Re: [PATCH v8 2/3] mfd: qcom-rpm: Driver for the Qualcomm RPM

From: Paul Bolle
Date: Mon Dec 22 2014 - 05:50:17 EST


Hi Bjorn,

On Wed, 2014-11-26 at 13:51 -0800, Bjorn Andersson wrote:
> Driver for the Resource Power Manager (RPM) found in Qualcomm 8660, 8960
> and 8064 based devices. The driver exposes resources that child drivers
> can operate on; to implementing regulator, clock and bus frequency
> drivers.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
> ---
>
> Lee, since your Acked-by earlier I've folded in the part of the RFC where I add
> an extra parameter to qcom_rpm_write(). Part of that this is unchanged.
>
> drivers/mfd/Kconfig | 14 ++
> drivers/mfd/Makefile | 1 +
> drivers/mfd/qcom_rpm.c | 581 +++++++++++++++++++++++++++++++++++++++++++
> include/linux/mfd/qcom_rpm.h | 13 +
> 4 files changed, 609 insertions(+)
> create mode 100644 drivers/mfd/qcom_rpm.c
> create mode 100644 include/linux/mfd/qcom_rpm.h
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 1456ea7..b6bcb79 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -567,6 +567,20 @@ config MFD_PM8921_CORE
> Say M here if you want to include support for PM8921 chip as a module.
> This will build a module called "pm8921-core".
>
> +config MFD_QCOM_RPM
> + tristate "Qualcomm Resource Power Manager (RPM)"
> + depends on ARCH_QCOM && OF
> + help
> + If you say yes to this option, support will be included for the
> + Resource Power Manager system found in the Qualcomm 8660, 8960 and
> + 8064 based devices.
> +
> + This is required to access many regulators, clocks and bus
> + frequencies controlled by the RPM on these devices.
> +
> + Say M here if you want to include support for the Qualcomm RPM as a
> + module. This will build a module called "qcom_rpm".
> +

The Qualcomm RPM regulator driver (see Kconfig symbol
REGULATOR_QCOM_RPM) was added in v3.18. It depends on the above symbol,
so it has not yet gotten build coverage. Even manual hacks like
make -C ../.. M=$PWD CONFIG_REGULATOR_QCOM_RPM=m qcom_rpm-regulator.ko

won't work for that driver, because it includes linux/mfd/qcom_rpm.h,
which is not part of the tree.

It seems there's no generally agreed upon guideline for situations like
this. So I guess it's up to Mark to decide how long the tree should
include an unbuildable driver.


Paul Bolle

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