dm: button: add a driver for button driven by gpio

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>

diff --git a/drivers/button/Kconfig b/drivers/button/Kconfig
index 83018589e575c3847763af8aa289e3e54c22d8c6..6b3ec7e55de539fb349a7a2c4f30d3ae93a78176 100644 (file)
--- 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 0b4c128cffda16bc23d98cb41d2100e38ffb5f4f..fcc10ebe8db6fbaef83683241affa262713a2fb4 100644 (file)
--- 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 (file)
index 0000000..985ae7f
--- /dev/null
+++ b/drivers/button/button-gpio.c
@@ -0,0 +1,112 @@
+// 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 = "gpio-keys" },
+       { .compatible = "gpio-keys-polled" },
+       { }
+};
+
+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,
+};