drivers/reset/reset-ti-syscon.c - third_party/kernel - Git at Google

 /*
  * TI SYSCON regmap reset driver
  *
  * Copyright (C) 2015-2016 Texas Instruments Incorporated - http://www.ti.com/
  *	Andrew F. Davis <afd@ti.com>
  *	Suman Anna <afd@ti.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  * kind, whether express or implied; without even the implied warranty
  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/reset-controller.h>

 #include <dt-bindings/reset/ti-syscon.h>

 /**
  * struct ti_syscon_reset_control - reset control structure
  * @assert_offset: reset assert control register offset from syscon base
  * @assert_bit: reset assert bit in the reset assert control register
  * @deassert_offset: reset deassert control register offset from syscon base
  * @deassert_bit: reset deassert bit in the reset deassert control register
  * @status_offset: reset status register offset from syscon base
  * @status_bit: reset status bit in the reset status register
  * @flags: reset flag indicating how the (de)assert and status are handled
  */
 struct ti_syscon_reset_control {
 	unsigned int assert_offset;
 	unsigned int assert_bit;
 	unsigned int deassert_offset;
 	unsigned int deassert_bit;
 	unsigned int status_offset;
 	unsigned int status_bit;
 	u32 flags;
 };

 /**
  * struct ti_syscon_reset_data - reset controller information structure
  * @rcdev: reset controller entity
  * @regmap: regmap handle containing the memory-mapped reset registers
  * @controls: array of reset controls
  * @nr_controls: number of controls in control array
  */
 struct ti_syscon_reset_data {
 	struct reset_controller_dev rcdev;
 	struct regmap *regmap;
 	struct ti_syscon_reset_control *controls;
 	unsigned int nr_controls;
 };

 #define to_ti_syscon_reset_data(rcdev)	\
 	container_of(rcdev, struct ti_syscon_reset_data, rcdev)

 /**
  * ti_syscon_reset_assert() - assert device reset
  * @rcdev: reset controller entity
  * @id: ID of the reset to be asserted
  *
  * This function implements the reset driver op to assert a device's reset.
  * This asserts the reset in a manner prescribed by the reset flags.
  *
  * Return: 0 for successful request, else a corresponding error value
  */
 static int ti_syscon_reset_assert(struct reset_controller_dev *rcdev,
 				  unsigned long id)
 {
 	struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
 	struct ti_syscon_reset_control *control;
 	unsigned int mask, value;

 	if (id >= data->nr_controls)
 		return -EINVAL;

 	control = &data->controls[id];

 	if (control->flags & ASSERT_NONE)
 		return -ENOTSUPP; /* assert not supported for this reset */

 	mask = BIT(control->assert_bit);
 	value = (control->flags & ASSERT_SET) ? mask : 0x0;

 	return regmap_update_bits(data->regmap, control->assert_offset, mask, value);
 }

 /**
  * ti_syscon_reset_deassert() - deassert device reset
  * @rcdev: reset controller entity
  * @id: ID of reset to be deasserted
  *
  * This function implements the reset driver op to deassert a device's reset.
  * This deasserts the reset in a manner prescribed by the reset flags.
  *
  * Return: 0 for successful request, else a corresponding error value
  */
 static int ti_syscon_reset_deassert(struct reset_controller_dev *rcdev,
 				    unsigned long id)
 {
 	struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
 	struct ti_syscon_reset_control *control;
 	unsigned int mask, value;

 	if (id >= data->nr_controls)
 		return -EINVAL;

 	control = &data->controls[id];

 	if (control->flags & DEASSERT_NONE)
 		return -ENOTSUPP; /* deassert not supported for this reset */

 	mask = BIT(control->deassert_bit);
 	value = (control->flags & DEASSERT_SET) ? mask : 0x0;

 	return regmap_update_bits(data->regmap, control->deassert_offset, mask, value);
 }

 /**
  * ti_syscon_reset_status() - check device reset status
  * @rcdev: reset controller entity
  * @id: ID of the reset for which the status is being requested
  *
  * This function implements the reset driver op to return the status of a
  * device's reset.
  *
  * Return: 0 if reset is deasserted, true if reset is asserted, else a
  * corresponding error value
  */
 static int ti_syscon_reset_status(struct reset_controller_dev *rcdev,
 				  unsigned long id)
 {
 	struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
 	struct ti_syscon_reset_control *control;
 	unsigned int reset_state;
 	int ret;

 	if (id >= data->nr_controls)
 		return -EINVAL;

 	control = &data->controls[id];

 	if (control->flags & STATUS_NONE)
 		return -ENOTSUPP; /* status not supported for this reset */

 	ret = regmap_read(data->regmap, control->status_offset, &reset_state);
 	if (ret)
 		return ret;

 	return !(reset_state & BIT(control->status_bit)) ==
 		!(control->flags & STATUS_SET);
 }

 static const struct reset_control_ops ti_syscon_reset_ops = {
 	.assert		= ti_syscon_reset_assert,
 	.deassert	= ti_syscon_reset_deassert,
 	.status		= ti_syscon_reset_status,
 };

 static int ti_syscon_reset_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	struct ti_syscon_reset_data *data;
 	struct regmap *regmap;
 	const __be32 *list;
 	struct ti_syscon_reset_control *controls;
 	int size, nr_controls, i;

