Add a simple driver which allows use of buttons attached to GPIOs.
Signed-off-by: Philippe Reynes <philippe.rey...@softathome.com>
---
drivers/button/Kconfig | 10 ++++
drivers/button/Makefile | 1 +
drivers/button/button-gpio.c | 111 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 122 insertions(+)
create mode 100644 drivers/button/button-gpio.c
diff --git a/drivers/button/Kconfig b/drivers/button/Kconfig
index 8301858..7de1a97 100644
--- a/drivers/button/Kconfig
+++ b/drivers/button/Kconfig
@@ -9,4 +9,14 @@ 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
+ default n
+ 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.rey...@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..6ad0094
--- /dev/null
+++ b/drivers/button/button-gpio.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Philippe Reynes <philippe.rey...@softathome.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/lists.h>
+#include <dm/uclass-internal.h>
+#include <log.h>
+#include <asm/gpio.h>
+#include <button.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,
+};
--
2.7.4
