diff options
| -rw-r--r-- | drivers/pwm/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/pwm/core.c | 72 | ||||
| -rw-r--r-- | include/linux/pwm.h | 3 |
3 files changed, 84 insertions, 0 deletions
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index f00ce973dddf..2aa24608a8df 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -38,6 +38,15 @@ config PWM_DEBUG It is expected to introduce some runtime overhead and diagnostic output to the kernel log, so only enable while working on a driver. +config PWM_PROVIDE_GPIO + bool "Provide a GPIO chip for each PWM chip" + depends on GPIOLIB + help + Most PWMs can emit both a constant active high and a constant active + low signal and so they can be used as GPIO. Say Y here to let each + PWM chip provide a GPIO chip and so be easily plugged into consumers + that know how to handle GPIOs but not PWMs. + config PWM_AB8500 tristate "AB8500 PWM support" depends on AB8500_CORE && ARCH_U8500 diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 2570ad6a7f59..ea2ccf42e814 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -2391,6 +2391,51 @@ static const struct file_operations pwm_cdev_fileops = { static dev_t pwm_devt; +static int pwm_gpio_request(struct gpio_chip *gc, unsigned int offset) +{ + struct pwm_chip *chip = gpiochip_get_data(gc); + struct pwm_device *pwm; + + pwm = pwm_request_from_chip(chip, offset, "pwm-gpio"); + if (IS_ERR(pwm)) + return PTR_ERR(pwm); + + return 0; +} + +static void pwm_gpio_free(struct gpio_chip *gc, unsigned int offset) +{ + struct pwm_chip *chip = gpiochip_get_data(gc); + + pwm_put(&chip->pwms[offset]); +} + +static int pwm_gpio_get_direction(struct gpio_chip *gc, unsigned int offset) +{ + return GPIO_LINE_DIRECTION_OUT; +} + +static int pwm_gpio_set(struct gpio_chip *gc, unsigned int offset, int value) +{ + struct pwm_chip *chip = gpiochip_get_data(gc); + struct pwm_device *pwm = &chip->pwms[offset]; + int ret; + struct pwm_waveform wf = { + .period_length_ns = 1, + }; + + ret = pwm_round_waveform_might_sleep(pwm, &wf); + if (ret < 0) + return ret; + + if (value) + wf.duty_length_ns = wf.period_length_ns; + else + wf.duty_length_ns = 0; + + return pwm_set_waveform_might_sleep(pwm, &wf, true); +} + /** * __pwmchip_add() - register a new PWM chip * @chip: the PWM chip to add @@ -2457,9 +2502,33 @@ int __pwmchip_add(struct pwm_chip *chip, struct module *owner) if (ret) goto err_device_add; + if (IS_ENABLED(CONFIG_PWM_PROVIDE_GPIO) && chip->ops->write_waveform) { + struct device *parent = pwmchip_parent(chip); + + chip->gpio = (typeof(chip->gpio)){ + .label = dev_name(parent), + .parent = parent, + .request = pwm_gpio_request, + .free = pwm_gpio_free, + .get_direction = pwm_gpio_get_direction, + .set = pwm_gpio_set, + .base = -1, + .ngpio = chip->npwm, + .can_sleep = true, + }; + + ret = gpiochip_add_data(&chip->gpio, chip); + if (ret) + goto err_gpiochip_add; + } + return 0; +err_gpiochip_add: + + cdev_device_del(&chip->cdev, &chip->dev); err_device_add: + scoped_guard(pwmchip, chip) chip->operational = false; @@ -2480,6 +2549,9 @@ EXPORT_SYMBOL_GPL(__pwmchip_add); */ void pwmchip_remove(struct pwm_chip *chip) { + if (IS_ENABLED(CONFIG_PWM_PROVIDE_GPIO) && chip->ops->write_waveform) + gpiochip_remove(&chip->gpio); + pwmchip_sysfs_unexport(chip); scoped_guard(mutex, &pwm_lock) { diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 8cafc483db53..549ac4aaad59 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -5,6 +5,7 @@ #include <linux/cdev.h> #include <linux/device.h> #include <linux/err.h> +#include <linux/gpio/driver.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> @@ -321,6 +322,7 @@ struct pwm_ops { * @npwm: number of PWMs controlled by this chip * @of_xlate: request a PWM device given a device tree PWM specifier * @atomic: can the driver's ->apply() be called in atomic context + * @gpio: &struct gpio_chip to operate this PWM chip's lines as GPO * @uses_pwmchip_alloc: signals if pwmchip_allow was used to allocate this chip * @operational: signals if the chip can be used (or is already deregistered) * @nonatomic_lock: mutex for nonatomic chips @@ -340,6 +342,7 @@ struct pwm_chip { bool atomic; /* only used internally by the PWM framework */ + struct gpio_chip gpio; bool uses_pwmchip_alloc; bool operational; union { |