diff mbox

[v6,4/5] phy: rockchip-typec: support variable phy config value

Message ID 1526895424-22894-4-git-send-email-hl@rock-chips.com (mailing list archive)
State New, archived
Headers show

Commit Message

huang lin May 21, 2018, 9:37 a.m. UTC
the phy config values used to fix in dp firmware, but some boards
need change these values to do training and get the better eye diagram
result. So support that in phy driver.

Signed-off-by: Chris Zhong <zyw@rock-chips.com>
Signed-off-by: Lin Huang <hl@rock-chips.com>
---
Changes in v2:
- update patch following Enric suggest
Changes in v3:
- delete need_software_training variable
- add default phy config value, if dts do not define phy config value, use these value
Changes in v4:
- rename variable config to tcphy_default_config
Changes in v5:
- None
Changes in v6:
- split the header file to new patch

 drivers/phy/rockchip/phy-rockchip-typec.c | 261 ++++++++++++++++++++++++------
 1 file changed, 208 insertions(+), 53 deletions(-)

Comments

Enric Balletbo Serra May 21, 2018, 2:13 p.m. UTC | #1
Hi Lin,

2018-05-21 11:37 GMT+02:00 Lin Huang <hl@rock-chips.com>:
> the phy config values used to fix in dp firmware, but some boards
> need change these values to do training and get the better eye diagram
> result. So support that in phy driver.
>
> Signed-off-by: Chris Zhong <zyw@rock-chips.com>
> Signed-off-by: Lin Huang <hl@rock-chips.com>
> ---
> Changes in v2:
> - update patch following Enric suggest
> Changes in v3:
> - delete need_software_training variable
> - add default phy config value, if dts do not define phy config value, use these value
> Changes in v4:
> - rename variable config to tcphy_default_config
> Changes in v5:
> - None
> Changes in v6:
> - split the header file to new patch
>
>  drivers/phy/rockchip/phy-rockchip-typec.c | 261 ++++++++++++++++++++++++------
>  1 file changed, 208 insertions(+), 53 deletions(-)
>
> diff --git a/drivers/phy/rockchip/phy-rockchip-typec.c b/drivers/phy/rockchip/phy-rockchip-typec.c
> index 795055f..4c4b925 100644
> --- a/drivers/phy/rockchip/phy-rockchip-typec.c
> +++ b/drivers/phy/rockchip/phy-rockchip-typec.c
> @@ -324,21 +324,29 @@
>   * clock 0: PLL 0 div 1
>   * clock 1: PLL 1 div 2
>   */
> -#define CLK_PLL_CONFIG                 0X30
> +#define CLK_PLL1_DIV1                  0x20
> +#define CLK_PLL1_DIV2                  0x30
>  #define CLK_PLL_MASK                   0x33
>
>  #define CMN_READY                      BIT(0)
>
> +#define DP_PLL_CLOCK_ENABLE_ACK                BIT(3)
>  #define DP_PLL_CLOCK_ENABLE            BIT(2)
> +#define DP_PLL_ENABLE_ACK              BIT(1)
>  #define DP_PLL_ENABLE                  BIT(0)
>  #define DP_PLL_DATA_RATE_RBR           ((2 << 12) | (4 << 8))
>  #define DP_PLL_DATA_RATE_HBR           ((2 << 12) | (4 << 8))
>  #define DP_PLL_DATA_RATE_HBR2          ((1 << 12) | (2 << 8))
> +#define DP_PLL_DATA_RATE_MASK          0xff00
>
> -#define DP_MODE_A0                     BIT(4)
> -#define DP_MODE_A2                     BIT(6)
> -#define DP_MODE_ENTER_A0               0xc101
> -#define DP_MODE_ENTER_A2               0xc104
> +#define DP_MODE_MASK                   0xf
> +#define DP_MODE_ENTER_A0               BIT(0)
> +#define DP_MODE_ENTER_A2               BIT(2)
> +#define DP_MODE_ENTER_A3               BIT(3)
> +#define DP_MODE_A0_ACK                 BIT(4)
> +#define DP_MODE_A2_ACK                 BIT(6)
> +#define DP_MODE_A3_ACK                 BIT(7)
> +#define DP_LINK_RESET_DEASSERTED       BIT(8)
>
>  #define PHY_MODE_SET_TIMEOUT           100000
>
> @@ -350,6 +358,8 @@
>  #define MODE_DFP_USB                   BIT(1)
>  #define MODE_DFP_DP                    BIT(2)
>
> +#define DP_DEFAULT_RATE                162000
> +
>  struct phy_reg {
>         u16 value;
>         u32 addr;
> @@ -372,15 +382,15 @@ struct phy_reg usb3_pll_cfg[] = {
>         { 0x8,          CMN_DIAG_PLL0_LF_PROG },
>  };
>
> -struct phy_reg dp_pll_cfg[] = {
> +struct phy_reg dp_pll_rbr_cfg[] = {
>         { 0xf0,         CMN_PLL1_VCOCAL_INIT },
>         { 0x18,         CMN_PLL1_VCOCAL_ITER },
>         { 0x30b9,       CMN_PLL1_VCOCAL_START },
> -       { 0x21c,        CMN_PLL1_INTDIV },
> +       { 0x87,         CMN_PLL1_INTDIV },
>         { 0,            CMN_PLL1_FRACDIV },
> -       { 0x5,          CMN_PLL1_HIGH_THR },
> -       { 0x35,         CMN_PLL1_SS_CTRL1 },
> -       { 0x7f1e,       CMN_PLL1_SS_CTRL2 },
> +       { 0x22,         CMN_PLL1_HIGH_THR },
> +       { 0x8000,       CMN_PLL1_SS_CTRL1 },
> +       { 0,            CMN_PLL1_SS_CTRL2 },
>         { 0x20,         CMN_PLL1_DSM_DIAG },
>         { 0,            CMN_PLLSM1_USER_DEF_CTRL },
>         { 0,            CMN_DIAG_PLL1_OVRD },
> @@ -391,9 +401,52 @@ struct phy_reg dp_pll_cfg[] = {
>         { 0x8,          CMN_DIAG_PLL1_LF_PROG },
