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/kernel.h>
12 #include <linux/platform_device.h>
13 #include <linux/slab.h>
14 #include <linux/device.h>
15 #include <linux/err.h>
16 #include <linux/of_gpio.h>
17 #include <linux/gpio/consumer.h>
19 #include <linux/mmc/host.h>
23 struct mmc_pwrseq_simple {
24 struct mmc_pwrseq pwrseq;
27 struct gpio_descs *reset_gpios;
30 #define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
32 static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
36 struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
37 int values[reset_gpios->ndescs];
39 for (i = 0; i < reset_gpios->ndescs; i++)
42 gpiod_set_array_value_cansleep(reset_gpios->ndescs, reset_gpios->desc,
46 static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
48 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
50 if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
51 clk_prepare_enable(pwrseq->ext_clk);
52 pwrseq->clk_enabled = true;
55 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
58 static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
60 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
62 mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
65 static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
67 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
69 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
71 if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
72 clk_disable_unprepare(pwrseq->ext_clk);
73 pwrseq->clk_enabled = false;
77 static void mmc_pwrseq_simple_free(struct mmc_host *host)
79 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
81 gpiod_put_array(pwrseq->reset_gpios);
83 if (!IS_ERR(pwrseq->ext_clk))
84 clk_put(pwrseq->ext_clk);
88 int mmc_pwrseq_simple_alloc(struct mmc_host *host)
90 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
91 struct device *dev = host->pwrseq->dev;
94 pwrseq->ext_clk = clk_get(dev, "ext_clock");
95 if (IS_ERR(pwrseq->ext_clk) &&
96 PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
97 return PTR_ERR(pwrseq->ext_clk);
101 pwrseq->reset_gpios = gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
102 if (IS_ERR(pwrseq->reset_gpios)) {
103 ret = PTR_ERR(pwrseq->reset_gpios);
104 clk_put(pwrseq->ext_clk);
111 static struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
112 .alloc = mmc_pwrseq_simple_alloc,
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 .free = mmc_pwrseq_simple_free,
119 static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
120 { .compatible = "mmc-pwrseq-simple",},
123 MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);
125 static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
127 struct mmc_pwrseq_simple *spwrseq;
128 struct device *dev = &pdev->dev;
131 nr_gpios = of_gpio_named_count(dev->of_node, "reset-gpios");
135 spwrseq = devm_kzalloc(dev, sizeof(struct mmc_pwrseq_simple) + nr_gpios *
136 sizeof(struct gpio_desc *), GFP_KERNEL);
140 spwrseq->pwrseq.dev = dev;
141 spwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
143 platform_set_drvdata(pdev, spwrseq);
145 return mmc_pwrseq_register(&spwrseq->pwrseq);
148 static int mmc_pwrseq_simple_remove(struct platform_device *pdev)
150 struct mmc_pwrseq_simple *spwrseq = platform_get_drvdata(pdev);
152 return mmc_pwrseq_unregister(&spwrseq->pwrseq);
155 static struct platform_driver mmc_pwrseq_simple_driver = {
156 .probe = mmc_pwrseq_simple_probe,
157 .remove = mmc_pwrseq_simple_remove,
159 .name = "pwrseq_simple",
160 .of_match_table = mmc_pwrseq_simple_of_match,
164 module_platform_driver(mmc_pwrseq_simple_driver);
165 MODULE_LICENSE("GPL v2");