mfd: qcom_rpm: Handle message RAM clock
The MSM8660, APQ8060, IPQ806x and MSM8960 have a GCC clock
to the message RAM used by the RPM. This needs to be enabled
for messages to pass through. This is a crude solution that
simply prepare/enable at probe() and disable/unprepare
at remove(). More elaborate PM is probably possible to
add later.
The construction uses IS_ERR() to gracefully handle the
platforms that do not provide a message RAM clock. It will
bail out of probe only if the clock is hitting a probe
deferral situation.
Of course this requires the proper device tree set-up:
rpm: rpm@104000 {
compatible = "qcom,rpm-msm8660";
clocks = <&gcc RPM_MSG_RAM_H_CLK>;
clock-names = "ram";
...
};
I have provided this in the MSM8660 device tree, and will
provide patches for the other targets.
Cc: Björn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/qcom_rpm.c b/drivers/mfd/qcom_rpm.c
index d330071..52fafea 100644
--- a/drivers/mfd/qcom_rpm.c
+++ b/drivers/mfd/qcom_rpm.c
@@ -21,6 +21,7 @@
#include <linux/mfd/qcom_rpm.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
+#include <linux/clk.h>
#include <dt-bindings/mfd/qcom-rpm.h>
@@ -48,6 +49,7 @@
struct regmap *ipc_regmap;
unsigned ipc_offset;
unsigned ipc_bit;
+ struct clk *ramclk;
struct completion ack;
struct mutex lock;
@@ -552,6 +554,20 @@
mutex_init(&rpm->lock);
init_completion(&rpm->ack);
+ /* Enable message RAM clock */
+ rpm->ramclk = devm_clk_get(&pdev->dev, "ram");
+ if (IS_ERR(rpm->ramclk)) {
+ ret = PTR_ERR(rpm->ramclk);
+ if (ret == -EPROBE_DEFER)
+ return ret;
+ /*
+ * Fall through in all other cases, as the clock is
+ * optional. (Does not exist on all platforms.)
+ */
+ rpm->ramclk = NULL;
+ }
+ clk_prepare_enable(rpm->ramclk); /* Accepts NULL */
+
irq_ack = platform_get_irq_byname(pdev, "ack");
if (irq_ack < 0) {
dev_err(&pdev->dev, "required ack interrupt missing\n");
@@ -672,7 +688,11 @@
static int qcom_rpm_remove(struct platform_device *pdev)
{
+ struct qcom_rpm *rpm = dev_get_drvdata(&pdev->dev);
+
of_platform_depopulate(&pdev->dev);
+ clk_disable_unprepare(rpm->ramclk);
+
return 0;
}