Re: [PATCH 2/3] hwmon: Add support for SPD5118 compliant temperature sensors

[Guenter Roeck]

On 5/30/24 02:08, Thomas Weißschuh wrote:
> On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
> > Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
> > sensors. Such sensors are typically found on DDR5 memory modules.
> >
> > Cc: René Rebe <rene@xxxxxxxxxxxx>
> > Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > ---
>
> <snip>
>
> > +/* Return 0 if detection is successful, -ENODEV otherwise */
> > +static int spd5118_detect(struct i2c_client *client, struct i2c_board_info *info)
> > +{
> > +	struct i2c_adapter *adapter = client->adapter;
> > +	int regval;
> > +
> > +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
> > +				     I2C_FUNC_SMBUS_WORD_DATA))
> > +		return -ENODEV;
> > +
> > +	regval = i2c_smbus_read_word_swapped(client, SPD5118_REG_TYPE);
> > +	if (regval != 0x5118)
> > +		return -ENODEV;
> > +
> > +	regval = i2c_smbus_read_word_data(client, SPD5118_REG_VENDOR);
> > +	if (regval < 0 || !spd5118_vendor_valid(regval & 0xff, regval >> 8))
> > +		return -ENODEV;
> > +
> > +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_CAPABILITY);
> > +	if (regval < 0)
> > +		return -ENODEV;
> > +
> > +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CLR);
> > +	if (regval)
> > +		return -ENODEV;
> > +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_ERROR_CLR);
> > +	if (regval)
> > +		return -ENODEV;
> > +
> > +	if (!(regval & SPD5118_CAP_TS_SUPPORT) || (regval & 0xfc))
> > +		return -ENODEV;
>
> This breaks automatic detection for me.
>
> I think the test should after the read of SPD5118_REG_CAPABILITY and
> test that register, similar on how it is done in _probe().

Yes, that got messed up when I added reading SPD5118_REG_TEMP_CLR and
SPD5118_REG_ERROR_CLR in the last minute. Thanks!

Thanks,
Guenter