From 3526403353c2a1b94c3181f900582626d23c339b Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Thu, 18 Aug 2016 20:40:45 +0200 Subject: mfd: qcom_rpm: Handle message RAM clock MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Linus Walleij Signed-off-by: Lee Jones --- drivers/mfd/qcom_rpm.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'drivers/mfd') diff --git a/drivers/mfd/qcom_rpm.c b/drivers/mfd/qcom_rpm.c index d3300714c27b..52fafea06067 100644 --- a/drivers/mfd/qcom_rpm.c +++ b/drivers/mfd/qcom_rpm.c @@ -21,6 +21,7 @@ #include #include #include +#include #include @@ -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; @@ -552,6 +554,20 @@ 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"); @@ -672,7 +688,11 @@ 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; } -- cgit v1.2.3-59-g8ed1b