 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	regmap = syscon_node_to_regmap(np->parent);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);

 	list = of_get_property(np, "ti,reset-bits", &size);
 	if (!list || (size / sizeof(*list)) % 7 != 0) {
 		dev_err(dev, "invalid DT reset description\n");
 		return -EINVAL;
 	}

 	nr_controls = (size / sizeof(*list)) / 7;
 	controls = devm_kcalloc(dev, nr_controls, sizeof(*controls),
 				GFP_KERNEL);
 	if (!controls)
 		return -ENOMEM;

 	for (i = 0; i < nr_controls; i++) {
 		controls[i].assert_offset = be32_to_cpup(list++);
 		controls[i].assert_bit = be32_to_cpup(list++);
 		controls[i].deassert_offset = be32_to_cpup(list++);
 		controls[i].deassert_bit = be32_to_cpup(list++);
 		controls[i].status_offset = be32_to_cpup(list++);
 		controls[i].status_bit = be32_to_cpup(list++);
 		controls[i].flags = be32_to_cpup(list++);
 	}

 	data->rcdev.ops = &ti_syscon_reset_ops;
 	data->rcdev.owner = THIS_MODULE;
 	data->rcdev.of_node = np;
 	data->rcdev.nr_resets = nr_controls;
 	data->regmap = regmap;
 	data->controls = controls;
 	data->nr_controls = nr_controls;

 	platform_set_drvdata(pdev, data);

 	return devm_reset_controller_register(dev, &data->rcdev);
 }

 static const struct of_device_id ti_syscon_reset_of_match[] = {
 	{ .compatible = "ti,syscon-reset", },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, ti_syscon_reset_of_match);

 static struct platform_driver ti_syscon_reset_driver = {
 	.probe = ti_syscon_reset_probe,
 	.driver = {
 		.name = "ti-syscon-reset",
 		.of_match_table = ti_syscon_reset_of_match,
 	},
 };
 module_platform_driver(ti_syscon_reset_driver);

 MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
 MODULE_AUTHOR("Suman Anna <s-anna@ti.com>");
 MODULE_DESCRIPTION("TI SYSCON Regmap Reset Driver");
 MODULE_LICENSE("GPL v2");
	/*
	* TI SYSCON regmap reset driver
	*
	* Copyright (C) 2015-2016 Texas Instruments Incorporated - http://www.ti.com/
	* Andrew F. Davis <afd@ti.com>
	* Suman Anna <afd@ti.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* This program is distributed "as is" WITHOUT ANY WARRANTY of any
	* kind, whether express or implied; without even the implied warranty
	* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#include <linux/mfd/syscon.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/regmap.h>
	#include <linux/reset-controller.h>

	#include <dt-bindings/reset/ti-syscon.h>

	/**
	* struct ti_syscon_reset_control - reset control structure
	* @assert_offset: reset assert control register offset from syscon base
	* @assert_bit: reset assert bit in the reset assert control register
	* @deassert_offset: reset deassert control register offset from syscon base
	* @deassert_bit: reset deassert bit in the reset deassert control register
	* @status_offset: reset status register offset from syscon base
	* @status_bit: reset status bit in the reset status register
	* @flags: reset flag indicating how the (de)assert and status are handled
	*/
	struct ti_syscon_reset_control {
	unsigned int assert_offset;
	unsigned int assert_bit;
	unsigned int deassert_offset;
	unsigned int deassert_bit;
	unsigned int status_offset;
	unsigned int status_bit;
	u32 flags;
	};

	/**
	* struct ti_syscon_reset_data - reset controller information structure
	* @rcdev: reset controller entity
	* @regmap: regmap handle containing the memory-mapped reset registers
	* @controls: array of reset controls
	* @nr_controls: number of controls in control array
	*/
	struct ti_syscon_reset_data {
	struct reset_controller_dev rcdev;
	struct regmap *regmap;
	struct ti_syscon_reset_control *controls;
	unsigned int nr_controls;
	};

	#define to_ti_syscon_reset_data(rcdev) \
	container_of(rcdev, struct ti_syscon_reset_data, rcdev)

