aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/reset/sti/reset-syscfg.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2014-04-05 18:37:40 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-05 18:37:40 -0400
commitcbda94e039c3862326a65d1d0506447af8330c3c (patch)
tree1147da54ec6eb7e1081977f07e62d514b981d9a3 /drivers/reset/sti/reset-syscfg.c
parentf83ccb93585d1f472c30fa2bbb8b56c23dbdb506 (diff)
parentf1d7d8c86bc8ca41c88acf10ce383c5104cf4920 (diff)
Merge tag 'drivers-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC driver changes from Arnd Bergmann: "These changes are mostly for ARM specific device drivers that either don't have an upstream maintainer, or that had the maintainer ask us to pick up the changes to avoid conflicts. A large chunk of this are clock drivers (bcm281xx, exynos, versatile, shmobile), aside from that, reset controllers for STi as well as a large rework of the Marvell Orion/EBU watchdog driver are notable" * tag 'drivers-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (99 commits) Revert "dts: socfpga: Add DTS entry for adding the stmmac glue layer for stmmac." Revert "net: stmmac: Add SOCFPGA glue driver" ARM: shmobile: r8a7791: Fix SCIFA3-5 clocks ARM: STi: Add reset controller support to mach-sti Kconfig drivers: reset: stih416: add softreset controller drivers: reset: stih415: add softreset controller drivers: reset: Reset controller driver for STiH416 drivers: reset: Reset controller driver for STiH415 drivers: reset: STi SoC system configuration reset controller support dts: socfpga: Add sysmgr node so the gmac can use to reference dts: socfpga: Add support for SD/MMC on the SOCFPGA platform reset: Add optional resets and stubs ARM: shmobile: r7s72100: fix bus clock calculation Power: Reset: Generalize qnap-poweroff to work on Synology devices. dts: socfpga: Update clock entry to support multiple parents ARM: socfpga: Update socfpga_defconfig dts: socfpga: Add DTS entry for adding the stmmac glue layer for stmmac. net: stmmac: Add SOCFPGA glue driver watchdog: orion_wdt: Use %pa to print 'phys_addr_t' drivers: cci: Export CCI PMU revision ...
Diffstat (limited to 'drivers/reset/sti/reset-syscfg.c')
-rw-r--r--drivers/reset/sti/reset-syscfg.c186
1 files changed, 186 insertions, 0 deletions
diff --git a/drivers/reset/sti/reset-syscfg.c b/drivers/reset/sti/reset-syscfg.c
new file mode 100644
index 000000000000..a145cc066d4a
--- /dev/null
+++ b/drivers/reset/sti/reset-syscfg.c
@@ -0,0 +1,186 @@
1/*
2 * Copyright (C) 2013 STMicroelectronics Limited
3 * Author: Stephen Gallimore <stephen.gallimore@st.com>
4 *
5 * Inspired by mach-imx/src.c
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 */
12#include <linux/kernel.h>
13#include <linux/platform_device.h>
14#include <linux/module.h>
15#include <linux/err.h>
16#include <linux/types.h>
17#include <linux/of_device.h>
18#include <linux/regmap.h>
19#include <linux/mfd/syscon.h>
20
21#include "reset-syscfg.h"
22
23/**
24 * Reset channel regmap configuration
25 *
26 * @reset: regmap field for the channel's reset bit.
27 * @ack: regmap field for the channel's ack bit (optional).
28 */
29struct syscfg_reset_channel {
30 struct regmap_field *reset;
31 struct regmap_field *ack;
32};
33
34/**
35 * A reset controller which groups together a set of related reset bits, which
36 * may be located in different system configuration registers.
37 *
38 * @rst: base reset controller structure.
39 * @active_low: are the resets in this controller active low, i.e. clearing
40 * the reset bit puts the hardware into reset.
41 * @channels: An array of reset channels for this controller.
