diff options
Diffstat (limited to 'drivers/pwm/pwm-pca9685.c')
| -rw-r--r-- | drivers/pwm/pwm-pca9685.c | 176 |
1 files changed, 163 insertions, 13 deletions
diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c index 117fccf7934a..0cfb3571a732 100644 --- a/drivers/pwm/pwm-pca9685.c +++ b/drivers/pwm/pwm-pca9685.c @@ -20,8 +20,10 @@ */ #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> @@ -65,7 +67,6 @@ #define PCA9685_MAXCHAN 0x10 #define LED_FULL (1 << 4) -#define MODE1_RESTART (1 << 7) #define MODE1_SLEEP (1 << 4) #define MODE2_INVRT (1 << 4) #define MODE2_OUTDRV (1 << 2) @@ -81,6 +82,10 @@ struct pca9685 { int active_cnt; 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) @@ -88,6 +93,151 @@ 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); + return 0; +} + +static void pca9685_pwm_gpio_free(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]; + pwm_set_chip_data(pwm, NULL); + mutex_unlock(&pca->lock); +} + +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 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 int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { @@ -117,16 +267,6 @@ static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, udelay(500); pca->period_ns = period_ns; - - /* - * If the duty cycle did not change, restart PWM with - * the same duty cycle to period ratio and return. - */ - if (duty_ns == pca->duty_ns) { - regmap_update_bits(pca->regmap, PCA9685_MODE1, - MODE1_RESTART, 0x1); - return 0; - } } else { dev_err(chip->dev, "prescaler not set: period out of bounds!\n"); @@ -264,6 +404,9 @@ static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) { struct pca9685 *pca = to_pca(chip); + if (pca9685_pwm_is_gpio(pca, pwm)) + return -EBUSY; + if (pca->active_cnt++ == 0) return regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP, 0x0); @@ -343,9 +486,16 @@ static int pca9685_pwm_probe(struct i2c_client *client, pca->chip.dev = &client->dev; pca->chip.base = -1; - pca->chip.can_sleep = true; - return pwmchip_add(&pca->chip); + 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; } static int pca9685_pwm_remove(struct i2c_client *client) |