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1// SPDX-License-Identifier: GPL-2.02 3#include <linux/gpio/consumer.h>4#include <linux/mod_devicetable.h>5#include <linux/module.h>6#include <linux/of.h>7#include <linux/platform_device.h>8#include <linux/reset-controller.h>9 10struct reset_gpio_priv {11 struct reset_controller_dev rc;12 struct gpio_desc *reset;13};14 15static inline struct reset_gpio_priv16*rc_to_reset_gpio(struct reset_controller_dev *rc)17{18 return container_of(rc, struct reset_gpio_priv, rc);19}20 21static int reset_gpio_assert(struct reset_controller_dev *rc, unsigned long id)22{23 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);24 25 gpiod_set_value_cansleep(priv->reset, 1);26 27 return 0;28}29 30static int reset_gpio_deassert(struct reset_controller_dev *rc,31 unsigned long id)32{33 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);34 35 gpiod_set_value_cansleep(priv->reset, 0);36 37 return 0;38}39 40static int reset_gpio_status(struct reset_controller_dev *rc, unsigned long id)41{42 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);43 44 return gpiod_get_value_cansleep(priv->reset);45}46 47static const struct reset_control_ops reset_gpio_ops = {48 .assert = reset_gpio_assert,49 .deassert = reset_gpio_deassert,50 .status = reset_gpio_status,51};52 53static int reset_gpio_of_xlate(struct reset_controller_dev *rcdev,54 const struct of_phandle_args *reset_spec)55{56 return reset_spec->args[0];57}58 59static void reset_gpio_of_node_put(void *data)60{61 of_node_put(data);62}63 64static int reset_gpio_probe(struct platform_device *pdev)65{66 struct device *dev = &pdev->dev;67 struct of_phandle_args *platdata = dev_get_platdata(dev);68 struct reset_gpio_priv *priv;69 int ret;70 71 if (!platdata)72 return -EINVAL;73 74 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);75 if (!priv)76 return -ENOMEM;77 78 platform_set_drvdata(pdev, &priv->rc);79 80 priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);81 if (IS_ERR(priv->reset))82 return dev_err_probe(dev, PTR_ERR(priv->reset),83 "Could not get reset gpios\n");84 85 priv->rc.ops = &reset_gpio_ops;86 priv->rc.owner = THIS_MODULE;87 priv->rc.dev = dev;88 priv->rc.of_args = platdata;89 ret = devm_add_action_or_reset(dev, reset_gpio_of_node_put,90 priv->rc.of_node);91 if (ret)92 return ret;93 94 /* Cells to match GPIO specifier, but it's not really used */95 priv->rc.of_reset_n_cells = 2;96 priv->rc.of_xlate = reset_gpio_of_xlate;97 priv->rc.nr_resets = 1;98 99 return devm_reset_controller_register(dev, &priv->rc);100}101 102static const struct platform_device_id reset_gpio_ids[] = {103 { .name = "reset-gpio", },104 {}105};106MODULE_DEVICE_TABLE(platform, reset_gpio_ids);107 108static struct platform_driver reset_gpio_driver = {109 .probe = reset_gpio_probe,110 .id_table = reset_gpio_ids,111 .driver = {112 .name = "reset-gpio",113 },114};115module_platform_driver(reset_gpio_driver);116 117MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>");118MODULE_DESCRIPTION("Generic GPIO reset driver");119MODULE_LICENSE("GPL");120