Re: [PATCH 4/9] net: mdio: realtek-rtl9300: Add pages to info structure

[Daniel Golle <daniel@makrotopia.org>]

On Tue, May 19, 2026 at 06:57:42PM +0200, Markus Stockhausen wrote:
> The Realtek MDIO controller has a paging feature that allows to run C22
> reads/writes in one turn. At least this holds true for attached Realtek
> based PHYs. The controller is given the page, the register and the data
> and it runs all the page switching in the background in hardware.
> 
> There is however one special page that allows to pass through all C22
> commands directly to the PHY - without any caching. This so called raw
> page is dependent of the hardware. It is the highest supported page
> number minus 1. This is either 4095 for low port count SOCs (up to 28
> ports) or 8191 for high port count SOCs (up to 56 ports).
> 
> Provide the number of supported pages as a device specific property.
> The raw page directly derives from that as "num_pages - 1". Make use
> of it where needed.
> 
> Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
> ---
>  drivers/net/mdio/mdio-realtek-rtl9300.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/mdio/mdio-realtek-rtl9300.c b/drivers/net/mdio/mdio-realtek-rtl9300.c
> index 4533c2f68cab..0ea691d9fc1b 100644
> --- a/drivers/net/mdio/mdio-realtek-rtl9300.c
> +++ b/drivers/net/mdio/mdio-realtek-rtl9300.c
> @@ -47,13 +47,16 @@
>  #define MAX_PORTS       28
>  #define MAX_SMI_BUSSES  4
>  #define MAX_SMI_ADDR	0x1f
> +#define RAW_PAGE(x)	((x) - 1)

Maybe use
#define RAW_PAGE(priv)	((priv)->info->num_pages - 1)

as anyway you are only calling it in that way.

>  
>  #define RTL9300_NUM_BUSES		4
> +#define RTL9300_NUM_PAGES		4096
>  #define RTL9300_NUM_PORTS		28
>  
>  struct rtl_mdio_info {
>  	u8 num_buses;
>  	u8 num_ports;
> +	u16 num_pages;
>  };
>  
>  struct rtl_mdio_priv {
> @@ -126,7 +129,7 @@ static int rtl9300_mdio_read_c22(struct mii_bus *bus, int phy_id, int regnum)
>  
>  	val = FIELD_PREP(PHY_CTRL_REG_ADDR, regnum) |
>  	      FIELD_PREP(PHY_CTRL_PARK_PAGE, 0x1f) |
> -	      FIELD_PREP(PHY_CTRL_MAIN_PAGE, 0xfff) |
> +	      FIELD_PREP(PHY_CTRL_MAIN_PAGE, RAW_PAGE(priv->info->num_pages)) |
>  	      PHY_CTRL_READ | PHY_CTRL_TYPE_C22 | PHY_CTRL_CMD;
>  	err = regmap_write(regmap, SMI_ACCESS_PHY_CTRL_1, val);
>  	if (err)
> @@ -179,7 +182,7 @@ static int rtl9300_mdio_write_c22(struct mii_bus *bus, int phy_id, int regnum, u
>  
>  	val = FIELD_PREP(PHY_CTRL_REG_ADDR, regnum) |
>  	      FIELD_PREP(PHY_CTRL_PARK_PAGE, 0x1f) |
> -	      FIELD_PREP(PHY_CTRL_MAIN_PAGE, 0xfff) |
> +	      FIELD_PREP(PHY_CTRL_MAIN_PAGE, RAW_PAGE(priv->info->num_pages)) |
>  	      PHY_CTRL_WRITE | PHY_CTRL_TYPE_C22 | PHY_CTRL_CMD;
>  	err = regmap_write(regmap, SMI_ACCESS_PHY_CTRL_1, val);
>  	if (err)
> @@ -512,6 +515,7 @@ static int rtl_mdiobus_probe(struct platform_device *pdev)
>  static const struct rtl_mdio_info rtl9300_mdio_info = {
>  	.num_buses = RTL9300_NUM_BUSES,
>  	.num_ports = RTL9300_NUM_PORTS,
> +	.num_pages = RTL9300_NUM_PAGES,
>  };
>  
>  static const struct of_device_id rtl_mdio_ids[] = {
> -- 
> 2.54.0
>