Hi Josh,

On Sun, Jul 14, 2013 at 04:04:26PM +0800, Josh Wu wrote:
> For at91 boards, there are different IPs for adc. Different IPs has different
> STARTUP & PRESCAL mask in ADC_MR.
> 
> This patch can change the masks according to the different IP version.
> 
> Signed-off-by: Josh Wu <josh.wu@atmel.com>
> ---
>  arch/arm/mach-at91/include/mach/at91_adc.h |    9 ++++--
>  drivers/iio/adc/at91_adc.c                 |   48 ++++++++++++++++++++++++++--
>  2 files changed, 53 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm/mach-at91/include/mach/at91_adc.h b/arch/arm/mach-at91/include/mach/at91_adc.h
> index 8e7ed5c..ab273ee 100644
> --- a/arch/arm/mach-at91/include/mach/at91_adc.h
> +++ b/arch/arm/mach-at91/include/mach/at91_adc.h
> @@ -28,9 +28,12 @@
>  #define			AT91_ADC_TRGSEL_EXTERNAL	(6 << 1)
>  #define		AT91_ADC_LOWRES		(1 << 4)	/* Low Resolution */
>  #define		AT91_ADC_SLEEP		(1 << 5)	/* Sleep Mode */
> -#define		AT91_ADC_PRESCAL	(0x3f << 8)	/* Prescalar Rate Selection */
> +#define		AT91_ADC_PRESCAL	(0xff << 8)	/* Prescalar Rate Selection */
> +#define		AT91_ADC_PRESCAL_9260	(0x3f << 8)
>  #define			AT91_ADC_PRESCAL_(x)	((x) << 8)
> -#define		AT91_ADC_STARTUP	(0x1f << 16)	/* Startup Up Time */
> +#define		AT91_ADC_STARTUP	(0xf << 16)	/* Startup Up Time */
> +#define		AT91_ADC_STARTUP_9260	(0x1f << 16)
> +#define		AT91_ADC_STARTUP_9G45	(0x7f << 16)
>  #define			AT91_ADC_STARTUP_(x)	((x) << 16)
>  #define		AT91_ADC_SHTIM		(0xf  << 24)	/* Sample & Hold Time */
>  #define			AT91_ADC_SHTIM_(x)	((x) << 24)
> @@ -58,4 +61,6 @@
>  #define AT91_ADC_CHR(n)		(0x30 + ((n) * 4))	/* Channel Data Register N */
>  #define		AT91_ADC_DATA		(0x3ff)
>  
> +#define AT91_ADC_VERSION	0xFC
> +
>  #endif
> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> index 18bd54f..14e99ba 100644
> --- a/drivers/iio/adc/at91_adc.c
> +++ b/drivers/iio/adc/at91_adc.c
> @@ -39,6 +39,12 @@
>  #define at91_adc_writel(st, reg, val) \
>  	(writel_relaxed(val, st->reg_base + reg))
>  
> +struct at91_adc_caps {
> +	bool	has_tsmr;	/* only at91sam9x5, sama5d3 have TSMR reg */
> +	u32	mr_prescal_mask;
> +	u32	mr_startup_mask;
> +};
> +
>  struct at91_adc_state {
>  	struct clk		*adc_clk;
>  	u16			*buffer;
> @@ -62,6 +68,7 @@ struct at91_adc_state {
>  	u32			res;		/* resolution used for convertions */
>  	bool			low_res;	/* the resolution corresponds to the lowest one */
>  	wait_queue_head_t	wq_data_avail;
> +	struct at91_adc_caps	caps;
>  };
>  
>  static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
> @@ -580,6 +587,41 @@ static const struct iio_info at91_adc_info = {
>  	.read_raw = &at91_adc_read_raw,
>  };
>  
> +/*
> + * Since atmel adc support different ip for touchscreen mode. Through the
> + * IP check, we will know the touchscreen capbilities.
> + */
> +static void atmel_adc_get_cap(struct at91_adc_state *st)
> +{
> +	unsigned int version;
> +	struct iio_dev *idev = iio_priv_to_dev(st);
> +
> +	version = at91_adc_readl(st, AT91_ADC_VERSION);
> +	dev_dbg(&idev->dev, "version: 0x%x\n", version);
> +
> +	st->caps.mr_prescal_mask = AT91_ADC_PRESCAL_9260;
> +	st->caps.mr_startup_mask = AT91_ADC_STARTUP_9260;
> +
> +	/* keep only major version number */
> +	switch (version & 0xf00) {
> +	case 0x500:	/* SAMA5D3 */
> +	case 0x400:	/* AT91SAM9X5/9N12 */
> +		st->caps.has_tsmr = 1;
> +		st->caps.mr_startup_mask = AT91_ADC_STARTUP;
> +	case 0x200:	/* AT91SAM9M10/9G45 */
> +		st->caps.mr_prescal_mask = AT91_ADC_PRESCAL;
> +
> +		if ((version & 0xf00) == 0x200)
> +			st->caps.mr_startup_mask = AT91_ADC_STARTUP_9G45;
> +	case 0x100:	/* AT91SAM9260/9G20 */
> +		break;
> +	default:
> +		dev_warn(&idev->dev,
> +				"Unmanaged adc version, use minimal capabilities\n");
> +		break;
> +	};
> +}

Why don't you use different compatible names and derive your
capabilities from which compatible is declared.

It seems safer.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com