Re: [PATCH v3 5/6] platform/x86: Add intel_skl_int3472 driver
From: Daniel Scally <djrscally@gmail.com>
Date: 2021-02-22 14:09:04
Also in:
linux-acpi, linux-i2c, lkml, platform-driver-x86
Hi all On 22/02/2021 13:07, Daniel Scally wrote:
quoted hunk ↗ jump to hunk
diff --git a/drivers/platform/x86/intel-int3472/Kconfig b/drivers/platform/x86/intel-int3472/Kconfig new file mode 100644 index 000000000000..b94622245c21 --- /dev/null +++ b/drivers/platform/x86/intel-int3472/Kconfig@@ -0,0 +1,31 @@ +config INTEL_SKL_INT3472 + tristate "Intel SkyLake ACPI INT3472 Driver" + depends on ACPI + depends on REGULATOR + depends on GPIOLIB + depends on COMMON_CLK && CLKDEV_LOOKUP + depends on I2C + select MFD_CORE + select REGMAP_I2C + help + This driver adds support for the INT3472 ACPI devices found on some + Intel SkyLake devices. + + The INT3472 is an Intel camera power controller, a logical device + found on some Skylake-based systems that can map to different + hardware devices depending on the platform. On machines + designed for Chrome OS, it maps to a TPS68470 camera PMIC. On + machines designed for Windows, it maps to either a TP68470 + camera PMIC, a uP6641Q sensor PMIC, or a set of discrete GPIOs + and power gates. + + If your device was designed for Chrome OS, this driver will provide + an ACPI OpRegion, which must be available before any of the devices + using it are probed. For this reason, you should select Y if your + device was designed for ChromeOS. For the same reason the + I2C_DESIGNWARE_PLATFORM option must be set to Y too. + + Say Y or M here if you have a SkyLake device designed for use + with Windows or ChromeOS. Say N here if you are not sure. + + The module will be named "intel-skl-int3472"
The Kconfig option for the existing tps68470 driver is a bool which depends on I2C_DESIGNWARE_PLATFORM=y, giving the following reason: This option is a bool as it provides an ACPI operation region, which must be available before any of the devices using this are probed. This option also configures the designware-i2c driver to be built-in, for the same reason. One problem I've faced is that that scenario only applies to some devices that this new driver can support, so hard-coding it as built in didn't make much sense. For that reason I opted to set it tristate, but of course that issue still exists for ChromeOS devices where the OpRegion will be registered. I opted for simply documenting that requirement, as is done in aaac4a2eadaa6: "mfd: axp20x-i2c: Document that this must be builtin on x86", but that's not entirely satisfactory. Possible alternatives might be setting "depends on I2C_DESIGNWARE_PLATFORM=y if CHROME_PLATFORMS" or something similar, though of course the User would still have to realise they need to build-in the INTEL_SKL_INT3472 Kconfig option too. Feedback around this issue would be particularly welcome, as I'm not sure what the best approach might be.