>         { 0x100,        CMN_DIAG_PLL1_PTATIS_TUNE1 },
>         { 0x7,          CMN_DIAG_PLL1_PTATIS_TUNE2 },
> -       { 0x4,          CMN_DIAG_PLL1_INCLK_CTRL },
> +       { 0x1,          CMN_DIAG_PLL1_INCLK_CTRL },
>  };
>
> +struct phy_reg dp_pll_hbr_cfg[] = {
> +       { 0xf0,         CMN_PLL1_VCOCAL_INIT },
> +       { 0x18,         CMN_PLL1_VCOCAL_ITER },
> +       { 0x30b4,       CMN_PLL1_VCOCAL_START },
> +       { 0xe1,         CMN_PLL1_INTDIV },
> +       { 0,            CMN_PLL1_FRACDIV },
> +       { 0x5,          CMN_PLL1_HIGH_THR },
> +       { 0x8000,       CMN_PLL1_SS_CTRL1 },
> +       { 0,            CMN_PLL1_SS_CTRL2 },
> +       { 0x20,         CMN_PLL1_DSM_DIAG },
> +       { 0x1000,       CMN_PLLSM1_USER_DEF_CTRL },
> +       { 0,            CMN_DIAG_PLL1_OVRD },
> +       { 0,            CMN_DIAG_PLL1_FBH_OVRD },
> +       { 0,            CMN_DIAG_PLL1_FBL_OVRD },
> +       { 0x7,          CMN_DIAG_PLL1_V2I_TUNE },
> +       { 0x45,         CMN_DIAG_PLL1_CP_TUNE },
> +       { 0x8,          CMN_DIAG_PLL1_LF_PROG },
> +       { 0x1,          CMN_DIAG_PLL1_PTATIS_TUNE1 },
> +       { 0x1,          CMN_DIAG_PLL1_PTATIS_TUNE2 },
> +       { 0x1,          CMN_DIAG_PLL1_INCLK_CTRL },
> +};
> +
> +struct phy_reg dp_pll_hbr2_cfg[] = {
> +       { 0xf0,         CMN_PLL1_VCOCAL_INIT },
> +       { 0x18,         CMN_PLL1_VCOCAL_ITER },
> +       { 0x30b4,       CMN_PLL1_VCOCAL_START },
> +       { 0xe1,         CMN_PLL1_INTDIV },
> +       { 0,            CMN_PLL1_FRACDIV },
> +       { 0x5,          CMN_PLL1_HIGH_THR },
> +       { 0x8000,       CMN_PLL1_SS_CTRL1 },
> +       { 0,            CMN_PLL1_SS_CTRL2 },
> +       { 0x20,         CMN_PLL1_DSM_DIAG },
> +       { 0x1000,       CMN_PLLSM1_USER_DEF_CTRL },
> +       { 0,            CMN_DIAG_PLL1_OVRD },
> +       { 0,            CMN_DIAG_PLL1_FBH_OVRD },
> +       { 0,            CMN_DIAG_PLL1_FBL_OVRD },
> +       { 0x7,          CMN_DIAG_PLL1_V2I_TUNE },
> +       { 0x45,         CMN_DIAG_PLL1_CP_TUNE },
> +       { 0x8,          CMN_DIAG_PLL1_LF_PROG },
> +       { 0x1,          CMN_DIAG_PLL1_PTATIS_TUNE1 },
> +       { 0x1,          CMN_DIAG_PLL1_PTATIS_TUNE2 },
> +       { 0x1,          CMN_DIAG_PLL1_INCLK_CTRL },
> +};
>  static const struct rockchip_usb3phy_port_cfg rk3399_usb3phy_port_cfgs[] = {
>         {
>                 .reg = 0xff7c0000,
> @@ -418,6 +471,24 @@ static const struct rockchip_usb3phy_port_cfg rk3399_usb3phy_port_cfgs[] = {
>         { /* sentinel */ }
>  };
>
> +/* default phy config */
> +static const struct phy_config tcphy_default_config[3][4] = {
> +       {{ .swing = 0x2a, .pe = 0x00 },
> +        { .swing = 0x1f, .pe = 0x15 },
> +        { .swing = 0x14, .pe = 0x22 },
> +        { .swing = 0x02, .pe = 0x2b } },
> +
> +       {{ .swing = 0x21, .pe = 0x00 },
> +        { .swing = 0x12, .pe = 0x15 },
> +        { .swing = 0x02, .pe = 0x22 },
> +        { .swing = 0,    .pe = 0 } },
> +
> +       {{ .swing = 0x15, .pe = 0x00 },
> +        { .swing = 0x00, .pe = 0x15 },
> +        { .swing = 0,    .pe = 0 },
> +        { .swing = 0,    .pe = 0 } },
> +};
> +
>  static void tcphy_cfg_24m(struct rockchip_typec_phy *tcphy)
>  {
>         u32 i, rdata;
> @@ -439,7 +510,7 @@ static void tcphy_cfg_24m(struct rockchip_typec_phy *tcphy)
>
>         rdata = readl(tcphy->base + CMN_DIAG_HSCLK_SEL);
>         rdata &= ~CLK_PLL_MASK;
> -       rdata |= CLK_PLL_CONFIG;
> +       rdata |= CLK_PLL1_DIV2;
>         writel(rdata, tcphy->base + CMN_DIAG_HSCLK_SEL);
>  }
>
> @@ -453,17 +524,44 @@ static void tcphy_cfg_usb3_pll(struct rockchip_typec_phy *tcphy)
>                        tcphy->base + usb3_pll_cfg[i].addr);
>  }
>
> -static void tcphy_cfg_dp_pll(struct rockchip_typec_phy *tcphy)
> +static void tcphy_cfg_dp_pll(struct rockchip_typec_phy *tcphy, int link_rate)
>  {
> -       u32 i;
> +       struct phy_reg *phy_cfg;
> +       u32 clk_ctrl;
> +       u32 i, cfg_size, hsclk_sel;
> +
> +       hsclk_sel = readl(tcphy->base + CMN_DIAG_HSCLK_SEL);
> +       hsclk_sel &= ~CLK_PLL_MASK;
> +
> +       switch (link_rate) {
> +       case 162000:
> +               clk_ctrl = DP_PLL_DATA_RATE_RBR;
> +               hsclk_sel |= CLK_PLL1_DIV2;
> +               phy_cfg = dp_pll_rbr_cfg;
> +               cfg_size = ARRAY_SIZE(dp_pll_rbr_cfg);
> +               break;
> +       case 270000:
> +               clk_ctrl = DP_PLL_DATA_RATE_HBR;
> +               hsclk_sel |= CLK_PLL1_DIV2;
> +               phy_cfg = dp_pll_hbr_cfg;
> +               cfg_size = ARRAY_SIZE(dp_pll_hbr_cfg);
> +               break;
> +       case 540000:
> +               clk_ctrl = DP_PLL_DATA_RATE_HBR2;
> +               hsclk_sel |= CLK_PLL1_DIV1;
> +               phy_cfg = dp_pll_hbr2_cfg;
> +               cfg_size = ARRAY_SIZE(dp_pll_hbr2_cfg);
> +               break;

