On 10/08/13 04:48, Josh Wu wrote:
> Since in at91sam9x5, sama5d3x chip. the start up time calucation is changed.
> This patch can choose different start up time calculation formula for different
> chips.
>
> Signed-off-by: Josh Wu <josh.wu@xxxxxxxxx>
> Acked-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Applied to the togreg branch of iio.git
Thanks
> ---
> drivers/iio/adc/at91_adc.c | 53 ++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 46 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> index 0f16b55..cee04a4 100644
> --- a/drivers/iio/adc/at91_adc.c
> +++ b/drivers/iio/adc/at91_adc.c
> @@ -40,6 +40,9 @@
> (writel_relaxed(val, st->reg_base + reg))
>
> struct at91_adc_caps {
> + /* startup time calculate function */
> + u32 (*calc_startup_ticks)(u8 startup_time, u32 adc_clk_khz);
> +
> struct at91_adc_reg_desc registers;
> };
>
> @@ -434,6 +437,45 @@ ret:
> return ret;
> }
>
> +static u32 calc_startup_ticks_9260(u8 startup_time, u32 adc_clk_khz)
> +{
> + /*
> + * Number of ticks needed to cover the startup time of the ADC
> + * as defined in the electrical characteristics of the board,
> + * divided by 8. The formula thus is :
> + * Startup Time = (ticks + 1) * 8 / ADC Clock
> + */
> + return round_up((startup_time * adc_clk_khz / 1000) - 1, 8) / 8;
> +}
> +
> +static u32 calc_startup_ticks_9x5(u8 startup_time, u32 adc_clk_khz)
> +{
> + /*
> + * For sama5d3x and at91sam9x5, the formula changes to:
> + * Startup Time = <lookup_table_value> / ADC Clock
> + */
> + const int startup_lookup[] = {
> + 0 , 8 , 16 , 24 ,
> + 64 , 80 , 96 , 112,
> + 512, 576, 640, 704,
> + 768, 832, 896, 960
> + };
> + int i, size = ARRAY_SIZE(startup_lookup);
> + unsigned int ticks;
> +
> + ticks = startup_time * adc_clk_khz / 1000;
> + for (i = 0; i < size; i++)
> + if (ticks < startup_lookup[i])
> + break;
> +
> + ticks = i;
> + if (ticks == size)
> + /* Reach the end of lookup table */
> + ticks = size - 1;
> +
> + return ticks;
> +}
> +
> static const struct of_device_id at91_adc_dt_ids[];
>
> static int at91_adc_probe_dt(struct at91_adc_state *st,
> @@ -657,15 +699,9 @@ static int at91_adc_probe(struct platform_device *pdev)
> ret = -EINVAL;
> goto error_disable_adc_clk;
> }
> + ticks = (*st->caps->calc_startup_ticks)(st->startup_time, adc_clk_khz);
>
> /*
> - * Number of ticks needed to cover the startup time of the ADC as
> - * defined in the electrical characteristics of the board, divided by 8.
> - * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock
> - */
> - ticks = round_up((st->startup_time * adc_clk_khz /
> - 1000) - 1, 8) / 8;
> - /*
> * a minimal Sample and Hold Time is necessary for the ADC to guarantee
> * the best converted final value between two channels selection
> * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock
> @@ -742,6 +778,7 @@ static int at91_adc_remove(struct platform_device *pdev)
>
> #ifdef CONFIG_OF
> static struct at91_adc_caps at91sam9260_caps = {
> + .calc_startup_ticks = calc_startup_ticks_9260,
> .registers = {
> .channel_base = AT91_ADC_CHR(0),
> .drdy_mask = AT91_ADC_DRDY,
> @@ -753,6 +790,7 @@ static struct at91_adc_caps at91sam9260_caps = {
> };
>
> static struct at91_adc_caps at91sam9g45_caps = {
> + .calc_startup_ticks = calc_startup_ticks_9260, /* same as 9260 */
> .registers = {
> .channel_base = AT91_ADC_CHR(0),
> .drdy_mask = AT91_ADC_DRDY,
> @@ -764,6 +802,7 @@ static struct at91_adc_caps at91sam9g45_caps = {
> };
>
> static struct at91_adc_caps at91sam9x5_caps = {
> + .calc_startup_ticks = calc_startup_ticks_9x5,
> .registers = {
> .channel_base = AT91_ADC_CDR0_9X5,
> .drdy_mask = AT91_ADC_SR_DRDY_9X5,
>
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