1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C) 2013 STMicroelectronics Limited
4 * Author: Stephen Gallimore <stephen.gallimore@st.com>
6 * Inspired by mach-imx/src.c
8 #include <linux/kernel.h>
9 #include <linux/platform_device.h>
10 #include <linux/module.h>
11 #include <linux/err.h>
12 #include <linux/types.h>
13 #include <linux/of_device.h>
14 #include <linux/regmap.h>
15 #include <linux/mfd/syscon.h>
17 #include "reset-syscfg.h"
20 * Reset channel regmap configuration
22 * @reset: regmap field for the channel's reset bit.
23 * @ack: regmap field for the channel's ack bit (optional).
25 struct syscfg_reset_channel {
26 struct regmap_field *reset;
27 struct regmap_field *ack;
31 * A reset controller which groups together a set of related reset bits, which
32 * may be located in different system configuration registers.
34 * @rst: base reset controller structure.
35 * @active_low: are the resets in this controller active low, i.e. clearing
36 * the reset bit puts the hardware into reset.
37 * @channels: An array of reset channels for this controller.
39 struct syscfg_reset_controller {
40 struct reset_controller_dev rst;
42 struct syscfg_reset_channel *channels;
45 #define to_syscfg_reset_controller(_rst) \
46 container_of(_rst, struct syscfg_reset_controller, rst)
48 static int syscfg_reset_program_hw(struct reset_controller_dev *rcdev,
49 unsigned long idx, int assert)
51 struct syscfg_reset_controller *rst = to_syscfg_reset_controller(rcdev);
52 const struct syscfg_reset_channel *ch;
53 u32 ctrl_val = rst->active_low ? !assert : !!assert;
56 if (idx >= rcdev->nr_resets)
59 ch = &rst->channels[idx];
61 err = regmap_field_write(ch->reset, ctrl_val);
66 unsigned long timeout = jiffies + msecs_to_jiffies(1000);
70 err = regmap_field_read(ch->ack, &ack_val);
74 if (ack_val == ctrl_val)
77 if (time_after(jiffies, timeout))
87 static int syscfg_reset_assert(struct reset_controller_dev *rcdev,
90 return syscfg_reset_program_hw(rcdev, idx, true);
93 static int syscfg_reset_deassert(struct reset_controller_dev *rcdev,
96 return syscfg_reset_program_hw(rcdev, idx, false);
99 static int syscfg_reset_dev(struct reset_controller_dev *rcdev,
104 err = syscfg_reset_assert(rcdev, idx);
108 return syscfg_reset_deassert(rcdev, idx);
111 static int syscfg_reset_status(struct reset_controller_dev *rcdev,
114 struct syscfg_reset_controller *rst = to_syscfg_reset_controller(rcdev);
115 const struct syscfg_reset_channel *ch;
119 if (idx >= rcdev->nr_resets)
122 ch = &rst->channels[idx];
124 err = regmap_field_read(ch->ack, &ret_val);
126 err = regmap_field_read(ch->reset, &ret_val);
130 return rst->active_low ? !ret_val : !!ret_val;
133 static const struct reset_control_ops syscfg_reset_ops = {
134 .reset = syscfg_reset_dev,
135 .assert = syscfg_reset_assert,
136 .deassert = syscfg_reset_deassert,
137 .status = syscfg_reset_status,
140 static int syscfg_reset_controller_register(struct device *dev,
141 const struct syscfg_reset_controller_data *data)
143 struct syscfg_reset_controller *rc;
146 rc = devm_kzalloc(dev, sizeof(*rc), GFP_KERNEL);
150 rc->channels = devm_kcalloc(dev, data->nr_channels,
151 sizeof(*rc->channels), GFP_KERNEL);
155 rc->rst.ops = &syscfg_reset_ops,
156 rc->rst.of_node = dev->of_node;
157 rc->rst.nr_resets = data->nr_channels;
158 rc->active_low = data->active_low;
160 for (i = 0; i < data->nr_channels; i++) {
162 struct regmap_field *f;
163 const char *compatible = data->channels[i].compatible;
165 map = syscon_regmap_lookup_by_compatible(compatible);
169 f = devm_regmap_field_alloc(dev, map, data->channels[i].reset);
173 rc->channels[i].reset = f;
175 if (!data->wait_for_ack)
178 f = devm_regmap_field_alloc(dev, map, data->channels[i].ack);
182 rc->channels[i].ack = f;
185 err = reset_controller_register(&rc->rst);
187 dev_info(dev, "registered\n");
192 int syscfg_reset_probe(struct platform_device *pdev)
194 struct device *dev = pdev ? &pdev->dev : NULL;
195 const struct of_device_id *match;
197 if (!dev || !dev->driver)
200 match = of_match_device(dev->driver->of_match_table, dev);
201 if (!match || !match->data)
204 return syscfg_reset_controller_register(dev, match->data);