ab5500: enable GPADC-0 and provide sysfs interfce

This patch enables GPADC-0 to convert from voltage range
0 to 1.8v and also adds sysfs interface for reading gpadc ch-0.

"/sys/devices/platform/ab5500-core.0/ab5500-adc.0/adc0volt"

ST-Ericsson ID: 370066
ST-Ericsson Linux next: NA
ST-Ericsson FOSS-OUT ID: Trivial

Change-Id: Ic23caa22ff4e10d3dbb151e10eb4625ec5d7078a
Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/36216
Reviewed-by: QATOOLS
Reviewed-by: QABUILD
Reviewed-by: Linus WALLEIJ <linus.walleij@stericsson.com>

3 files changed, 62 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-devices-platform-ab5500-core-adc b/Documentation/ABI/testing/sysfs-devices-platform-ab5500-core-adc
new file mode 100644
index 00000000000..fcfc0ed26fb
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-platform-ab5500-core-adc
@@ -0,0 +1,20 @@
+What:           /sys/devices/platform/ab5500-core.0/ab5500-adc.0/adc0volt
+Date:           Nov 2011
+KernelVersion:  3.0
+Contact:        Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>
+Description:    The adc0volt attribute allows the userspace to read the
+                voltage of the device connected to the General Purpose
+                Analog to Digital Converter (GPADC) channel-0. Voltage
+                conversion from analog to digital happens only when this
+                attribute is read. GPADC block is present in AB5500 chip
+                and has input voltage range of 0-1.8 volt for GPADC Ch-0.
+                It provides result of the converted voltage in 10 bits.
+                Other GPADC channels attributes may appear in this path
+                later. For minimum and maximum input voltage range for
+                each channel please refer to the ST-Ericssons AB5500
+                datasheet. An example usage of GPADC can be an ALS device
+                connected to the channel and user space adapts the
+                LCD backlight brightness based on ambient light value
+                read from the attribute.
+Users:          HAL.
+
diff --git a/drivers/mfd/ab5500-gpadc.c b/drivers/mfd/ab5500-gpadc.c
index 6756d3cf37a..51d1fa9049a 100644
--- a/drivers/mfd/ab5500-gpadc.c
+++ b/drivers/mfd/ab5500-gpadc.c
@@ -67,6 +67,7 @@
 #define GPADC_MANUAL_ADOUT1_MASK	0xC0
 #define GPADC_MANUAL_ADOUT0_ON		0x10
 #define GPADC_MANUAL_ADOUT1_ON		0x40
+#define MUX_SCALE_GPADC0_MASK		0x08
 #define MUX_SCALE_VBAT_MASK		0x02
 #define MUX_SCALE_45			0x02
 #define MUX_SCALE_BDATA_MASK		0x01
@@ -74,6 +75,8 @@
 #define MUX_SCALE_BDATA18		0x01
 #define MUX_SCALE_ACCDET2_MASK		0x01
 #define MUX_SCALE_ACCDET3_MASK		0x02
+#define GPADC0_SCALE_VOL27		0x00
+#define GPADC0_SCALE_VOL18		0x01
 #define ACCDET2_SCALE_VOL27		0x00
 #define ACCDET3_SCALE_VOL27		0x00
 #define TRIGX_FREQ_MASK			0x07
@@ -98,6 +101,8 @@
 #define CTRL_INDEX			0x01
 
 /* GPADC constants from AB5500 spec  */
+#define GPADC0_MIN		0
+#define GPADC0_MAX		1800
 #define BTEMP_MIN		0
 #define BTEMP_MAX		1800
 #define BDATA_MIN		0
@@ -229,6 +234,7 @@ struct adc_data {
 	}
 
