Change in coreboot[master]: drivers/i2c/designware: Report I2C timings for additional bus speeds

[Patrick Georgi (Code Review)]

Patrick Georgi has submitted this change. ( https://review.coreboot.org/c/coreboot/+/55088 )

Change subject: drivers/i2c/designware: Report I2C timings for additional bus speeds
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drivers/i2c/designware: Report I2C timings for additional bus speeds

Since the OS provides its own driver for the I2C controller it can
choose to use a bus speed other than the one used at coreboot runtime.
In this case it would be good to provide a way how the needed bus
timings are communicated to the OS, since these are very board-specific
and there is no way that the OS can know them other than read the
appropriate ACPI reported timings.
This patch adds some code to report additional bus speed timings if
there are some defined in the devicetree.

Change-Id: If921e0613864660dc1bb8d7c1b30fb9db8ac655d
Signed-off-by: Werner Zeh 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55088
Tested-by: build bot (Jenkins) 
Reviewed-by: Tim Wawrzynczak 
Reviewed-by: Mario Scheithauer 
Reviewed-by: Paul Menzel 
---
M src/drivers/i2c/designware/dw_i2c.c
1 file changed, 9 insertions(+), 4 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Paul Menzel: Looks good to me, but someone else must approve
  Mario Scheithauer: Looks good to me, approved
  Tim Wawrzynczak: Looks good to me, but someone else must approve

diff --git a/src/drivers/i2c/designware/dw_i2c.c b/src/drivers/i2c/designware/dw_i2c.c
index 2e2d20d..a6498fb 100644
--- a/src/drivers/i2c/designware/dw_i2c.c
+++ b/src/drivers/i2c/designware/dw_i2c.c
@@ -803,7 +803,7 @@
    struct dw_i2c_speed_config sgen;
    int bus;
    const char *path;
-	unsigned int speed;
+	unsigned int speed, i;

bus = dw_i2c_soc_dev_to_bus(dev);

@@ -826,12 +826,17 @@
    /* Ensure a default speed is available */
    speed = (bcfg->speed == 0) ? I2C_SPEED_FAST : bcfg->speed;

-	/* Report timing values for the OS driver */
+	/* Report currently used timing values for the OS driver */
+	acpigen_write_scope(path);
    if (dw_i2c_gen_speed_config(dw_i2c_addr, speed, bcfg, &sgen) >= 0) {
-		acpigen_write_scope(path);
    	dw_i2c_acpi_write_speed_config(&sgen);
-		acpigen_pop_len();
    }
+	/* Now check if there are more speed settings available and report them as well. */
+	for (i = 0; i < DW_I2C_SPEED_CONFIG_COUNT; i++) {
+		if (bcfg->speed_config[i].speed && speed != bcfg->speed_config[i].speed)
+			dw_i2c_acpi_write_speed_config(&bcfg->speed_config[i]);
+	}
+	acpigen_write_scope_end();
 }

static int dw_i2c_dev_transfer(struct device *dev,