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authorPatil, Rachna <rachna@ti.com>2013-07-20 17:27:00 +0100
committerJonathan Cameron <jic23@kernel.org>2013-07-21 18:27:35 +0100
commitb1451e546899bc8f450773b2af02e0cd000cf1fa (patch)
treeb4147d4c31a3572c0c6c427fcd1ae8dfc7401c6c /include
parenta1a8e1dc111d6f05e7164e851e58219d428359e1 (diff)
iio: ti_am335x_adc: Fix wrong samples received on 1st read
Previously we tried to read data form ADC even before ADC sequencer finished sampling. This led to wrong samples. We now wait on ADC status register idle bit to be set. Signed-off-by: Patil, Rachna <rachna@ti.com> Signed-off-by: Zubair Lutfullah <zubair.lutfullah@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/mfd/ti_am335x_tscadc.h16
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
index 8d73fe29796..db1791bb997 100644
--- a/include/linux/mfd/ti_am335x_tscadc.h
+++ b/include/linux/mfd/ti_am335x_tscadc.h
@@ -113,11 +113,27 @@
#define CNTRLREG_8WIRE CNTRLREG_AFE_CTRL(3)
#define CNTRLREG_TSCENB BIT(7)
+/* FIFO READ Register */
+#define FIFOREAD_DATA_MASK (0xfff << 0)
+#define FIFOREAD_CHNLID_MASK (0xf << 16)
+
+/* Sequencer Status */
+#define SEQ_STATUS BIT(5)
+
#define ADC_CLK 3000000
#define MAX_CLK_DIV 7
#define TOTAL_STEPS 16
#define TOTAL_CHANNELS 8
+/*
+* ADC runs at 3MHz, and it takes
+* 15 cycles to latch one data output.
+* Hence the idle time for ADC to
+* process one sample data would be
+* around 5 micro seconds.
+*/
+#define IDLE_TIMEOUT 5 /* microsec */
+
#define TSCADC_CELLS 2
struct ti_tscadc_dev {