iio: adc: exynos-adc: Use proper number of channels for Exynos4x12

Exynos4212 and Exynos4412 have only four ADC channels so using
"samsung,exynos-adc-v1" compatible (for eight channels ADCv1) on them is
wrong.  Add a new compatible for Exynos4x12.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/samsung,exynos-adc.txt

@@ -11,11 +11,13 @@ New driver handles the following
 
 Required properties:
 - compatible:		Must be "samsung,exynos-adc-v1"
-				for exynos4412/5250 controllers.
+				for Exynos5250 controllers.
 			Must be "samsung,exynos-adc-v2" for
 				future controllers.
 			Must be "samsung,exynos3250-adc" for
 				controllers compatible with ADC of Exynos3250.
+			Must be "samsung,exynos4212-adc" for
+				controllers compatible with ADC of Exynos4212 and Exynos4412.
 			Must be "samsung,exynos7-adc" for
 				the ADC in Exynos7 and compatibles
 			Must be "samsung,s3c2410-adc" for

drivers/iio/adc/exynos_adc.c

@@ -115,6 +115,7 @@
 #define MAX_ADC_V2_CHANNELS		10
 #define MAX_ADC_V1_CHANNELS		8
 #define MAX_EXYNOS3250_ADC_CHANNELS	2
+#define MAX_EXYNOS4212_ADC_CHANNELS	4
 #define MAX_S5PV210_ADC_CHANNELS	10
 
 /* Bit definitions common for ADC_V1 and ADC_V2 */
@@ -271,6 +272,19 @@ static void exynos_adc_v1_start_conv(struct exynos_adc *info,
 	writel(con1 | ADC_CON_EN_START, ADC_V1_CON(info->regs));
 }
 
+/* Exynos4212 and 4412 is like ADCv1 but with four channels only */
+static const struct exynos_adc_data exynos4212_adc_data = {
+	.num_channels	= MAX_EXYNOS4212_ADC_CHANNELS,
+	.mask		= ADC_DATX_MASK,	/* 12 bit ADC resolution */
+	.needs_adc_phy	= true,
+	.phy_offset	= EXYNOS_ADCV1_PHY_OFFSET,
+
+	.init_hw	= exynos_adc_v1_init_hw,
+	.exit_hw	= exynos_adc_v1_exit_hw,
+	.clear_irq	= exynos_adc_v1_clear_irq,
+	.start_conv	= exynos_adc_v1_start_conv,
+};
+
 static const struct exynos_adc_data exynos_adc_v1_data = {
 	.num_channels	= MAX_ADC_V1_CHANNELS,
 	.mask		= ADC_DATX_MASK,	/* 12 bit ADC resolution */
@@ -492,6 +506,9 @@ static const struct of_device_id exynos_adc_match[] = {
 	}, {
 		.compatible = "samsung,s5pv210-adc",
 		.data = &exynos_adc_s5pv210_data,
+	}, {
+		.compatible = "samsung,exynos4212-adc",
+		.data = &exynos4212_adc_data,
 	}, {
 		.compatible = "samsung,exynos-adc-v1",
 		.data = &exynos_adc_v1_data,