If someone calls this function with a link_rate different to the ones
in the switch statement, some variables will be uninitialized and the
kernel will crash.  I'd add a default case or return an error if a
different link_rate is passed to the function.

> +       }
>
> -       /* set the default mode to RBR */
> -       writel(DP_PLL_CLOCK_ENABLE | DP_PLL_ENABLE | DP_PLL_DATA_RATE_RBR,
> -              tcphy->base + DP_CLK_CTL);
> +       clk_ctrl |= DP_PLL_CLOCK_ENABLE | DP_PLL_ENABLE;
> +       writel(clk_ctrl, tcphy->base + DP_CLK_CTL);
> +
> +       writel(hsclk_sel, tcphy->base + CMN_DIAG_HSCLK_SEL);
>
>         /* load the configuration of PLL1 */
> -       for (i = 0; i < ARRAY_SIZE(dp_pll_cfg); i++)
> -               writel(dp_pll_cfg[i].value, tcphy->base + dp_pll_cfg[i].addr);
> +       for (i = 0; i < cfg_size; i++)
> +               writel(phy_cfg[i].value, tcphy->base + phy_cfg[i].addr);
>  }
>
>  static void tcphy_tx_usb3_cfg_lane(struct rockchip_typec_phy *tcphy, u32 lane)
> @@ -490,9 +588,10 @@ static void tcphy_rx_usb3_cfg_lane(struct rockchip_typec_phy *tcphy, u32 lane)
>         writel(0xfb, tcphy->base + XCVR_DIAG_BIDI_CTRL(lane));
>  }
>
> -static void tcphy_dp_cfg_lane(struct rockchip_typec_phy *tcphy, u32 lane)
> +static void tcphy_dp_cfg_lane(struct rockchip_typec_phy *tcphy, int link_rate,
> +                             u8 swing, u8 pre_emp, u32 lane)
>  {
> -       u16 rdata;
> +       u16 val;
>

Just use rdata in your added code, you don't need to rename the
variable. That will result in a smaller diff.

