[PATCH] phy: rockchip-snps-pcie3: add support for rockchip,phy-ref-use-pad
Damien Le Moal
dlemoal at kernel.org
Tue Jul 15 16:18:10 PDT 2025
On 7/15/25 19:58, Rick Wertenbroek wrote:
>>From the RK3588 Technical Reference Manual, Part1,
> section 6.19 PCIe3PHY_GRF Register Description: "ref_use_pad"
>
> "Select reference clock connected to ref_pad_clk_p/ref_pad_clk_m.
> Selects the external ref_pad_clk_p and ref_pad_clk_m inputs as the
> reference clock source when asserted. When de-asserted, ref_alt_clk_p
> and ref_alt_clk_m are the sources of the reference clock."
>
> The hardware reset value for this field is 0x1 (enabled).
> Note that this register field is only available on RK3588, not on RK3568.
>
> Add support for the device tree property rockchip,phy-ref-use-pad,
> such that the PCIe PHY can be used on boards where there is no PCIe
> reference clock generated or connected to the external pad, by setting
> this property to 0 so that the internal clock is used.
>
> DT bindings for internal clocks are CLK_PHY0_REF_ALT_P/M and
> CLK_PHY1_REF_ALT_P/M and clock rate should be set to 100MHz in
> the RK3588 cru clock controller (PLL_PPLL).
>
> Example DT overlay where PHY0 uses internal clock (the first clock of
> the cru (PLL_PPLL) must be set to 100MHz, other values are copied from
> rk3588-base.dtsi) and PHY1 uses the external pad (the default):
>
> ---
> &cru {
> assigned-clock-rates =
> <100000000>, <786432000>,
> <850000000>, <1188000000>,
> <702000000>,
> <400000000>, <500000000>,
> <800000000>, <100000000>,
> <400000000>, <100000000>,
> <200000000>, <500000000>,
> <375000000>, <150000000>,
> <200000000>;
> };
>
> &pcie30phy {
> rockchip,rx-common-refclk-mode = <0 0 1 1>;
> rockchip,phy-ref-use-pad = <0 1>;
> clocks = <&cru PCLK_PCIE_COMBO_PIPE_PHY>, <&cru CLK_PHY0_REF_ALT_P>,
> <&cru CLK_PHY0_REF_ALT_M>, <&cru CLK_PHY1_REF_ALT_P>,
> <&cru CLK_PHY1_REF_ALT_M>;
> clock-names = "pclk", "phy0_ref_alt_p",
> "phy0_ref_alt_m", "phy1_ref_alt_p",
> "phy1_ref_alt_m";
> };
> ---
>
This looks OK to me, but don't you need to also update the dt-bindings yaml to
document this new "phy-ref-use-pad" property ?
> Signed-off-by: Rick Wertenbroek <rick.wertenbroek at gmail.com>
> ---
> .../phy/rockchip/phy-rockchip-snps-pcie3.c | 32 +++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c b/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c
> index 4e8ffd173096..0859c7960167 100644
> --- a/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c
> +++ b/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c
> @@ -33,6 +33,8 @@
> /* Register for RK3588 */
> #define PHP_GRF_PCIESEL_CON 0x100
> #define RK3588_PCIE3PHY_GRF_CMN_CON0 0x0
> +#define RK3588_PCIE3PHY_GRF_PHY0_CONTROL6 0x118
> +#define RK3588_PCIE3PHY_GRF_PHY1_CONTROL6 0x218
> #define RK3588_PCIE3PHY_GRF_PHY0_STATUS1 0x904
> #define RK3588_PCIE3PHY_GRF_PHY1_STATUS1 0xa04
> #define RK3588_PCIE3PHY_GRF_PHY0_LN0_CON1 0x1004
> @@ -44,6 +46,8 @@
> #define RK3588_BIFURCATION_LANE_0_1 BIT(0)
> #define RK3588_BIFURCATION_LANE_2_3 BIT(1)
> #define RK3588_LANE_AGGREGATION BIT(2)
> +#define RK3588_PHY_REF_USE_PAD_EN ((BIT(2) << 16 | BIT(2)))
> +#define RK3588_PHY_REF_USE_PAD_DIS ((BIT(2) << 16))
> #define RK3588_RX_CMN_REFCLK_MODE_EN ((BIT(7) << 16) | BIT(7))
> #define RK3588_RX_CMN_REFCLK_MODE_DIS (BIT(7) << 16)
> #define RK3588_PCIE1LN_SEL_EN (GENMASK(1, 0) << 16)
> @@ -67,6 +71,7 @@ struct rockchip_p3phy_priv {
> int num_lanes;
> u32 lanes[4];
> u32 rx_cmn_refclk_mode[4];
> + u32 phy_ref_use_pad[2];
> };
>
> struct rockchip_p3phy_ops {
> @@ -157,6 +162,14 @@ static int rockchip_p3phy_rk3588_init(struct rockchip_p3phy_priv *priv)
> priv->rx_cmn_refclk_mode[3] ? RK3588_RX_CMN_REFCLK_MODE_EN :
> RK3588_RX_CMN_REFCLK_MODE_DIS);
>
> + /* Select PHY reference clock, external pad or internal clock */
> + regmap_write(priv->phy_grf, RK3588_PCIE3PHY_GRF_PHY0_CONTROL6,
> + priv->phy_ref_use_pad[0] ? RK3588_PHY_REF_USE_PAD_EN :
> + RK3588_PHY_REF_USE_PAD_DIS);
> + regmap_write(priv->phy_grf, RK3588_PCIE3PHY_GRF_PHY1_CONTROL6,
> + priv->phy_ref_use_pad[1] ? RK3588_PHY_REF_USE_PAD_EN :
> + RK3588_PHY_REF_USE_PAD_DIS);
> +
> /* Deassert PCIe PMA output clamp mode */
> regmap_write(priv->phy_grf, RK3588_PCIE3PHY_GRF_CMN_CON0, BIT(8) | BIT(24));
>
> @@ -312,6 +325,25 @@ static int rockchip_p3phy_probe(struct platform_device *pdev)
> return ret;
> }
>
> + ret = of_property_read_variable_u32_array(dev->of_node,
> + "rockchip,phy-ref-use-pad",
> + priv->phy_ref_use_pad, 1,
> + ARRAY_SIZE(priv->phy_ref_use_pad));
> +
> + /*
> + * if no rockhip,phy-use-internal-clk, assume PHY uses pad for the
> + * reference clock in order to be DT backwards compatible. (Since HW
> + * reset val is enabled.)
> + */
> + if (ret == -EINVAL) {
> + for (int i = 0; i < ARRAY_SIZE(priv->phy_ref_use_pad); i++)
> + priv->phy_ref_use_pad[i] = 1;
> + } else if (ret < 0) {
> + dev_err(dev, "failed to read rockchip,phy-ref-use-pad property %d\n",
> + ret);
> + return ret;
> + }
> +
> priv->phy = devm_phy_create(dev, NULL, &rockchip_p3phy_ops);
> if (IS_ERR(priv->phy)) {
> dev_err(dev, "failed to create combphy\n");
--
Damien Le Moal
Western Digital Research
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