Re: [PATCH 1/2] misc: atmel-ssc: support to read ssc version

Nicolas Ferre
2014-06-10T16:32:27Z

On 06/06/2014 09:41, Bo Shen :
> Read SSC IP version to check whether it supports frame sync
> length extension feature.
>
> Signed-off-by: Bo Shen <voice.shen@atmel.com>

No. We already have 2 compatible versions for the DT or id table. Simply
add one.
Please use this infrastructure to describe such features, I don't want
to mix the approaches: "compatible string" xor "IP revision".

The DT of the product will then describe on which version of the IP it
can rely to have this feature.

Best regards,

> ---
>
> drivers/misc/atmel-ssc.c | 7 +++++++
> include/linux/atmel-ssc.h | 3 +++
> 2 files changed, 10 insertions(+)
>
> diff --git a/drivers/misc/atmel-ssc.c b/drivers/misc/atmel-ssc.c
> index 22de137..9f49bcb 100644
> --- a/drivers/misc/atmel-ssc.c
> +++ b/drivers/misc/atmel-ssc.c
> @@ -136,6 +136,7 @@ static int ssc_probe(struct platform_device *pdev)
> struct resource *regs;
> struct ssc_device *ssc;
> const struct atmel_ssc_platform_data *plat_dat;
> + u32 version;
>
> ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL);
> if (!ssc) {
> @@ -173,8 +174,14 @@ static int ssc_probe(struct platform_device *pdev)
> clk_prepare_enable(ssc->clk);
> ssc_writel(ssc->regs, IDR, -1);
> ssc_readl(ssc->regs, SR);
> + version = ssc_readl(ssc->regs, VERSION);
> clk_disable_unprepare(ssc->clk);
>
> + if (version >= 0x300)
> + ssc->has_fslen_ext = 1;
> + else
> + ssc->has_fslen_ext = 0;
> +
> ssc->irq = platform_get_irq(pdev, 0);
> if (!ssc->irq) {
> dev_dbg(&pdev->dev, "could not get irq\n");
> diff --git a/include/linux/atmel-ssc.h b/include/linux/atmel-ssc.h
> index 571a12e..9ee1b68 100644
> --- a/include/linux/atmel-ssc.h
> +++ b/include/linux/atmel-ssc.h
> @@ -19,6 +19,7 @@ struct ssc_device {
> int user;
> int irq;
> bool clk_from_rk_pin;
> + int has_fslen_ext;
> };
>
> struct ssc_device * __must_check ssc_request(unsigned int ssc_num);
> @@ -258,6 +259,8 @@ void ssc_free(struct ssc_device *ssc);
> #define SSC_IMR_TXSYN_SIZE 1
> #define SSC_IMR_TXSYN_OFFSET 10
>
> +#define SSC_VERSION 0x000000fc
> +
> /* SSC PDC Receive Pointer Register */
> #define SSC_PDC_RPR 0x00000100
>
>

--
Nicolas Ferre