>         writel(0xbefc, tcphy->base + XCVR_PSM_RCTRL(lane));
>         writel(0x6799, tcphy->base + TX_PSC_A0(lane));
> @@ -500,25 +599,31 @@ static void tcphy_dp_cfg_lane(struct rockchip_typec_phy *tcphy, u32 lane)
>         writel(0x98, tcphy->base + TX_PSC_A2(lane));
>         writel(0x98, tcphy->base + TX_PSC_A3(lane));
>
> -       writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_000(lane));
> -       writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_001(lane));
> -       writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_010(lane));
> -       writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_011(lane));
> -       writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_100(lane));
> -       writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_101(lane));
> -       writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_110(lane));
> -       writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_111(lane));
> -       writel(0, tcphy->base + TX_TXCC_CPOST_MULT_10(lane));
> -       writel(0, tcphy->base + TX_TXCC_CPOST_MULT_01(lane));
> -       writel(0, tcphy->base + TX_TXCC_CPOST_MULT_00(lane));
> -       writel(0, tcphy->base + TX_TXCC_CPOST_MULT_11(lane));
> -
> -       writel(0x128, tcphy->base + TX_TXCC_CAL_SCLR_MULT(lane));
> -       writel(0x400, tcphy->base + TX_DIAG_TX_DRV(lane));
> -
> -       rdata = readl(tcphy->base + XCVR_DIAG_PLLDRC_CTRL(lane));
> -       rdata = (rdata & 0x8fff) | 0x6000;
> -       writel(rdata, tcphy->base + XCVR_DIAG_PLLDRC_CTRL(lane));
> +       writel(tcphy->config[swing][pre_emp].swing,
> +              tcphy->base + TX_TXCC_MGNFS_MULT_000(lane));
> +       writel(tcphy->config[swing][pre_emp].pe,
> +              tcphy->base + TX_TXCC_CPOST_MULT_00(lane));
> +
> +       if (swing == 2 && pre_emp == 0 && link_rate != 540000) {
> +               writel(0x700, tcphy->base + TX_DIAG_TX_DRV(lane));
> +               writel(0x13c, tcphy->base + TX_TXCC_CAL_SCLR_MULT(lane));
> +       } else {
> +               writel(0x128, tcphy->base + TX_TXCC_CAL_SCLR_MULT(lane));
> +               writel(0x0400, tcphy->base + TX_DIAG_TX_DRV(lane));
> +       }
> +
> +       val = readl(tcphy->base + XCVR_DIAG_PLLDRC_CTRL(lane));
> +       val = val & 0x8fff;
> +       switch (link_rate) {
> +       case 162000:
> +       case 270000:
> +               val |= (6 << 12);
> +               break;
> +       case 540000:
> +               val |= (4 << 12);
> +               break;

If link_rate is another value you will write (val & 0x8fff), is ok?

Before this patch, we were writing (rdata & 0x8fff) | 0x6000 by
default, maybe we should default to this value?

