| /* |
| * Copyright (C) 2013 STMicroelectronics Limited |
| * Author: Stephen Gallimore <stephen.gallimore@st.com> |
| * |
| * Inspired by mach-imx/src.c |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| */ |
| #include <linux/kernel.h> |
| #include <linux/platform_device.h> |
| #include <linux/module.h> |
| #include <linux/err.h> |
| #include <linux/types.h> |
| #include <linux/of_device.h> |
| #include <linux/regmap.h> |
| #include <linux/mfd/syscon.h> |
| |
| #include "reset-syscfg.h" |
| |
| /** |
| * Reset channel regmap configuration |
| * |
| * @reset: regmap field for the channel's reset bit. |
| * @ack: regmap field for the channel's ack bit (optional). |
| */ |
| struct syscfg_reset_channel { |
| struct regmap_field *reset; |
| struct regmap_field *ack; |
| }; |
| |
| /** |
| * A reset controller which groups together a set of related reset bits, which |
| * may be located in different system configuration registers. |
| * |
| * @rst: base reset controller structure. |
| * @active_low: are the resets in this controller active low, i.e. clearing |
| * the reset bit puts the hardware into reset. |
| * @channels: An array of reset channels for this controller. |
| */ |
| struct syscfg_reset_controller { |
| struct reset_controller_dev rst; |
| bool active_low; |
| struct syscfg_reset_channel *channels; |
| }; |
| |
| #define to_syscfg_reset_controller(_rst) \ |
| container_of(_rst, struct syscfg_reset_controller, rst) |
| |
| static int syscfg_reset_program_hw(struct reset_controller_dev *rcdev, |
| unsigned long idx, int assert) |
| { |
| struct syscfg_reset_controller *rst = to_syscfg_reset_controller(rcdev); |
| const struct syscfg_reset_channel *ch; |
| u32 ctrl_val = rst->active_low ? !assert : !!assert; |
| int err; |
| |
| if (idx >= rcdev->nr_resets) |
| return -EINVAL; |
| |
| ch = &rst->channels[idx]; |
| |
| err = regmap_field_write(ch->reset, ctrl_val); |
| if (err) |
| return err; |
| |
| if (ch->ack) { |
| unsigned long timeout = jiffies + msecs_to_jiffies(1000); |
| u32 ack_val; |
| |
| while (true) { |
| err = regmap_field_read(ch->ack, &ack_val); |
| if (err) |
| return err; |
| |
| if (ack_val == ctrl_val) |
| break; |
| |
| if (time_after(jiffies, timeout)) |
| return -ETIME; |
| |
| cpu_relax(); |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int syscfg_reset_assert(struct reset_controller_dev *rcdev, |
| unsigned long idx) |
| { |
| return syscfg_reset_program_hw(rcdev, idx, true); |
| } |
| |
| static int syscfg_reset_deassert(struct reset_controller_dev *rcdev, |
| unsigned long idx) |
| { |
| return syscfg_reset_program_hw(rcdev, idx, false); |
| } |
| |
| static int syscfg_reset_dev(struct reset_controller_dev *rcdev, |
| unsigned long idx) |
| { |
| int err; |
| |
| err = syscfg_reset_assert(rcdev, idx); |
| if (err) |
| return err; |
| |
| return syscfg_reset_deassert(rcdev, idx); |
| } |
| |
| static int syscfg_reset_status(struct reset_controller_dev *rcdev, |
| unsigned long idx) |
| { |
| struct syscfg_reset_controller *rst = to_syscfg_reset_controller(rcdev); |
| const struct syscfg_reset_channel *ch; |
| u32 ret_val = 0; |
| int err; |
| |
| if (idx >= rcdev->nr_resets) |
| return -EINVAL; |
| |
| ch = &rst->channels[idx]; |
| if (ch->ack) |
| err = regmap_field_read(ch->ack, &ret_val); |
| else |
| err = regmap_field_read(ch->reset, &ret_val); |
| if (err) |
| return err; |
| |
| return rst->active_low ? !ret_val : !!ret_val; |
| } |
| |
| static struct reset_control_ops syscfg_reset_ops = { |
| .reset = syscfg_reset_dev, |
| .assert = syscfg_reset_assert, |
| .deassert = syscfg_reset_deassert, |
| .status = syscfg_reset_status, |
| }; |
| |
| static int syscfg_reset_controller_register(struct device *dev, |
| const struct syscfg_reset_controller_data *data) |
| { |
| struct syscfg_reset_controller *rc; |
| size_t size; |
| int i, err; |
| |
| rc = devm_kzalloc(dev, sizeof(*rc), GFP_KERNEL); |
| if (!rc) |
| return -ENOMEM; |
| |
| size = sizeof(struct syscfg_reset_channel) * data->nr_channels; |
| |
| rc->channels = devm_kzalloc(dev, size, GFP_KERNEL); |
| if (!rc->channels) |
| return -ENOMEM; |
| |
| rc->rst.ops = &syscfg_reset_ops, |
| rc->rst.of_node = dev->of_node; |
| rc->rst.nr_resets = data->nr_channels; |
| rc->active_low = data->active_low; |
| |
| for (i = 0; i < data->nr_channels; i++) { |
| struct regmap *map; |
| struct regmap_field *f; |
| const char *compatible = data->channels[i].compatible; |
| |
| map = syscon_regmap_lookup_by_compatible(compatible); |
| if (IS_ERR(map)) |
| return PTR_ERR(map); |
| |
| f = devm_regmap_field_alloc(dev, map, data->channels[i].reset); |
| if (IS_ERR(f)) |
| return PTR_ERR(f); |
| |
| rc->channels[i].reset = f; |
| |
| if (!data->wait_for_ack) |
| continue; |
| |
| f = devm_regmap_field_alloc(dev, map, data->channels[i].ack); |
| if (IS_ERR(f)) |
| return PTR_ERR(f); |
| |
| rc->channels[i].ack = f; |
| } |
| |
| err = reset_controller_register(&rc->rst); |
| if (!err) |
| dev_info(dev, "registered\n"); |
| |
| return err; |
| } |
| |
| int syscfg_reset_probe(struct platform_device *pdev) |
| { |
| struct device *dev = pdev ? &pdev->dev : NULL; |
| const struct of_device_id *match; |
| |
| if (!dev || !dev->driver) |
| return -ENODEV; |
| |
| match = of_match_device(dev->driver->of_match_table, dev); |
| if (!match || !match->data) |
| return -EINVAL; |
| |
| return syscfg_reset_controller_register(dev, match->data); |
| } |