On Mon, 17 Jul 2017 12:00:35 +0300
Mykola Kostenok <c_mykolak@xxxxxxxxxxxx> wrote:
> This patch enables adc engine at initialization time and waits
> for the initial sequence completion before enabling adc channels.
>
> Without this code adc channels are not functional and shows
> zeros for all connected channels.
>
> Tested on mellanox msn platform.
>
> v1 -> v2:
> Pointed by Rick Altherr:
> - Wait init sequence code enabled by bool
> from OF match table.
>
> Reviewed-by: Rick Altherr <raltherr@xxxxxxxxxx>
>
> Signed-off-by: Mykola Kostenok <c_mykolak@xxxxxxxxxxxx>
Applied to the fixes-togreg branch of iio.git and marked for
stable.
Thanks,
Jonathan
> ---
> drivers/iio/adc/aspeed_adc.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c
> index 2283ed2..cfa7ee1 100644
> --- a/drivers/iio/adc/aspeed_adc.c
> +++ b/drivers/iio/adc/aspeed_adc.c
> @@ -22,6 +22,7 @@
>
> #include <linux/iio/iio.h>
> #include <linux/iio/driver.h>
> +#include <linux/iopoll.h>
>
> #define ASPEED_RESOLUTION_BITS 10
> #define ASPEED_CLOCKS_PER_SAMPLE 12
> @@ -38,11 +39,17 @@
>
> #define ASPEED_ENGINE_ENABLE BIT(0)
>
> +#define ASPEED_ADC_CTRL_INIT_RDY BIT(8)
> +
> +#define ASPEED_ADC_INIT_POLLING_TIME 500
> +#define ASPEED_ADC_INIT_TIMEOUT 500000
> +
> struct aspeed_adc_model_data {
> const char *model_name;
> unsigned int min_sampling_rate; // Hz
> unsigned int max_sampling_rate; // Hz
> unsigned int vref_voltage; // mV
> + bool wait_init_sequence;
> };
>
> struct aspeed_adc_data {
> @@ -210,6 +217,24 @@ static int aspeed_adc_probe(struct platform_device *pdev)
> goto scaler_error;
> }
>
> + model_data = of_device_get_match_data(&pdev->dev);
> +
> + if (model_data->wait_init_sequence) {
> + /* Enable engine in normal mode. */
> + writel(ASPEED_OPERATION_MODE_NORMAL | ASPEED_ENGINE_ENABLE,
> + data->base + ASPEED_REG_ENGINE_CONTROL);
> +
> + /* Wait for initial sequence complete. */
> + ret = readl_poll_timeout(data->base + ASPEED_REG_ENGINE_CONTROL,
> + adc_engine_control_reg_val,
> + adc_engine_control_reg_val &
> + ASPEED_ADC_CTRL_INIT_RDY,
> + ASPEED_ADC_INIT_POLLING_TIME,
> + ASPEED_ADC_INIT_TIMEOUT);
> + if (ret)
> + goto scaler_error;
> + }
> +
> /* Start all channels in normal mode. */
> clk_prepare_enable(data->clk_scaler->clk);
> adc_engine_control_reg_val = GENMASK(31, 16) |
> @@ -269,6 +294,7 @@ static const struct aspeed_adc_model_data ast2500_model_data = {
> .vref_voltage = 1800, // mV
> .min_sampling_rate = 1,
> .max_sampling_rate = 1000000,
> + .wait_init_sequence = true,
> };
>
> static const struct of_device_id aspeed_adc_matches[] = {
--
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