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 
18 static DEFINE_MUTEX(pwrseq_list_mutex);
19 static LIST_HEAD(pwrseq_list);
20 
mmc_pwrseq_alloc(struct mmc_host * host)21 int 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 (device_match_of_node(p->dev, 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 
mmc_pwrseq_pre_power_on(struct mmc_host * host)54 void 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 
mmc_pwrseq_post_power_on(struct mmc_host * host)62 void 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 
mmc_pwrseq_power_off(struct mmc_host * host)70 void 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 
mmc_pwrseq_reset(struct mmc_host * host)78 void 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 
mmc_pwrseq_free(struct mmc_host * host)86 void 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 
mmc_pwrseq_register(struct mmc_pwrseq * pwrseq)96 int 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 }
107 EXPORT_SYMBOL_GPL(mmc_pwrseq_register);
108 
mmc_pwrseq_unregister(struct mmc_pwrseq * pwrseq)109 void 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 }
117 EXPORT_SYMBOL_GPL(mmc_pwrseq_unregister);
118