Message-id: <545384D3.5050000@samsung.com>
Date: Fri, 31 Oct 2014 21:47:15 +0900
From: Chanwoo Choi <cw00.choi@samsung.com>
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To: Abhilash Kesavan <a.kesavan@samsung.com>
Cc: linux-iio@vger.kernel.org, jic23@kernel.org, naveenkrishna.ch@gmail.com,
        kesavan.abhilash@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iio: adc: exynos_adc: Add support for ADCv3 on exynos7
References: <1414759083-4555-1-git-send-email-a.kesavan@samsung.com>
In-reply-to: <1414759083-4555-1-git-send-email-a.kesavan@samsung.com>
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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@samsung.com>
> ---
> - 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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