101 lines
2.4 KiB
C
101 lines
2.4 KiB
C
/*
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* Copyright (C) 2015, Samsung Electronics Co., Ltd.
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*
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* Author: Marek Szyprowski <m.szyprowski@samsung.com>
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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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* Simple eMMC hardware reset provider
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*/
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#include <linux/delay.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/gpio/consumer.h>
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#include <linux/reboot.h>
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#include <linux/mmc/host.h>
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#include "pwrseq.h"
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struct mmc_pwrseq_emmc {
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struct mmc_pwrseq pwrseq;
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struct notifier_block reset_nb;
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struct gpio_desc *reset_gpio;
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};
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static void __mmc_pwrseq_emmc_reset(struct mmc_pwrseq_emmc *pwrseq)
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{
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gpiod_set_value(pwrseq->reset_gpio, 1);
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udelay(1);
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gpiod_set_value(pwrseq->reset_gpio, 0);
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udelay(200);
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}
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static void mmc_pwrseq_emmc_reset(struct mmc_host *host)
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{
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struct mmc_pwrseq_emmc *pwrseq = container_of(host->pwrseq,
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struct mmc_pwrseq_emmc, pwrseq);
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__mmc_pwrseq_emmc_reset(pwrseq);
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}
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static void mmc_pwrseq_emmc_free(struct mmc_host *host)
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{
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struct mmc_pwrseq_emmc *pwrseq = container_of(host->pwrseq,
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struct mmc_pwrseq_emmc, pwrseq);
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unregister_restart_handler(&pwrseq->reset_nb);
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gpiod_put(pwrseq->reset_gpio);
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kfree(pwrseq);
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}
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static struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
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.post_power_on = mmc_pwrseq_emmc_reset,
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.free = mmc_pwrseq_emmc_free,
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};
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static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this,
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unsigned long mode, void *cmd)
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{
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struct mmc_pwrseq_emmc *pwrseq = container_of(this,
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struct mmc_pwrseq_emmc, reset_nb);
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__mmc_pwrseq_emmc_reset(pwrseq);
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return NOTIFY_DONE;
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}
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struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
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struct device *dev)
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{
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struct mmc_pwrseq_emmc *pwrseq;
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int ret = 0;
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pwrseq = kzalloc(sizeof(struct mmc_pwrseq_emmc), GFP_KERNEL);
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if (!pwrseq)
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return ERR_PTR(-ENOMEM);
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pwrseq->reset_gpio = gpiod_get_index(dev, "reset", 0, GPIOD_OUT_LOW);
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if (IS_ERR(pwrseq->reset_gpio)) {
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ret = PTR_ERR(pwrseq->reset_gpio);
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goto free;
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}
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/*
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* register reset handler to ensure emmc reset also from
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* emergency_reboot(), priority 129 schedules it just before
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* system reboot
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*/
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pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb;
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pwrseq->reset_nb.priority = 129;
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register_restart_handler(&pwrseq->reset_nb);
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pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;
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return &pwrseq->pwrseq;
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free:
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kfree(pwrseq);
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return ERR_PTR(ret);
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}
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