1 files changed, 120 insertions, 0 deletions
diff --git a/drivers/mmc/core/pwrseq_emmc.c b/drivers/mmc/core/pwrseq_emmc.c
new file mode 100644
index 000000000..f6dde9edd
--- /dev/null
+++ b/drivers/mmc/core/pwrseq_emmc.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015, Samsung Electronics Co., Ltd.
+ *
+ * Author: Marek Szyprowski <m.szyprowski@samsung.com>
+ *
+ * Simple eMMC hardware reset provider
+ */
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/reboot.h>
+
+#include <linux/mmc/host.h>
+
+#include "pwrseq.h"
+
+struct mmc_pwrseq_emmc {
+	struct mmc_pwrseq pwrseq;
+	struct notifier_block reset_nb;
+	struct gpio_desc *reset_gpio;
+};
+
+#define to_pwrseq_emmc(p) container_of(p, struct mmc_pwrseq_emmc, pwrseq)
+
+static void mmc_pwrseq_emmc_reset(struct mmc_host *host)
+{
+	struct mmc_pwrseq_emmc *pwrseq =  to_pwrseq_emmc(host->pwrseq);
+
+	gpiod_set_value_cansleep(pwrseq->reset_gpio, 1);
+	udelay(1);
+	gpiod_set_value_cansleep(pwrseq->reset_gpio, 0);
+	udelay(200);
+}
+
+static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this,
+				    unsigned long mode, void *cmd)
+{
+	struct mmc_pwrseq_emmc *pwrseq = container_of(this,
+					struct mmc_pwrseq_emmc, reset_nb);
+	gpiod_set_value(pwrseq->reset_gpio, 1);
+	udelay(1);
+	gpiod_set_value(pwrseq->reset_gpio, 0);
+	udelay(200);
+
+	return NOTIFY_DONE;
+}
+
+static const struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
+	.reset = mmc_pwrseq_emmc_reset,
+};
+
+static int mmc_pwrseq_emmc_probe(struct platform_device *pdev)
+{
+	struct mmc_pwrseq_emmc *pwrseq;
+	struct device *dev = &pdev->dev;
+
+	pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
+	if (!pwrseq)
+		return -ENOMEM;
+
+	pwrseq->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(pwrseq->reset_gpio))
+		return PTR_ERR(pwrseq->reset_gpio);
+
+	if (!gpiod_cansleep(pwrseq->reset_gpio)) {
+		/*
+		 * register reset handler to ensure emmc reset also from
+		 * emergency_reboot(), priority 255 is the highest priority
+		 * so it will be executed before any system reboot handler.
+		 */
+		pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb;
+		pwrseq->reset_nb.priority = 255;
+		register_restart_handler(&pwrseq->reset_nb);
+	} else {
+		dev_notice(dev, "EMMC reset pin tied to a sleepy GPIO driver; reset on emergency-reboot disabled\n");
+	}
+
+	pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;
+	pwrseq->pwrseq.dev = dev;
+	pwrseq->pwrseq.owner = THIS_MODULE;
+	platform_set_drvdata(pdev, pwrseq);
+
+	return mmc_pwrseq_register(&pwrseq->pwrseq);
+}
+
+static int mmc_pwrseq_emmc_remove(struct platform_device *pdev)
+{
+	struct mmc_pwrseq_emmc *pwrseq = platform_get_drvdata(pdev);
+
+	unregister_restart_handler(&pwrseq->reset_nb);
+	mmc_pwrseq_unregister(&pwrseq->pwrseq);
+
+	return 0;
+}
+
+static const struct of_device_id mmc_pwrseq_emmc_of_match[] = {
+	{ .compatible = "mmc-pwrseq-emmc",},
+	{/* sentinel */},
+};
+
+MODULE_DEVICE_TABLE(of, mmc_pwrseq_emmc_of_match);
+
+static struct platform_driver mmc_pwrseq_emmc_driver = {
+	.probe = mmc_pwrseq_emmc_probe,
+	.remove = mmc_pwrseq_emmc_remove,
+	.driver = {
+		.name = "pwrseq_emmc",
+		.of_match_table = mmc_pwrseq_emmc_of_match,
+	},
+};
+
+module_platform_driver(mmc_pwrseq_emmc_driver);
+MODULE_LICENSE("GPL v2");