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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2014 Linaro Ltd
4 *
5 * Author: Ulf Hansson <ulf.hansson@linaro.org>
6 *
7 * Simple MMC power sequence management
8 */
9#include <linux/clk.h>
10#include <linux/init.h>
11#include <linux/kernel.h>
12#include <linux/platform_device.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/device.h>
16#include <linux/err.h>
17#include <linux/gpio/consumer.h>
18#include <linux/delay.h>
19#include <linux/property.h>
20
21#include <linux/mmc/host.h>
22
23#include "pwrseq.h"
24
25struct mmc_pwrseq_simple {
26 struct mmc_pwrseq pwrseq;
27 bool clk_enabled;
28 u32 post_power_on_delay_ms;
29 u32 power_off_delay_us;
30 struct clk *ext_clk;
31 struct gpio_descs *reset_gpios;
32};
33
34#define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
35
36static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
37 int value)
38{
39 struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
40
41 if (!IS_ERR(reset_gpios)) {
42 unsigned long *values;
43 int nvalues = reset_gpios->ndescs;
44
45 values = bitmap_alloc(nvalues, GFP_KERNEL);
46 if (!values)
47 return;
48
49 if (value)
50 bitmap_fill(values, nvalues);
51 else
52 bitmap_zero(values, nvalues);
53
54 gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc,
55 reset_gpios->info, values);
56
57 bitmap_free(values);
58 }
59}
60
61static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
62{
63 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
64
65 if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
66 clk_prepare_enable(pwrseq->ext_clk);
67 pwrseq->clk_enabled = true;
68 }
69
70 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
71}
72
73static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
74{
75 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
76
77 mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
78
79 if (pwrseq->post_power_on_delay_ms)
80 msleep(pwrseq->post_power_on_delay_ms);
81}
82
83static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
84{
85 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
86
87 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
88
89 if (pwrseq->power_off_delay_us)
90 usleep_range(pwrseq->power_off_delay_us,
91 2 * pwrseq->power_off_delay_us);
92
93 if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
94 clk_disable_unprepare(pwrseq->ext_clk);
95 pwrseq->clk_enabled = false;
96 }
97}
98
99static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
100 .pre_power_on = mmc_pwrseq_simple_pre_power_on,
101 .post_power_on = mmc_pwrseq_simple_post_power_on,
102 .power_off = mmc_pwrseq_simple_power_off,
103};
104
105static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
106 { .compatible = "mmc-pwrseq-simple",},
107 {/* sentinel */},
108};
109MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);
110
111static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
112{
113 struct mmc_pwrseq_simple *pwrseq;
114 struct device *dev = &pdev->dev;
115
116 pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
117 if (!pwrseq)
118 return -ENOMEM;
119
120 pwrseq->ext_clk = devm_clk_get(dev, "ext_clock");
121 if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT)
122 return PTR_ERR(pwrseq->ext_clk);
123
124 pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset",
125 GPIOD_OUT_HIGH);
126 if (IS_ERR(pwrseq->reset_gpios) &&
127 PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
128 PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
129 return PTR_ERR(pwrseq->reset_gpios);
130 }
131
132 device_property_read_u32(dev, "post-power-on-delay-ms",
133 &pwrseq->post_power_on_delay_ms);
134 device_property_read_u32(dev, "power-off-delay-us",
135 &pwrseq->power_off_delay_us);
136
137 pwrseq->pwrseq.dev = dev;
138 pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
139 pwrseq->pwrseq.owner = THIS_MODULE;
140 platform_set_drvdata(pdev, pwrseq);
141
142 return mmc_pwrseq_register(&pwrseq->pwrseq);
143}
144
145static int mmc_pwrseq_simple_remove(struct platform_device *pdev)
146{
147 struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev);
148
149 mmc_pwrseq_unregister(&pwrseq->pwrseq);
150
151 return 0;
152}
153
154static struct platform_driver mmc_pwrseq_simple_driver = {
155 .probe = mmc_pwrseq_simple_probe,
156 .remove = mmc_pwrseq_simple_remove,
157 .driver = {
158 .name = "pwrseq_simple",
159 .of_match_table = mmc_pwrseq_simple_of_match,
160 },
161};
162
163module_platform_driver(mmc_pwrseq_simple_driver);
164MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2014 Linaro Ltd
4 *
5 * Author: Ulf Hansson <ulf.hansson@linaro.org>
6 *
7 * Simple MMC power sequence management
8 */
9#include <linux/clk.h>
10#include <linux/init.h>
11#include <linux/kernel.h>
12#include <linux/platform_device.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/device.h>
16#include <linux/err.h>
17#include <linux/gpio/consumer.h>
18#include <linux/delay.h>
19#include <linux/property.h>
20#include <linux/of.h>
21#include <linux/reset.h>
