Re: [PATCH 2/2] mfd: atmel-flexcom: Add support for lan966 flexcom shared configurations

[<Tudor.Ambarus@microchip.com>]

On 2/10/22 09:45, Kavyasree Kotagiri wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Each flexcom of LAN966 SoC has 2 chip selects. For each chip
> select of each flexcom there is a configuration register
> FLEXCOM_SHARED[0-4]:SS_MASK[0-1]. The width of configuration
> register is 21 because there are 21 shared pins on each of
> which the chip select can be mapped. Each bit of the register
> represents a different FLEXCOM_SHARED pin.
> 
> Signed-off-by: Kavyasree Kotagiri <kavyasree.kotagiri@microchip.com>
> ---
>  drivers/mfd/atmel-flexcom.c | 49 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
> 
> diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
> index 559eb4d352b6..b8fc476e411d 100644
> --- a/drivers/mfd/atmel-flexcom.c
> +++ b/drivers/mfd/atmel-flexcom.c
> @@ -27,6 +27,12 @@
>  #define FLEX_MR_OPMODE_MASK    (0x3 << FLEX_MR_OPMODE_OFFSET)
>  #define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) &  \
>                                  FLEX_MR_OPMODE_MASK)
> +#ifdef CONFIG_SOC_LAN966
> +/* LAN966 register offsets */
> +#define FLEX_SHRD_SS_MASK_0 0x0
> +#define FLEX_SHRD_SS_MASK_1 0x4
> +#define FLEX_SHRD_MASK      0x1FFFFF
> +#endif
> 
>  struct atmel_flexcom {
>         void __iomem *base;
> @@ -39,6 +45,10 @@ static int atmel_flexcom_probe(struct platform_device *pdev)
>         struct device_node *np = pdev->dev.of_node;
>         struct resource *res;
>         struct atmel_flexcom *ddata;
> +#ifdef CONFIG_SOC_LAN966
> +       u32 lan966x_ss_pin, lan966x_cs, val;
> +       void __iomem *shared_base;
> +#endif
>         int err;
> 
>         ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
> @@ -76,6 +86,45 @@ static int atmel_flexcom_probe(struct platform_device *pdev)
>          */
>         writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR);
> 
> +#ifdef CONFIG_SOC_LAN966

this may be better handled via a dedicated compatible to which you
associate a capabilities structure and use the caps to avoid ifdefery
throughout the code.

Cheers,
ta

> +       /*
> +        * Flexcom Shared Register Configurations:
> +        * In order to map chip select index X of Flexcom Y to FLEXCOM_SHARED Z,
> +        * write 0 to bit index Z of FLEXCOM_SHARED[Y]:SS_MASK[X].
> +        */
> +       if (of_property_read_bool(np, "lan966x-flx-shared-cfg")) {
> +               /* Shared pin */
> +               err = of_property_read_u32(np, "lan966x-ss-pin", &lan966x_ss_pin);
> +               if (err)
> +                       return err;
> +
> +               if (lan966x_ss_pin > 20)
> +                       return -EINVAL;
> +
> +               /* chip-select */
> +               err = of_property_read_u32(np, "lan966x-cs", &lan966x_cs);
> +               if (err)
> +                       return err;
> +
> +               if (lan966x_cs > 1)
> +                       return -EINVAL;
> +
> +               shared_base = devm_ioremap_resource(&pdev->dev,
> +                               platform_get_resource(pdev, IORESOURCE_MEM, 1));
> +               if (IS_ERR(shared_base)) {
> +                       dev_dbg(&pdev->dev, "No Flexcom shared register config\n");
> +                       return PTR_ERR(shared_base);
> +               }
> +
> +               val = ~(1 << lan966x_ss_pin) & FLEX_SHRD_MASK;
> +
> +               if (lan966x_cs == 0)
> +                       writel(val, shared_base + FLEX_SHRD_SS_MASK_0);
> +               else
> +                       writel(val, shared_base + FLEX_SHRD_SS_MASK_1);
> +       }
> +#endif
> +
>         clk_disable_unprepare(ddata->clk);
> 
>         return devm_of_platform_populate(&pdev->dev);
> --
> 2.17.1
> 
> 
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