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authorRussell King <rmk+kernel@arm.linux.org.uk>2013-10-07 10:43:04 -0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-10-07 10:43:04 -0400
commita56e74f546b64be93731e42d83baf5b538cc1b11 (patch)
tree18f6dee45d801e57ac9db2a31664b0d5c0762c50 /drivers/iio/adc
parentd08e2e09042bd3f7ef66a35cb4bb92794ab26bb2 (diff)
parente4e7f10bfc4069925e99cc4b428c3434e30b6c3f (diff)
Merge branch 'arm-aesbs' of git://git.linaro.org/people/ardbiesheuvel/linux-arm into devel-stable
Diffstat (limited to 'drivers/iio/adc')
-rw-r--r--drivers/iio/adc/at91_adc.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index 84be63bdf038..0f16b553e063 100644
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -556,7 +556,7 @@ static const struct iio_info at91_adc_info = {
556 556
557static int at91_adc_probe(struct platform_device *pdev) 557static int at91_adc_probe(struct platform_device *pdev)
558{ 558{
559 unsigned int prsc, mstrclk, ticks, adc_clk, shtim; 559 unsigned int prsc, mstrclk, ticks, adc_clk, adc_clk_khz, shtim;
560 int ret; 560 int ret;
561 struct iio_dev *idev; 561 struct iio_dev *idev;
562 struct at91_adc_state *st; 562 struct at91_adc_state *st;
@@ -649,6 +649,7 @@ static int at91_adc_probe(struct platform_device *pdev)
649 */ 649 */
650 mstrclk = clk_get_rate(st->clk); 650 mstrclk = clk_get_rate(st->clk);
651 adc_clk = clk_get_rate(st->adc_clk); 651 adc_clk = clk_get_rate(st->adc_clk);
652 adc_clk_khz = adc_clk / 1000;
652 prsc = (mstrclk / (2 * adc_clk)) - 1; 653 prsc = (mstrclk / (2 * adc_clk)) - 1;
653 654
654 if (!st->startup_time) { 655 if (!st->startup_time) {
@@ -662,15 +663,15 @@ static int at91_adc_probe(struct platform_device *pdev)
662 * defined in the electrical characteristics of the board, divided by 8. 663 * defined in the electrical characteristics of the board, divided by 8.
663 * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock 664 * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock
664 */ 665 */
665 ticks = round_up((st->startup_time * adc_clk / 666 ticks = round_up((st->startup_time * adc_clk_khz /
666 1000000) - 1, 8) / 8; 667 1000) - 1, 8) / 8;
667 /* 668 /*
668 * a minimal Sample and Hold Time is necessary for the ADC to guarantee 669 * a minimal Sample and Hold Time is necessary for the ADC to guarantee
669 * the best converted final value between two channels selection 670 * the best converted final value between two channels selection
670 * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock 671 * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock
671 */ 672 */
672 shtim = round_up((st->sample_hold_time * adc_clk / 673 shtim = round_up((st->sample_hold_time * adc_clk_khz /
673 1000000) - 1, 1); 674 1000) - 1, 1);
674 675
675 reg = AT91_ADC_PRESCAL_(prsc) & st->registers->mr_prescal_mask; 676 reg = AT91_ADC_PRESCAL_(prsc) & st->registers->mr_prescal_mask;
676 reg |= AT91_ADC_STARTUP_(ticks) & st->registers->mr_startup_mask; 677 reg |= AT91_ADC_STARTUP_(ticks) & st->registers->mr_startup_mask;