Re: [PATCH net-next v2 4/4] net: dp83869: Add RGMII internal delay configuration

[Florian Fainelli <f.fainelli@gmail.com>]

On 5/22/2020 5:25 AM, Dan Murphy wrote:
> Add RGMII internal delay configuration for Rx and Tx.
> 
> Signed-off-by: Dan Murphy <dmurphy@ti.com>
> ---
>  drivers/net/phy/dp83869.c | 101 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 101 insertions(+)
> 
> diff --git a/drivers/net/phy/dp83869.c b/drivers/net/phy/dp83869.c
> index cfb22a21a2e6..a9008d32e2b6 100644
> --- a/drivers/net/phy/dp83869.c
> +++ b/drivers/net/phy/dp83869.c
> @@ -99,6 +99,14 @@
>  #define DP83869_OP_MODE_MII			BIT(5)
>  #define DP83869_SGMII_RGMII_BRIDGE		BIT(6)
>  
> +/* RGMIIDCTL bits */
> +#define DP83869_RGMII_TX_CLK_DELAY_SHIFT	4
> +#define DP83869_RGMII_CLK_DELAY_INV		0
> +
> +static int dp83869_internal_delay[] = {250, 500, 750, 1000, 1250, 1500, 1750,
> +				       2000, 2250, 2500, 2750, 3000, 3250,
> +				       3500, 3750, 4000};
> +
>  enum {
>  	DP83869_PORT_MIRRORING_KEEP,
>  	DP83869_PORT_MIRRORING_EN,
> @@ -108,6 +116,8 @@ enum {
>  struct dp83869_private {
>  	int tx_fifo_depth;
>  	int rx_fifo_depth;
> +	u32 rx_id_delay;
> +	u32 tx_id_delay;
>  	int io_impedance;
>  	int port_mirroring;
>  	bool rxctrl_strap_quirk;
> @@ -182,6 +192,7 @@ static int dp83869_of_init(struct phy_device *phydev)
>  	struct dp83869_private *dp83869 = phydev->priv;
>  	struct device *dev = &phydev->mdio.dev;
>  	struct device_node *of_node = dev->of_node;
> +	int delay_size = ARRAY_SIZE(dp83869_internal_delay);
>  	int ret;
>  
>  	if (!of_node)
> @@ -232,6 +243,26 @@ static int dp83869_of_init(struct phy_device *phydev)
>  				 &dp83869->tx_fifo_depth))
>  		dp83869->tx_fifo_depth = DP83869_PHYCR_FIFO_DEPTH_4_B_NIB;
>  
> +	dp83869->rx_id_delay = DP83869_RGMII_CLK_DELAY_INV;
> +	ret = of_property_read_u32(of_node, "rx-internal-delay-ps",
> +				   &dp83869->rx_id_delay);
> +	if (!ret && dp83869->rx_id_delay > dp83869_internal_delay[delay_size]) {
> +		phydev_err(phydev,
> +			   "rx-internal-delay value of %u out of range\n",
> +			   dp83869->rx_id_delay);
> +		return -EINVAL;
> +	}
> +
> +	dp83869->tx_id_delay = DP83869_RGMII_CLK_DELAY_INV;
> +	ret = of_property_read_u32(of_node, "tx-internal-delay-ps",
> +				   &dp83869->tx_id_delay);
> +	if (!ret && dp83869->tx_id_delay > dp83869_internal_delay[delay_size]) {
> +		phydev_err(phydev,
> +			   "tx-internal-delay value of %u out of range\n",
> +			   dp83869->tx_id_delay);
> +		return -EINVAL;
> +	}

This is the kind of validation that I would be expecting from the PHY
library to do, in fact, since you use Device Tree standard property, I
would expect you only need to pass the maximum delay value and some
storage for your array of delays.

