linux-kernel - Re: [PATCH] mfd: intel_soc_pmic: use 'depends on' instead of 'select'

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Message-ID: <20170615080905.3p325p4dxenll5l6@dell>
Date:   Thu, 15 Jun 2017 09:09:05 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Rob Herring <robh@...nel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Hans de Goede <hdegoede@...hat.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mfd: intel_soc_pmic: use 'depends on' instead of 'select'

On Fri, 09 Jun 2017, Arnd Bergmann wrote:

> I ran into a build error on ARM with a platform that has a non-standard
> clk implementation:
> 
> drivers/clk/clk.o: In function `clk_disable':
> clk.c:(.text.clk_disable+0x0): multiple definition of `clk_disable'
> arch/arm/mach-omap1/clock.o:clock.c:(.text.clk_disable+0x0): first defined here
> drivers/clk/clk.o: In function `clk_enable':
> clk.c:(.text.clk_enable+0x0): multiple definition of `clk_enable'
> arch/arm/mach-omap1/clock.o:clock.c:(.text.clk_enable+0x0): first defined here
> 
> The problem is a device driver that uses 'select COMMON_CLK', which is
> generally a bad idea: selecting a subsystem should only be done from
> a platform, otherwise we run into circular dependencies. The same driver
> also selects 'GPIOLIB' and 'I2C', which has a similar effect.
> 
> This turns all three into 'depends on', as it should be. The same pattern
> exists for INTEL_SOC_PMIC and INTEL_SOC_PMIC_CHTWC, so we fix both the
> same way to keep them in sync. INTEL_SOC_PMIC does not depend on ACPI,
> so we don't need to 'select' the I2C master driver when ACPI is disabled.
> 
> Finally, we can limit the build to x86, unless we are compile testing.
> 
> Fixes: 2f91ded5f8f4 ("mfd: Add Cherry Trail Whiskey Cove PMIC driver")
> Fixes: 5f125f1f5705 ("mfd: intel_soc_pmic: Select designware i2c-bus driver")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  drivers/mfd/Kconfig | 15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)

I need 2 patches, one for each of the Fixes above.  The plan being to
squash them into the original commits (keeping sign-off credits of
course) to prevent bisectability breakage.

If that does not happen, I will have to remove both offending patches
until they are fixed.

> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index ea5daa935518..74fa52582f06 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -454,14 +454,12 @@ config LPC_SCH
>  
>  config INTEL_SOC_PMIC
>  	bool "Support for Crystal Cove PMIC"
> -	depends on HAS_IOMEM
> -	select GPIOLIB
> -	select I2C
> +	depends on HAS_IOMEM && I2C=y && GPIOLIB && COMMON_CLK
> +	depends on X86 || COMPILE_TEST
>  	select MFD_CORE
>  	select REGMAP_I2C
>  	select REGMAP_IRQ
> -	select COMMON_CLK
> -	select I2C_DESIGNWARE_PLATFORM
> +	select I2C_DESIGNWARE_PLATFORM if ACPI
>  	help
>  	  Select this option to enable support for Crystal Cove PMIC
>  	  on some Intel SoC systems. The PMIC provides ADC, GPIO,
> @@ -484,13 +482,12 @@ config INTEL_SOC_PMIC_BXTWC
>  	  on these systems.
>  
>  config INTEL_SOC_PMIC_CHTWC
> -	bool "Support for Intel Cherry Trail Whiskey Cove PMIC"
> -	depends on ACPI && HAS_IOMEM
> +	tristate "Support for Intel Cherry Trail Whiskey Cove PMIC"
> +	depends on ACPI && HAS_IOMEM && I2C=y && COMMON_CLK
> +	depends on X86 || COMPILE_TEST
>  	select MFD_CORE
> -	select I2C
>  	select REGMAP_I2C
>  	select REGMAP_IRQ
> -	select COMMON_CLK
>  	select I2C_DESIGNWARE_PLATFORM
>  	help
>  	  Select this option to enable support for the Intel Cherry Trail

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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