2 * Copyright (C) 2014 Linaro Ltd
4 * Author: Ulf Hansson <ulf.hansson@linaro.org>
6 * License terms: GNU General Public License (GPL) version 2
8 * Simple MMC power sequence management
10 #include <linux/clk.h>
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/platform_device.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/device.h>
17 #include <linux/err.h>
18 #include <linux/gpio/consumer.h>
19 #include <linux/delay.h>
20 #include <linux/property.h>
22 #include <linux/mmc/host.h>
26 struct mmc_pwrseq_simple {
27 struct mmc_pwrseq pwrseq;
29 u32 post_power_on_delay_ms;
30 u32 power_off_delay_us;
32 struct gpio_descs *reset_gpios;
35 #define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
37 static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
40 struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
42 if (!IS_ERR(reset_gpios)) {
43 DECLARE_BITMAP(values, BITS_PER_TYPE(value));
44 int nvalues = reset_gpios->ndescs;
48 gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc,
49 reset_gpios->info, values);
53 static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
55 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
57 if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
58 clk_prepare_enable(pwrseq->ext_clk);
59 pwrseq->clk_enabled = true;
62 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
65 static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
67 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
69 mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
71 if (pwrseq->post_power_on_delay_ms)
72 msleep(pwrseq->post_power_on_delay_ms);
75 static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
77 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
79 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
81 if (pwrseq->power_off_delay_us)
82 usleep_range(pwrseq->power_off_delay_us,
83 2 * pwrseq->power_off_delay_us);
85 if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
86 clk_disable_unprepare(pwrseq->ext_clk);
87 pwrseq->clk_enabled = false;
91 static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
92 .pre_power_on = mmc_pwrseq_simple_pre_power_on,
93 .post_power_on = mmc_pwrseq_simple_post_power_on,
94 .power_off = mmc_pwrseq_simple_power_off,
97 static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
98 { .compatible = "mmc-pwrseq-simple",},
101 MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);
103 static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
105 struct mmc_pwrseq_simple *pwrseq;
106 struct device *dev = &pdev->dev;
108 pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
112 pwrseq->ext_clk = devm_clk_get(dev, "ext_clock");
113 if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT)
114 return PTR_ERR(pwrseq->ext_clk);
116 pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset",
118 if (IS_ERR(pwrseq->reset_gpios) &&
119 PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
120 PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
121 return PTR_ERR(pwrseq->reset_gpios);
124 device_property_read_u32(dev, "post-power-on-delay-ms",
125 &pwrseq->post_power_on_delay_ms);
126 device_property_read_u32(dev, "power-off-delay-us",
127 &pwrseq->power_off_delay_us);
129 pwrseq->pwrseq.dev = dev;
130 pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
131 pwrseq->pwrseq.owner = THIS_MODULE;
132 platform_set_drvdata(pdev, pwrseq);
134 return mmc_pwrseq_register(&pwrseq->pwrseq);
137 static int mmc_pwrseq_simple_remove(struct platform_device *pdev)
139 struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev);
141 mmc_pwrseq_unregister(&pwrseq->pwrseq);
146 static struct platform_driver mmc_pwrseq_simple_driver = {
147 .probe = mmc_pwrseq_simple_probe,
148 .remove = mmc_pwrseq_simple_remove,
150 .name = "pwrseq_simple",
151 .of_match_table = mmc_pwrseq_simple_of_match,
155 module_platform_driver(mmc_pwrseq_simple_driver);
156 MODULE_LICENSE("GPL v2");