> +       }
> +       writel(val, tcphy->base + XCVR_DIAG_PLLDRC_CTRL(lane));
>  }
>
>  static inline int property_enable(struct rockchip_typec_phy *tcphy,
> @@ -709,30 +814,33 @@ static int tcphy_phy_init(struct rockchip_typec_phy *tcphy, u8 mode)
>         tcphy_cfg_24m(tcphy);
>
>         if (mode == MODE_DFP_DP) {
> -               tcphy_cfg_dp_pll(tcphy);
> +               tcphy_cfg_dp_pll(tcphy, DP_DEFAULT_RATE);
>                 for (i = 0; i < 4; i++)
> -                       tcphy_dp_cfg_lane(tcphy, i);
> +                       tcphy_dp_cfg_lane(tcphy, DP_DEFAULT_RATE, 0, 0, i);
>
>                 writel(PIN_ASSIGN_C_E, tcphy->base + PMA_LANE_CFG);
>         } else {
>                 tcphy_cfg_usb3_pll(tcphy);
> -               tcphy_cfg_dp_pll(tcphy);
> +               tcphy_cfg_dp_pll(tcphy, DP_DEFAULT_RATE);
>                 if (tcphy->flip) {
>                         tcphy_tx_usb3_cfg_lane(tcphy, 3);
>                         tcphy_rx_usb3_cfg_lane(tcphy, 2);
> -                       tcphy_dp_cfg_lane(tcphy, 0);
> -                       tcphy_dp_cfg_lane(tcphy, 1);
> +                       tcphy_dp_cfg_lane(tcphy, DP_DEFAULT_RATE, 0, 0, 0);
> +                       tcphy_dp_cfg_lane(tcphy, DP_DEFAULT_RATE, 0, 0, 1);
>                 } else {
>                         tcphy_tx_usb3_cfg_lane(tcphy, 0);
>                         tcphy_rx_usb3_cfg_lane(tcphy, 1);
> -                       tcphy_dp_cfg_lane(tcphy, 2);
> -                       tcphy_dp_cfg_lane(tcphy, 3);
> +                       tcphy_dp_cfg_lane(tcphy, DP_DEFAULT_RATE, 0, 0, 2);
> +                       tcphy_dp_cfg_lane(tcphy, DP_DEFAULT_RATE, 0, 0, 3);
>                 }
>
>                 writel(PIN_ASSIGN_D_F, tcphy->base + PMA_LANE_CFG);
>         }
>
> -       writel(DP_MODE_ENTER_A2, tcphy->base + DP_MODE_CTL);
> +       val = readl(tcphy->base + DP_MODE_CTL);
> +       val &= ~DP_MODE_MASK;
> +       val |= DP_MODE_ENTER_A2 | DP_LINK_RESET_DEASSERTED;
> +       writel(val, tcphy->base + DP_MODE_CTL);
>
>         reset_control_deassert(tcphy->uphy_rst);
>
> @@ -945,7 +1053,7 @@ static int rockchip_dp_phy_power_on(struct phy *phy)
>         property_enable(tcphy, &cfg->uphy_dp_sel, 1);
>
>         ret = readx_poll_timeout(readl, tcphy->base + DP_MODE_CTL,
> -                                val, val & DP_MODE_A2, 1000,
> +                                val, val & DP_MODE_A2_ACK, 1000,
>                                  PHY_MODE_SET_TIMEOUT);
>         if (ret < 0) {
>                 dev_err(tcphy->dev, "failed to wait TCPHY enter A2\n");
> @@ -954,13 +1062,19 @@ static int rockchip_dp_phy_power_on(struct phy *phy)
>
>         tcphy_dp_aux_calibration(tcphy);
>
> -       writel(DP_MODE_ENTER_A0, tcphy->base + DP_MODE_CTL);
> +       /* enter A0 mode */
> +       val = readl(tcphy->base + DP_MODE_CTL);
> +       val &= ~DP_MODE_MASK;
> +       val |= DP_MODE_ENTER_A0;
> +       writel(val, tcphy->base + DP_MODE_CTL);
>
>         ret = readx_poll_timeout(readl, tcphy->base + DP_MODE_CTL,
> -                                val, val & DP_MODE_A0, 1000,
> +                                val, val & DP_MODE_A0_ACK, 1000,
>                                  PHY_MODE_SET_TIMEOUT);
>         if (ret < 0) {
> -               writel(DP_MODE_ENTER_A2, tcphy->base + DP_MODE_CTL);
> +               val &= ~DP_MODE_MASK;
> +               val |= DP_MODE_ENTER_A2;
> +               writel(val, tcphy->base + DP_MODE_CTL);
>                 dev_err(tcphy->dev, "failed to wait TCPHY enter A0\n");
>                 goto power_on_finish;
>         }
> @@ -978,6 +1092,7 @@ static int rockchip_dp_phy_power_on(struct phy *phy)
>  static int rockchip_dp_phy_power_off(struct phy *phy)
>  {
>         struct rockchip_typec_phy *tcphy = phy_get_drvdata(phy);
> +       u32 val;
>
>         mutex_lock(&tcphy->lock);
>
> @@ -986,7 +1101,10 @@ static int rockchip_dp_phy_power_off(struct phy *phy)
>
>         tcphy->mode &= ~MODE_DFP_DP;
>
> -       writel(DP_MODE_ENTER_A2, tcphy->base + DP_MODE_CTL);
> +       val = readl(tcphy->base + DP_MODE_CTL);
> +       val &= ~DP_MODE_MASK;
> +       val |= DP_MODE_ENTER_A2;
> +       writel(val, tcphy->base + DP_MODE_CTL);
>
>         if (tcphy->mode == MODE_DISCONNECT)
>                 tcphy_phy_deinit(tcphy);
> @@ -1002,9 +1120,35 @@ static const struct phy_ops rockchip_dp_phy_ops = {
>         .owner          = THIS_MODULE,
>  };
>
> +static int typec_dp_phy_config(struct phy *phy, int link_rate,
> +                        int lanes, u8 swing, u8 pre_emp)
> +{
> +       struct rockchip_typec_phy *tcphy = phy_get_drvdata(phy);
> +       u8 i;
> +
> +       tcphy_cfg_dp_pll(tcphy, link_rate);
> +
> +       if (tcphy->mode == MODE_DFP_DP) {
> +               for (i = 0; i < 4; i++)
> +                       tcphy_dp_cfg_lane(tcphy, link_rate, swing, pre_emp, i);
> +       } else {
> +               if (tcphy->flip) {
> +                       tcphy_dp_cfg_lane(tcphy, link_rate, swing, pre_emp, 0);
> +                       tcphy_dp_cfg_lane(tcphy, link_rate, swing, pre_emp, 1);
> +               } else {
> +                       tcphy_dp_cfg_lane(tcphy, link_rate, swing, pre_emp, 2);
> +                       tcphy_dp_cfg_lane(tcphy, link_rate, swing, pre_emp, 3);
> +               }
> +       }
> +
> +       return 0;
> +}
> +
>  static int tcphy_parse_dt(struct rockchip_typec_phy *tcphy,
>                           struct device *dev)
>  {
> +       int ret;
> +
>         tcphy->grf_regs = syscon_regmap_lookup_by_phandle(dev->of_node,
>                                                           "rockchip,grf");
>         if (IS_ERR(tcphy->grf_regs)) {
> @@ -1042,6 +1186,16 @@ static int tcphy_parse_dt(struct rockchip_typec_phy *tcphy,
>                 return PTR_ERR(tcphy->tcphy_rst);
>         }
>
> +       /*
> +        * check if phy_config pass from dts, if no,
> +        * use default phy config value.

nit: Check if phy-config is passed from the dts, if no, use the
default phy configuration.

