1 // SPDX-License-Identifier: GPL-2.0 2 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 10 struct reset_gpio_priv { 11 struct reset_controller_dev rc; 12 struct gpio_desc *reset; 13 }; 14 15 static inline struct reset_gpio_priv 16 *rc_to_reset_gpio(struct reset_controller_dev *rc) 17 { 18 return container_of(rc, struct reset_gpio_priv, rc); 19 } 20 21 static 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 30 static 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 40 static 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 47 static 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 53 static 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 59 static void reset_gpio_of_node_put(void *data) 60 { 61 of_node_put(data); 62 } 63 64 static 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 } 101 102 static const struct platform_device_id reset_gpio_ids[] = { 103 { .name = "reset-gpio", }, 104 {} 105 }; 106 MODULE_DEVICE_TABLE(platform, reset_gpio_ids); 107 108 static 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 }; 115 module_platform_driver(reset_gpio_driver); 116 117 MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>"); 118 MODULE_DESCRIPTION("Generic GPIO reset driver"); 119 MODULE_LICENSE("GPL"); 120