On Fri, Dec 16, 2022 at 12:30:13PM +0100, Hans de Goede wrote: > According to: > https://github.com/intel/ipu6-drivers/blob/master/patch/int3472-support-independent-clock-and-LED-gpios-5.17%2B.patch > > Bits 31-24 of the _DSM pin entry integer value codes the active-value, Here and in the code you actually can refer to it as 3rd byte. > that is the actual physical signal (0 or 1) which needs to be output on > the pin to turn the sensor chip on (to make it active). > > So if bits 31-24 are 0 for a reset pin, then the actual value of the reset > pin needs to be 0 to take the chip out of reset. IOW in this case the reset > signal is active-high rather then the default active-low. > > And if bits 31-24 are 0 for a clk-en pin then the actual value of the clk > pin needs to be 0 to enable the clk. So in this case the clk-en signal > is active-low rather then the default active-high. > > IOW if bits 31-24 are 0 for a pin, then the default polarity of the pin > is inverted. > > Add a check for this and also propagate this new polarity to the clock > registration. ... > + /* If bits 31-24 of the _DSM entry are all 0 then the signal is inverted */ > + active_value = obj->integer.value >> 24; > + if (!active_value) Not sure why you need a temporary variable for this. Just use GENMASK()/GENMASK_ULL()? if (obj->integer.value & GENMASK(31, 24)); In this case you even don't need to repeat bit numbers in the comment. > + polarity ^= GPIO_ACTIVE_LOW; > + dev_dbg(int3472->dev, "%s %s pin %d active-%s\n", func, > + agpio->resource_source.string_ptr, agpio->pin_table[0], > + (polarity == GPIO_ACTIVE_HIGH) ? "high" : "low"); Yet another high/low :-) -- With Best Regards, Andy Shevchenko
