lp5523/lp5xx-common : Keyboard and RGB LEDs Not Working on Nokia N900

[Sicelo <absicsz@gmail.com>]

Hi

For some time now, the keyboard LEDs on Nokia N900 have not been
working. In dmesg is the error:
  
    lp5523x probe of 2-0032 failed with error -22

and consequently they do not get populated under /sys/class/leds.

I have finally had time to look into this, and found that the N900 dts
falls short of the current lp55xx binding specs. I have updated it and
will be submitting a separate patch. However, this was not enough to
make them work, and a new error appeared:

    [11363.247375] lp5523x 2-0032: GPIO lookup for consumer enable
    [11363.254394] lp5523x 2-0032: using device tree for GPIO lookup
    [11363.254455] of_get_named_gpiod_flags: can't parse 'enable-gpios' property of node '/ocp@68000000/i2c@48072000/lp5523@32[0]'
    [11363.254547] of_get_named_gpiod_flags: parsed 'enable-gpio' property of node '/ocp@68000000/i2c@48072000/lp5523@32[0]' - status (0)
    [11363.254638] gpio gpiochip1: Persistence not supported for GPIO 9
    [11363.254669] gpio-41 (enable): no flags found for enable
    [11363.295959] lp5523x 2-0032: device detection err: -121
    [11363.303710] lp5523x: probe of 2-0032 failed with error -121


This is because the chip does not get enabled even though dts contains:

    enable-gpios = <&gpio2 9 GPIO_ACTIVE_HIGH>; /* 41 */

which is correct for this board.


I came up with this patch (against 5.12-rc6), which makes it work again.


diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c
index 81de1346bf5d..9af84fc335b3 100644
--- a/drivers/leds/leds-lp55xx-common.c
+++ b/drivers/leds/leds-lp55xx-common.c
@@ -694,7 +694,7 @@ struct lp55xx_platform_data *lp55xx_of_populate_pdata(struct device *dev,
        of_property_read_u8(np, "clock-mode", &pdata->clock_mode);

        pdata->enable_gpiod = devm_gpiod_get_optional(dev, "enable",
-                                                     GPIOD_ASIS);
+                                                     GPIOD_OUT_HIGH);
        if (IS_ERR(pdata->enable_gpiod))
                return ERR_CAST(pdata->enable_gpiod);


However, I am not sure if this is a proper way to fix the issue, or if
it is a dirty hack. It looks like all the chips handled by this driver
(lp5521, lp5523, lp5562, and lp8501) get enabled by pulling their ENable
pin high, so I suppose it is fine, but would like to get some feedback
before submitting a cleaned up patch. It is also possible that this
should be defined via dts elsewhere, although at this point I am not
sure how.

Looking forward to your help.

Sincerely
Sicelo