Re: [PATCH] misc: add driver for Renesas R-Car Gyro-ADC/speed-pulseinterfaces

From: Sergei Shtylyov
Date: Fri Jul 12 2013 - 21:15:29 EST


Hello.

Can't get to sleep, sigh...

On 07/13/2013 04:57 AM, Greg KH wrote:

Add the driver for Gyro-ADC/speed-pulse interfaces found in Renesas R-Car SoCs.
Though being two separate devices, they have to be driven together because of
the shared start/stop register (located in Gyro-ADC still). At this time, only
speed-pulse interface is fully supported, the Gyro-ADC is just initialized and
started/stopped synchronously with the speed-pulse interface. A user interface
is implemented via several sysfs files which allow to read and reset the speed-
pulse interface's registers.

If you modify/create/remove sysfs files, you also have to document them
in Documentation/ABI/ which is missing from this patch.

I've looked there and didn't find the documentation for my closest
model driver, drivers/misc/ti_dac7512.c (or for many other drivers), so I thought I too can do without it.

Your sysfs files are also being created in a "racy" way, i.e. after
userspace is told about the device, please fix that as well.

Not sure I understand you. Could you elaborate?

And are you sure you want to control this through sysfs? There's no
other better user/kernel apis for it?

I found none, besides ioctl(), as the device driven is rather unique. But I thought that sysfs is "ioctl() today", so I went with it...

thanks,

greg k-h

WBR, Sergei

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