/* * TI SYSCON regmap reset driver * * Copyright (C) 2015-2016 Texas Instruments Incorporated - http://www.ti.com/ * Andrew F. Davis * Suman Anna * * 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 #include #include #include #include #include #include /** * 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_write_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_write_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 "); MODULE_AUTHOR("Suman Anna "); MODULE_DESCRIPTION("TI SYSCON Regmap Reset Driver"); MODULE_LICENSE("GPL v2");