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