summaryrefslogtreecommitdiffstats
path: root/drivers/reset/reset-gpio.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/reset/reset-gpio.c')
-rw-r--r--drivers/reset/reset-gpio.c119
1 files changed, 119 insertions, 0 deletions
diff --git a/drivers/reset/reset-gpio.c b/drivers/reset/reset-gpio.c
new file mode 100644
index 0000000000..2290b25b67
--- /dev/null
+++ b/drivers/reset/reset-gpio.c
@@ -0,0 +1,119 @@
+// 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 int reset_gpio_of_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ return reset_spec->args[0];
+}
+
+static void reset_gpio_of_node_put(void *data)
+{
+ of_node_put(data);
+}
+
+static int reset_gpio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct of_phandle_args *platdata = dev_get_platdata(dev);
+ struct reset_gpio_priv *priv;
+ int ret;
+
+ if (!platdata)
+ return -EINVAL;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, &priv->rc);
+
+ 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");
+
+ priv->rc.ops = &reset_gpio_ops;
+ priv->rc.owner = THIS_MODULE;
+ priv->rc.dev = dev;
+ priv->rc.of_args = platdata;
+ ret = devm_add_action_or_reset(dev, reset_gpio_of_node_put,
+ priv->rc.of_node);
+ if (ret)
+ return ret;
+
+ /* Cells to match GPIO specifier, but it's not really used */
+ priv->rc.of_reset_n_cells = 2;
+ priv->rc.of_xlate = reset_gpio_of_xlate;
+ priv->rc.nr_resets = 1;
+
+ 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");