@@ -8866,6 +8866,11 @@ F: Documentation/i2c/muxes/i2c-mux-gpio.rst
F: drivers/i2c/muxes/i2c-mux-gpio.c
F: include/linux/platform_data/i2c-mux-gpio.h
+GENERIC GPIO RESET DRIVER
+M: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
+S: Maintained
+F: drivers/reset/reset-gpio.c
+
GENERIC HDLC (WAN) DRIVERS
M: Krzysztof Halasa <khc@pm.waw.pl>
S: Maintained
@@ -66,6 +66,15 @@ config RESET_BRCMSTB_RESCAL
This enables the RESCAL reset controller for SATA, PCIe0, or PCIe1 on
BCM7216.
+config RESET_GPIO
+ tristate "GPIO reset controller"
+ help
+ This enables a generic reset controller for resets attached via
+ GPIOs. Typically for OF platforms this driver expects "reset-gpios"
+ property.
+
+ If compiled as module, it will be called reset-gpio.
+
config RESET_HSDK
bool "Synopsys HSDK Reset Driver"
depends on HAS_IOMEM
@@ -11,6 +11,7 @@ obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
obj-$(CONFIG_RESET_BRCMSTB) += reset-brcmstb.o
obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
+obj-$(CONFIG_RESET_GPIO) += reset-gpio.o
obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
obj-$(CONFIG_RESET_INTEL_GW) += reset-intel-gw.o
new file mode 100644
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/gpio/consumer.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+struct reset_gpio_priv {
+ struct reset_controller_dev rc;
+ struct gpio_desc *reset;
+};
+
+static inline struct reset_gpio_priv
+*rc_to_reset_gpio(struct reset_controller_dev *rc)
+{
+ return container_of(rc, struct reset_gpio_priv, rc);
+}
+
+static int reset_gpio_assert(struct reset_controller_dev *rc, unsigned long id)
+{
+ struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
+
+ gpiod_set_value_cansleep(priv->reset, 1);
+
+ return 0;
+}
+
+static int reset_gpio_deassert(struct reset_controller_dev *rc,
+ unsigned long id)
+{
+ struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
+
+ gpiod_set_value_cansleep(priv->reset, 0);
+
+ return 0;
+}
+
+static int reset_gpio_status(struct reset_controller_dev *rc, unsigned long id)
+{
+ struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
+
+ return gpiod_get_value_cansleep(priv->reset);
+}
+
+static const struct reset_control_ops reset_gpio_ops = {
+ .assert = reset_gpio_assert,
+ .deassert = reset_gpio_deassert,
+ .status = reset_gpio_status,
+};
+
+static void reset_gpio_of_args_put(void *data)
+{
+ of_node_put(data);
+}
+
+static int reset_gpio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node **platdata = dev_get_platdata(dev);
+ struct of_phandle_args gpio_args;
+ struct reset_gpio_priv *priv;
+ int ret;
+
+ if (!platdata || !*platdata)
+ return -EINVAL;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, &priv->rc);
+ device_set_node(dev, of_fwnode_handle(*platdata));
+
+ priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(priv->reset))
+ return dev_err_probe(dev, PTR_ERR(priv->reset),
+ "Could not get reset gpios\n");
+
+ ret = of_parse_phandle_with_args(*platdata, "reset-gpios",
+ "#gpio-cells", 0, &gpio_args);
+ if (ret)
+ return ret;
+
+ priv->rc.ops = &reset_gpio_ops;
+ priv->rc.owner = THIS_MODULE;
+ priv->rc.dev = dev;
+ priv->rc.nr_resets = 1;
+ priv->rc.of_node = gpio_args.np;
+ ret = devm_add_action_or_reset(dev, reset_gpio_of_args_put,
+ priv->rc.of_node);
+ if (ret)
+ return ret;
+
+ priv->rc.of_args = devm_kmemdup(dev, &gpio_args, sizeof(gpio_args),
+ GFP_KERNEL);
+ if (!priv->rc.of_args)
+ return -ENOMEM;
+
+ return devm_reset_controller_register(dev, &priv->rc);
+}
+
+static const struct platform_device_id reset_gpio_ids[] = {
+ { .name = "reset-gpio", },
+ {}
+};
+MODULE_DEVICE_TABLE(platform, reset_gpio_ids);
+
+static struct platform_driver reset_gpio_driver = {
+ .probe = reset_gpio_probe,
+ .id_table = reset_gpio_ids,
+ .driver = {
+ .name = "reset-gpio",
+ },
+};
+module_platform_driver(reset_gpio_driver);
+
+MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>");
+MODULE_DESCRIPTION("Generic GPIO reset driver");
+MODULE_LICENSE("GPL");
Add a simple driver to control GPIO-based resets using the reset controller API for the cases when the GPIOs are shared and reset should be coordinated. The driver is expected to be used by reset core framework for ad-hoc reset controllers. Cc: Bartosz Golaszewski <brgl@bgdev.pl> Cc: Sean Anderson <sean.anderson@seco.com> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> --- MAINTAINERS | 5 ++ drivers/reset/Kconfig | 9 +++ drivers/reset/Makefile | 1 + drivers/reset/reset-gpio.c | 121 +++++++++++++++++++++++++++++++++++++ 4 files changed, 136 insertions(+) create mode 100644 drivers/reset/reset-gpio.c