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path: root/drivers/mmc/core/pwrseq_emmc.c
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Diffstat (limited to 'drivers/mmc/core/pwrseq_emmc.c')
-rw-r--r--drivers/mmc/core/pwrseq_emmc.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/drivers/mmc/core/pwrseq_emmc.c b/drivers/mmc/core/pwrseq_emmc.c
new file mode 100644
index 000000000000..a2d545904fbf
--- /dev/null
+++ b/drivers/mmc/core/pwrseq_emmc.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2015, Samsung Electronics Co., Ltd.
+ *
+ * Author: Marek Szyprowski <m.szyprowski@samsung.com>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Simple eMMC hardware reset provider
+ */
+#include <linux/delay.h>
+#include <linux/kernel.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;
+};
+
+static void __mmc_pwrseq_emmc_reset(struct mmc_pwrseq_emmc *pwrseq)
+{
+ gpiod_set_value(pwrseq->reset_gpio, 1);
+ udelay(1);
+ gpiod_set_value(pwrseq->reset_gpio, 0);
+ udelay(200);
+}
+
+static void mmc_pwrseq_emmc_reset(struct mmc_host *host)
+{
+ struct mmc_pwrseq_emmc *pwrseq = container_of(host->pwrseq,
+ struct mmc_pwrseq_emmc, pwrseq);
+
+ __mmc_pwrseq_emmc_reset(pwrseq);
+}
+
+static void mmc_pwrseq_emmc_free(struct mmc_host *host)
+{
+ struct mmc_pwrseq_emmc *pwrseq = container_of(host->pwrseq,
+ struct mmc_pwrseq_emmc, pwrseq);
+
+ unregister_restart_handler(&pwrseq->reset_nb);
+ gpiod_put(pwrseq->reset_gpio);
+ kfree(pwrseq);
+ host->pwrseq = NULL;
+}
+
+static struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
+ .post_power_on = mmc_pwrseq_emmc_reset,
+ .free = mmc_pwrseq_emmc_free,
+};
+
+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);
+
+ __mmc_pwrseq_emmc_reset(pwrseq);
+ return NOTIFY_DONE;
+}
+
+int mmc_pwrseq_emmc_alloc(struct mmc_host *host, struct device *dev)
+{
+ struct mmc_pwrseq_emmc *pwrseq;
+ int ret = 0;
+
+ pwrseq = kzalloc(sizeof(struct mmc_pwrseq_emmc), GFP_KERNEL);
+ if (!pwrseq)
+ return -ENOMEM;
+
+ pwrseq->reset_gpio = gpiod_get_index(dev, "reset", 0, GPIOD_OUT_LOW);
+ if (IS_ERR(pwrseq->reset_gpio)) {
+ ret = PTR_ERR(pwrseq->reset_gpio);
+ goto free;
+ }
+
+ /*
+ * register reset handler to ensure emmc reset also from
+ * emergency_reboot(), priority 129 schedules it just before
+ * system reboot
+ */
+ pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb;
+ pwrseq->reset_nb.priority = 129;
+ register_restart_handler(&pwrseq->reset_nb);
+
+ pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;
+ host->pwrseq = &pwrseq->pwrseq;
+
+ return 0;
+free:
+ kfree(pwrseq);
+ return ret;
+}