i2c: Add Qualcomm CCI I2C driver

This commit adds I2C bus support for the Camera Control Interface
(CCI) I2C controller found on the Qualcomm SoC processors. This I2C
controller supports two masters and they are registered to the core.

CCI versions supported in the driver are msm8916, msm8996 and sdm845.

This is a rework of the patch posted by Vinod:
https://patchwork.kernel.org/patch/10569961/

With additional fixes + most of the comments addressed.

Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Tested-by: Robert Foss <robert.foss@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
[wsa: removed err msg after platform_get_irq]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/Kconfig

@@ -885,6 +885,16 @@ config I2C_PXA_SLAVE
 	  is necessary for systems where the PXA may be a target on the
 	  I2C bus.
 
+config I2C_QCOM_CCI
+	tristate "Qualcomm Camera Control Interface"
+	depends on ARCH_QCOM || COMPILE_TEST
+	help
+	  If you say yes to this option, support will be included for the
+	  built-in camera control interface on the Qualcomm SoCs.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-qcom-cci.
+
 config I2C_QCOM_GENI
 	tristate "Qualcomm Technologies Inc.'s GENI based I2C controller"
 	depends on ARCH_QCOM || COMPILE_TEST

drivers/i2c/busses/Makefile

@@ -91,6 +91,7 @@ obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
 obj-$(CONFIG_I2C_PUV3)		+= i2c-puv3.o
 obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
 obj-$(CONFIG_I2C_PXA_PCI)	+= i2c-pxa-pci.o
+obj-$(CONFIG_I2C_QCOM_CCI)	+= i2c-qcom-cci.o
 obj-$(CONFIG_I2C_QCOM_GENI)	+= i2c-qcom-geni.o
 obj-$(CONFIG_I2C_QUP)		+= i2c-qup.o
 obj-$(CONFIG_I2C_RIIC)		+= i2c-riic.o