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1/*
2 * Copyright (C) 2014 Linaro Ltd
3 *
4 * Author: Ulf Hansson <ulf.hansson@linaro.org>
5 *
6 * License terms: GNU General Public License (GPL) version 2
7 *
8 * Simple MMC power sequence management
9 */
10#include <linux/clk.h>
11#include <linux/kernel.h>
12#include <linux/slab.h>
13#include <linux/device.h>
14#include <linux/err.h>
15#include <linux/gpio/consumer.h>
16
17#include <linux/mmc/host.h>
18
19#include "pwrseq.h"
20
21struct mmc_pwrseq_simple {
22 struct mmc_pwrseq pwrseq;
23 bool clk_enabled;
24 struct clk *ext_clk;
25 struct gpio_descs *reset_gpios;
26};
27
28static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
29 int value)
30{
31 struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
32
33 if (!IS_ERR(reset_gpios)) {
34 int i;
35 int values[reset_gpios->ndescs];
36
37 for (i = 0; i < reset_gpios->ndescs; i++)
38 values[i] = value;
39
40 gpiod_set_array_value_cansleep(
41 reset_gpios->ndescs, reset_gpios->desc, values);
42 }
43}
44
45static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
46{
47 struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
48 struct mmc_pwrseq_simple, pwrseq);
49
50 if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
51 clk_prepare_enable(pwrseq->ext_clk);
52 pwrseq->clk_enabled = true;
53 }
54
55 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
56}
57
58static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
59{
60 struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
61 struct mmc_pwrseq_simple, pwrseq);
62
63 mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
64}
65
66static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
67{
68 struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
69 struct mmc_pwrseq_simple, pwrseq);
70
71 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
72
73 if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
74 clk_disable_unprepare(pwrseq->ext_clk);
75 pwrseq->clk_enabled = false;
76 }
77}
78
79static void mmc_pwrseq_simple_free(struct mmc_host *host)
80{
81 struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
82 struct mmc_pwrseq_simple, pwrseq);
83
84 if (!IS_ERR(pwrseq->reset_gpios))
85 gpiod_put_array(pwrseq->reset_gpios);
86
87 if (!IS_ERR(pwrseq->ext_clk))
88 clk_put(pwrseq->ext_clk);
89
90 kfree(pwrseq);
91}
92
93static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
94 .pre_power_on = mmc_pwrseq_simple_pre_power_on,
95 .post_power_on = mmc_pwrseq_simple_post_power_on,
96 .power_off = mmc_pwrseq_simple_power_off,
97 .free = mmc_pwrseq_simple_free,
98};
99
100struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host,
101 struct device *dev)
102{
103 struct mmc_pwrseq_simple *pwrseq;
104 int ret = 0;
105
106 pwrseq = kzalloc(sizeof(*pwrseq), GFP_KERNEL);
107 if (!pwrseq)
108 return ERR_PTR(-ENOMEM);
109
110 pwrseq->ext_clk = clk_get(dev, "ext_clock");
111 if (IS_ERR(pwrseq->ext_clk) &&
112 PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
113 ret = PTR_ERR(pwrseq->ext_clk);
114 goto free;
115 }
116
117 pwrseq->reset_gpios = gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
118 if (IS_ERR(pwrseq->reset_gpios) &&
119 PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
120 PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
121 ret = PTR_ERR(pwrseq->reset_gpios);
122 goto clk_put;
123 }
124
125 pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
126
127 return &pwrseq->pwrseq;
128clk_put:
129 if (!IS_ERR(pwrseq->ext_clk))
130 clk_put(pwrseq->ext_clk);
131free:
132 kfree(pwrseq);
133 return ERR_PTR(ret);
134}
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");