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/slab.h>
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/of_gpio.h>
16 #include <linux/gpio/consumer.h>
18 #include <linux/mmc/host.h>
22 struct mmc_pwrseq_simple {
23 struct mmc_pwrseq pwrseq;
27 struct gpio_desc *reset_gpios[0];
30 static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
35 for (i = 0; i < pwrseq->nr_gpios; i++)
36 if (!IS_ERR(pwrseq->reset_gpios[i]))
37 gpiod_set_value_cansleep(pwrseq->reset_gpios[i], value);
40 static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
42 struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
43 struct mmc_pwrseq_simple, pwrseq);
45 if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
46 clk_prepare_enable(pwrseq->ext_clk);
47 pwrseq->clk_enabled = true;
50 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
53 static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
55 struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
56 struct mmc_pwrseq_simple, pwrseq);
58 mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
61 static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
63 struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
64 struct mmc_pwrseq_simple, pwrseq);
66 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
68 if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
69 clk_disable_unprepare(pwrseq->ext_clk);
70 pwrseq->clk_enabled = false;
74 static void mmc_pwrseq_simple_free(struct mmc_host *host)
76 struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
77 struct mmc_pwrseq_simple, pwrseq);
80 for (i = 0; i < pwrseq->nr_gpios; i++)
81 if (!IS_ERR(pwrseq->reset_gpios[i]))
82 gpiod_put(pwrseq->reset_gpios[i]);
84 if (!IS_ERR(pwrseq->ext_clk))
85 clk_put(pwrseq->ext_clk);
91 static 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,
95 .free = mmc_pwrseq_simple_free,
98 int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
100 struct mmc_pwrseq_simple *pwrseq;
101 int i, nr_gpios, ret = 0;
103 nr_gpios = of_gpio_named_count(dev->of_node, "reset-gpios");
107 pwrseq = kzalloc(sizeof(struct mmc_pwrseq_simple) + nr_gpios *
108 sizeof(struct gpio_desc *), GFP_KERNEL);
112 pwrseq->ext_clk = clk_get(dev, "ext_clock");
113 if (IS_ERR(pwrseq->ext_clk) &&
114 PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
115 ret = PTR_ERR(pwrseq->ext_clk);
119 for (i = 0; i < nr_gpios; i++) {
120 pwrseq->reset_gpios[i] = gpiod_get_index(dev, "reset", i,
122 if (IS_ERR(pwrseq->reset_gpios[i]) &&
123 PTR_ERR(pwrseq->reset_gpios[i]) != -ENOENT &&
124 PTR_ERR(pwrseq->reset_gpios[i]) != -ENOSYS) {
125 ret = PTR_ERR(pwrseq->reset_gpios[i]);
128 gpiod_put(pwrseq->reset_gpios[i]);
134 pwrseq->nr_gpios = nr_gpios;
135 pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
136 host->pwrseq = &pwrseq->pwrseq;
140 if (!IS_ERR(pwrseq->ext_clk))
141 clk_put(pwrseq->ext_clk);