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