hwmon: Add Freescale MC13783 ADC driver

This driver provides support for the ADC integrated into the
Freescale MC13783 PMIC.

Signed-off-by: Luotao Fu <l.fu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Cc: Eric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 50 insertions, 0 deletions

diff --git a/Documentation/hwmon/mc13783-adc b/Documentation/hwmon/mc13783-adc
new file mode 100644
index 000000000000..044531a86405
--- /dev/null
+++ b/Documentation/hwmon/mc13783-adc
@@ -0,0 +1,50 @@
+Kernel driver mc13783-adc
+=========================
+
+Supported chips:
+  * Freescale Atlas MC13783
+    Prefix: 'mc13783_adc'
+    Datasheet: http://www.freescale.com/files/rf_if/doc/data_sheet/MC13783.pdf?fsrch=1
+
+Authors:
+    Sascha Hauer <s.hauer@pengutronix.de>
+    Luotao Fu <l.fu@pengutronix.de>
+
+Description
+-----------
+
+The Freescale MC13783 is a Power Management and Audio Circuit. Among
+other things it contains a 10-bit A/D converter. The converter has 16
+channels which can be used in different modes.
+The A/D converter has a resolution of 2.25mV. Channels 0-4 have
+a dedicated meaning with chip internal scaling applied. Channels 5-7
+can be used as general purpose inputs or alternatively in a dedicated
+mode. Channels 12-15 are occupied by the touchscreen if it's active.
+
+Currently the driver only supports channels 2 and 5-15 with no alternative
+modes for channels 5-7.
+
+See this table for the meaning of the different channels and their chip
+internal scaling:
+
+Channel Signal                                          Input Range     Scaling
+-------------------------------------------------------------------------------
+0       Battery Voltage (BATT)                          2.50 - 4.65V    -2.40V
+1       Battery Current (BATT - BATTISNS)               -50 - 50 mV     x20
+2       Application Supply (BP)                         2.50 - 4.65V    -2.40V
+3       Charger Voltage (CHRGRAW)                       0 - 10V /       /5
+                                                        0 - 20V         /10
+4       Charger Current (CHRGISNSP-CHRGISNSN)           -0.25V - 0.25V  x4
+5       General Purpose ADIN5 / Battery Pack Thermistor 0 - 2.30V       No
+6       General Purpose ADIN6 / Backup Voltage (LICELL) 0 - 2.30V /     No /
+                                                        1.50 - 3.50V    -1.20V
+7       General Purpose ADIN7 / UID / Die Temperature   0 - 2.30V /     No /
+                                                        0 - 2.55V /     x0.9 / No
+8       General Purpose ADIN8                           0 - 2.30V       No
+9       General Purpose ADIN9                           0 - 2.30V       No
+10      General Purpose ADIN10                          0 - 2.30V       No
+11      General Purpose ADIN11                          0 - 2.30V       No
+12      General Purpose TSX1 / Touchscreen X-plate 1    0 - 2.30V       No
+13      General Purpose TSX2 / Touchscreen X-plate 2    0 - 2.30V       No
+14      General Purpose TSY1 / Touchscreen Y-plate 1    0 - 2.30V       No
+15      General Purpose TSY2 / Touchscreen Y-plate 2    0 - 2.30V       No