[PATCH RFC] mfd: twl4030-madc: Enable ADC channels 3-6

[PATCH RFC] mfd: twl4030-madc: Enable ADC channels 3-6

[Steve Sakoman]

Currently the driver does not explicitly set the TWL4030_USB_SEL_MADC_MCPC
bit to enable madc input channels 3 through 6.  This results in readings near
zero for these channels since the inputs are grounded if this bit is not set.

Signed-off-by: Steve Sakoman <steve@sakoman.com>
---

diff --git a/drivers/mfd/twl4030-madc.c b/drivers/mfd/twl4030-madc.c
index 834f824..56a8e9b 100644
--- a/drivers/mfd/twl4030-madc.c
+++ b/drivers/mfd/twl4030-madc.c
@@ -725,6 +725,23 @@ static int __devinit twl4030_madc_probe(struct
platform_device *pdev)
 	if (ret < 0)
 		goto err_current_generator;

+	/* Enable ADCIN3 through 6 */
+	ret = twl_i2c_read_u8(TWL4030_MODULE_USB,
+			      &regval, TWL4030_USB_CARKIT_ANA_CTRL);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to read reg CARKIT_ANA_CTRL 0x%X\n",
+			TWL4030_USB_CARKIT_ANA_CTRL);
+		goto err_i2c;
+	}
+	regval |= TWL4030_USB_SEL_MADC_MCPC;
+	ret = twl_i2c_write_u8(TWL4030_MODULE_USB,
+			       regval, TWL4030_USB_CARKIT_ANA_CTRL);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to write reg CARKIT_ANA_CTRL 0x%X\n",
+			TWL4030_USB_CARKIT_ANA_CTRL);
+		goto err_i2c;
+	}
+
 	ret = twl_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
 			      &regval, TWL4030_BCI_BCICTL1);
 	if (ret) {
diff --git a/include/linux/i2c/twl4030-madc.h b/include/linux/i2c/twl4030-madc.h
index 530e11b..f017495 100644
--- a/include/linux/i2c/twl4030-madc.h
+++ b/include/linux/i2c/twl4030-madc.h
@@ -120,6 +120,9 @@ enum sample_type {
 #define CURR_PSR_R1		44
 #define CURR_PSR_R2		88

+#define TWL4030_USB_CARKIT_ANA_CTRL	0xBB
+#define TWL4030_USB_SEL_MADC_MCPC	(1<<3)
+
 #define TWL4030_BCI_BCICTL1	0x23
 #define TWL4030_BCI_CGAIN	0x020
 #define TWL4030_BCI_MESBAT	(1 << 1)

Re: [PATCH RFC] mfd: twl4030-madc: Enable ADC channels 3-6

[Kyle Manna]

On 12/08/2011 05:13 PM, Steve Sakoman wrote:
> Currently the driver does not explicitly set the TWL4030_USB_SEL_MADC_MCPC
> bit to enable madc input channels 3 through 6.  This results in readings near
> zero for these channels since the inputs are grounded if this bit is not set.

I've run into this same problem and have fixed it the same way, looks 
good to me.

Reviewed-by: Kyle Manna <kyle@kylemanna.com>

- Kyle