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 *  MMC power sequence management
8 */
9#include <linux/kernel.h>
10#include <linux/err.h>
11#include <linux/module.h>
12#include <linux/of.h>
13
14#include <linux/mmc/host.h>
15
16#include "pwrseq.h"
17
18static DEFINE_MUTEX(pwrseq_list_mutex);
19static LIST_HEAD(pwrseq_list);
20
21int mmc_pwrseq_alloc(struct mmc_host *host)
22{
23	struct device_node *np;
24	struct mmc_pwrseq *p;
25
26	np = of_parse_phandle(host->parent->of_node, "mmc-pwrseq", 0);
27	if (!np)
28		return 0;
29
30	mutex_lock(&pwrseq_list_mutex);
31	list_for_each_entry(p, &pwrseq_list, pwrseq_node) {
32		if (p->dev->of_node == np) {
33			if (!try_module_get(p->owner))
34				dev_err(host->parent,
35					"increasing module refcount failed\n");
36			else
37				host->pwrseq = p;
38
39			break;
40		}
41	}
42
43	of_node_put(np);
44	mutex_unlock(&pwrseq_list_mutex);
45
46	if (!host->pwrseq)
47		return -EPROBE_DEFER;
48
49	dev_info(host->parent, "allocated mmc-pwrseq\n");
50
51	return 0;
52}
53
54void mmc_pwrseq_pre_power_on(struct mmc_host *host)
55{
56	struct mmc_pwrseq *pwrseq = host->pwrseq;
57
58	if (pwrseq && pwrseq->ops->pre_power_on)
59		pwrseq->ops->pre_power_on(host);
60}
61
62void mmc_pwrseq_post_power_on(struct mmc_host *host)
63{
64	struct mmc_pwrseq *pwrseq = host->pwrseq;
65
66	if (pwrseq && pwrseq->ops->post_power_on)
67		pwrseq->ops->post_power_on(host);
68}
69
70void mmc_pwrseq_power_off(struct mmc_host *host)
71{
72	struct mmc_pwrseq *pwrseq = host->pwrseq;
73
74	if (pwrseq && pwrseq->ops->power_off)
75		pwrseq->ops->power_off(host);
76}
77
78void mmc_pwrseq_reset(struct mmc_host *host)
79{
80	struct mmc_pwrseq *pwrseq = host->pwrseq;
81
82	if (pwrseq && pwrseq->ops->reset)
83		pwrseq->ops->reset(host);
84}
85
86void mmc_pwrseq_free(struct mmc_host *host)
87{
88	struct mmc_pwrseq *pwrseq = host->pwrseq;
89
90	if (pwrseq) {
91		module_put(pwrseq->owner);
92		host->pwrseq = NULL;
93	}
94}
95
96int mmc_pwrseq_register(struct mmc_pwrseq *pwrseq)
97{
98	if (!pwrseq || !pwrseq->ops || !pwrseq->dev)
99		return -EINVAL;
100
101	mutex_lock(&pwrseq_list_mutex);
102	list_add(&pwrseq->pwrseq_node, &pwrseq_list);
103	mutex_unlock(&pwrseq_list_mutex);
104
105	return 0;
106}
107EXPORT_SYMBOL_GPL(mmc_pwrseq_register);
108
109void mmc_pwrseq_unregister(struct mmc_pwrseq *pwrseq)
110{
111	if (pwrseq) {
112		mutex_lock(&pwrseq_list_mutex);
113		list_del(&pwrseq->pwrseq_node);
114		mutex_unlock(&pwrseq_list_mutex);
115	}
116}
117EXPORT_SYMBOL_GPL(mmc_pwrseq_unregister);
118