ec/kontron/kempld: Add minimal GPIO driver
The patch adds an interface for configuring GPIOs inside the Kontron
CPLD/EC. This allows to statically define the mode for each GPIO pin
in devicetree.cb of the motherboard or carrier board. For example:
chip ec/kontron/kempld
device gpio 0 on
register "gpio[0]" = "KEMPLD_GPIO_INPUT"
register "gpio[4]" = "KEMPLD_GPIO_OUTPUT_LOW"
register "gpio[5]" = "KEMPLD_GPIO_OUTPUT_HIGH"
register "gpio[11]" = "KEMPLD_GPIO_DEFAULT"
end
end
In this case, <device gpio 0>, like all other devices, is not a real
device inside the EC. These definitions are used to understand the EC
resources and systematize configuration options, but if mark this as
<off>, the initialization step will be skipped in the driver code.
Use KEMPLD_GPIO_DEFAULT or skip it in devicetree.cb to not configure
the GPIO and keep the default mode after CPLD reset.
This work is based on code from the drivers/gpio/gpio-kempld.c linux
driver. Tested on Kontron mAL-10 COMe module [1].
[1] CB:54380 , Change-Id: I7d354aa32ac8c64f54b2bcbdb4f1b8915f55264e
Change-Id: Id767aa451fbf2ca1c0dccfc9aa2c024c6f37c1bb
Signed-off-by: Maxim Polyakov <max.senia.poliak@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47595
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/ec/kontron/kempld/kempld.c b/src/ec/kontron/kempld/kempld.c
index f8371a8..0489bac 100644
--- a/src/ec/kontron/kempld/kempld.c
+++ b/src/ec/kontron/kempld/kempld.c
@@ -93,6 +93,14 @@
printk(BIOS_WARNING, "KEMPLD: Spurious device %s.\n", dev_path(dev));
break;
}
+ } else if (dev->path.type == DEVICE_PATH_GPIO) {
+ if (dev->path.gpio.id == 0) {
+ if (kempld_gpio_pads_config(dev) < 0)
+ printk(BIOS_ERR, "KEMPLD: GPIO configuration failed!\n");
+ } else {
+ printk(BIOS_WARNING, "KEMPLD: Spurious GPIO device %s.\n",
+ dev_path(dev));
+ }
}
}