[PATCH] ARM: multi_v7_defconfig: fix failure setting CPU voltage by enabling dependent I2C controller

Tyler Baker tyler.baker at linaro.org
Tue Nov 18 11:10:53 PST 2014

This patch fixes a long standing issue introduced during the 3.16 merge window.
Shortly after the merge, exynos5250-based arndale boards began to produce the 
following errors:

kern.err kernel:  exynos-cpufreq exynos-cpufreq: failed to set cpu voltage
kern.err kernel:  cpufreq: __target_index: Failed to change cpu frequency: -22

Further analysis revealed that the S5M8767 voltage regulator used on the 
exynos5250-based arndale board utilizes the S3C2410 I2C controller. If the 
S3C2410 I2C controller driver is not enabled, the S5M8767 voltage regulator 
fails to probe. Therefore a dependency exists between these two drivers. 
In the exynos_defconfig both CONFIG_REGULATOR_S5M8767 and CONFIG_I2C_S3C2410 
options are enabled, and no errors are produced. However, in the 
multi_v7_defconfig only the CONFIG_REGULATOR_S5M8767 option is enabled and the 
errors are present. So let's enable the CONFIG_I2C_S3C2410 option in the 
multi_v7_defconfig to allow the S5M8767 voltage regulator to probe.

Signed-off-by: Tyler Baker <tyler.baker at linaro.org>
This issue was reported [1]. I've also confirmed this fix on two different 
arndale boards.

[1] https://www.mail-archive.com/linux-samsung-soc@vger.kernel.org/msg38765.html

 arch/arm/configs/multi_v7_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/configs/multi_v7_defconfig b/arch/arm/configs/multi_v7_defconfig
index 3487046..9d7a32f 100644
--- a/arch/arm/configs/multi_v7_defconfig
+++ b/arch/arm/configs/multi_v7_defconfig
@@ -217,6 +217,7 @@ CONFIG_I2C_CADENCE=y

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