> +        */
> +       ret = of_property_read_u32_array(dev->of_node, "rockchip,phy-config",
> +               (u32 *)tcphy->config, sizeof(tcphy->config) / sizeof(u32));
> +       if (ret)
> +               memcpy(tcphy->config, tcphy_default_config,
> +                      sizeof(tcphy->config));
> +
>         return 0;
>  }
>
> @@ -1126,6 +1280,7 @@ static int rockchip_typec_phy_probe(struct platform_device *pdev)
>                 }
>         }
>
> +       tcphy->typec_phy_config = typec_dp_phy_config;
>         pm_runtime_enable(dev);
>
>         for_each_available_child_of_node(np, child_np) {
> --
> 2.7.4
>

Best regards,
 Enric
diff mbox

Patch

diff --git a/drivers/phy/rockchip/phy-rockchip-typec.c b/drivers/phy/rockchip/phy-rockchip-typec.c
index 795055f..4c4b925 100644
--- a/drivers/phy/rockchip/phy-rockchip-typec.c
+++ b/drivers/phy/rockchip/phy-rockchip-typec.c
@@ -324,21 +324,29 @@ 
  * clock 0: PLL 0 div 1
  * clock 1: PLL 1 div 2
  */
-#define CLK_PLL_CONFIG			0X30
+#define CLK_PLL1_DIV1			0x20
+#define CLK_PLL1_DIV2			0x30
 #define CLK_PLL_MASK			0x33
 
 #define CMN_READY			BIT(0)
 
+#define DP_PLL_CLOCK_ENABLE_ACK		BIT(3)
 #define DP_PLL_CLOCK_ENABLE		BIT(2)
+#define DP_PLL_ENABLE_ACK		BIT(1)
 #define DP_PLL_ENABLE			BIT(0)
 #define DP_PLL_DATA_RATE_RBR		((2 << 12) | (4 << 8))
 #define DP_PLL_DATA_RATE_HBR		((2 << 12) | (4 << 8))
 #define DP_PLL_DATA_RATE_HBR2		((1 << 12) | (2 << 8))
+#define DP_PLL_DATA_RATE_MASK		0xff00
 
-#define DP_MODE_A0			BIT(4)
-#define DP_MODE_A2			BIT(6)
-#define DP_MODE_ENTER_A0		0xc101
-#define DP_MODE_ENTER_A2		0xc104
+#define DP_MODE_MASK			0xf
+#define DP_MODE_ENTER_A0		BIT(0)
+#define DP_MODE_ENTER_A2		BIT(2)
+#define DP_MODE_ENTER_A3		BIT(3)
+#define DP_MODE_A0_ACK			BIT(4)
+#define DP_MODE_A2_ACK			BIT(6)
+#define DP_MODE_A3_ACK			BIT(7)
+#define DP_LINK_RESET_DEASSERTED	BIT(8)
 
 #define PHY_MODE_SET_TIMEOUT		100000
 
@@ -350,6 +358,8 @@ 
 #define MODE_DFP_USB			BIT(1)
 #define MODE_DFP_DP			BIT(2)
 
+#define DP_DEFAULT_RATE		162000
+
 struct phy_reg {
 	u16 value;
 	u32 addr;
@@ -372,15 +382,15 @@  struct phy_reg usb3_pll_cfg[] = {
 	{ 0x8,		CMN_DIAG_PLL0_LF_PROG },
 };
 
-struct phy_reg dp_pll_cfg[] = {
+struct phy_reg dp_pll_rbr_cfg[] = {
 	{ 0xf0,		CMN_PLL1_VCOCAL_INIT },
 	{ 0x18,		CMN_PLL1_VCOCAL_ITER },
 	{ 0x30b9,	CMN_PLL1_VCOCAL_START },
-	{ 0x21c,	CMN_PLL1_INTDIV },
+	{ 0x87,		CMN_PLL1_INTDIV },
 	{ 0,		CMN_PLL1_FRACDIV },
-	{ 0x5,		CMN_PLL1_HIGH_THR },
-	{ 0x35,		CMN_PLL1_SS_CTRL1 },
-	{ 0x7f1e,	CMN_PLL1_SS_CTRL2 },
+	{ 0x22,		CMN_PLL1_HIGH_THR },
+	{ 0x8000,	CMN_PLL1_SS_CTRL1 },
+	{ 0,		CMN_PLL1_SS_CTRL2 },
 	{ 0x20,		CMN_PLL1_DSM_DIAG },
 	{ 0,		CMN_PLLSM1_USER_DEF_CTRL },
 	{ 0,		CMN_DIAG_PLL1_OVRD },
@@ -391,9 +401,52 @@  struct phy_reg dp_pll_cfg[] = {
 	{ 0x8,		CMN_DIAG_PLL1_LF_PROG },
 	{ 0x100,	CMN_DIAG_PLL1_PTATIS_TUNE1 },
 	{ 0x7,		CMN_DIAG_PLL1_PTATIS_TUNE2 },
-	{ 0x4,		CMN_DIAG_PLL1_INCLK_CTRL },
+	{ 0x1,		CMN_DIAG_PLL1_INCLK_CTRL },
 };
 
