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/gpio/consumer.h>
 16
 17#include <linux/mmc/host.h>
 18
 19#include "pwrseq.h"
 20
 21struct mmc_pwrseq_simple {
 22	struct mmc_pwrseq pwrseq;
 23	bool clk_enabled;
 24	struct clk *ext_clk;
 25	struct gpio_descs *reset_gpios;
 26};
 27
 28static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
 29					      int value)
 30{
 31	struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
 32
 33	if (!IS_ERR(reset_gpios)) {
 34		int i;
 35		int values[reset_gpios->ndescs];
 36
 37		for (i = 0; i < reset_gpios->ndescs; i++)
 38			values[i] = value;
 39
 40		gpiod_set_array_value_cansleep(
 41			reset_gpios->ndescs, reset_gpios->desc, values);
 42	}
 43}
 44
 45static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
 46{
 47	struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
 48					struct mmc_pwrseq_simple, pwrseq);
 49
 50	if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
 51		clk_prepare_enable(pwrseq->ext_clk);
 52		pwrseq->clk_enabled = true;
 53	}
 54
 55	mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
 56}
 57
 58static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
 59{
 60	struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
 61					struct mmc_pwrseq_simple, pwrseq);
 62
 63	mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
 64}
 65
 66static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
 67{
 68	struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
 69					struct mmc_pwrseq_simple, pwrseq);
 70
 71	mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
 72
 73	if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
 74		clk_disable_unprepare(pwrseq->ext_clk);
 75		pwrseq->clk_enabled = false;
 76	}
 77}
 78
 79static void mmc_pwrseq_simple_free(struct mmc_host *host)
 80{
 81	struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
 82					struct mmc_pwrseq_simple, pwrseq);
 83
 84	if (!IS_ERR(pwrseq->reset_gpios))
 85		gpiod_put_array(pwrseq->reset_gpios);
 86
 87	if (!IS_ERR(pwrseq->ext_clk))
 88		clk_put(pwrseq->ext_clk);
 89
 90	kfree(pwrseq);
 91}
 92
 93static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
 94	.pre_power_on = mmc_pwrseq_simple_pre_power_on,
 95	.post_power_on = mmc_pwrseq_simple_post_power_on,
 96	.power_off = mmc_pwrseq_simple_power_off,
 97	.free = mmc_pwrseq_simple_free,
 98};
 99
100struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host,
101					   struct device *dev)
102{
103	struct mmc_pwrseq_simple *pwrseq;
104	int ret = 0;
105
106	pwrseq = kzalloc(sizeof(*pwrseq), GFP_KERNEL);
107	if (!pwrseq)
108		return ERR_PTR(-ENOMEM);
109
110	pwrseq->ext_clk = clk_get(dev, "ext_clock");
111	if (IS_ERR(pwrseq->ext_clk) &&
112	    PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
113		ret = PTR_ERR(pwrseq->ext_clk);
114		goto free;
115	}
116
117	pwrseq->reset_gpios = gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
118	if (IS_ERR(pwrseq->reset_gpios) &&
119	    PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
120	    PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
121		ret = PTR_ERR(pwrseq->reset_gpios);
122		goto clk_put;
123	}
124
125	pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
126
127	return &pwrseq->pwrseq;
128clk_put:
129	if (!IS_ERR(pwrseq->ext_clk))
130		clk_put(pwrseq->ext_clk);
131free:
132	kfree(pwrseq);
133	return ERR_PTR(ret);
134}