
.pm = &pca9685_pwm_pm,
},
.probe = pca9685_pwm_probe,
.remove = pca9685_pwm_remove,
.id_table = pca9685_id,
};
module_i2c_driver(pca9685_i2c_driver);
MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
MODULE_DESCRIPTION("PWM driver for PCA9685");
MODULE_LICENSE("GPL");