openwrt/target/linux/ath79/dts/ar9330_pqi_air-pen.dts
Adrian Schmutzler ebc090e420 ath79: reduce spi-max-frequency to 50 MHz
The introduction of ebf0d8dade ("ath79: add new ar934x spi driver")
made the SPI memory unusable on devices with very high spi-max-frequency
(104 MHz).

Here's how the actual clock is calculated: (AHB_CLK/((CLOCK_DIVIDER+1)*2))
where AHB_CLK is a fixed clock (e.g. 200MHz on AR9331) and CLOCK_DIVIDER
is the parameter we can set. Highest clock according to this formula is
AHB_CLK/2 (100MHz, but that didn't work in device tests).
The next possible value is AHB_CLK/4 (50MHz). Speeds between 50 MHz and
100 MHz will be rounded down, so using values higher than 50 MHz does
not provide any benefit.

Consequently, this patch reduces spi-max-frequency for all devices with
values higher than 50 MHz to 50 MHz (effectively, this only affects
devices with 104 MHz before this patch).

Tested on GL.inet GL-AR150:
Boot fails with 104 MHz but is successful with both 50 MHz and 80 MHz
(fast-read), where the latter two yield identical read speeds.

Fixes: ebf0d8dade ("ath79: add new ar934x spi driver")

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
2020-02-27 12:14:09 +01:00

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// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
/dts-v1/;
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/input/input.h>
#include "ar9330.dtsi"
/ {
model = "PQI Air-Pen";
compatible = "pqi,air-pen", "qca,ar9330";
aliases {
serial0 = &uart;
led-boot = &led_wlan;
led-failsafe = &led_wlan;
led-upgrade = &led_wlan;
};
leds {
compatible = "gpio-leds";
led_wlan: wlan {
label = "air-pen:blue:wlan";
gpios = <&gpio 0 GPIO_ACTIVE_HIGH>;
linux,default-trigger = "phy0tpt";
};
wps {
label = "air-pen:blue:wps";
gpios = <&gpio 23 GPIO_ACTIVE_HIGH>;
};
};
keys {
compatible = "gpio-keys";
wps {
label = "wps";
linux,code = <KEY_WPS_BUTTON>;
gpios = <&gpio 22 GPIO_ACTIVE_HIGH>;
debounce-interval = <60>;
};
reset {
label = "reset";
linux,code = <KEY_RESTART>;
gpios = <&gpio 12 GPIO_ACTIVE_HIGH>;
debounce-interval = <60>;
};
};
};
&uart {
status = "okay";
};
&gpio {
status = "okay";
};
&usb {
dr_mode = "host";
status = "okay";
};
&usb_phy {
status = "okay";
};
&spi {
status = "okay";
num-cs = <1>;
flash@0 {
compatible = "jedec,spi-nor";
spi-max-frequency = <50000000>;
reg = <0>;
partitions {
compatible = "fixed-partitions";
#address-cells = <1>;
#size-cells = <1>;
partition@0 {
label = "u-boot";
reg = <0x000000 0x040000>;
read-only;
};
partition@40000 {
label = "u-boot-env";
reg = <0x040000 0x010000>;
};
art: partition@50000 {
label = "art";
reg = <0x050000 0x010000>;
read-only;
};
partition@60000 {
label = "NVRAM";
reg = <0x060000 0x010000>;
read-only;
};
partition@70000 {
compatible = "denx,uimage";
label = "firmware";
reg = <0x070000 0x780000>;
};
partition@7f0000 {
label = "CONF";
reg = <0x7f0000 0x010000>;
read-only;
};
};
};
};
&eth0 {
status = "okay";
mtd-mac-address = <&art 0x1002>;
gmac-config {
device = <&gmac>;
switch-phy-addr-swap = <0>;
switch-phy-swap = <0>;
};
};
&eth1 {
status = "okay";
compatible = "syscon", "simple-mfd";
};
&wmac {
status = "okay";
mtd-cal-data = <&art 0x1000>;
mtd-mac-address = <&art 0x2>;
};