42 */
43struct syscfg_reset_controller {
44 struct reset_controller_dev rst;
45 bool active_low;
46 struct syscfg_reset_channel *channels;
47};
48
49#define to_syscfg_reset_controller(_rst) \
50 container_of(_rst, struct syscfg_reset_controller, rst)
51
52static int syscfg_reset_program_hw(struct reset_controller_dev *rcdev,
53 unsigned long idx, int assert)
54{
55 struct syscfg_reset_controller *rst = to_syscfg_reset_controller(rcdev);
56 const struct syscfg_reset_channel *ch;
57 u32 ctrl_val = rst->active_low ? !assert : !!assert;
58 int err;
59
60 if (idx >= rcdev->nr_resets)
61 return -EINVAL;
62
63 ch = &rst->channels[idx];
64
65 err = regmap_field_write(ch->reset, ctrl_val);
66 if (err)
67 return err;
68
69 if (ch->ack) {
70 unsigned long timeout = jiffies + msecs_to_jiffies(1000);
71 u32 ack_val;
72
73 while (true) {
74 err = regmap_field_read(ch->ack, &ack_val);
75 if (err)
76 return err;
77
78 if (ack_val == ctrl_val)
79 break;
80
81 if (time_after(jiffies, timeout))
82 return -ETIME;
83
84 cpu_relax();
85 }
86 }
87
88 return 0;
89}
90
91static int syscfg_reset_assert(struct reset_controller_dev *rcdev,
92 unsigned long idx)
93{
94 return syscfg_reset_program_hw(rcdev, idx, true);
95}
96
97static int syscfg_reset_deassert(struct reset_controller_dev *rcdev,
98 unsigned long idx)
99{
100 return syscfg_reset_program_hw(rcdev, idx, false);
101}
102
103static int syscfg_reset_dev(struct reset_controller_dev *rcdev,
104 unsigned long idx)
105{
106 int err = syscfg_reset_assert(rcdev, idx);
107 if (err)
108 return err;
109
110 return syscfg_reset_deassert(rcdev, idx);
111}
112
113static struct reset_control_ops syscfg_reset_ops = {
114 .reset = syscfg_reset_dev,
115 .assert = syscfg_reset_assert,
116 .deassert = syscfg_reset_deassert,
117};
118
119static int syscfg_reset_controller_register(struct device *dev,
120 const struct syscfg_reset_controller_data *data)
121{
122 struct syscfg_reset_controller *rc;
123 size_t size;
124 int i, err;
125
126 rc = devm_kzalloc(dev, sizeof(*rc), GFP_KERNEL);
127 if (!rc)
128 return -ENOMEM;
129
130 size = sizeof(struct syscfg_reset_channel) * data->nr_channels;
131
132 rc->channels = devm_kzalloc(dev, size, GFP_KERNEL);
133 if (!rc->channels)
134 return -ENOMEM;
135
136 rc->rst.ops = &syscfg_reset_ops,
137 rc->rst.of_node = dev->of_node;
138 rc->rst.nr_resets = data->nr_channels;
139 rc->active_low = data->active_low;
140
141 for (i = 0; i < data->nr_channels; i++) {
142 struct regmap *map;
143 struct regmap_field *f;
144 const char *compatible = data->channels[i].compatible;
145
146 map = syscon_regmap_lookup_by_compatible(compatible);
147 if (IS_ERR(map))
148 return PTR_ERR(map);
149
150 f = devm_regmap_field_alloc(dev, map, data->channels[i].reset);
151 if (IS_ERR(f))
152 return PTR_ERR(f);
153
154 rc->channels[i].reset = f;
155
156 if (!data->wait_for_ack)
157 continue;
158
159 f = devm_regmap_field_alloc(dev, map, data->channels[i].ack);
160 if (IS_ERR(f))
161 return PTR_ERR(f);
162
163 rc->channels[i].ack = f;
164 }
165
166 err = reset_controller_register(&rc->rst);
167 if (!err)
168 dev_info(dev, "registered\n");
169
170 return err;
171}
172
173int syscfg_reset_probe(struct platform_device *pdev)
174{
175 struct device *dev = pdev ? &pdev->dev : NULL;
176 const struct of_device_id *match;
177
178 if (!dev || !dev->driver)
179 return -ENODEV;
180
181 match = of_match_device(dev->driver->of_match_table, dev);
182 if (!match || !match->data)
183 return -EINVAL;
184
185 return syscfg_reset_controller_register(dev, match->data);
186}