[U-Boot] [PATCH] env: ti: boot: Use ttyS2 instead of ttyO2

[Sam Protsenko]

ttyO2 console enables legacy CONFIG_SERIAL_OMAP driver in kernel.
Nowadays it's preferred to use the generic CONFIG_SERIAL_8250_OMAP
driver, which being enabled via ttyS2 console. Both drivers are enabled
in multi_v7_defconfig and in omap2plus_defconfig, for compatibility
reasons. Let's switch to ttyS2 console, to be sure that standard 8250
serial driver is used.

Similar behavior can be also achieved by enabling
CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP option in kernel, but it's better not
to rely on that, as it can be disabled or removed after transitional
period.

Right now on DRA7/AM57x platforms the 8250-omap driver is being probed
first, and omap-serial driver is only probed if the first one failed.
It can be seen from uart3 definition in arch/arm/boot/dts/dra7-l4.dtsi:

    compatible = "ti,dra742-uart", "ti,omap4-uart";

So the kernel already uses 8250 driver. This change basically allows
kernel developers to throw away the omap-serial driver and associated
compatibility options. Similar discussions [1,2] have started several
years ago, so it should be safe to do that now.

[1] https://patchwork.kernel.org/patch/6198471/
[2] http://processors.wiki.ti.com/index.php/Sitara_Linux_UART_-_Switching_to_8250_Driver

Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
---
Changes in v2:
  - use ttyS also in AM57x EVM and in DRA7xx EVM configs

 include/configs/am57xx_evm.h  | 2 +-
 include/configs/dra7xx_evm.h  | 4 ++--
 include/environment/ti/boot.h | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/configs/am57xx_evm.h b/include/configs/am57xx_evm.h
index 45fd21878c..e181b30564 100644
--- a/include/configs/am57xx_evm.h
+++ b/include/configs/am57xx_evm.h
@@ -24,7 +24,7 @@
 
 #define CONFIG_SYS_BOOTM_LEN		SZ_64M
 
-#define CONSOLEDEV			"ttyO2"
+#define CONSOLEDEV			"ttyS2"
 #define CONFIG_SYS_NS16550_COM1		UART1_BASE	/* Base EVM has UART0 */
 #define CONFIG_SYS_NS16550_COM2		UART2_BASE	/* UART2 */
 #define CONFIG_SYS_NS16550_COM3		UART3_BASE	/* UART3 */
diff --git a/include/configs/dra7xx_evm.h b/include/configs/dra7xx_evm.h
index 9c8141de2e..7ec6e691c7 100644
--- a/include/configs/dra7xx_evm.h
+++ b/include/configs/dra7xx_evm.h
@@ -26,9 +26,9 @@
 #endif
 
 #if (CONFIG_CONS_INDEX == 1)
-#define CONSOLEDEV			"ttyO0"
+#define CONSOLEDEV			"ttyS0"
 #elif (CONFIG_CONS_INDEX == 3)
-#define CONSOLEDEV			"ttyO2"
+#define CONSOLEDEV			"ttyS2"
 #endif
 #define CONFIG_SYS_NS16550_COM1		UART1_BASE	/* Base EVM has UART0 */
 #define CONFIG_SYS_NS16550_COM2		UART2_BASE	/* UART2 */
diff --git a/include/environment/ti/boot.h b/include/environment/ti/boot.h
index 01b2981c5b..22206b9467 100644
--- a/include/environment/ti/boot.h
+++ b/include/environment/ti/boot.h
@@ -10,7 +10,7 @@
 #define __TI_BOOT_H
 
 #ifndef CONSOLEDEV
-#define CONSOLEDEV "ttyO2"
+#define CONSOLEDEV "ttyS2"
 #endif
 
 #define VBMETA_PART_SIZE		(64 * 1024)
-- 
2.20.1