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120 lines
3.1 KiB
120 lines
3.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2015, Samsung Electronics Co., Ltd. |
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* |
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* Author: Marek Szyprowski <[email protected]> |
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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/init.h> |
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#include <linux/platform_device.h> |
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#include <linux/module.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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#define to_pwrseq_emmc(p) container_of(p, struct mmc_pwrseq_emmc, pwrseq) |
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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 = to_pwrseq_emmc(host->pwrseq); |
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gpiod_set_value_cansleep(pwrseq->reset_gpio, 1); |
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udelay(1); |
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gpiod_set_value_cansleep(pwrseq->reset_gpio, 0); |
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udelay(200); |
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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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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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return NOTIFY_DONE; |
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} |
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static const struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = { |
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.reset = mmc_pwrseq_emmc_reset, |
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}; |
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static int mmc_pwrseq_emmc_probe(struct platform_device *pdev) |
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{ |
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struct mmc_pwrseq_emmc *pwrseq; |
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struct device *dev = &pdev->dev; |
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pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL); |
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if (!pwrseq) |
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return -ENOMEM; |
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pwrseq->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW); |
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if (IS_ERR(pwrseq->reset_gpio)) |
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return PTR_ERR(pwrseq->reset_gpio); |
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if (!gpiod_cansleep(pwrseq->reset_gpio)) { |
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/* |
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* register reset handler to ensure emmc reset also from |
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* emergency_reboot(), priority 255 is the highest priority |
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* so it will be executed before any system reboot handler. |
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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 = 255; |
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register_restart_handler(&pwrseq->reset_nb); |
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} else { |
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dev_notice(dev, "EMMC reset pin tied to a sleepy GPIO driver; reset on emergency-reboot disabled\n"); |
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} |
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pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops; |
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pwrseq->pwrseq.dev = dev; |
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pwrseq->pwrseq.owner = THIS_MODULE; |
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platform_set_drvdata(pdev, pwrseq); |
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return mmc_pwrseq_register(&pwrseq->pwrseq); |
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} |
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static int mmc_pwrseq_emmc_remove(struct platform_device *pdev) |
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{ |
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struct mmc_pwrseq_emmc *pwrseq = platform_get_drvdata(pdev); |
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unregister_restart_handler(&pwrseq->reset_nb); |
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mmc_pwrseq_unregister(&pwrseq->pwrseq); |
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return 0; |
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} |
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static const struct of_device_id mmc_pwrseq_emmc_of_match[] = { |
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{ .compatible = "mmc-pwrseq-emmc",}, |
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{/* sentinel */}, |
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}; |
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MODULE_DEVICE_TABLE(of, mmc_pwrseq_emmc_of_match); |
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static struct platform_driver mmc_pwrseq_emmc_driver = { |
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.probe = mmc_pwrseq_emmc_probe, |
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.remove = mmc_pwrseq_emmc_remove, |
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.driver = { |
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.name = "pwrseq_emmc", |
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.of_match_table = mmc_pwrseq_emmc_of_match, |
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}, |
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}; |
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module_platform_driver(mmc_pwrseq_emmc_driver); |
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MODULE_LICENSE("GPL v2");
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