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269 lines
8.1 KiB
269 lines
8.1 KiB
/* |
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* Texas Instrument's System Control Interface (TI-SCI) reset driver |
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* |
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* Copyright (C) 2015-2017 Texas Instruments Incorporated - https://www.ti.com/ |
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* Andrew F. Davis <[email protected]> |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License version 2 as |
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* published by the Free Software Foundation. |
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* |
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any |
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* kind, whether express or implied; without even the implied warranty |
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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*/ |
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#include <linux/idr.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/reset-controller.h> |
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#include <linux/soc/ti/ti_sci_protocol.h> |
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/** |
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* struct ti_sci_reset_control - reset control structure |
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* @dev_id: SoC-specific device identifier |
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* @reset_mask: reset mask to use for toggling reset |
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* @lock: synchronize reset_mask read-modify-writes |
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*/ |
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struct ti_sci_reset_control { |
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u32 dev_id; |
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u32 reset_mask; |
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struct mutex lock; |
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}; |
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/** |
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* struct ti_sci_reset_data - reset controller information structure |
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* @rcdev: reset controller entity |
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* @dev: reset controller device pointer |
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* @sci: TI SCI handle used for communication with system controller |
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* @idr: idr structure for mapping ids to reset control structures |
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*/ |
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struct ti_sci_reset_data { |
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struct reset_controller_dev rcdev; |
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struct device *dev; |
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const struct ti_sci_handle *sci; |
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struct idr idr; |
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}; |
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#define to_ti_sci_reset_data(p) \ |
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container_of((p), struct ti_sci_reset_data, rcdev) |
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/** |
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* ti_sci_reset_set() - program a device's reset |
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* @rcdev: reset controller entity |
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* @id: ID of the reset to toggle |
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* @assert: boolean flag to indicate assert or deassert |
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* |
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* This is a common internal function used to assert or deassert a device's |
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* reset using the TI SCI protocol. The device's reset is asserted if the |
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* @assert argument is true, or deasserted if @assert argument is false. |
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* The mechanism itself is a read-modify-write procedure, the current device |
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* reset register is read using a TI SCI device operation, the new value is |
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* set or un-set using the reset's mask, and the new reset value written by |
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* using another TI SCI device operation. |
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* |
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* Return: 0 for successful request, else a corresponding error value |
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*/ |
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static int ti_sci_reset_set(struct reset_controller_dev *rcdev, |
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unsigned long id, bool assert) |
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{ |
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struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev); |
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const struct ti_sci_handle *sci = data->sci; |
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const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops; |
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struct ti_sci_reset_control *control; |
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u32 reset_state; |
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int ret; |
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control = idr_find(&data->idr, id); |
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if (!control) |
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return -EINVAL; |
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mutex_lock(&control->lock); |
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ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state); |
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if (ret) |
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goto out; |
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if (assert) |
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reset_state |= control->reset_mask; |
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else |
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reset_state &= ~control->reset_mask; |
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ret = dev_ops->set_device_resets(sci, control->dev_id, reset_state); |
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out: |
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mutex_unlock(&control->lock); |
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return ret; |
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} |
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/** |
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* ti_sci_reset_assert() - assert device reset |
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* @rcdev: reset controller entity |
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* @id: ID of the reset to be asserted |
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* |
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* This function implements the reset driver op to assert a device's reset |
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* using the TI SCI protocol. This invokes the function ti_sci_reset_set() |
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* with the corresponding parameters as passed in, but with the @assert |
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* argument set to true for asserting the reset. |
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* |
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* Return: 0 for successful request, else a corresponding error value |
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*/ |
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static int ti_sci_reset_assert(struct reset_controller_dev *rcdev, |
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unsigned long id) |
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{ |
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return ti_sci_reset_set(rcdev, id, true); |
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} |
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/** |
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* ti_sci_reset_deassert() - deassert device reset |
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* @rcdev: reset controller entity |
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* @id: ID of the reset to be deasserted |
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* |
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* This function implements the reset driver op to deassert a device's reset |
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* using the TI SCI protocol. This invokes the function ti_sci_reset_set() |
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* with the corresponding parameters as passed in, but with the @assert |
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* argument set to false for deasserting the reset. |
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* |
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* Return: 0 for successful request, else a corresponding error value |
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*/ |
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static int ti_sci_reset_deassert(struct reset_controller_dev *rcdev, |
