Add a simple driver which allows use of buttons attached to GPIOs.
Reviewed-by: Simon Glass sjg@chromium.org Signed-off-by: Philippe Reynes philippe.reynes@softathome.com --- Changelog: v2: - remove useless default in Kconfig - re-order include - fix condition in button_gpio_remove
drivers/button/Kconfig | 9 ++++ drivers/button/Makefile | 1 + drivers/button/button-gpio.c | 111 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 121 insertions(+) create mode 100644 drivers/button/button-gpio.c
diff --git a/drivers/button/Kconfig b/drivers/button/Kconfig index 8301858..6b3ec7e 100644 --- a/drivers/button/Kconfig +++ b/drivers/button/Kconfig @@ -9,4 +9,13 @@ config BUTTON can provide access to board-specific buttons. Use of the device tree for configuration is encouraged.
+config BUTTON_GPIO + bool "Button gpio" + depends on BUTTON + help + Enable support for buttons which are connected to GPIO lines. These + GPIOs may be on the SoC or some other device which provides GPIOs. + The GPIO driver must used driver model. Buttons are configured using + the device tree. + endmenu diff --git a/drivers/button/Makefile b/drivers/button/Makefile index 0b4c128..fcc10eb 100644 --- a/drivers/button/Makefile +++ b/drivers/button/Makefile @@ -3,3 +3,4 @@ # Copyright (C) 2020 Philippe Reynes philippe.reynes@softathome.com
obj-$(CONFIG_BUTTON) += button-uclass.o +obj-$(CONFIG_BUTTON_GPIO) += button-gpio.o diff --git a/drivers/button/button-gpio.c b/drivers/button/button-gpio.c new file mode 100644 index 0000000..4f71fce --- /dev/null +++ b/drivers/button/button-gpio.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020 Philippe Reynes philippe.reynes@softathome.com + */ + +#include <common.h> +#include <button.h> +#include <dm.h> +#include <dm/lists.h> +#include <dm/uclass-internal.h> +#include <log.h> +#include <asm/gpio.h> + +struct button_gpio_priv { + struct gpio_desc gpio; +}; + +static enum button_state_t button_gpio_get_state(struct udevice *dev) +{ + struct button_gpio_priv *priv = dev_get_priv(dev); + int ret; + + if (!dm_gpio_is_valid(&priv->gpio)) + return -EREMOTEIO; + ret = dm_gpio_get_value(&priv->gpio); + if (ret < 0) + return ret; + + return ret ? BUTTON_ON : BUTTON_OFF; +} + +static int button_gpio_probe(struct udevice *dev) +{ + struct button_uc_plat *uc_plat = dev_get_uclass_platdata(dev); + struct button_gpio_priv *priv = dev_get_priv(dev); + int ret; + + /* Ignore the top-level button node */ + if (!uc_plat->label) + return 0; + + ret = gpio_request_by_name(dev, "gpios", 0, &priv->gpio, GPIOD_IS_IN); + if (ret) + return ret; + + return 0; +} + +static int button_gpio_remove(struct udevice *dev) +{ + /* + * The GPIO driver may have already been removed. We will need to + * address this more generally. + */ + if (!IS_ENABLED(CONFIG_SANDBOX)) { + struct button_gpio_priv *priv = dev_get_priv(dev); + + if (dm_gpio_is_valid(&priv->gpio)) + dm_gpio_free(dev, &priv->gpio); + } + + return 0; +} + +static int button_gpio_bind(struct udevice *parent) +{ + struct udevice *dev; + ofnode node; + int ret; + + dev_for_each_subnode(node, parent) { + struct button_uc_plat *uc_plat; + const char *label; + + label = ofnode_read_string(node, "label"); + if (!label) { + debug("%s: node %s has no label\n", __func__, + ofnode_get_name(node)); + return -EINVAL; + } + ret = device_bind_driver_to_node(parent, "button_gpio", + ofnode_get_name(node), + node, &dev); + if (ret) + return ret; + uc_plat = dev_get_uclass_platdata(dev); + uc_plat->label = label; + } + + return 0; +} + +static const struct button_ops button_gpio_ops = { + .get_state = button_gpio_get_state, +}; + +static const struct udevice_id button_gpio_ids[] = { + { .compatible = "button-gpio" }, + { } +}; + +U_BOOT_DRIVER(button_gpio) = { + .name = "button_gpio", + .id = UCLASS_BUTTON, + .of_match = button_gpio_ids, + .ops = &button_gpio_ops, + .priv_auto_alloc_size = sizeof(struct button_gpio_priv), + .bind = button_gpio_bind, + .probe = button_gpio_probe, + .remove = button_gpio_remove, +};