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 (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
 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);