Eric Lee / smarc-fsl-linux-kernel

28
Download as
Browse Code »

Commit 3526403353c2a1b94c3181f900582626d23c339b

Authored by Linus Walleij
Committed by Lee Jones
1 parent 8c5d057159

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>

Showing 1 changed file with 20 additions and 0 deletions Side-by-side Diff

drivers/mfd/qcom_rpm.c
Diff comments   View file @ 3526403
... ... @@ -21,6 +21,7 @@
21 21 #include <linux/mfd/qcom_rpm.h>
22 22 #include <linux/mfd/syscon.h>
23 23 #include <linux/regmap.h>
  24 +#include <linux/clk.h>
24 25  
25 26 #include <dt-bindings/mfd/qcom-rpm.h>
26 27  
... ... @@ -48,6 +49,7 @@
48 49 struct regmap *ipc_regmap;
49 50 unsigned ipc_offset;
50 51 unsigned ipc_bit;
  52 + struct clk *ramclk;
51 53  
52 54 struct completion ack;
53 55 struct mutex lock;
... ... @@ -552,6 +554,20 @@
552 554 mutex_init(&rpm->lock);
553 555 init_completion(&rpm->ack);
554 556  
  557 + /* Enable message RAM clock */
  558 + rpm->ramclk = devm_clk_get(&pdev->dev, "ram");
  559 + if (IS_ERR(rpm->ramclk)) {
  560 + ret = PTR_ERR(rpm->ramclk);
  561 + if (ret == -EPROBE_DEFER)
  562 + return ret;
  563 + /*
  564 + * Fall through in all other cases, as the clock is
  565 + * optional. (Does not exist on all platforms.)
  566 + */
  567 + rpm->ramclk = NULL;
  568 + }
  569 + clk_prepare_enable(rpm->ramclk); /* Accepts NULL */
  570 +
555 571 irq_ack = platform_get_irq_byname(pdev, "ack");
556 572 if (irq_ack < 0) {
557 573 dev_err(&pdev->dev, "required ack interrupt missing\n");
558 574  
... ... @@ -672,7 +688,11 @@
672 688  
673 689 static int qcom_rpm_remove(struct platform_device *pdev)
674 690 {
  691 + struct qcom_rpm *rpm = dev_get_drvdata(&pdev->dev);
  692 +
675 693 of_platform_depopulate(&pdev->dev);
  694 + clk_disable_unprepare(rpm->ramclk);
  695 +
676 696 return 0;
677 697 }
678 698