Some devices need a while to boot their firmware after providing clks /
de-asserting resets before they are ready to receive sdio commands.
This commits adds a post-power-on-delay-ms devicetree property to
mmc-pwrseq-simple for use with such devices.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt | 2 ++
drivers/mmc/core/pwrseq_simple.c | 9 +++++++++
2 files changed, 11 insertions(+)
diff --git a/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt b/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt
index ce0e767..e254368 100644
--- a/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt
@@ -16,6 +16,8 @@ Optional properties:
See ../clocks/clock-bindings.txt for details.
- clock-names : Must include the following entry:
"ext_clock" (External clock provided to the card).
+- post-power-on-delay-ms : Delay in ms after powering the card and
+ de-asserting the reset-gpios (if any)
Example:
diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
index 450d907..1304160 100644
--- a/drivers/mmc/core/pwrseq_simple.c
+++ b/drivers/mmc/core/pwrseq_simple.c
@@ -16,6 +16,8 @@
#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>
@@ -24,6 +26,7 @@
struct mmc_pwrseq_simple {
struct mmc_pwrseq pwrseq;
bool clk_enabled;
+ u32 post_power_on_delay_ms;
struct clk *ext_clk;
struct gpio_descs *reset_gpios;
};
@@ -64,6 +67,9 @@ 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)
@@ -111,6 +117,9 @@ static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
return PTR_ERR(pwrseq->reset_gpios);
}
+ device_property_read_u32(dev, "post-power-on-delay-ms",
+ &pwrseq->post_power_on_delay_ms);
+
pwrseq->pwrseq.dev = dev;
pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
pwrseq->pwrseq.owner = THIS_MODULE;
--
2.7.4
--
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