22
23#include <linux/mmc/host.h>
24
25#include "pwrseq.h"
26
27struct mmc_pwrseq_simple {
28 struct mmc_pwrseq pwrseq;
29 bool clk_enabled;
30 u32 post_power_on_delay_ms;
31 u32 power_off_delay_us;
32 struct clk *ext_clk;
33 struct gpio_descs *reset_gpios;
34 struct reset_control *reset_ctrl;
35};
36
37#define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
38
39static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
40 int value)
41{
42 struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
43
44 if (!IS_ERR(reset_gpios)) {
45 unsigned long *values;
46 int nvalues = reset_gpios->ndescs;
47
48 values = bitmap_alloc(nvalues, GFP_KERNEL);
49 if (!values)
50 return;
51
52 if (value)
53 bitmap_fill(values, nvalues);
54 else
55 bitmap_zero(values, nvalues);
56
57 gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc,
58 reset_gpios->info, values);
59
60 bitmap_free(values);
61 }
62}
63
64static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
65{
66 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
67
68 if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
69 clk_prepare_enable(pwrseq->ext_clk);
70 pwrseq->clk_enabled = true;
71 }
72
73 if (pwrseq->reset_ctrl) {
74 reset_control_deassert(pwrseq->reset_ctrl);
75 reset_control_assert(pwrseq->reset_ctrl);
76 } else
77 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
78}
79
80static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
81{
82 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
83
84 if (pwrseq->reset_ctrl)
85 reset_control_deassert(pwrseq->reset_ctrl);
86 else
87 mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
88
89 if (pwrseq->post_power_on_delay_ms)
90 msleep(pwrseq->post_power_on_delay_ms);
91}
92
93static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
94{
95 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
96
97 if (pwrseq->reset_ctrl)
98 reset_control_assert(pwrseq->reset_ctrl);
99 else
100 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
101
102 if (pwrseq->power_off_delay_us)
103 usleep_range(pwrseq->power_off_delay_us,
104 2 * pwrseq->power_off_delay_us);
105
106 if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
107 clk_disable_unprepare(pwrseq->ext_clk);
108 pwrseq->clk_enabled = false;
109 }
110}
111
112static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
113 .pre_power_on = mmc_pwrseq_simple_pre_power_on,
114 .post_power_on = mmc_pwrseq_simple_post_power_on,
115 .power_off = mmc_pwrseq_simple_power_off,
116};
117
118static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
119 { .compatible = "mmc-pwrseq-simple",},
120 {/* sentinel */},
121};
122MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);
123
124static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
125{
126 struct mmc_pwrseq_simple *pwrseq;
127 struct device *dev = &pdev->dev;
128 int ngpio;
129
130 pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
131 if (!pwrseq)
132 return -ENOMEM;
133
134 pwrseq->ext_clk = devm_clk_get(dev, "ext_clock");
135 if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT)
136 return dev_err_probe(dev, PTR_ERR(pwrseq->ext_clk), "external clock not ready\n");
137
138 ngpio = of_count_phandle_with_args(dev->of_node, "reset-gpios", "#gpio-cells");
139 if (ngpio == 1) {
140 pwrseq->reset_ctrl = devm_reset_control_get_optional_shared(dev, NULL);
141 if (IS_ERR(pwrseq->reset_ctrl))
142 return dev_err_probe(dev, PTR_ERR(pwrseq->reset_ctrl),
143 "reset control not ready\n");
144 }
145
146 /*
147 * Fallback to GPIO based reset control in case of multiple reset lines
148 * are specified or the platform doesn't have support for RESET at all.
149 */
150 if (!pwrseq->reset_ctrl) {
151 pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
152 if (IS_ERR(pwrseq->reset_gpios) &&
153 PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
154 PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
155 return dev_err_probe(dev, PTR_ERR(pwrseq->reset_gpios),
156 "reset GPIOs not ready\n");
157 }
158 }
159
160 device_property_read_u32(dev, "post-power-on-delay-ms",
161 &pwrseq->post_power_on_delay_ms);
162 device_property_read_u32(dev, "power-off-delay-us",
163 &pwrseq->power_off_delay_us);
164
165 pwrseq->pwrseq.dev = dev;
166 pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
167 pwrseq->pwrseq.owner = THIS_MODULE;
168 platform_set_drvdata(pdev, pwrseq);
169
170 return mmc_pwrseq_register(&pwrseq->pwrseq);
171}
172
173static void mmc_pwrseq_simple_remove(struct platform_device *pdev)
174{
175 struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev);
176
177 mmc_pwrseq_unregister(&pwrseq->pwrseq);
178}
179
180static struct platform_driver mmc_pwrseq_simple_driver = {
181 .probe = mmc_pwrseq_simple_probe,
182 .remove = mmc_pwrseq_simple_remove,
183 .driver = {
184 .name = "pwrseq_simple",
185 .of_match_table = mmc_pwrseq_simple_of_match,
186 },
187};
188
189module_platform_driver(mmc_pwrseq_simple_driver);
190MODULE_DESCRIPTION("Simple power sequence management for MMC");
191MODULE_LICENSE("GPL v2");