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iio:adc:at91-sama5d2: cleanup mode register use

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Do not erase previous configuration of the mode register when setting
the sampling frequency.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Ludovic Desroches 2016-03-22 17:08:45 +01:00 committed by Jonathan Cameron
parent 22d199a539
commit 94b2423019
1 changed files with 10 additions and 5 deletions
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15
drivers/iio/adc/at91-sama5d2_adc.c
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@ -66,8 +66,10 @@
#define AT91_SAMA5D2_MR_PRESCAL(v) ((v) << AT91_SAMA5D2_MR_PRESCAL_OFFSET)
#define AT91_SAMA5D2_MR_PRESCAL_OFFSET 8
#define AT91_SAMA5D2_MR_PRESCAL_MAX 0xff
#define AT91_SAMA5D2_MR_PRESCAL_MASK GENMASK(15, 8)
/* Startup Time */
#define AT91_SAMA5D2_MR_STARTUP(v) ((v) << 16)
#define AT91_SAMA5D2_MR_STARTUP_MASK GENMASK(19, 16)
/* Analog Change */
#define AT91_SAMA5D2_MR_ANACH BIT(23)
/* Tracking Time */
@ -226,7 +228,7 @@ static unsigned at91_adc_startup_time(unsigned startup_time_min,
static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
{
struct iio_dev *indio_dev = iio_priv_to_dev(st);
unsigned f_per, prescal, startup;
unsigned f_per, prescal, startup, mr;
f_per = clk_get_rate(st->per_clk);
prescal = (f_per / (2 * freq)) - 1;
@ -234,10 +236,11 @@ static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
startup = at91_adc_startup_time(st->soc_info.startup_time,
freq / 1000);
at91_adc_writel(st, AT91_SAMA5D2_MR,
AT91_SAMA5D2_MR_TRANSFER(2)
| AT91_SAMA5D2_MR_STARTUP(startup)
| AT91_SAMA5D2_MR_PRESCAL(prescal));
mr = at91_adc_readl(st, AT91_SAMA5D2_MR);
mr &= ~(AT91_SAMA5D2_MR_STARTUP_MASK | AT91_SAMA5D2_MR_PRESCAL_MASK);
mr |= AT91_SAMA5D2_MR_STARTUP(startup);
mr |= AT91_SAMA5D2_MR_PRESCAL(prescal);
at91_adc_writel(st, AT91_SAMA5D2_MR, mr);
dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
freq, startup, prescal);
@ -444,6 +447,8 @@ static int at91_adc_probe(struct platform_device *pdev)
at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
/* Transfer field must be set to 2 according to the datasheet. */
at91_adc_writel(st, AT91_SAMA5D2_MR, AT91_SAMA5D2_MR_TRANSFER(2));
at91_adc_setup_samp_freq(st, st->soc_info.min_sample_rate);