2  * Texas Instrument's System Control Interface (TI-SCI) reset driver
4  * Copyright (C) 2015-2017 Texas Instruments Incorporated - https://www.ti.com/
22 #include <linux/reset-controller.h>
26  * struct ti_sci_reset_control - reset control structure
27  * @dev_id: SoC-specific device identifier
28  * @reset_mask: reset mask to use for toggling reset
29  * @lock: synchronize reset_mask read-modify-writes
38  * struct ti_sci_reset_data - reset controller information structure
39  * @rcdev: reset controller entity
40  * @dev: reset controller device pointer
41  * @sci: TI SCI handle used for communication with system controller
42  * @idr: idr structure for mapping ids to reset control structures
55  * ti_sci_reset_set() - program a device's reset
56  * @rcdev: reset controller entity
57  * @id: ID of the reset to toggle
61  * reset using the TI SCI protocol. The device's reset is asserted if the
63  * The mechanism itself is a read-modify-write procedure, the current device
64  * reset register is read using a TI SCI device operation, the new value is
65  * set or un-set using the reset's mask, and the new reset value written by
74 	const struct ti_sci_handle *sci = data->sci;  in ti_sci_reset_set()
75 	const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops;  in ti_sci_reset_set()
80 	control = idr_find(&data->idr, id);  in ti_sci_reset_set()
82 		return -EINVAL;  in ti_sci_reset_set()
84 	mutex_lock(&control->lock);  in ti_sci_reset_set()
86 	ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state);  in ti_sci_reset_set()
91 		reset_state |= control->reset_mask;  in ti_sci_reset_set()
93 		reset_state &= ~control->reset_mask;  in ti_sci_reset_set()
95 	ret = dev_ops->set_device_resets(sci, control->dev_id, reset_state);  in ti_sci_reset_set()
97 	mutex_unlock(&control->lock);  in ti_sci_reset_set()
103  * ti_sci_reset_assert() - assert device reset
104  * @rcdev: reset controller entity
105  * @id: ID of the reset to be asserted
107  * This function implements the reset driver op to assert a device's reset
110  * argument set to true for asserting the reset.
121  * ti_sci_reset_deassert() - deassert device reset
122  * @rcdev: reset controller entity
123  * @id: ID of the reset to be deasserted
125  * This function implements the reset driver op to deassert a device's reset
128  * argument set to false for deasserting the reset.
139  * ti_sci_reset_status() - check device reset status
140  * @rcdev: reset controller entity
141  * @id: ID of reset to be checked
143  * This function implements the reset driver op to return the status of a
144  * device's reset using the TI SCI protocol. The reset register value is read
146  * status of the specific reset is extracted and returned using this reset's
147  * reset mask.
149  * Return: 0 if reset is deasserted, or a non-zero value if reset is asserted
155 	const struct ti_sci_handle *sci = data->sci;  in ti_sci_reset_status()
156 	const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops;  in ti_sci_reset_status()
161 	control = idr_find(&data->idr, id);  in ti_sci_reset_status()
163 		return -EINVAL;  in ti_sci_reset_status()
165 	ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state);  in ti_sci_reset_status()
169 	return reset_state & control->reset_mask;  in ti_sci_reset_status()
179  * ti_sci_reset_of_xlate() - translate a set of OF arguments to a reset ID
180  * @rcdev: reset controller entity
181  * @reset_spec: OF reset argument specifier
183  * This function performs the translation of the reset argument specifier
184  * values defined in a reset consumer device node. The function allocates a
185  * reset control structure for that device reset, and will be used by the
186  * driver for performing any reset functions on that reset. An idr structure
187  * is allocated and used to map to the reset control structure. This idr
188  * is used by the driver to do reset lookups.
198 	if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))  in ti_sci_reset_of_xlate()
199 		return -EINVAL;  in ti_sci_reset_of_xlate()
201 	control = devm_kzalloc(data->dev, sizeof(*control), GFP_KERNEL);  in ti_sci_reset_of_xlate()
203 		return -ENOMEM;  in ti_sci_reset_of_xlate()
205 	control->dev_id = reset_spec->args[0];  in ti_sci_reset_of_xlate()
206 	control->reset_mask = reset_spec->args[1];  in ti_sci_reset_of_xlate()
207 	mutex_init(&control->lock);  in ti_sci_reset_of_xlate()
209 	return idr_alloc(&data->idr, control, 0, 0, GFP_KERNEL);  in ti_sci_reset_of_xlate()
213 	{ .compatible = "ti,sci-reset", },
222 	if (!pdev->dev.of_node)  in ti_sci_reset_probe()
223 		return -ENODEV;  in ti_sci_reset_probe()
225 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);  in ti_sci_reset_probe()
227 		return -ENOMEM;  in ti_sci_reset_probe()
229 	data->sci = devm_ti_sci_get_handle(&pdev->dev);  in ti_sci_reset_probe()
230 	if (IS_ERR(data->sci))  in ti_sci_reset_probe()
231 		return PTR_ERR(data->sci);  in ti_sci_reset_probe()
233 	data->rcdev.ops = &ti_sci_reset_ops;  in ti_sci_reset_probe()
234 	data->rcdev.owner = THIS_MODULE;  in ti_sci_reset_probe()
235 	data->rcdev.of_node = pdev->dev.of_node;  in ti_sci_reset_probe()
236 	data->rcdev.of_reset_n_cells = 2;  in ti_sci_reset_probe()
237 	data->rcdev.of_xlate = ti_sci_reset_of_xlate;  in ti_sci_reset_probe()
238 	data->dev = &pdev->dev;  in ti_sci_reset_probe()
239 	idr_init(&data->idr);  in ti_sci_reset_probe()
243 	return reset_controller_register(&data->rcdev);  in ti_sci_reset_probe()
250 	reset_controller_unregister(&data->rcdev);  in ti_sci_reset_remove()
252 	idr_destroy(&data->idr);  in ti_sci_reset_remove()
261 		.name = "ti-sci-reset",
268 MODULE_DESCRIPTION("TI System Control Interface (TI SCI) Reset driver");