1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/auxiliary_bus.h> 4 #include <linux/gpio/consumer.h> 5 #include <linux/module.h> 6 #include <linux/property.h> 7 #include <linux/reset-controller.h> 8 9 struct reset_gpio_priv { 10 struct reset_controller_dev rc; 11 struct gpio_desc *reset; 12 }; 13 14 static inline struct reset_gpio_priv 15 *rc_to_reset_gpio(struct reset_controller_dev *rc) 16 { 17 return container_of(rc, struct reset_gpio_priv, rc); 18 } 19 20 static int reset_gpio_assert(struct reset_controller_dev *rc, unsigned long id) 21 { 22 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc); 23 24 return gpiod_set_value_cansleep(priv->reset, 1); 25 } 26 27 static int reset_gpio_deassert(struct reset_controller_dev *rc, 28 unsigned long id) 29 { 30 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc); 31 32 return gpiod_set_value_cansleep(priv->reset, 0); 33 } 34 35 static int reset_gpio_status(struct reset_controller_dev *rc, unsigned long id) 36 { 37 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc); 38 39 return gpiod_get_value_cansleep(priv->reset); 40 } 41 42 static const struct reset_control_ops reset_gpio_ops = { 43 .assert = reset_gpio_assert, 44 .deassert = reset_gpio_deassert, 45 .status = reset_gpio_status, 46 }; 47 48 static int reset_gpio_fwnode_xlate(struct reset_controller_dev *rcdev, 49 const struct fwnode_reference_args *reset_spec) 50 { 51 return reset_spec->args[0]; 52 } 53 54 static int reset_gpio_probe(struct auxiliary_device *adev, 55 const struct auxiliary_device_id *id) 56 { 57 struct device *dev = &adev->dev; 58 struct reset_gpio_priv *priv; 59 60 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 61 if (!priv) 62 return -ENOMEM; 63 64 priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); 65 if (IS_ERR(priv->reset)) 66 return dev_err_probe(dev, PTR_ERR(priv->reset), 67 "Could not get reset gpios\n"); 68 69 priv->rc.ops = &reset_gpio_ops; 70 priv->rc.owner = THIS_MODULE; 71 priv->rc.dev = dev; 72 73 /* Cells to match GPIO specifier, but it's not really used */ 74 priv->rc.fwnode_reset_n_cells = 2; 75 priv->rc.fwnode_xlate = reset_gpio_fwnode_xlate; 76 priv->rc.nr_resets = 1; 77 78 return devm_reset_controller_register(dev, &priv->rc); 79 } 80 81 static const struct auxiliary_device_id reset_gpio_ids[] = { 82 { .name = "reset.gpio" }, 83 {} 84 }; 85 MODULE_DEVICE_TABLE(auxiliary, reset_gpio_ids); 86 87 static struct auxiliary_driver reset_gpio_driver = { 88 .probe = reset_gpio_probe, 89 .id_table = reset_gpio_ids, 90 .driver = { 91 .name = "reset-gpio", 92 .suppress_bind_attrs = true, 93 }, 94 }; 95 module_auxiliary_driver(reset_gpio_driver); 96 97 MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>"); 98 MODULE_DESCRIPTION("Generic GPIO reset driver"); 99 MODULE_LICENSE("GPL"); 100