| Message ID | 1471525219-647-1-git-send-email-linus.walleij@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
On Thu 18 Aug 06:00 PDT 2016, Linus Walleij wrote: > 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. > Even more convenient is that clk_prepare_enable() and clk_disable_unprepare() accepts a NULL. So set rpm->ramclk = NULL in the error path and move the clk_enable/disable() out of their conditional. > 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"; > ... > }; > Please write a few lines in the binding document as well: Documentation/devicetree/bindings/mfd/qcom-rpm.txt > 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> > --- > 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 [..] > @@ -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; > + } else { > + clk_prepare_enable(rpm->ramclk); > + } > + > irq_ack = platform_get_irq_byname(pdev, "ack"); > if (irq_ack < 0) { > dev_err(&pdev->dev, "required ack interrupt missing\n"); > @@ -620,6 +636,10 @@ 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); > + > + if (!IS_ERR(rpm->ramclk)) > + clk_disable_unprepare(rpm->ramclk); I suggest that you do this after of_platform_depopulate(). > of_platform_depopulate(&pdev->dev); > return 0; > } Regards, Bjorn
diff --git a/drivers/mfd/qcom_rpm.c b/drivers/mfd/qcom_rpm.c index 2e44323455dd..58d0617d9a0a 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.) + */ + } else { + clk_prepare_enable(rpm->ramclk); + } + irq_ack = platform_get_irq_byname(pdev, "ack"); if (irq_ack < 0) { dev_err(&pdev->dev, "required ack interrupt missing\n"); @@ -620,6 +636,10 @@ 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); + + if (!IS_ERR(rpm->ramclk)) + clk_disable_unprepare(rpm->ramclk); of_platform_depopulate(&pdev->dev); return 0; }
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> --- drivers/mfd/qcom_rpm.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) -- 2.7.4