Some reset lines are implemented by toggling the line via a GPIO.
Add a driver to properly drive such reset lines.
Signed-off-by: Mario Six <mario....@gdsys.cc>
---
drivers/reset/Kconfig | 7 ++++
drivers/reset/Makefile | 1 +
drivers/reset/gpio-reset.c | 100 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 108 insertions(+)
create mode 100644 drivers/reset/gpio-reset.c
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 71a786bab5..b8416fa85a 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -83,4 +83,11 @@ config RESET_ROCKCHIP
though is that some reset signals, like I2C or MISC reset multiple
devices.
+config GPIO_RESET
+ bool "Reset driver for GPIO-based reset lines"
+ depends on DM_RESET
+ help
+ Support a generic reset controller that encapsulates a number of
+ GPIOs of which each controls a single reset line.
+
endmenu
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 7d7e080c78..a5d766b183 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
obj-$(CONFIG_AST2500_RESET) += ast2500-reset.o
obj-$(CONFIG_RESET_ROCKCHIP) += reset-rockchip.o
+obj-$(CONFIG_GPIO_RESET) += gpio-reset.o
diff --git a/drivers/reset/gpio-reset.c b/drivers/reset/gpio-reset.c
new file mode 100644
index 0000000000..52dd47df60
--- /dev/null
+++ b/drivers/reset/gpio-reset.c
@@ -0,0 +1,100 @@
+/*
+ * (C) Copyright 2017
+ * Mario Six, Guntermann & Drunck GmbH, mario....@gdsys.cc
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <reset-uclass.h>
+#include <asm/gpio.h>
+
+struct gpio_reset_priv {
+ struct gpio_desc gpios[16];
+ uint gpio_num;
+};
+
+static int gpio_reset_request(struct reset_ctl *reset_ctl)
+{
+ struct gpio_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+
+ debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
+ reset_ctl->dev, reset_ctl->id);
+
+ /* Reset ID = number of GPIO in list */
+ if (reset_ctl->id >= priv->gpio_num)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int gpio_reset_free(struct reset_ctl *reset_ctl)
+{
+ debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
+ reset_ctl->dev, reset_ctl->id);
+
+ return 0;
+}
+
+static int gpio_reset_assert(struct reset_ctl *reset_ctl)
+{
+ struct gpio_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+
+ debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
+ reset_ctl->dev, reset_ctl->id);
+
+ dm_gpio_set_value(&priv->gpios[reset_ctl->id], 1);
+
+ return 0;
+}
+
+static int gpio_reset_deassert(struct reset_ctl *reset_ctl)
+{
+ struct gpio_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+
+ debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
+ reset_ctl->dev, reset_ctl->id);
+
+ dm_gpio_set_value(&priv->gpios[reset_ctl->id], 0);
+
+ return 0;
+}
+
+struct reset_ops gpio_reset_ops = {
+ .request = gpio_reset_request,
+ .free = gpio_reset_free,
+ .rst_assert = gpio_reset_assert,
+ .rst_deassert = gpio_reset_deassert,
+};
+
+static int gpio_reset_probe(struct udevice *dev)
+{
+ struct gpio_reset_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ debug("%s(dev=%p)\n", __func__, dev);
+
+ ret = gpio_request_list_by_name(dev, "gpios", priv->gpios,
+ ARRAY_SIZE(priv->gpios), GPIOD_IS_OUT);
+ if (ret <= 0)
+ return ret;
+
+ priv->gpio_num = ret;
+
+ return 0;
+}
+
+static const struct udevice_id gpio_reset[] = {
+ { .compatible = "gpio-reset", },
+ { /* sentinel */ }
+};
+
+U_BOOT_DRIVER(gpio_reset) = {
+ .name = "gpio_reset",
+ .id = UCLASS_RESET,
+ .of_match = gpio_reset,
+ .probe = gpio_reset_probe,
+ .ops = &gpio_reset_ops,
+ .priv_auto_alloc_size = sizeof(struct gpio_reset_priv),
+};
--
2.16.1
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