+struct phy_reg dp_pll_hbr_cfg[] = {
+	{ 0xf0,		CMN_PLL1_VCOCAL_INIT },
+	{ 0x18,		CMN_PLL1_VCOCAL_ITER },
+	{ 0x30b4,	CMN_PLL1_VCOCAL_START },
+	{ 0xe1,		CMN_PLL1_INTDIV },
+	{ 0,		CMN_PLL1_FRACDIV },
+	{ 0x5,		CMN_PLL1_HIGH_THR },
+	{ 0x8000,	CMN_PLL1_SS_CTRL1 },
+	{ 0,		CMN_PLL1_SS_CTRL2 },
+	{ 0x20,		CMN_PLL1_DSM_DIAG },
+	{ 0x1000,	CMN_PLLSM1_USER_DEF_CTRL },
+	{ 0,		CMN_DIAG_PLL1_OVRD },
+	{ 0,		CMN_DIAG_PLL1_FBH_OVRD },
+	{ 0,		CMN_DIAG_PLL1_FBL_OVRD },
+	{ 0x7,		CMN_DIAG_PLL1_V2I_TUNE },
+	{ 0x45,		CMN_DIAG_PLL1_CP_TUNE },
+	{ 0x8,		CMN_DIAG_PLL1_LF_PROG },
+	{ 0x1,		CMN_DIAG_PLL1_PTATIS_TUNE1 },
+	{ 0x1,		CMN_DIAG_PLL1_PTATIS_TUNE2 },
+	{ 0x1,		CMN_DIAG_PLL1_INCLK_CTRL },
+};
+
+struct phy_reg dp_pll_hbr2_cfg[] = {
+	{ 0xf0,		CMN_PLL1_VCOCAL_INIT },
+	{ 0x18,		CMN_PLL1_VCOCAL_ITER },
+	{ 0x30b4,	CMN_PLL1_VCOCAL_START },
+	{ 0xe1,		CMN_PLL1_INTDIV },
+	{ 0,		CMN_PLL1_FRACDIV },
+	{ 0x5,		CMN_PLL1_HIGH_THR },
+	{ 0x8000,	CMN_PLL1_SS_CTRL1 },
+	{ 0,		CMN_PLL1_SS_CTRL2 },
+	{ 0x20,		CMN_PLL1_DSM_DIAG },
+	{ 0x1000,	CMN_PLLSM1_USER_DEF_CTRL },
+	{ 0,		CMN_DIAG_PLL1_OVRD },
+	{ 0,		CMN_DIAG_PLL1_FBH_OVRD },
+	{ 0,		CMN_DIAG_PLL1_FBL_OVRD },
+	{ 0x7,		CMN_DIAG_PLL1_V2I_TUNE },
+	{ 0x45,		CMN_DIAG_PLL1_CP_TUNE },
+	{ 0x8,		CMN_DIAG_PLL1_LF_PROG },
+	{ 0x1,		CMN_DIAG_PLL1_PTATIS_TUNE1 },
+	{ 0x1,		CMN_DIAG_PLL1_PTATIS_TUNE2 },
+	{ 0x1,		CMN_DIAG_PLL1_INCLK_CTRL },
+};
 static const struct rockchip_usb3phy_port_cfg rk3399_usb3phy_port_cfgs[] = {
 	{
 		.reg = 0xff7c0000,
@@ -418,6 +471,24 @@  static const struct rockchip_usb3phy_port_cfg rk3399_usb3phy_port_cfgs[] = {
 	{ /* sentinel */ }
 };
 
+/* default phy config */
+static const struct phy_config tcphy_default_config[3][4] = {
+	{{ .swing = 0x2a, .pe = 0x00 },
+	 { .swing = 0x1f, .pe = 0x15 },
+	 { .swing = 0x14, .pe = 0x22 },
+	 { .swing = 0x02, .pe = 0x2b } },
+
+	{{ .swing = 0x21, .pe = 0x00 },
+	 { .swing = 0x12, .pe = 0x15 },
+	 { .swing = 0x02, .pe = 0x22 },
+	 { .swing = 0,    .pe = 0 } },
+
+	{{ .swing = 0x15, .pe = 0x00 },
+	 { .swing = 0x00, .pe = 0x15 },
+	 { .swing = 0,    .pe = 0 },
+	 { .swing = 0,    .pe = 0 } },
+};
+
 static void tcphy_cfg_24m(struct rockchip_typec_phy *tcphy)
 {
 	u32 i, rdata;
@@ -439,7 +510,7 @@  static void tcphy_cfg_24m(struct rockchip_typec_phy *tcphy)
 
 	rdata = readl(tcphy->base + CMN_DIAG_HSCLK_SEL);
 	rdata &= ~CLK_PLL_MASK;
-	rdata |= CLK_PLL_CONFIG;
+	rdata |= CLK_PLL1_DIV2;
 	writel(rdata, tcphy->base + CMN_DIAG_HSCLK_SEL);
 }
 
@@ -453,17 +524,44 @@  static void tcphy_cfg_usb3_pll(struct rockchip_typec_phy *tcphy)
 		       tcphy->base + usb3_pll_cfg[i].addr);
 }
 
