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// 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>
/*
* 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_DEFAULT_PERIOD 5000000 /* Default period_ns = 1/200 Hz */
#define PCA9685_OSC_CLOCK_MHZ 25 /* Internal oscillator with 25 MHz */
#define PCA9685_NUMREGS 0xFF
#define PCA9685_MAXCHAN 0x10
#define LED_FULL (1 << 4)
#define MODE1_SLEEP (1 << 4)
#define MODE2_INVRT (1 << 4)
#define MODE2_OUTDRV (1 << 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)))
struct pca9685 {
struct pwm_chip chip;
struct regmap *regmap;
int duty_ns;
int period_ns;
#if IS_ENABLED(CONFIG_GPIOLIB)
struct mutex lock;
struct gpio_chip gpio;
#endif
};
static inline struct pca9685 *to_pca(struct pwm_chip *chip)
{
return container_of(chip, struct pca9685, chip);
}
#if IS_ENABLED(CONFIG_GPIOLIB)
static int pca9685_pwm_gpio_request(struct gpio_chip *gpio, unsigned int offset)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
struct pwm_device *pwm;
mutex_lock(&pca->lock);
pwm = &pca->chip.pwms[offset];
if (pwm->flags & (PWMF_REQUESTED | PWMF_EXPORTED)) {
mutex_unlock(&pca->lock);
return -EBUSY;
}
pwm_set_chip_data(pwm, (void *)1);
mutex_unlock(&pca->lock);
pm_runtime_get_sync(pca->chip.dev);
return 0;
}
static bool pca9685_pwm_is_gpio(struct pca9685 *pca, struct pwm_device *pwm)
{
bool is_gpio = false;
mutex_lock(&pca->lock);
if (pwm->hwpwm >= PCA9685_MAXCHAN) {
unsigned int i;
/*
* Check if any of the GPIOs are requested and in that case
* prevent using the "all LEDs" channel.
*/
for (i = 0; i < pca->gpio.ngpio; i++)
if (gpiochip_is_requested(&pca->gpio, i)) {
is_gpio = true;
break;
}
} else if (pwm_get_chip_data(pwm)) {
is_gpio = true;
}
mutex_unlock(&pca->lock);
return is_gpio;
}
static int pca9685_pwm_gpio_get(struct gpio_chip *gpio, unsigned int offset)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
struct pwm_device *pwm = &pca->chip.pwms[offset];
unsigned int value;
regmap_read(pca->regmap, LED_N_ON_H(pwm->hwpwm), &value);
return value & LED_FULL;
}
static void pca9685_pwm_gpio_set(struct gpio_chip *gpio, unsigned int offset,
int value)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
struct pwm_device *pwm = &pca->chip.pwms[offset];
unsigned int on = value ? LED_FULL : 0;
/* Clear both OFF registers */
regmap_write(pca->regmap, LED_N_OFF_L(pwm->hwpwm), 0);
regmap_write(pca->regmap, LED_N_OFF_H(pwm->hwpwm), 0);
/* Set the full ON bit */
regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), on);
}
static void pca9685_pwm_gpio_free(struct gpio_chip *gpio, unsigned int offset)
{
struct pca9685 *pca = gpiochip_get_data(gpio);
pca9685_pwm_gpio_set(gpio, offset, 0);
pm_runtime_put(pca->chip.dev);
}
static int pca9685_pwm_gpio_get_direction(struct gpio_chip *chip,
unsigned int offset)
{
/* Always out */
return 0;
}
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_is_gpio(struct pca9685 *pca,
struct pwm_device *pwm)
{
return false;
}
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_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct pca9685 *pca = to_pca(chip);
unsigned long long duty;
unsigned int reg;
int prescale;
if (period_ns != pca->period_ns) {
prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
PCA9685_COUNTER_RANGE * 1000) - 1;
if (prescale >= PCA9685_PRESCALE_MIN &&
prescale <= PCA9685_PRESCALE_MAX) {
/*
* 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->
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