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path: root/drivers/mmc/core/pwrseq_simple.c
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Diffstat (limited to 'drivers/mmc/core/pwrseq_simple.c')
-rw-r--r--drivers/mmc/core/pwrseq_simple.c164
1 files changed, 164 insertions, 0 deletions
diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
new file mode 100644
index 000000000..ea4d36705
--- /dev/null
+++ b/drivers/mmc/core/pwrseq_simple.c
@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2014 Linaro Ltd
+ *
+ * Author: Ulf Hansson <ulf.hansson@linaro.org>
+ *
+ * Simple MMC power sequence management
+ */
+#include <linux/clk.h>
+#include <linux/init.h>
+#include <linux/kernel.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/delay.h>
+#include <linux/property.h>
+
+#include <linux/mmc/host.h>
+
+#include "pwrseq.h"
+
+struct mmc_pwrseq_simple {
+ struct mmc_pwrseq pwrseq;
+ bool clk_enabled;
+ u32 post_power_on_delay_ms;
+ u32 power_off_delay_us;
+ struct clk *ext_clk;
+ struct gpio_descs *reset_gpios;
+};
+
+#define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)
+
+static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
+ int value)
+{
+ struct gpio_descs *reset_gpios = pwrseq->reset_gpios;
+
+ if (!IS_ERR(reset_gpios)) {
+ unsigned long *values;
+ int nvalues = reset_gpios->ndescs;
+
+ values = bitmap_alloc(nvalues, GFP_KERNEL);
+ if (!values)
+ return;
+
+ if (value)
+ bitmap_fill(values, nvalues);
+ else
+ bitmap_zero(values, nvalues);
+
+ gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc,
+ reset_gpios->info, values);
+
+ kfree(values);
+ }
+}
+
+static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
+{
+ struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
+
+ if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
+ clk_prepare_enable(pwrseq->ext_clk);
+ pwrseq->clk_enabled = true;
+ }
+
+ mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
+}
+
+static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
+{
+ struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
+
+ mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
+
+ if (pwrseq->post_power_on_delay_ms)
+ msleep(pwrseq->post_power_on_delay_ms);
+}
+
+static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
+{
+ struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
+
+ mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
+
+ if (pwrseq->power_off_delay_us)
+ usleep_range(pwrseq->power_off_delay_us,
+ 2 * pwrseq->power_off_delay_us);
+
+ if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
+ clk_disable_unprepare(pwrseq->ext_clk);
+ pwrseq->clk_enabled = false;
+ }
+}
+
+static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
+ .pre_power_on = mmc_pwrseq_simple_pre_power_on,
+ .post_power_on = mmc_pwrseq_simple_post_power_on,
+ .power_off = mmc_pwrseq_simple_power_off,
+};
+
+static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
+ { .compatible = "mmc-pwrseq-simple",},
+ {/* sentinel */},
+};
+MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);
+
+static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
+{
+ struct mmc_pwrseq_simple *pwrseq;
+ struct device *dev = &pdev->dev;
+
+ pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
+ if (!pwrseq)
+ return -ENOMEM;
+
+ pwrseq->ext_clk = devm_clk_get(dev, "ext_clock");
+ if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT)
+ return PTR_ERR(pwrseq->ext_clk);
+
+ pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(pwrseq->reset_gpios) &&
+ PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
+ PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
+ return PTR_ERR(pwrseq->reset_gpios);
+ }
+
+ device_property_read_u32(dev, "post-power-on-delay-ms",
+ &pwrseq->post_power_on_delay_ms);
+ device_property_read_u32(dev, "power-off-delay-us",
+ &pwrseq->power_off_delay_us);
+
+ pwrseq->pwrseq.dev = dev;
+ pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
+ pwrseq->pwrseq.owner = THIS_MODULE;
+ platform_set_drvdata(pdev, pwrseq);
+
+ return mmc_pwrseq_register(&pwrseq->pwrseq);
+}
+
+static int mmc_pwrseq_simple_remove(struct platform_device *pdev)
+{
+ struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev);
+
+ mmc_pwrseq_unregister(&pwrseq->pwrseq);
+
+ return 0;
+}
+
+static struct platform_driver mmc_pwrseq_simple_driver = {
+ .probe = mmc_pwrseq_simple_probe,
+ .remove = mmc_pwrseq_simple_remove,
+ .driver = {
+ .name = "pwrseq_simple",
+ .of_match_table = mmc_pwrseq_simple_of_match,
+ },
+};
+
+module_platform_driver(mmc_pwrseq_simple_driver);
+MODULE_LICENSE("GPL v2");