diff options
Diffstat (limited to 'drivers/gpio/gpio-aggregator.c')
| -rw-r--r-- | drivers/gpio/gpio-aggregator.c | 110 |
1 files changed, 104 insertions, 6 deletions
diff --git a/drivers/gpio/gpio-aggregator.c b/drivers/gpio/gpio-aggregator.c index 20a686f12df7..38e0fff9afe7 100644 --- a/drivers/gpio/gpio-aggregator.c +++ b/drivers/gpio/gpio-aggregator.c @@ -10,12 +10,15 @@ #include <linux/bitmap.h> #include <linux/bitops.h> #include <linux/ctype.h> +#include <linux/delay.h> #include <linux/idr.h> #include <linux/kernel.h> +#include <linux/mod_devicetable.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/overflow.h> #include <linux/platform_device.h> +#include <linux/property.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/string.h> @@ -239,6 +242,11 @@ static void __exit gpio_aggregator_remove_all(void) * GPIO Forwarder */ +struct gpiochip_fwd_timing { + u32 ramp_up_us; + u32 ramp_down_us; +}; + struct gpiochip_fwd { struct gpio_chip chip; struct gpio_desc **descs; @@ -246,6 +254,7 @@ struct gpiochip_fwd { struct mutex mlock; /* protects tmp[] if can_sleep */ spinlock_t slock; /* protects tmp[] if !can_sleep */ }; + struct gpiochip_fwd_timing *delay_timings; unsigned long tmp[]; /* values and descs for multiple ops */ }; @@ -330,6 +339,27 @@ static int gpio_fwd_get_multiple_locked(struct gpio_chip *chip, return error; } +static void gpio_fwd_delay(struct gpio_chip *chip, unsigned int offset, int value) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + const struct gpiochip_fwd_timing *delay_timings; + bool is_active_low = gpiod_is_active_low(fwd->descs[offset]); + u32 delay_us; + + delay_timings = &fwd->delay_timings[offset]; + if ((!is_active_low && value) || (is_active_low && !value)) + delay_us = delay_timings->ramp_up_us; + else + delay_us = delay_timings->ramp_down_us; + if (!delay_us) + return; + + if (chip->can_sleep) + fsleep(delay_us); + else + udelay(delay_us); +} + static void gpio_fwd_set(struct gpio_chip *chip, unsigned int offset, int value) { struct gpiochip_fwd *fwd = gpiochip_get_data(chip); @@ -338,6 +368,9 @@ static void gpio_fwd_set(struct gpio_chip *chip, unsigned int offset, int value) gpiod_set_value_cansleep(fwd->descs[offset], value); else gpiod_set_value(fwd->descs[offset], value); + + if (fwd->delay_timings) + gpio_fwd_delay(chip, offset, value); } static void gpio_fwd_set_multiple(struct gpiochip_fwd *fwd, unsigned long *mask, @@ -390,6 +423,59 @@ static int gpio_fwd_to_irq(struct gpio_chip *chip, unsigned int offset) return gpiod_to_irq(fwd->descs[offset]); } +/* + * The GPIO delay provides a way to configure platform specific delays + * for the GPIO ramp-up or ramp-down delays. This can serve the following + * purposes: + * - Open-drain output using an RC filter + */ +#define FWD_FEATURE_DELAY BIT(0) + +#ifdef CONFIG_OF_GPIO +static int gpiochip_fwd_delay_of_xlate(struct gpio_chip *chip, + const struct of_phandle_args *gpiospec, + u32 *flags) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + struct gpiochip_fwd_timing *timings; + u32 line; + + if (gpiospec->args_count != chip->of_gpio_n_cells) + return -EINVAL; + + line = gpiospec->args[0]; + if (line >= chip->ngpio) + return -EINVAL; + + timings = &fwd->delay_timings[line]; + timings->ramp_up_us = gpiospec->args[1]; + timings->ramp_down_us = gpiospec->args[2]; + + return line; +} + +static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *chip, + struct gpiochip_fwd *fwd) +{ + fwd->delay_timings = devm_kcalloc(dev, chip->ngpio, + sizeof(*fwd->delay_timings), + GFP_KERNEL); + if (!fwd->delay_timings) + return -ENOMEM; + + chip->of_xlate = gpiochip_fwd_delay_of_xlate; + chip->of_gpio_n_cells = 3; + + return 0; +} +#else +static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *chip, + struct gpiochip_fwd *fwd) +{ + return 0; +} +#endif /* !CONFIG_OF_GPIO */ + /** * gpiochip_fwd_create() - Create a new GPIO forwarder * @dev: Parent device pointer @@ -397,6 +483,7 @@ static int gpio_fwd_to_irq(struct gpio_chip *chip, unsigned int offset) * @descs: Array containing the GPIO descriptors to forward to. * This array must contain @ngpios entries, and must not be deallocated * before the forwarder has been destroyed again. + * @features: Bitwise ORed features as defined with FWD_FEATURE_*. * * This function creates a new gpiochip, which forwards all GPIO operations to * the passed GPIO descriptors. @@ -406,7 +493,8 @@ static int gpio_fwd_to_irq(struct gpio_chip *chip, unsigned int offset) */ static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev, unsigned int ngpios, - struct gpio_desc *descs[]) + struct gpio_desc *descs[], + unsigned long features) { const char *label = dev_name(dev); struct gpiochip_fwd *fwd; @@ -459,6 +547,12 @@ static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev, else spin_lock_init(&fwd->slock); + if (features & FWD_FEATURE_DELAY) { + error = gpiochip_fwd_setup_delay_line(dev, chip, fwd); + if (error) + return ERR_PTR(error); + } + error = devm_gpiochip_add_data(dev, chip, fwd); if (error) return ERR_PTR(error); @@ -476,6 +570,7 @@ static int gpio_aggregator_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct gpio_desc **descs; struct gpiochip_fwd *fwd; + unsigned long features; int i, n; n = gpiod_count(dev, NULL); @@ -492,7 +587,8 @@ static int gpio_aggregator_probe(struct platform_device *pdev) return PTR_ERR(descs[i]); } - fwd = gpiochip_fwd_create(dev, n, descs); + features = (uintptr_t)device_get_match_data(dev); + fwd = gpiochip_fwd_create(dev, n, descs, features); if (IS_ERR(fwd)) return PTR_ERR(fwd); @@ -500,23 +596,25 @@ static int gpio_aggregator_probe(struct platform_device *pdev) return 0; } -#ifdef CONFIG_OF static const struct of_device_id gpio_aggregator_dt_ids[] = { + { + .compatible = "gpio-delay", + .data = (void *)FWD_FEATURE_DELAY, + }, /* * Add GPIO-operated devices controlled from userspace below, - * or use "driver_override" in sysfs + * or use "driver_override" in sysfs. */ {} }; MODULE_DEVICE_TABLE(of, gpio_aggregator_dt_ids); -#endif static struct platform_driver gpio_aggregator_driver = { .probe = gpio_aggregator_probe, .driver = { .name = DRV_NAME, .groups = gpio_aggregator_groups, - .of_match_table = of_match_ptr(gpio_aggregator_dt_ids), + .of_match_table = gpio_aggregator_dt_ids, }, }; |