 struct adc_data adc_tab[] = {
+	ADC_DATA(GPADC0_V, 0x00, GPADC0_MIN, GPADC0_MAX, 0),
 	ADC_DATA(BTEMP_BALL, 0x0D, BTEMP_MIN, BTEMP_MAX, ADOUT0),
 	ADC_DATA(BAT_CTRL, 0x0D, BDATA_MIN, BDATA_MAX, 0),
 	ADC_DATA(MAIN_BAT_V, 0x0C, VBAT_MIN, VBAT_MAX, 0),
@@ -270,6 +276,7 @@ static int ab5500_gpadc_ad_to_voltage(struct ab5500_gpadc *gpadc,
 	int res;
 
 	switch (in) {
+	case GPADC0_V:
 	case PCB_TEMP:
 	case BTEMP_BALL:
 	case MAIN_BAT_V:
@@ -367,6 +374,15 @@ int ab5500_gpadc_convert(struct ab5500_gpadc *gpadc, u8 input)
 			goto out;
 		}
 		break;
+	case GPADC0_V:
+		ret = abx500_mask_and_set_register_interruptible(gpadc->dev,
+				AB5500_BANK_ADC, AB5500_GPADC_MANUAL_MODE_CTRL,
+				MUX_SCALE_GPADC0_MASK, GPADC0_SCALE_VOL18);
+		if (ret < 0) {
+			dev_err(gpadc->dev, "gpadc: fail to set gpadc0\n");
+			goto out;
+		}
+		break;
 	case ACC_DETECT2:
 		ret = abx500_mask_and_set_register_interruptible(gpadc->dev,
 				AB5500_BANK_ADC, AB5500_GPADC_MANUAL_MODE_CTRL2,
@@ -775,6 +791,19 @@ out:
 }
 EXPORT_SYMBOL(ab5500_gpadc_convert_auto);
 
+/* sysfs interface for GPADC0 */
+static ssize_t ab5500_gpadc0_get(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	int voltage;
+	struct ab5500_gpadc *gpadc = dev_get_drvdata(dev);
+
+	voltage = ab5500_gpadc_convert(gpadc, GPADC0_V);
+
+	return sprintf(buf, "%d\n", voltage);
+}
+static DEVICE_ATTR(adc0volt, 0644, ab5500_gpadc0_get, NULL);
+
 static void ab5500_gpadc_trigx_work(struct ab5500_gpadc *gp, int trig)
 {
 	unsigned long flags;
@@ -1114,9 +1143,19 @@ static int __devinit ab5500_gpadc_probe(struct platform_device *pdev)
 		dev_err(gpadc->dev, "gpadc: configuration failed\n");
 		goto free_wq;
 	}
+
+	ret = device_create_file(gpadc->dev, &dev_attr_adc0volt);
+	if (ret < 0) {
+		dev_err(gpadc->dev, "File device creation failed: %d\n", ret);
+		ret = -ENODEV;
+		goto fail_sysfs;
+	}
 	list_add_tail(&gpadc->node, &ab5500_gpadc_list);
 
+	platform_set_drvdata(pdev, gpadc);
+
 	return 0;
+fail_sysfs:
 free_wq:
 	destroy_workqueue(gpadc->gpadc_wq);
 fail_irq:
@@ -1134,6 +1173,8 @@ static int __devexit ab5500_gpadc_remove(struct platform_device *pdev)
 	int i, irq;
 	struct ab5500_gpadc *gpadc = platform_get_drvdata(pdev);
 
+	device_remove_file(gpadc->dev, &dev_attr_adc0volt);
+
 	/* remove this gpadc entry from the list */
 	list_del(&gpadc->node);
 	/* Disable interrupts */
diff --git a/include/linux/mfd/abx500/ab5500-gpadc.h b/include/linux/mfd/abx500/ab5500-gpadc.h
index 3282b44114e..67dc3cc9034 100644
--- a/include/linux/mfd/abx500/ab5500-gpadc.h
+++ b/include/linux/mfd/abx500/ab5500-gpadc.h
@@ -33,6 +33,7 @@
 #define MAIN_BAT_V_TXON_TRIG_MIN	13
 /* VBAT with TX off only min trigger */
 #define MAIN_BAT_V_TRIG_MIN		14
+#define GPADC0_V		15
 
 /*
  * Frequency of auto adc conversion