Re: [PATCH] iio: adc: exynos_adc: Add support for ADCv3 on exynos7

From: Chanwoo Choi
Date: Fri Oct 31 2014 - 08:47:22 EST


Hi Abhilash,

On 10/31/2014 09:38 PM, Abhilash Kesavan wrote:
> The ADC on exynos7 is quite similar to ADCv2. The differences are as
> follows:
> - v3 has 8 input channels (10 in v2).
> - v3 does not include an ADC PHY control register.
> - Some ADC_CON2 register bits being used in v2 are listed as
> reserved in v3. This results in a different init_hw function
> for v3.
>
> Signed-off-by: Abhilash Kesavan <a.kesavan@xxxxxxxxxxx>
> ---
> - Based on Naveen's "iio: exynos-adc: use syscon instead of ioremap" patchset
> http://comments.gmane.org/gmane.linux.kernel.iio/13943
>
> .../devicetree/bindings/arm/samsung/exynos-adc.txt | 2 ++
> drivers/iio/adc/exynos_adc.c | 32 ++++++++++++++++++++
> 2 files changed, 34 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt b/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt
> index c368210..a11e32c 100644
> --- a/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt
> +++ b/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt
> @@ -14,6 +14,8 @@ Required properties:
> for exynos4412/5250 and s5pv210 controllers.
> Must be "samsung,exynos-adc-v2" for
> future controllers.
> + Must be "samsung,exynos-adc-v3" for
> + the ADC in Exynos7 and compatibles

I prefer to use 'exynos7-adc' instead of 'exynos-adc-v3'.
Exynos7 has little different from existing ADCv2.

Also, If you want to use 'exynos-adc-v3' compatible,
Exynos7's TRM have to include the correct version(v3) infromation.

Thanks,
Chanwoo Choi



> Must be "samsung,exynos3250-adc" for
> controllers compatible with ADC of Exynos3250.
> Must be "samsung,s3c2410-adc" for
> diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
> index fe03177..74d0a9d 100644
> --- a/drivers/iio/adc/exynos_adc.c
> +++ b/drivers/iio/adc/exynos_adc.c
> @@ -390,6 +390,35 @@ static const struct exynos_adc_data exynos3250_adc_data = {
> .start_conv = exynos_adc_v2_start_conv,
> };
>
> +static void exynos_adc_v3_init_hw(struct exynos_adc *info)
> +{
> + u32 con1, con2;
> +
> + if (info->data->needs_adc_phy)
> + regmap_write(info->pmu_map, info->data->phy_offset, 1);
> +
> + con1 = ADC_V2_CON1_SOFT_RESET;
> + writel(con1, ADC_V2_CON1(info->regs));
> +
> + con2 = readl(ADC_V2_CON2(info->regs));
> + con2 &= ~ADC_V2_CON2_C_TIME(7);
> + con2 |= ADC_V2_CON2_C_TIME(0);
> + writel(con2, ADC_V2_CON2(info->regs));
> +
> + /* Enable interrupts */
> + writel(1, ADC_V2_INT_EN(info->regs));
> +}
> +
> +static const struct exynos_adc_data exynos_adc_v3_data = {
> + .num_channels = MAX_ADC_V1_CHANNELS,
> + .mask = ADC_DATX_MASK, /* 12 bit ADC resolution */
> +
> + .init_hw = exynos_adc_v3_init_hw,
> + .exit_hw = exynos_adc_v2_exit_hw,
> + .clear_irq = exynos_adc_v2_clear_irq,
> + .start_conv = exynos_adc_v2_start_conv,
> +};
> +
> static const struct of_device_id exynos_adc_match[] = {
> {
> .compatible = "samsung,s3c2410-adc",
> @@ -413,6 +442,9 @@ static const struct of_device_id exynos_adc_match[] = {
> .compatible = "samsung,exynos-adc-v2",
> .data = &exynos_adc_v2_data,
> }, {
> + .compatible = "samsung,exynos-adc-v3",
> + .data = &exynos_adc_v3_data,
> + }, {
> .compatible = "samsung,exynos3250-adc",
> .data = &exynos3250_adc_data,
> },
>

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