1 // SPDX-License-Identifier: GPL-2.0-only
3  * Texas Instrument's System Control Interface (TI-SCI) reset driver
5  * Copyright (C) 2015-2017 Texas Instruments Incorporated - https://www.ti.com/
14 #include <linux/reset-controller.h>
18  * struct ti_sci_reset_control - reset control structure
19  * @dev_id: SoC-specific device identifier
21  * @lock: synchronize reset_mask read-modify-writes
30  * struct ti_sci_reset_data - reset controller information structure
32  * @dev: reset controller device pointer
33  * @sci: TI SCI handle used for communication with system controller
38 	struct device *dev;  member
39 	const struct ti_sci_handle *sci;  member
47  * ti_sci_reset_set() - program a device's reset
49  * @id: ID of the reset to toggle
53  * reset using the TI SCI protocol. The device's reset is asserted if the
55  * The mechanism itself is a read-modify-write procedure, the current device
56  * reset register is read using a TI SCI device operation, the new value is
57  * set or un-set using the reset's mask, and the new reset value written by
58  * using another TI SCI device operation.
63 			    unsigned long id, bool assert)  in ti_sci_reset_set()  argument
66 	const struct ti_sci_handle *sci = data->sci;  in ti_sci_reset_set()  local
67 	const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops;  in ti_sci_reset_set()
72 	control = idr_find(&data->idr, id);  in ti_sci_reset_set()
74 		return -EINVAL;  in ti_sci_reset_set()
76 	mutex_lock(&control->lock);  in ti_sci_reset_set()
78 	ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state);  in ti_sci_reset_set()
83 		reset_state |= control->reset_mask;  in ti_sci_reset_set()
85 		reset_state &= ~control->reset_mask;  in ti_sci_reset_set()
87 	ret = dev_ops->set_device_resets(sci, control->dev_id, reset_state);  in ti_sci_reset_set()
89 	mutex_unlock(&control->lock);  in ti_sci_reset_set()
95  * ti_sci_reset_assert() - assert device reset
97  * @id: ID of the reset to be asserted
100  * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
107 			       unsigned long id)  in ti_sci_reset_assert()  argument
109 	return ti_sci_reset_set(rcdev, id, true);  in ti_sci_reset_assert()
113  * ti_sci_reset_deassert() - deassert device reset
115  * @id: ID of the reset to be deasserted
118  * using the TI SCI protocol. This invokes the function ti_sci_reset_set()
125 				 unsigned long id)  in ti_sci_reset_deassert()  argument
127 	return ti_sci_reset_set(rcdev, id, false);  in ti_sci_reset_deassert()
131  * ti_sci_reset_status() - check device reset status
133  * @id: ID of reset to be checked
136  * device's reset using the TI SCI protocol. The reset register value is read
137  * by invoking the TI SCI device operation .get_device_resets(), and the
141  * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
144 			       unsigned long id)  in ti_sci_reset_status()  argument
147 	const struct ti_sci_handle *sci = data->sci;  in ti_sci_reset_status()  local
148 	const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops;  in ti_sci_reset_status()
153 	control = idr_find(&data->idr, id);  in ti_sci_reset_status()
155 		return -EINVAL;  in ti_sci_reset_status()
157 	ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state);  in ti_sci_reset_status()
161 	return reset_state & control->reset_mask;  in ti_sci_reset_status()
171  * ti_sci_reset_of_xlate() - translate a set of OF arguments to a reset ID
190 	if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))  in ti_sci_reset_of_xlate()
191 		return -EINVAL;  in ti_sci_reset_of_xlate()
193 	control = devm_kzalloc(data->dev, sizeof(*control), GFP_KERNEL);  in ti_sci_reset_of_xlate()
195 		return -ENOMEM;  in ti_sci_reset_of_xlate()
197 	control->dev_id = reset_spec->args[0];  in ti_sci_reset_of_xlate()
198 	control->reset_mask = reset_spec->args[1];  in ti_sci_reset_of_xlate()
199 	mutex_init(&control->lock);  in ti_sci_reset_of_xlate()
201 	return idr_alloc(&data->idr, control, 0, 0, GFP_KERNEL);  in ti_sci_reset_of_xlate()
205 	{ .compatible = "ti,sci-reset", },
214 	if (!pdev->dev.of_node)  in ti_sci_reset_probe()
215 		return -ENODEV;  in ti_sci_reset_probe()
217 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);  in ti_sci_reset_probe()
219 		return -ENOMEM;  in ti_sci_reset_probe()
221 	data->sci = devm_ti_sci_get_handle(&pdev->dev);  in ti_sci_reset_probe()
222 	if (IS_ERR(data->sci))  in ti_sci_reset_probe()
223 		return PTR_ERR(data->sci);  in ti_sci_reset_probe()
225 	data->rcdev.ops = &ti_sci_reset_ops;  in ti_sci_reset_probe()
226 	data->rcdev.owner = THIS_MODULE;  in ti_sci_reset_probe()
227 	data->rcdev.of_node = pdev->dev.of_node;  in ti_sci_reset_probe()
228 	data->rcdev.of_reset_n_cells = 2;  in ti_sci_reset_probe()
229 	data->rcdev.of_xlate = ti_sci_reset_of_xlate;  in ti_sci_reset_probe()
230 	data->dev = &pdev->dev;  in ti_sci_reset_probe()
231 	idr_init(&data->idr);  in ti_sci_reset_probe()
235 	return reset_controller_register(&data->rcdev);  in ti_sci_reset_probe()
242 	reset_controller_unregister(&data->rcdev);  in ti_sci_reset_remove()
244 	idr_destroy(&data->idr);  in ti_sci_reset_remove()
253 		.name = "ti-sci-reset",
260 MODULE_DESCRIPTION("TI System Control Interface (TI SCI) Reset driver");