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https://github.com/torvalds/linux
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726b6324e3
This patch provides a simple mmc-pwrseq-emmc driver, which controls single gpio line. It perform standard eMMC hw reset procedure, as descibed by Jedec 4.4 specification. This procedure is performed just after MMC core enabled power to the given mmc host (to fix possible issues if bootloader has left eMMC card in initialized or unknown state), and before performing complete system reboot (also in case of emergency reboot call). The latter is needed on boards, which doesn't have hardware reset logic connected to emmc card and (limited or broken) ROM bootloaders are unable to read second stage from the emmc card if the card is left in unknown or already initialized state. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
113 lines
2.3 KiB
C
113 lines
2.3 KiB
C
/*
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* Copyright (C) 2014 Linaro Ltd
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*
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* Author: Ulf Hansson <ulf.hansson@linaro.org>
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*
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* License terms: GNU General Public License (GPL) version 2
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*
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* MMC power sequence management
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*/
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/mmc/host.h>
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#include "pwrseq.h"
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struct mmc_pwrseq_match {
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const char *compatible;
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int (*alloc)(struct mmc_host *host, struct device *dev);
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};
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static struct mmc_pwrseq_match pwrseq_match[] = {
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{
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.compatible = "mmc-pwrseq-simple",
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.alloc = mmc_pwrseq_simple_alloc,
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}, {
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.compatible = "mmc-pwrseq-emmc",
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.alloc = mmc_pwrseq_emmc_alloc,
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},
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};
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static struct mmc_pwrseq_match *mmc_pwrseq_find(struct device_node *np)
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{
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struct mmc_pwrseq_match *match = ERR_PTR(-ENODEV);
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int i;
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for (i = 0; i < ARRAY_SIZE(pwrseq_match); i++) {
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if (of_device_is_compatible(np, pwrseq_match[i].compatible)) {
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match = &pwrseq_match[i];
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break;
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}
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}
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return match;
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}
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int mmc_pwrseq_alloc(struct mmc_host *host)
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{
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struct platform_device *pdev;
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struct device_node *np;
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struct mmc_pwrseq_match *match;
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int ret = 0;
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np = of_parse_phandle(host->parent->of_node, "mmc-pwrseq", 0);
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if (!np)
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return 0;
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pdev = of_find_device_by_node(np);
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if (!pdev) {
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ret = -ENODEV;
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goto err;
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}
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match = mmc_pwrseq_find(np);
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if (IS_ERR(match)) {
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ret = PTR_ERR(match);
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goto err;
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}
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ret = match->alloc(host, &pdev->dev);
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if (!ret)
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dev_info(host->parent, "allocated mmc-pwrseq\n");
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err:
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of_node_put(np);
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return ret;
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}
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void mmc_pwrseq_pre_power_on(struct mmc_host *host)
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{
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struct mmc_pwrseq *pwrseq = host->pwrseq;
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if (pwrseq && pwrseq->ops && pwrseq->ops->pre_power_on)
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pwrseq->ops->pre_power_on(host);
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}
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void mmc_pwrseq_post_power_on(struct mmc_host *host)
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{
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struct mmc_pwrseq *pwrseq = host->pwrseq;
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if (pwrseq && pwrseq->ops && pwrseq->ops->post_power_on)
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pwrseq->ops->post_power_on(host);
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}
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void mmc_pwrseq_power_off(struct mmc_host *host)
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{
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struct mmc_pwrseq *pwrseq = host->pwrseq;
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if (pwrseq && pwrseq->ops && pwrseq->ops->power_off)
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pwrseq->ops->power_off(host);
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}
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void mmc_pwrseq_free(struct mmc_host *host)
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{
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struct mmc_pwrseq *pwrseq = host->pwrseq;
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if (pwrseq && pwrseq->ops && pwrseq->ops->free)
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pwrseq->ops->free(host);
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}
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