[PATCH v2 5/7] platform/chrome: of_hw_prober: Add delay for hana trackpads

[Chen-Yu Tsai <wenst@chromium.org>]

Up until now, the MT8173 elm/hana device tree has set the dedicated
regulator supplying the trackpad as always-on, simply because the Elan
driver was missing proper delays. As a result the delay for the
Synaptics trackpad was also omitted, as it was not strictly required
under such a model and delayed the availability of the trackpad to the
user.

The Elan driver recently gained proper delays after power-up, with
adaptive skipping of the delay if the regulator was originally
on. The I2C HID driver and I2C OF component prober library gained
similar adaptive delay skipping. The device tree will be fixed to have
the regulator not be always on, and proper post-power-on delay time
added to the I2C HID device.

Also add the post-power-on delay to the ChromeOS OF component prober,
so that if the regulator is off at the time of probing, the prober knows
to wait for the hardware to initialize.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
 drivers/platform/chrome/chromeos_of_hw_prober.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/platform/chrome/chromeos_of_hw_prober.c b/drivers/platform/chrome/chromeos_of_hw_prober.c
index 8562a0e89dc6..54d8941617e2 100644
--- a/drivers/platform/chrome/chromeos_of_hw_prober.c
+++ b/drivers/platform/chrome/chromeos_of_hw_prober.c
@@ -70,10 +70,8 @@ static const struct chromeos_i2c_probe_data chromeos_i2c_probe_hana_trackpad = {
 		/*
 		 * ELAN trackpad needs 2 ms for H/W init and 100 ms for F/W init.
 		 * Synaptics trackpad needs 100 ms.
-		 * However, the regulator is set to "always-on", presumably to
-		 * avoid this delay. The ELAN driver is also missing delays.
 		 */
-		.post_power_on_delay_ms = 0,
+		.post_power_on_delay_ms = 110,
 	},
 };
 
-- 
2.55.0.rc0.799.gd6f94ed593-goog