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238 lines
7.1 KiB
238 lines
7.1 KiB
/* |
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* TI SYSCON regmap reset driver |
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* |
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* Copyright (C) 2015-2016 Texas Instruments Incorporated - https://www.ti.com/ |
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* Andrew F. Davis <[email protected]> |
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* Suman Anna <[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/mfd/syscon.h> |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/regmap.h> |
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#include <linux/reset-controller.h> |
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#include <dt-bindings/reset/ti-syscon.h> |
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/** |
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* struct ti_syscon_reset_control - reset control structure |
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* @assert_offset: reset assert control register offset from syscon base |
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* @assert_bit: reset assert bit in the reset assert control register |
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* @deassert_offset: reset deassert control register offset from syscon base |
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* @deassert_bit: reset deassert bit in the reset deassert control register |
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* @status_offset: reset status register offset from syscon base |
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* @status_bit: reset status bit in the reset status register |
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* @flags: reset flag indicating how the (de)assert and status are handled |
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*/ |
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struct ti_syscon_reset_control { |
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unsigned int assert_offset; |
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unsigned int assert_bit; |
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unsigned int deassert_offset; |
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unsigned int deassert_bit; |
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unsigned int status_offset; |
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unsigned int status_bit; |
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u32 flags; |
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}; |
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/** |
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* struct ti_syscon_reset_data - reset controller information structure |
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* @rcdev: reset controller entity |
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* @regmap: regmap handle containing the memory-mapped reset registers |
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* @controls: array of reset controls |
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* @nr_controls: number of controls in control array |
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*/ |
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struct ti_syscon_reset_data { |
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struct reset_controller_dev rcdev; |
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struct regmap *regmap; |
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struct ti_syscon_reset_control *controls; |
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unsigned int nr_controls; |
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}; |
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#define to_ti_syscon_reset_data(rcdev) \ |
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container_of(rcdev, struct ti_syscon_reset_data, rcdev) |
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/** |
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* ti_syscon_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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* This asserts the reset in a manner prescribed by the reset flags. |
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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_syscon_reset_assert(struct reset_controller_dev *rcdev, |
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unsigned long id) |
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{ |
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struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev); |
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struct ti_syscon_reset_control *control; |
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unsigned int mask, value; |
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if (id >= data->nr_controls) |
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return -EINVAL; |
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control = &data->controls[id]; |
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if (control->flags & ASSERT_NONE) |
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return -ENOTSUPP; /* assert not supported for this reset */ |
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mask = BIT(control->assert_bit); |
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value = (control->flags & ASSERT_SET) ? mask : 0x0; |
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return regmap_write_bits(data->regmap, control->assert_offset, mask, value); |
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} |
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/** |
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* ti_syscon_reset_deassert() - deassert device reset |
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* @rcdev: reset controller entity |
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* @id: ID of 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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* This deasserts the reset in a manner prescribed by the reset flags. |
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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_syscon_reset_deassert(struct reset_controller_dev *rcdev, |
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unsigned long id) |
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{ |
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struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev); |
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struct ti_syscon_reset_control *control; |
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unsigned int mask, value; |
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if (id >= data->nr_controls) |
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return -EINVAL; |
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control = &data->controls[id]; |
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if (control->flags & DEASSERT_NONE) |
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return -ENOTSUPP; /* deassert not supported for this reset */ |
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mask = BIT(control->deassert_bit); |
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value = (control->flags & DEASSERT_SET) ? mask : 0x0; |
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return regmap_write_bits(data->regmap, control->deassert_offset, mask, value); |
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} |
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/** |
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* ti_syscon_reset_status() - check device reset status |
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* @rcdev: reset controller entity |
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* @id: ID of the reset for which the status is being requested |
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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. |
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* |
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* Return: 0 if reset is deasserted, true if reset is asserted, else a |
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* corresponding error value |
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*/ |
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static int ti_syscon_reset_status(struct reset_controller_dev *rcdev, |
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unsigned long id) |
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{ |
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struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev); |
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struct ti_syscon_reset_control *control; |
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unsigned int reset_state; |
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int ret; |
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if (id >= data->nr_controls) |
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return -EINVAL; |
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control = &data->controls[id]; |
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if (control->flags & STATUS_NONE) |
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return -ENOTSUPP; /* status not supported for this reset */ |
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ret = regmap_read(data->regmap, control->status_offset, &reset_state); |
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if (ret) |
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return ret; |
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return !(reset_state & BIT(control->status_bit)) == |
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!(control->flags & STATUS_SET); |
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} |
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static const struct reset_control_ops ti_syscon_reset_ops = { |
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.assert = ti_syscon_reset_assert, |
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.deassert = ti_syscon_reset_deassert, |
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.status = ti_syscon_reset_status, |
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}; |
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static int ti_syscon_reset_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct device_node *np = dev->of_node; |
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struct ti_syscon_reset_data *data; |
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struct regmap *regmap; |
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const __be32 *list; |
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struct ti_syscon_reset_control *controls; |
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int size, nr_controls, i; |
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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regmap = syscon_node_to_regmap(np->parent); |
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if (IS_ERR(regmap)) |
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return PTR_ERR(regmap); |
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list = of_get_property(np, "ti,reset-bits", &size); |
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if (!list || (size / sizeof(*list)) % 7 != 0) { |
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dev_err(dev, "invalid DT reset description\n"); |
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return -EINVAL; |
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} |
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nr_controls = (size / sizeof(*list)) / 7; |
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controls = devm_kcalloc(dev, nr_controls, sizeof(*controls), |
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GFP_KERNEL); |
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if (!controls) |
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return -ENOMEM; |
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for (i = 0; i < nr_controls; i++) { |
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controls[i].assert_offset = be32_to_cpup(list++); |
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controls[i].assert_bit = be32_to_cpup(list++); |
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controls[i].deassert_offset = be32_to_cpup(list++); |
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controls[i].deassert_bit = be32_to_cpup(list++); |
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controls[i].status_offset = be32_to_cpup(list++); |
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controls[i].status_bit = be32_to_cpup(list++); |
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controls[i].flags = be32_to_cpup(list++); |
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} |
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data->rcdev.ops = &ti_syscon_reset_ops; |
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data->rcdev.owner = THIS_MODULE; |
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data->rcdev.of_node = np; |
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data->rcdev.nr_resets = nr_controls; |
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data->regmap = regmap; |
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data->controls = controls; |
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data->nr_controls = nr_controls; |
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platform_set_drvdata(pdev, data); |
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return devm_reset_controller_register(dev, &data->rcdev); |
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} |
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static const struct of_device_id ti_syscon_reset_of_match[] = { |
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{ .compatible = "ti,syscon-reset", }, |
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{ /* sentinel */ }, |
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}; |
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MODULE_DEVICE_TABLE(of, ti_syscon_reset_of_match); |
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static struct platform_driver ti_syscon_reset_driver = { |
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.probe = ti_syscon_reset_probe, |
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.driver = { |
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.name = "ti-syscon-reset", |
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.of_match_table = ti_syscon_reset_of_match, |
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}, |
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}; |
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module_platform_driver(ti_syscon_reset_driver); |
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MODULE_AUTHOR("Andrew F. Davis <[email protected]>"); |
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MODULE_AUTHOR("Suman Anna <[email protected]>"); |
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MODULE_DESCRIPTION("TI SYSCON Regmap Reset Driver"); |
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MODULE_LICENSE("GPL v2");
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