	/**
	* ti_syscon_reset_assert() - assert device reset
	* @rcdev: reset controller entity
	* @id: ID of the reset to be asserted
	*
	* This function implements the reset driver op to assert a device's reset.
	* This asserts the reset in a manner prescribed by the reset flags.
	*
	* Return: 0 for successful request, else a corresponding error value
	*/
	static int ti_syscon_reset_assert(struct reset_controller_dev *rcdev,
	unsigned long id)
	{
	struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
	struct ti_syscon_reset_control *control;
	unsigned int mask, value;

	if (id >= data->nr_controls)
	return -EINVAL;

	control = &data->controls[id];

	if (control->flags & ASSERT_NONE)
	return -ENOTSUPP; /* assert not supported for this reset */

	mask = BIT(control->assert_bit);
	value = (control->flags & ASSERT_SET) ? mask : 0x0;

	return regmap_update_bits(data->regmap, control->assert_offset, mask, value);
	}

	/**
	* ti_syscon_reset_deassert() - deassert device reset
	* @rcdev: reset controller entity
	* @id: ID of reset to be deasserted
	*
	* This function implements the reset driver op to deassert a device's reset.
	* This deasserts the reset in a manner prescribed by the reset flags.
	*
	* Return: 0 for successful request, else a corresponding error value
	*/
	static int ti_syscon_reset_deassert(struct reset_controller_dev *rcdev,
	unsigned long id)
	{
	struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
	struct ti_syscon_reset_control *control;
	unsigned int mask, value;

	if (id >= data->nr_controls)
	return -EINVAL;

	control = &data->controls[id];

	if (control->flags & DEASSERT_NONE)
	return -ENOTSUPP; /* deassert not supported for this reset */

	mask = BIT(control->deassert_bit);
	value = (control->flags & DEASSERT_SET) ? mask : 0x0;

	return regmap_update_bits(data->regmap, control->deassert_offset, mask, value);
	}

	/**
	* ti_syscon_reset_status() - check device reset status
	* @rcdev: reset controller entity
	* @id: ID of the reset for which the status is being requested
	*
	* This function implements the reset driver op to return the status of a
	* device's reset.
	*
	* Return: 0 if reset is deasserted, true if reset is asserted, else a
	* corresponding error value
	*/
	static int ti_syscon_reset_status(struct reset_controller_dev *rcdev,
	unsigned long id)
	{
	struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
	struct ti_syscon_reset_control *control;
	unsigned int reset_state;
	int ret;

	if (id >= data->nr_controls)
	return -EINVAL;

	control = &data->controls[id];

	if (control->flags & STATUS_NONE)
	return -ENOTSUPP; /* status not supported for this reset */

	ret = regmap_read(data->regmap, control->status_offset, &reset_state);
	if (ret)
	return ret;

	return !(reset_state & BIT(control->status_bit)) ==
	!(control->flags & STATUS_SET);
	}

	static const struct reset_control_ops ti_syscon_reset_ops = {
	.assert = ti_syscon_reset_assert,
	.deassert = ti_syscon_reset_deassert,
	.status = ti_syscon_reset_status,
	};

	static int ti_syscon_reset_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct ti_syscon_reset_data *data;
	struct regmap *regmap;
	const __be32 *list;
	struct ti_syscon_reset_control *controls;
	int size, nr_controls, i;

	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	regmap = syscon_node_to_regmap(np->parent);
	if (IS_ERR(regmap))
	return PTR_ERR(regmap);

	list = of_get_property(np, "ti,reset-bits", &size);
	if (!list \|\| (size / sizeof(*list)) % 7 != 0) {
	dev_err(dev, "invalid DT reset description\n");
	return -EINVAL;
	}

	nr_controls = (size / sizeof(*list)) / 7;
	controls = devm_kcalloc(dev, nr_controls, sizeof(*controls),
	GFP_KERNEL);
	if (!controls)
	return -ENOMEM;

	for (i = 0; i < nr_controls; i++) {
	controls[i].assert_offset = be32_to_cpup(list++);
	controls[i].assert_bit = be32_to_cpup(list++);
	controls[i].deassert_offset = be32_to_cpup(list++);
	controls[i].deassert_bit = be32_to_cpup(list++);
	controls[i].status_offset = be32_to_cpup(list++);
	controls[i].status_bit = be32_to_cpup(list++);
	controls[i].flags = be32_to_cpup(list++);
	}

	data->rcdev.ops = &ti_syscon_reset_ops;
	data->rcdev.owner = THIS_MODULE;
	data->rcdev.of_node = np;
	data->rcdev.nr_resets = nr_controls;
	data->regmap = regmap;
	data->controls = controls;
	data->nr_controls = nr_controls;

	platform_set_drvdata(pdev, data);

	return devm_reset_controller_register(dev, &data->rcdev);
	}

	static const struct of_device_id ti_syscon_reset_of_match[] = {
	{ .compatible = "ti,syscon-reset", },
	{ /* sentinel */ },
	};
	MODULE_DEVICE_TABLE(of, ti_syscon_reset_of_match);

	static struct platform_driver ti_syscon_reset_driver = {
	.probe = ti_syscon_reset_probe,
	.driver = {
	.name = "ti-syscon-reset",
	.of_match_table = ti_syscon_reset_of_match,
	},
	};
	module_platform_driver(ti_syscon_reset_driver);

	MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
	MODULE_AUTHOR("Suman Anna <s-anna@ti.com>");
	MODULE_DESCRIPTION("TI SYSCON Regmap Reset Driver");
	MODULE_LICENSE("GPL v2");