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unsigned long id) |
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{ |
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return ti_sci_reset_set(rcdev, id, false); |
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} |
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/** |
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* ti_sci_reset_status() - check device reset status |
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* @rcdev: reset controller entity |
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* @id: ID of reset to be checked |
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* |
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* This function implements the reset driver op to return the status of a |
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* device's reset using the TI SCI protocol. The reset register value is read |
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* by invoking the TI SCI device operation .get_device_resets(), and the |
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* status of the specific reset is extracted and returned using this reset's |
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* reset mask. |
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* |
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* Return: 0 if reset is deasserted, or a non-zero value if reset is asserted |
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*/ |
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static int ti_sci_reset_status(struct reset_controller_dev *rcdev, |
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unsigned long id) |
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{ |
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struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev); |
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const struct ti_sci_handle *sci = data->sci; |
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const struct ti_sci_dev_ops *dev_ops = &sci->ops.dev_ops; |
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struct ti_sci_reset_control *control; |
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u32 reset_state; |
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int ret; |
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control = idr_find(&data->idr, id); |
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if (!control) |
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return -EINVAL; |
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ret = dev_ops->get_device_resets(sci, control->dev_id, &reset_state); |
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if (ret) |
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return ret; |
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return reset_state & control->reset_mask; |
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} |
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static const struct reset_control_ops ti_sci_reset_ops = { |
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.assert = ti_sci_reset_assert, |
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.deassert = ti_sci_reset_deassert, |
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.status = ti_sci_reset_status, |
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}; |
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/** |
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* ti_sci_reset_of_xlate() - translate a set of OF arguments to a reset ID |
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* @rcdev: reset controller entity |
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* @reset_spec: OF reset argument specifier |
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* |
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* This function performs the translation of the reset argument specifier |
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* values defined in a reset consumer device node. The function allocates a |
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* reset control structure for that device reset, and will be used by the |
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* driver for performing any reset functions on that reset. An idr structure |
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* is allocated and used to map to the reset control structure. This idr |
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* is used by the driver to do reset lookups. |
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* |
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* Return: 0 for successful request, else a corresponding error value |
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*/ |
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static int ti_sci_reset_of_xlate(struct reset_controller_dev *rcdev, |
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const struct of_phandle_args *reset_spec) |
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{ |
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struct ti_sci_reset_data *data = to_ti_sci_reset_data(rcdev); |
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struct ti_sci_reset_control *control; |
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if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells)) |
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return -EINVAL; |
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control = devm_kzalloc(data->dev, sizeof(*control), GFP_KERNEL); |
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if (!control) |
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return -ENOMEM; |
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control->dev_id = reset_spec->args[0]; |
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control->reset_mask = reset_spec->args[1]; |
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mutex_init(&control->lock); |
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return idr_alloc(&data->idr, control, 0, 0, GFP_KERNEL); |
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} |
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static const struct of_device_id ti_sci_reset_of_match[] = { |
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{ .compatible = "ti,sci-reset", }, |
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{ /* sentinel */ }, |
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}; |
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MODULE_DEVICE_TABLE(of, ti_sci_reset_of_match); |
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static int ti_sci_reset_probe(struct platform_device *pdev) |
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{ |
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struct ti_sci_reset_data *data; |
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if (!pdev->dev.of_node) |
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return -ENODEV; |
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data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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data->sci = devm_ti_sci_get_handle(&pdev->dev); |
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if (IS_ERR(data->sci)) |
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return PTR_ERR(data->sci); |
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data->rcdev.ops = &ti_sci_reset_ops; |
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data->rcdev.owner = THIS_MODULE; |
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data->rcdev.of_node = pdev->dev.of_node; |
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data->rcdev.of_reset_n_cells = 2; |
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data->rcdev.of_xlate = ti_sci_reset_of_xlate; |
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data->dev = &pdev->dev; |
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idr_init(&data->idr); |
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platform_set_drvdata(pdev, data); |
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return reset_controller_register(&data->rcdev); |
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} |
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static int ti_sci_reset_remove(struct platform_device *pdev) |
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{ |
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struct ti_sci_reset_data *data = platform_get_drvdata(pdev); |
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reset_controller_unregister(&data->rcdev); |
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idr_destroy(&data->idr); |
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return 0; |
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} |
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static struct platform_driver ti_sci_reset_driver = { |
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.probe = ti_sci_reset_probe, |
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.remove = ti_sci_reset_remove, |
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.driver = { |
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.name = "ti-sci-reset", |
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.of_match_table = ti_sci_reset_of_match, |
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}, |
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}; |
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module_platform_driver(ti_sci_reset_driver); |
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MODULE_AUTHOR("Andrew F. Davis <[email protected]>"); |
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MODULE_DESCRIPTION("TI System Control Interface (TI SCI) Reset driver"); |
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MODULE_LICENSE("GPL v2");
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