Commit 0df12a01 authored by Tony Lindgren's avatar Tony Lindgren

ARM: dts: omap4-droid4: Fix spi configuration and increase rate

We can currently sometimes get "RXS timed out" errors and "EOT timed out"
errors with spi transfers.

These errors can be made easy to reproduce by reading the cpcap iio
values in a loop while keeping the CPUs busy by also reading /dev/urandom.

The "RXS timed out" errors we can fix by adding spi-cpol and spi-cpha
in addition to the spi-cs-high property we already have.

The "EOT timed out" errors we can fix by increasing the spi clock rate
to 9.6 MHz. Looks similar MC13783 PMIC says it works at spi clock rates
up to 20 MHz, so let's assume we can pick any rate up to 20 MHz also
for cpcap.

Cc: maemo-leste@lists.dyne.org
Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Sebastian Reichel <sre@kernel.org>
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
parent 5ce8aee8
...@@ -13,8 +13,10 @@ cpcap: pmic@0 { ...@@ -13,8 +13,10 @@ cpcap: pmic@0 {
#interrupt-cells = <2>; #interrupt-cells = <2>;
#address-cells = <1>; #address-cells = <1>;
#size-cells = <0>; #size-cells = <0>;
spi-max-frequency = <3000000>; spi-max-frequency = <9600000>;
spi-cs-high; spi-cs-high;
spi-cpol;
spi-cpha;
cpcap_adc: adc { cpcap_adc: adc {
compatible = "motorola,mapphone-cpcap-adc"; compatible = "motorola,mapphone-cpcap-adc";
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment