target/linux/ipq806x/patches-4.4/006-mfd-qcom_rpm-Handle-message-RAM-clock.patch

   1 From 3526403353c2a1b94c3181f900582626d23c339b Mon Sep 17 00:00:00 2001
   2 From: Linus Walleij <linus.walleij@linaro.org>
   3 Date: Thu, 18 Aug 2016 20:40:45 +0200
   4 Subject: mfd: qcom_rpm: Handle message RAM clock
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 The MSM8660, APQ8060, IPQ806x and MSM8960 have a GCC clock
  10 to the message RAM used by the RPM. This needs to be enabled
  11 for messages to pass through. This is a crude solution that
  12 simply prepare/enable at probe() and disable/unprepare
  13 at remove(). More elaborate PM is probably possible to
  14 add later.
  15
  16 The construction uses IS_ERR() to gracefully handle the
  17 platforms that do not provide a message RAM clock. It will
  18 bail out of probe only if the clock is hitting a probe
  19 deferral situation.
  20
  21 Of course this requires the proper device tree set-up:
  22
  23 rpm: rpm@104000 {
  24     compatible = "qcom,rpm-msm8660";
  25     clocks = <&gcc RPM_MSG_RAM_H_CLK>;
  26     clock-names = "ram";
  27     ...
  28 };
  29
  30 I have provided this in the MSM8660 device tree, and will
  31 provide patches for the other targets.
  32
  33 Cc: Björn Andersson <bjorn.andersson@linaro.org>
  34 Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
  35 Signed-off-by: Lee Jones <lee.jones@linaro.org>
  36 ---
  37  drivers/mfd/qcom_rpm.c | 20 ++++++++++++++++++++
  38  1 file changed, 20 insertions(+)
  39
  40 diff --git a/drivers/mfd/qcom_rpm.c b/drivers/mfd/qcom_rpm.c
  41 index d330071..52fafea 100644
  42 --- a/drivers/mfd/qcom_rpm.c
  43 +++ b/drivers/mfd/qcom_rpm.c
  44 @@ -21,6 +21,7 @@
  45  #include <linux/mfd/qcom_rpm.h>
  46  #include <linux/mfd/syscon.h>
  47  #include <linux/regmap.h>
  48 +#include <linux/clk.h>
  49
  50  #include <dt-bindings/mfd/qcom-rpm.h>
  51
  52 @@ -48,6 +49,7 @@ struct qcom_rpm {
  53         struct regmap *ipc_regmap;
  54         unsigned ipc_offset;
  55         unsigned ipc_bit;
  56 +       struct clk *ramclk;
  57
  58         struct completion ack;
  59         struct mutex lock;
  60 @@ -552,6 +554,20 @@ static int qcom_rpm_probe(struct platform_device *pdev)
  61         mutex_init(&rpm->lock);
  62         init_completion(&rpm->ack);
  63
  64 +       /* Enable message RAM clock */
  65 +       rpm->ramclk = devm_clk_get(&pdev->dev, "ram");
  66 +       if (IS_ERR(rpm->ramclk)) {
  67 +               ret = PTR_ERR(rpm->ramclk);
  68 +               if (ret == -EPROBE_DEFER)
  69 +                       return ret;
  70 +               /*
  71 +                * Fall through in all other cases, as the clock is
  72 +                * optional. (Does not exist on all platforms.)
  73 +                */
  74 +               rpm->ramclk = NULL;
  75 +       }
  76 +       clk_prepare_enable(rpm->ramclk); /* Accepts NULL */
  77 +
  78         irq_ack = platform_get_irq_byname(pdev, "ack");
  79         if (irq_ack < 0) {
  80                 dev_err(&pdev->dev, "required ack interrupt missing\n");
  81 @@ -672,7 +688,11 @@ static int qcom_rpm_probe(struct platform_device *pdev)
  82
  83  static int qcom_rpm_remove(struct platform_device *pdev)
  84  {
  85 +       struct qcom_rpm *rpm = dev_get_drvdata(&pdev->dev);
  86 +
  87         of_platform_depopulate(&pdev->dev);
  88 +       clk_disable_unprepare(rpm->ramclk);
  89 +
  90         return 0;
  91  }
  92
  93 --
  94 cgit v0.12