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| 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 <[email protected]>"); |
| 118 | +MODULE_DESCRIPTION("Generic GPIO reset driver"); |
| 119 | +MODULE_LICENSE("GPL"); |
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