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>
This commit is contained in:
Patil, Rachna
2013-07-20 17:27:00 +01:00
committed by Jonathan Cameron
parent a1a8e1dc11
commit b1451e5468
2 changed files with 38 additions and 8 deletions

View File

@@ -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 {