iio: adc: at91_adc: Add support for touchscreens without TSMR

Old ADCs, as present on the sam9rl and the sam9g45 don't have a TSMR register
and the touchscreen support should be handled differently.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/platform_data/at91_adc.h b/include/linux/platform_data/at91_adc.h
index fcf73879dbfe..7819fc787731 100644
--- a/include/linux/platform_data/at91_adc.h
+++ b/include/linux/platform_data/at91_adc.h
@@ -7,6 +7,12 @@
 #ifndef _AT91_ADC_H_
 #define _AT91_ADC_H_
 
+enum atmel_adc_ts_type {
+        ATMEL_ADC_TOUCHSCREEN_NONE = 0,
+        ATMEL_ADC_TOUCHSCREEN_4WIRE = 4,
+        ATMEL_ADC_TOUCHSCREEN_5WIRE = 5,
+};
+
 /**
  * struct at91_adc_trigger - description of triggers
  * @name:               name of the trigger advertised to the user
@@ -28,6 +34,7 @@ struct at91_adc_trigger {
  * @trigger_number:             Number of triggers available in the ADC
  * @use_external_triggers:      does the board has external triggers availables
  * @vref:                       Reference voltage for the ADC in millivolts
+ * @touchscreen_type:           If a touchscreen is connected, its type (4 or 5 wires)
  */
 struct at91_adc_data {
         unsigned long                   channels_used;
@@ -36,6 +43,7 @@ struct at91_adc_data {
         u8                              trigger_number;
         bool                            use_external_triggers;
         u16                             vref;
+        enum atmel_adc_ts_type          touchscreen_type;
 };
 
 extern void __init at91_add_device_adc(struct at91_adc_data *data);