linux-kernel - Re: [PATCH 4/6] phy: meson-g12a-usb3-pcie: Add support for PCIe mode

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Date:   Wed, 11 Sep 2019 13:19:56 +0100
From:   Andrew Murray <andrew.murray@....com>
To:     Neil Armstrong <narmstrong@...libre.com>
Cc:     khilman@...libre.com, bhelgaas@...gle.com,
        lorenzo.pieralisi@....com, yue.wang@...ogic.com, kishon@...com,
        repk@...plefau.lt, maz@...nel.org,
        linux-amlogic@...ts.infradead.org, linux-pci@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/6] phy: meson-g12a-usb3-pcie: Add support for PCIe mode

On Sun, Sep 08, 2019 at 01:42:56PM +0000, Neil Armstrong wrote:
> This adds extended PCIe PHY functions for the Amlogic G12A
> USB3+PCIE Combo PHY to support reset, power_on and power_off for
> PCIe exclusively.
> 
> With these callbacks, we can handle all the needed operations of the
> Amlogic PCIe controller driver.
> 
> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
> ---
>  .../phy/amlogic/phy-meson-g12a-usb3-pcie.c    | 70 ++++++++++++++++---
>  1 file changed, 61 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/phy/amlogic/phy-meson-g12a-usb3-pcie.c b/drivers/phy/amlogic/phy-meson-g12a-usb3-pcie.c
> index ac322d643c7a..08e322789e59 100644
> --- a/drivers/phy/amlogic/phy-meson-g12a-usb3-pcie.c
> +++ b/drivers/phy/amlogic/phy-meson-g12a-usb3-pcie.c
> @@ -50,6 +50,8 @@
>  	#define PHY_R5_PHY_CR_ACK				BIT(16)
>  	#define PHY_R5_PHY_BS_OUT				BIT(17)
>  
> +#define PCIE_RESET_DELAY					500
> +
>  struct phy_g12a_usb3_pcie_priv {
>  	struct regmap		*regmap;
>  	struct regmap		*regmap_cr;
> @@ -196,6 +198,10 @@ static int phy_g12a_usb3_init(struct phy *phy)
>  	struct phy_g12a_usb3_pcie_priv *priv = phy_get_drvdata(phy);
>  	int data, ret;
>  
> +	ret = reset_control_reset(priv->reset);
> +	if (ret)
> +		return ret;
> +

Right, so we've moved this to apply to USB only, thus assuming PCI will
call .reset for its reset (why the asymmetry?).

Thanks,

Andrew Murray

>  	/* Switch PHY to USB3 */
>  	/* TODO figure out how to handle when PCIe was set in the bootloader */
>  	regmap_update_bits(priv->regmap, PHY_R0,
> @@ -272,24 +278,64 @@ static int phy_g12a_usb3_init(struct phy *phy)
>  	return 0;
>  }
>  
> -static int phy_g12a_usb3_pcie_init(struct phy *phy)
> +static int phy_g12a_usb3_pcie_power_on(struct phy *phy)
> +{
> +	struct phy_g12a_usb3_pcie_priv *priv = phy_get_drvdata(phy);
> +
> +	if (priv->mode == PHY_TYPE_USB3)
> +		return 0;
> +
> +	regmap_update_bits(priv->regmap, PHY_R0,
> +			   PHY_R0_PCIE_POWER_STATE,
> +			   FIELD_PREP(PHY_R0_PCIE_POWER_STATE, 0x1c));
> +
> +	return 0;
> +}
> +
> +static int phy_g12a_usb3_pcie_power_off(struct phy *phy)
> +{
> +	struct phy_g12a_usb3_pcie_priv *priv = phy_get_drvdata(phy);
> +
> +	if (priv->mode == PHY_TYPE_USB3)
> +		return 0;
> +
> +	regmap_update_bits(priv->regmap, PHY_R0,
> +			   PHY_R0_PCIE_POWER_STATE,
> +			   FIELD_PREP(PHY_R0_PCIE_POWER_STATE, 0x1d));
> +
> +	return 0;
> +}
> +
> +static int phy_g12a_usb3_pcie_reset(struct phy *phy)
>  {
>  	struct phy_g12a_usb3_pcie_priv *priv = phy_get_drvdata(phy);
>  	int ret;
>  
> -	ret = reset_control_reset(priv->reset);
> +	if (priv->mode == PHY_TYPE_USB3)
> +		return 0;
> +
> +	ret = reset_control_assert(priv->reset);
>  	if (ret)
>  		return ret;
>  
> +	udelay(PCIE_RESET_DELAY);
> +
> +	ret = reset_control_deassert(priv->reset);
> +	if (ret)
> +		return ret;
> +
> +	udelay(PCIE_RESET_DELAY);
> +
> +	return 0;
> +}
> +
> +static int phy_g12a_usb3_pcie_init(struct phy *phy)
> +{
> +	struct phy_g12a_usb3_pcie_priv *priv = phy_get_drvdata(phy);
> +
>  	if (priv->mode == PHY_TYPE_USB3)
>  		return phy_g12a_usb3_init(phy);
>  
> -	/* Power UP PCIE */
> -	/* TODO figure out when the bootloader has set USB3 mode before */
> -	regmap_update_bits(priv->regmap, PHY_R0,
> -			   PHY_R0_PCIE_POWER_STATE,
> -			   FIELD_PREP(PHY_R0_PCIE_POWER_STATE, 0x1c));
> -
>  	return 0;
>  }
>  
> @@ -297,7 +343,10 @@ static int phy_g12a_usb3_pcie_exit(struct phy *phy)
>  {
>  	struct phy_g12a_usb3_pcie_priv *priv = phy_get_drvdata(phy);
>  
> -	return reset_control_reset(priv->reset);
> +	if (priv->mode == PHY_TYPE_USB3)
> +		return reset_control_reset(priv->reset);
> +
> +	return 0;
>  }
>  
>  static struct phy *phy_g12a_usb3_pcie_xlate(struct device *dev,
> @@ -326,6 +375,9 @@ static struct phy *phy_g12a_usb3_pcie_xlate(struct device *dev,
>  static const struct phy_ops phy_g12a_usb3_pcie_ops = {
>  	.init		= phy_g12a_usb3_pcie_init,
>  	.exit		= phy_g12a_usb3_pcie_exit,
> +	.power_on	= phy_g12a_usb3_pcie_power_on,
> +	.power_off	= phy_g12a_usb3_pcie_power_off,
> +	.reset		= phy_g12a_usb3_pcie_reset,
>  	.owner		= THIS_MODULE,
>  };
>  
> -- 
> 2.17.1
>