Hi Heiner, On Tue, 31 Oct 2023 21:30:22 +0100, Heiner Kallweit wrote: > In case there ever should be a jc42-driven device on a muxed child bus, > we may end up with multiple logical devices, see linked discussion. > > jc42 is the only remaining i2c client device driver supporting > I2C_CLASS_SPD, however it supports I2C_CLASS_HWMON too. Therefore > we can safely switch to I2C_CLASS_HWMON on the muxed child busses. > IMO it's more logical anyway that the muxed child busses support > the same class that the parent supports if it's not muxed. > > This change is one further step towards removing I2C_CLASS_SPD. > > Link: https://www.spinics.net/lists/linux-i2c/msg65458.html > Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx> > --- > drivers/i2c/busses/i2c-i801.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c > index 070999139..8c9bb2e09 100644 > --- a/drivers/i2c/busses/i2c-i801.c > +++ b/drivers/i2c/busses/i2c-i801.c > @@ -1298,7 +1298,7 @@ static struct i801_mux_config i801_mux_config_asus_z8_d12 = { > .gpio_chip = "gpio_ich", > .values = { 0x02, 0x03 }, > .n_values = 2, > - .classes = { I2C_CLASS_SPD, I2C_CLASS_SPD }, > + .classes = { I2C_CLASS_HWMON, I2C_CLASS_HWMON }, > .gpios = { 52, 53 }, > .n_gpios = 2, > }; > @@ -1307,7 +1307,7 @@ static struct i801_mux_config i801_mux_config_asus_z8_d18 = { > .gpio_chip = "gpio_ich", > .values = { 0x02, 0x03, 0x01 }, > .n_values = 3, > - .classes = { I2C_CLASS_SPD, I2C_CLASS_SPD, I2C_CLASS_SPD }, > + .classes = { I2C_CLASS_HWMON, I2C_CLASS_HWMON, I2C_CLASS_HWMON }, > .gpios = { 52, 53 }, > .n_gpios = 2, > }; > @@ -1395,6 +1395,9 @@ static void i801_add_mux(struct i801_priv *priv) > > mux_config = id->driver_data; > > + /* Parent and mux children class support must not overlap */ > + priv->adapter.class = 0; There may also be a hardware monitoring device on the parent segment on these boards. With this change, that device will no longer be detected. That would be a regression, so I have to nack this proposed change, sorry. The only way forward I can think of (if we want to get rid of I2C_CLASS_SPD) would be to remove device auto-detection on children segments completely (.class = 0 for them) and instead actively probe for SPD EEPROMs and JC42 thermal sensors on these segments. For SPD we should be able to just reuse i2c_register_spd(). For JC42 we would need similar code, which doesn't exist yet. -- Jean Delvare SUSE L3 Support
