1 files changed, 12 insertions, 7 deletions
diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
index 25f2c611ab01..4befdb85dd9c 100644
--- a/include/linux/mfd/ti_am335x_tscadc.h
+++ b/include/linux/mfd/ti_am335x_tscadc.h
@@ -125,13 +125,18 @@
 #define TOTAL_CHANNELS          8
 /*
-* ADC runs at 3MHz, and it takes
+ * time in us for processing a single channel, calculated as follows:
-* 15 cycles to latch one data output.
+ *
-* Hence the idle time for ADC to
+ * num cycles = open delay + (sample delay + conv time) * averaging
-* process one sample data would be
+ *
-* around 5 micro seconds.
+ * num cycles: 152 + (1 + 13) * 16 = 376
-*/
+ *
-#define IDLE_TIMEOUT 5 /* microsec */
+ * clock frequency: 26MHz / 8 = 3.25MHz
+ * clock period: 1 / 3.25MHz = 308ns
+ *
+ * processing time: 376 * 308ns = 116us
+ */
+#define IDLE_TIMEOUT 116 /* microsec */
 #define TSCADC_CELLS            2

diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h index 25f2c611ab01..4befdb85dd9c 100644 --- a/include/linux/mfd/ti_am335x_tscadc.h +++ b/include/linux/mfd/ti_am335x_tscadc.h
@@ -125,13 +125,18 @@
125	#define TOTAL_CHANNELS 8	125	#define TOTAL_CHANNELS 8
126		126
127	/*	127	/*
128	* ADC runs at 3MHz, and it takes	128	* time in us for processing a single channel, calculated as follows:
129	* 15 cycles to latch one data output.	129	*
130	* Hence the idle time for ADC to	130	* num cycles = open delay + (sample delay + conv time) * averaging
131	* process one sample data would be	131	*
132	* around 5 micro seconds.	132	* num cycles: 152 + (1 + 13) * 16 = 376
133	*/	133	*
134	#define IDLE_TIMEOUT 5 /* microsec */	134	* clock frequency: 26MHz / 8 = 3.25MHz
		135	* clock period: 1 / 3.25MHz = 308ns
		136	*
		137	* processing time: 376 * 308ns = 116us
		138	*/
		139	#define IDLE_TIMEOUT 116 /* microsec */
135		140
136	#define TSCADC_CELLS 2	141	#define TSCADC_CELLS 2
137		142