On 11/20/20 8:17 PM, Matt Ranostay wrote:

On Fri, Nov 20, 2020 at 5:15 AM rishi gupta [off-list ref] wrote:

quoted

On Fri, Nov 20, 2020 at 8:31 AM Matt Ranostay
[off-list ref] wrote:

quoted

Add support for the three 10-bit ADC channels registered via
the IIO subsystem.

Cc: linux-input@vger.kernel.org
Cc: linux-iio@vger.kernel.org
CC: Rishi Gupta <gupt21@gmail.com>
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
---
  drivers/hid/Kconfig       |  1 +
  drivers/hid/hid-mcp2221.c | 65 ++++++++++++++++++++++++++++++++++++++-
  2 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 05315b434276..4795744d9979 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig

@@ -1157,6 +1157,7 @@ config HID_MCP2221
         tristate "Microchip MCP2221 HID USB-to-I2C/SMbus host support"
         depends on USB_HID && I2C
         depends on GPIOLIB
+       depends on IIO

I am wondering what will happen on systems which do not enable IIO.
This driver can not be used there.
Is my understanding correct?

Actually yeah this should be "select IIO" to avoid that issue.

No, we should not have a individual driver select a framework. This will 
cause all kinds of issues with reverse dependencies.

It might be worth splitting this driver into a MFD driver, then the MFD 
cells could have their own module that depend on the subsystem and if 
not enabled the functionality will not be provided.

- Lars