[S] Change in coreboot[main]: console/i2c_smbus: Allow to send data w/o register offset

[Nico Huber (Code Review)]

Nico Huber has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/82762?usp=email )

Change subject: console/i2c_smbus: Allow to send data w/o register offset
......................................................................

console/i2c_smbus: Allow to send data w/o register offset

Not every I2C target requires a register address. Not sending one
for every console char saves us a lot of overhead.

Change-Id: I1c714768fdd4aea4885e40a85d21fa42414ce32c
Signed-off-by: Nico Huber 
---
M src/console/Kconfig
M src/drivers/smbus/i2c_smbus_console.c
2 files changed, 16 insertions(+), 3 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/62/82762/1

diff --git a/src/console/Kconfig b/src/console/Kconfig
index 30b2862..db71204 100644
--- a/src/console/Kconfig
+++ b/src/console/Kconfig
@@ -318,8 +318,16 @@
    help
      I2C address of the device which logs the data.

+config CONSOLE_I2C_SMBUS_HAVE_DATA_REGISTER
+	bool "Write to a specific data register"
+	default y if SC16IS7XX_INIT
+	help
+	  Select this to provide a register address that will
+	  be sent before every data byte.
+
 config CONSOLE_I2C_SMBUS_SLAVE_DATA_REGISTER
    hex "Data register address of the I2C logging device"
+	depends on CONSOLE_I2C_SMBUS_HAVE_DATA_REGISTER
    default 0x00 if SC16IS7XX_INIT
    help
      This an 8-bit data register.
diff --git a/src/drivers/smbus/i2c_smbus_console.c b/src/drivers/smbus/i2c_smbus_console.c
index d651790..00b5393 100644
--- a/src/drivers/smbus/i2c_smbus_console.c
+++ b/src/drivers/smbus/i2c_smbus_console.c
@@ -13,7 +13,12 @@

void i2c_smbus_console_tx_byte(unsigned char c)
 {
-	do_smbus_write_byte(CONFIG_FIXED_SMBUS_IO_BASE,
-		CONFIG_CONSOLE_I2C_SMBUS_SLAVE_ADDRESS,
-		CONFIG_CONSOLE_I2C_SMBUS_SLAVE_DATA_REGISTER, c);
+	if (CONFIG(CONSOLE_I2C_SMBUS_HAVE_DATA_REGISTER)) {
+		do_smbus_write_byte(CONFIG_FIXED_SMBUS_IO_BASE,
+			CONFIG_CONSOLE_I2C_SMBUS_SLAVE_ADDRESS,
+			CONFIG_CONSOLE_I2C_SMBUS_SLAVE_DATA_REGISTER, c);
+	} else {
+		do_smbus_send_byte(CONFIG_FIXED_SMBUS_IO_BASE,
+			CONFIG_CONSOLE_I2C_SMBUS_SLAVE_ADDRESS, c);
+	}
 }