1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/auxiliary_bus.h> 4 #include <linux/gpio/consumer.h> 5 #include <linux/mod_devicetable.h> 6 #include <linux/module.h> 7 #include <linux/of.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 return gpiod_set_value_cansleep(priv->reset, 1); 26 } 27 28 static int reset_gpio_deassert(struct reset_controller_dev *rc, 29 unsigned long id) 30 { 31 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc); 32 33 return gpiod_set_value_cansleep(priv->reset, 0); 34 } 35 36 static int reset_gpio_status(struct reset_controller_dev *rc, unsigned long id) 37 { 38 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc); 39 40 return gpiod_get_value_cansleep(priv->reset); 41 } 42 43 static const struct reset_control_ops reset_gpio_ops = { 44 .assert = reset_gpio_assert, 45 .deassert = reset_gpio_deassert, 46 .status = reset_gpio_status, 47 }; 48 49 static int reset_gpio_of_xlate(struct reset_controller_dev *rcdev, 50 const struct of_phandle_args *reset_spec) 51 { 52 return reset_spec->args[0]; 53 } 54 55 static void reset_gpio_of_node_put(void *data) 56 { 57 of_node_put(data); 58 } 59 60 static int reset_gpio_probe(struct auxiliary_device *adev, 61 const struct auxiliary_device_id *id) 62 { 63 struct device *dev = &adev->dev; 64 struct of_phandle_args *platdata = dev_get_platdata(dev); 65 struct reset_gpio_priv *priv; 66 int ret; 67 68 if (!platdata) 69 return -EINVAL; 70 71 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 72 if (!priv) 73 return -ENOMEM; 74 75 auxiliary_set_drvdata(adev, &priv->rc); 76 77 priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); 78 if (IS_ERR(priv->reset)) 79 return dev_err_probe(dev, PTR_ERR(priv->reset), 80 "Could not get reset gpios\n"); 81 82 priv->rc.ops = &reset_gpio_ops; 83 priv->rc.owner = THIS_MODULE; 84 priv->rc.dev = dev; 85 priv->rc.of_args = platdata; 86 ret = devm_add_action_or_reset(dev, reset_gpio_of_node_put, 87 priv->rc.of_node); 88 if (ret) 89 return ret; 90 91 /* Cells to match GPIO specifier, but it's not really used */ 92 priv->rc.of_reset_n_cells = 2; 93 priv->rc.of_xlate = reset_gpio_of_xlate; 94 priv->rc.nr_resets = 1; 95 96 return devm_reset_controller_register(dev, &priv->rc); 97 } 98 99 static const struct auxiliary_device_id reset_gpio_ids[] = { 100 { .name = "reset.gpio" }, 101 {} 102 }; 103 MODULE_DEVICE_TABLE(auxiliary, reset_gpio_ids); 104 105 static struct auxiliary_driver reset_gpio_driver = { 106 .probe = reset_gpio_probe, 107 .id_table = reset_gpio_ids, 108 .driver = { 109 .name = "reset-gpio", 110 .suppress_bind_attrs = true, 111 }, 112 }; 113 module_auxiliary_driver(reset_gpio_driver); 114 115 MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>"); 116 MODULE_DESCRIPTION("Generic GPIO reset driver"); 117 MODULE_LICENSE("GPL"); 118