Messages in this thread |  | | Subject | Re: [RFC PATCH] hwmon: (jc42) Add I2C_CLASS_HWMON to detection class | From | Guenter Roeck <> | Date | Mon, 4 Jul 2016 16:27:07 -0700 |
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On 07/04/2016 04:04 PM, Alison Schofield wrote: > On Mon, Jul 04, 2016 at 02:04:34PM -0700, Guenter Roeck wrote: >> On 07/04/2016 12:19 PM, Alison Schofield wrote: >>> In 2011, commit 774466add7c810fd7e4c8bcf41995b6799608880 changed >>> the detection class of these chips to I2C_CLASS_SPD based on this >>> premise: "makes more sense because these chips always live on >>> memory modules" >>> >>> Today these chips have applications beyond memory modules. >>> >> >> Do you have a specific example ? > The mcp9808 is popular among hobbyists and makers in projects that > monitor everything from their fish pond to their wine cellar. Beyond > that I'm just referring to Microchips datasheet and marketing words > saying that they target it for a wide range of apps beyond memory > devices. I guess the chance of one of them trying to use it, with a > Linux driver, and caring about auto detect are pretty slim. >
A better example would be the MCP9085, which is officially JC42.4 compliant but also suggested for use as general purpose temperature sensor in its datasheet.
I'll add your patch to -next.
Thanks, Guenter
> As you've guessed, I changed the Diolan for my purposes. I just found > it odd that jc42 was the only driver in hwmon, without I2C_CLASS_HWMON, > so I thought it was worth a look and rethink. > > So, no, nothing broken, nothing suspected incompatible. > > alisons > > >> >>> Add I2C_CLASS_HWMON as an additional detection class to allow >>> detection by hwmon class i2c adapters. >>> >> >> Practical impact should be limited, though. Most adapters have both >> I2C_CLASS_HWMON and I2C_CLASS_SPD flags set. Besides the Diolan adapters, >> which are experimental in nature anyway (and where it actually might make >> sense to add I2C_CLASS_SPD), do you have an example where a JC-42 compatible >> chip is used with an adapter which does not have I2C_CLASS_SPD set in >> its flags ? >> >>> Alternative is to replace the SPD w HWMON class, but that carries >>> risk for existing usage. >>> >> Yes, the driver would stop working on adapters which only have I2C_CLASS_SPD >> set. There are only two of those, but those two presumably _do_ have memory >> modules connected. >> >> Guenter >> >>> Signed-off-by: Alison Schofield <amsfield22@gmail.com> >>> Cc: Daniel Baluta <daniel.baluta@gmail.com> >>> --- >>> drivers/hwmon/jc42.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c >>> index 9887d32..1537ba0 100644 >>> --- a/drivers/hwmon/jc42.c >>> +++ b/drivers/hwmon/jc42.c >>> @@ -538,7 +538,7 @@ static const struct i2c_device_id jc42_id[] = { >>> MODULE_DEVICE_TABLE(i2c, jc42_id); >>> >>> static struct i2c_driver jc42_driver = { >>> - .class = I2C_CLASS_SPD, >>> + .class = I2C_CLASS_SPD | I2C_CLASS_HWMON, >>> .driver = { >>> .name = "jc42", >>> .pm = JC42_DEV_PM_OPS, >>> >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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