> +
>  	return ret;
>  }
>  #else
> @@ -270,6 +301,29 @@ static int dp83869_configure_rgmii(struct phy_device *phydev,
>  	return ret;
>  }
>  
> +static int dp83869_verify_rgmii_cfg(struct phy_device *phydev)
> +{
> +	struct dp83869_private *dp83869 = phydev->priv;
> +
> +	/* RX delay *must* be specified if internal delay of RX is used. */
> +	if ((phydev->interface == PHY_INTERFACE_MODE_RGMII_ID ||
> +	     phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID) &&
> +	     dp83869->rx_id_delay == DP83869_RGMII_CLK_DELAY_INV) {
> +		phydev_err(phydev, "ti,rx-internal-delay must be specified\n");
> +		return -EINVAL;
> +	}
> +
> +	/* TX delay *must* be specified if internal delay of TX is used. */
> +	if ((phydev->interface == PHY_INTERFACE_MODE_RGMII_ID ||
> +	     phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID) &&
> +	     dp83869->tx_id_delay == DP83869_RGMII_CLK_DELAY_INV) {
> +		phydev_err(phydev, "ti,tx-internal-delay must be specified\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>  static int dp83869_configure_mode(struct phy_device *phydev,
>  				  struct dp83869_private *dp83869)
>  {
> @@ -371,6 +425,12 @@ static int dp83869_config_init(struct phy_device *phydev)
>  {
>  	struct dp83869_private *dp83869 = phydev->priv;
>  	int ret, val;
> +	int delay_size = ARRAY_SIZE(dp83869_internal_delay);
> +	int delay = 0;
> +
> +	ret = dp83869_verify_rgmii_cfg(phydev);
> +	if (ret)
> +		return ret;
>  
>  	ret = dp83869_configure_mode(phydev, dp83869);
>  	if (ret)
> @@ -394,6 +454,47 @@ static int dp83869_config_init(struct phy_device *phydev)
>  				     dp83869->clk_output_sel <<
>  				     DP83869_IO_MUX_CFG_CLK_O_SEL_SHIFT);
>  
> +	if (phy_interface_is_rgmii(phydev)) {
> +		val = phy_read_mmd(phydev, DP83869_DEVADDR, DP83869_RGMIICTL);
> +
> +		val &= ~(DP83869_RGMII_TX_CLK_DELAY_EN | DP83869_RGMII_RX_CLK_DELAY_EN);
> +		if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID)
> +			val |= (DP83869_RGMII_TX_CLK_DELAY_EN | DP83869_RGMII_RX_CLK_DELAY_EN);
> +
> +		if (phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID)
> +			val |= DP83869_RGMII_TX_CLK_DELAY_EN;
> +
> +		if (phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID)
> +			val |= DP83869_RGMII_RX_CLK_DELAY_EN;
> +
> +		phy_write_mmd(phydev, DP83869_DEVADDR, DP83869_RGMIICTL, val);
> +
> +		if (dp83869->rx_id_delay) {
> +			val = phy_get_delay_index(phydev,
> +						  &dp83869_internal_delay[0],
> +						  delay_size,
> +						  dp83869->rx_id_delay);
> +			if (val < 0)
> +				return val;
> +
> +			delay |= val;

Don't you need to do a bitwise AND with the maximum delay value
supported by the range since you do a Read/Modify/Write operation here?

> +		}
> +
> +		if (dp83869->tx_id_delay) {
> +			val = phy_get_delay_index(phydev,
> +						  &dp83869_internal_delay[0],
> +						  delay_size,
> +						  dp83869->tx_id_delay);
> +			if (val < 0)
> +				return val;
> +
> +			delay |= val << DP83869_RGMII_TX_CLK_DELAY_SHIFT;

Likewise.

> +		}
> +
> +		phy_write_mmd(phydev, DP83869_DEVADDR, DP83869_RGMIIDCTL,
> +			      delay);
> +	}
> +
>  	return ret;
>  }
>  
> 

-- 
Florian