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mmc: pwrseq_simple: Parse DTS for the power-off-delay-us property 

If the optional power-off-delay-us property is found, insert the
corresponding delay after asserting the GPIO during power off. This enables
a graceful shutdown sequence for some devices.

Cc: linux-mmc@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Ulf Hansson 2017-05-06 11:43:05 +02:00
parent c477ebe21f
commit e9256e142f
1 changed files with 7 additions and 0 deletions
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7
drivers/mmc/core/pwrseq_simple.c
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@ -27,6 +27,7 @@ struct mmc_pwrseq_simple {
struct mmc_pwrseq pwrseq; struct mmc_pwrseq pwrseq;
bool clk_enabled; bool clk_enabled;
u32 post_power_on_delay_ms; u32 post_power_on_delay_ms;
u32 power_off_delay_us;
struct clk *ext_clk; struct clk *ext_clk;
struct gpio_descs *reset_gpios; struct gpio_descs *reset_gpios;
}; };
@ -78,6 +79,10 @@ static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
mmc_pwrseq_simple_set_gpios_value(pwrseq, 1); 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) { if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
clk_disable_unprepare(pwrseq->ext_clk); clk_disable_unprepare(pwrseq->ext_clk);
pwrseq->clk_enabled = false; pwrseq->clk_enabled = false;
@ -119,6 +124,8 @@ static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
device_property_read_u32(dev, "post-power-on-delay-ms", device_property_read_u32(dev, "post-power-on-delay-ms",
&pwrseq->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.dev = dev;
pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops; pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;