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authorJavier Martinez Canillas <javier.martinez@collabora.co.uk>2015-01-29 16:00:06 +0100
committerUlf Hansson <ulf.hansson@linaro.org>2015-01-30 12:10:23 +0100
commitc13045b1e939a9ecffab4a8f8d514e8a2a0bd2c9 (patch)
tree8485f823dafec20c596457251ad36826d30cc293 /drivers/mmc
parent3f656a168c70a583a5d87614eb4a707abd7f80b9 (diff)
downloadkernel-c13045b1e939a9ecffab4a8f8d514e8a2a0bd2c9.tar.gz
mmc: pwrseq_simple: Add optional reference clock support
Some WLAN chips attached to a SDIO interface, need a reference clock. Since this is very common, extend the prseq_simple driver to support an optional clock that is enabled prior the card power up procedure. Note: the external clock is optional. Thus an error is not returned if the clock is not found. Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/core/pwrseq_simple.c38
1 files changed, 36 insertions, 2 deletions
diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
index e53d3c7e059c..e9f1d8d84613 100644
--- a/drivers/mmc/core/pwrseq_simple.c
+++ b/drivers/mmc/core/pwrseq_simple.c
@@ -7,6 +7,7 @@
*
* Simple MMC power sequence management
*/
+#include <linux/clk.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>
@@ -20,6 +21,8 @@
struct mmc_pwrseq_simple {
struct mmc_pwrseq pwrseq;
+ bool clk_enabled;
+ struct clk *ext_clk;
int nr_gpios;
struct gpio_desc *reset_gpios[0];
};
@@ -39,6 +42,11 @@ static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
struct mmc_pwrseq_simple, 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);
}
@@ -50,6 +58,19 @@ static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
}
+static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
+{
+ struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
+ struct mmc_pwrseq_simple, pwrseq);
+
+ mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
+
+ if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
+ clk_disable_unprepare(pwrseq->ext_clk);
+ pwrseq->clk_enabled = false;
+ }
+}
+
static void mmc_pwrseq_simple_free(struct mmc_host *host)
{
struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
@@ -60,6 +81,9 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
if (!IS_ERR(pwrseq->reset_gpios[i]))
gpiod_put(pwrseq->reset_gpios[i]);
+ if (!IS_ERR(pwrseq->ext_clk))
+ clk_put(pwrseq->ext_clk);
+
kfree(pwrseq);
host->pwrseq = NULL;
}
@@ -67,7 +91,7 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
static 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_pre_power_on,
+ .power_off = mmc_pwrseq_simple_power_off,
.free = mmc_pwrseq_simple_free,
};
@@ -85,6 +109,13 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
if (!pwrseq)
return -ENOMEM;
+ pwrseq->ext_clk = clk_get(dev, "ext_clock");
+ if (IS_ERR(pwrseq->ext_clk) &&
+ PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
+ ret = PTR_ERR(pwrseq->ext_clk);
+ goto free;
+ }
+
for (i = 0; i < nr_gpios; i++) {
pwrseq->reset_gpios[i] = gpiod_get_index(dev, "reset", i,
GPIOD_OUT_HIGH);
@@ -96,7 +127,7 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
while (--i)
gpiod_put(pwrseq->reset_gpios[i]);
- goto free;
+ goto clk_put;
}
}
@@ -105,6 +136,9 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
host->pwrseq = &pwrseq->pwrseq;
return 0;
+clk_put:
+ if (!IS_ERR(pwrseq->ext_clk))
+ clk_put(pwrseq->ext_clk);
free:
kfree(pwrseq);
return ret;