RE: [PATCH v7 0/4] Extend device_get_match_data() to struct bus_type

From: Biju Das <biju.das.jz@bp.renesas.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jonathan Cameron <jic23@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Peter Rosin <peda@axentia.se>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Daniel Scally <djrscally@gmail.com>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
	Andi Shyti <andi.shyti@kernel.org>, Wolfram Sang <wsa@kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	"linux-rtc@vger.kernel.org" <linux-rtc@vger.kernel.org>,
	"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
	"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>
Subject: RE: [PATCH v7 0/4] Extend device_get_match_data() to struct bus_type
Date: Fri, 11 Aug 2023 14:46:10 +0000	[thread overview]
Message-ID: <OS0PR01MB5922E09340CDCFF54A9A6CBA8610A@OS0PR01MB5922.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <ZNZF6cjx5N+ZsIJx@smile.fi.intel.com>

Hi Andy,

> Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct
> bus_type
> 
> On Fri, Aug 11, 2023 at 01:27:36PM +0000, Biju Das wrote:
> > > On Thu, Aug 10, 2023 at 09:05:10AM +0000, Biju Das wrote:
> 
> ...
> 
> > > I'm good with this approach, but make sure you checked the whole
> > > kernel source tree for a such.
> >
> > Checking against 16 is too short I guess??
> >
> > drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h has 18 enums.
> 
> So, what does prevent us from moving that tables to use pointers?

I think that will lead to ABI breakage(client->name vs id->name)

	match = device_get_match_data(&client->dev);
	if (match) {
		chip_type = (uintptr_t)match;
		name = client->name;
	} else if (id) {
		chip_type = (enum inv_devices)
			id->driver_data;
		name = id->name;
	} else {
		return -ENOSYS;
	}

> 
> > /*device enum */
> > enum inv_devices {
> > 	INV_MPU6050,
> > 	INV_MPU6500,
> > 	INV_MPU6515,
> > 	INV_MPU6880,
> > 	INV_MPU6000,
> > 	INV_MPU9150,
> > 	INV_MPU9250,
> > 	INV_MPU9255,
> > 	INV_ICM20608,
> > 	INV_ICM20608D,
> > 	INV_ICM20609,
> > 	INV_ICM20689,
> > 	INV_ICM20600,
> > 	INV_ICM20602,
> > 	INV_ICM20690,
> > 	INV_IAM20680,
> > 	INV_NUM_PARTS
> > };
> >
> > The new helper function
> 
> You mean for debugging? We don't need that in production.

That is sample code for iterating through id table to find max enum
and check against ZERO_OR_NULL_PTR

> 
> I think what you need is a coccinelle script to find these.

I need to explore using coccinelle script as I have n't tried before.

Cheers,
Biju 