sysreset: Add poweroff-gpio driver

Add GPIO poweroff driver, which is based on the Linux
driver and uses the same DT binding.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/sysreset/Kconfig

@@ -43,6 +43,13 @@ config SYSRESET_CMD_POWEROFF
 
 endif
 
+config POWEROFF_GPIO
+	bool "Enable support for GPIO poweroff driver"
+	select DM_GPIO
+	help
+	  Support for system poweroff using a GPIO pin. This can be used
+	  for systems having a single GPIO to trigger a system poweroff.
+
 config SYSRESET_GPIO
 	bool "Enable support for GPIO reset driver"
 	select DM_GPIO

drivers/sysreset/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_ARCH_ASPEED) += sysreset_ast.o
 obj-$(CONFIG_ARCH_ROCKCHIP) += sysreset_rockchip.o
 obj-$(CONFIG_ARCH_STI) += sysreset_sti.o
 obj-$(CONFIG_SANDBOX) += sysreset_sandbox.o
+obj-$(CONFIG_POWEROFF_GPIO) += poweroff_gpio.o
 obj-$(CONFIG_SYSRESET_GPIO) += sysreset_gpio.o
 obj-$(CONFIG_SYSRESET_MPC83XX) += sysreset_mpc83xx.o
 obj-$(CONFIG_SYSRESET_MICROBLAZE) += sysreset_microblaze.o

drivers/sysreset/poweroff_gpio.c

@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Toggles a GPIO pin to power down a device
+ *
+ * Created using the Linux driver as reference, which
+ * has been written by:
+ *
+ * Jamie Lentin <jm@lentin.co.uk>
+ * Andrew Lunn <andrew@lunn.ch>
+ *
+ * Copyright (C) 2012 Jamie Lentin
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <log.h>
+#include <sysreset.h>
+
+#include <asm/gpio.h>
+#include <linux/delay.h>
+
+struct poweroff_gpio_info {
+	struct gpio_desc gpio;
+	u32 active_delay_ms;
+	u32 inactive_delay_ms;
+	u32 timeout_ms;
+};
+
+static int poweroff_gpio_request(struct udevice *dev, enum sysreset_t type)
+{
+	struct poweroff_gpio_info *priv = dev_get_priv(dev);
+	int r;
+
+	if (type != SYSRESET_POWER_OFF)
+		return -ENOSYS;
+
+	debug("GPIO poweroff\n");
+
+	/* drive it active, also inactive->active edge */
+	r = dm_gpio_set_value(&priv->gpio, 1);
+	if (r < 0)
+		return r;
+	mdelay(priv->active_delay_ms);
+
+	/* drive inactive, also active->inactive edge */
+	r = dm_gpio_set_value(&priv->gpio, 0);
+	if (r < 0)
+		return r;
+	mdelay(priv->inactive_delay_ms);
+
+	/* drive it active, also inactive->active edge */
+	r = dm_gpio_set_value(&priv->gpio, 1);
+	if (r < 0)
+		return r;
+
+	/* give it some time */
+	mdelay(priv->timeout_ms);
+
+	return -EINPROGRESS;
+}
+
+static int poweroff_gpio_probe(struct udevice *dev)
+{
+	struct poweroff_gpio_info *priv = dev_get_priv(dev);
+	int flags;
+
+	flags = dev_read_bool(dev, "input") ? GPIOD_IS_IN : GPIOD_IS_OUT;
+	priv->active_delay_ms = dev_read_u32_default(dev, "active-delay-ms", 100);
+	priv->inactive_delay_ms = dev_read_u32_default(dev, "inactive-delay-ms", 100);
+	priv->timeout_ms = dev_read_u32_default(dev, "timeout-ms", 3000);
+
+	return gpio_request_by_name(dev, "gpios", 0, &priv->gpio, flags);
+}
+
+static struct sysreset_ops poweroff_gpio_ops = {
+	.request = poweroff_gpio_request,
+};
+
+static const struct udevice_id poweroff_gpio_ids[] = {
+	{ .compatible = "gpio-poweroff", },
+	{},
+};
+
+U_BOOT_DRIVER(poweroff_gpio) = {
+	.name		= "poweroff-gpio",
+	.id		= UCLASS_SYSRESET,
+	.ops		= &poweroff_gpio_ops,
+	.probe		= poweroff_gpio_probe,
+	.priv_auto_alloc_size = sizeof(struct poweroff_gpio_info),
+	.of_match	= poweroff_gpio_ids,
+};