Re: [PATCH 15/16] backlight: remove pandora_bl

Am 10.08.2026 um 14:39 schrieb Andreas Kemnade [off-list ref]:

On Mon, 10 Aug 2026 12:45:16 +0200
"H. Nikolaus Schaller" [off-list ref] wrote:

quoted

Hi Daniel,

quoted

Am 10.08.2026 um 12:35 schrieb Daniel Thompson [off-list ref]:

On Sat, Jul 11, 2026 at 08:02:02AM +0200, H. Nikolaus Schaller wrote:  

quoted

Retire the platform specific pandora backlight driver since
it can now be replaced by twl_pm and device tree.

Signed-off-by: H. Nikolaus Schaller <redacted>  

Yay!

Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>  

Well, there were some good comments by Sahiko to the prerequisites of this patch,
because it has one speciality the PWM BL driver does not handle (avoid
interpretation of PWM signals as W1 protocol).

I haven't found time to work on this, so we can't remove this yet.

In the end it may either remain a pandora_bl driver (converted to DT)
or become a patch for something else.

But then it is a TPS61161 on top of PWM, not a pandora driver.
And then there might be just a quirk for that chip in the pwm_bl using
triggered by a compatible. I guess the quirk is this:


if (priv->old_state == PANDORABL_WAS_OFF) {
- /*
- * set PWM duty cycle to max. TPS61161 seems to use this
- * to calibrate it's PWM sensitivity when it starts.
- */
- twl_i2c_write_u8(TWL_MODULE_PWM, MAX_VALUE, TWL_PWM0_OFF);
-
- /* first enable clock, then PWM0 out */
- twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1);
- r &= ~PWM0_ENABLE;
- r |= PWM0_CLK_ENABLE;
- twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
- r |= PWM0_ENABLE;
- twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
-
- /*
- * TI made it very easy to enable digital control, so easy that
- * it often triggers unintentionally and disabes PWM control,
- * so wait until 1 wire mode detection window ends.
- */
- usleep_range(2000, 10000);
- }

Yes that is what I mean. It needs to be ported somewhere. If it can be ported to
some compatible = "pwm_bl_for_tps61161" or what fits best it will be fine. Or it
could be in some compatible = "pandora_bl" driver.

Has to be worked out when the development machines are not blocked by 3 or 4 other
projects already running in parallel :)

BR,
Nikolaus