Messages in this thread Patch in this message | | | From | Linus Walleij <> | Subject | [PATCH v2] mfd: qcom_rpm: handle message RAM clock | Date | Thu, 18 Aug 2016 20:40:45 +0200 |
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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> --- ChangeLog v1->v2: - Exploit that a clk can be NULL and handled transparently by the clock framework, simplifying the code - Move clock disablement after the OF depopulation call --- drivers/mfd/qcom_rpm.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
diff --git a/drivers/mfd/qcom_rpm.c b/drivers/mfd/qcom_rpm.c index 2e44323455dd..315da71bde49 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 qcom_rpm { struct regmap *ipc_regmap; unsigned ipc_offset; unsigned ipc_bit; + struct clk *ramclk; struct completion ack; struct mutex lock; @@ -501,6 +503,20 @@ static int qcom_rpm_probe(struct platform_device *pdev) 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"); @@ -620,7 +636,11 @@ static int qcom_rpm_probe(struct platform_device *pdev) 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; } -- 2.7.4
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