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
25 struct 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
mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple * pwrseq,int value)36 static 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
mmc_pwrseq_simple_pre_power_on(struct mmc_host * host)61 static 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
mmc_pwrseq_simple_post_power_on(struct mmc_host * host)73 static 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
mmc_pwrseq_simple_power_off(struct mmc_host * host)83 static 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
99 static 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
105 static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
106 { .compatible = "mmc-pwrseq-simple",},
107 {/* sentinel */},
108 };
109 MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);
110
mmc_pwrseq_simple_probe(struct platform_device * pdev)111 static 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
mmc_pwrseq_simple_remove(struct platform_device * pdev)145 static 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
154 static 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
163 module_platform_driver(mmc_pwrseq_simple_driver);
164 MODULE_LICENSE("GPL v2");
165