-static void tcphy_cfg_dp_pll(struct rockchip_typec_phy *tcphy)
+static void tcphy_cfg_dp_pll(struct rockchip_typec_phy *tcphy, int link_rate)
 {
-	u32 i;
+	struct phy_reg *phy_cfg;
+	u32 clk_ctrl;
+	u32 i, cfg_size, hsclk_sel;
+
+	hsclk_sel = readl(tcphy->base + CMN_DIAG_HSCLK_SEL);
+	hsclk_sel &= ~CLK_PLL_MASK;
+
+	switch (link_rate) {
+	case 162000:
+		clk_ctrl = DP_PLL_DATA_RATE_RBR;
+		hsclk_sel |= CLK_PLL1_DIV2;
+		phy_cfg = dp_pll_rbr_cfg;
+		cfg_size = ARRAY_SIZE(dp_pll_rbr_cfg);
+		break;
+	case 270000:
+		clk_ctrl = DP_PLL_DATA_RATE_HBR;
+		hsclk_sel |= CLK_PLL1_DIV2;
+		phy_cfg = dp_pll_hbr_cfg;
+		cfg_size = ARRAY_SIZE(dp_pll_hbr_cfg);
+		break;
+	case 540000:
+		clk_ctrl = DP_PLL_DATA_RATE_HBR2;
+		hsclk_sel |= CLK_PLL1_DIV1;
+		phy_cfg = dp_pll_hbr2_cfg;
+		cfg_size = ARRAY_SIZE(dp_pll_hbr2_cfg);
+		break;
+	}
 
-	/* set the default mode to RBR */
-	writel(DP_PLL_CLOCK_ENABLE | DP_PLL_ENABLE | DP_PLL_DATA_RATE_RBR,
-	       tcphy->base + DP_CLK_CTL);
+	clk_ctrl |= DP_PLL_CLOCK_ENABLE | DP_PLL_ENABLE;
+	writel(clk_ctrl, tcphy->base + DP_CLK_CTL);
+
+	writel(hsclk_sel, tcphy->base + CMN_DIAG_HSCLK_SEL);
 
 	/* load the configuration of PLL1 */
-	for (i = 0; i < ARRAY_SIZE(dp_pll_cfg); i++)
-		writel(dp_pll_cfg[i].value, tcphy->base + dp_pll_cfg[i].addr);
+	for (i = 0; i < cfg_size; i++)
+		writel(phy_cfg[i].value, tcphy->base + phy_cfg[i].addr);
 }
 
 static void tcphy_tx_usb3_cfg_lane(struct rockchip_typec_phy *tcphy, u32 lane)
@@ -490,9 +588,10 @@  static void tcphy_rx_usb3_cfg_lane(struct rockchip_typec_phy *tcphy, u32 lane)
 	writel(0xfb, tcphy->base + XCVR_DIAG_BIDI_CTRL(lane));
 }
 
-static void tcphy_dp_cfg_lane(struct rockchip_typec_phy *tcphy, u32 lane)
+static void tcphy_dp_cfg_lane(struct rockchip_typec_phy *tcphy, int link_rate,
+			      u8 swing, u8 pre_emp, u32 lane)
 {
-	u16 rdata;
+	u16 val;
 
 	writel(0xbefc, tcphy->base + XCVR_PSM_RCTRL(lane));
 	writel(0x6799, tcphy->base + TX_PSC_A0(lane));
@@ -500,25 +599,31 @@  static void tcphy_dp_cfg_lane(struct rockchip_typec_phy *tcphy, u32 lane)
 	writel(0x98, tcphy->base + TX_PSC_A2(lane));
 	writel(0x98, tcphy->base + TX_PSC_A3(lane));
 
-	writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_000(lane));
-	writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_001(lane));
-	writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_010(lane));
-	writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_011(lane));
-	writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_100(lane));
-	writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_101(lane));
-	writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_110(lane));
-	writel(0, tcphy->base + TX_TXCC_MGNFS_MULT_111(lane));
-	writel(0, tcphy->base + TX_TXCC_CPOST_MULT_10(lane));
-	writel(0, tcphy->base + TX_TXCC_CPOST_MULT_01(lane));
-	writel(0, tcphy->base + TX_TXCC_CPOST_MULT_00(lane));
-	writel(0, tcphy->base + TX_TXCC_CPOST_MULT_11(lane));
-
-	writel(0x128, tcphy->base + TX_TXCC_CAL_SCLR_MULT(lane));
-	writel(0x400, tcphy->base + TX_DIAG_TX_DRV(lane));
-
-	rdata = readl(tcphy->base + XCVR_DIAG_PLLDRC_CTRL(lane));
-	rdata = (rdata & 0x8fff) | 0x6000;
-	writel(rdata, tcphy->base + XCVR_DIAG_PLLDRC_CTRL(lane));
+	writel(tcphy->config[swing][pre_emp].swing,
+	       tcphy->base + TX_TXCC_MGNFS_MULT_000(lane));
+	writel(tcphy->config[swing][pre_emp].pe,
+	       tcphy->base + TX_TXCC_CPOST_MULT_00(lane));
+
+	if (swing == 2 && pre_emp == 0 && link_rate != 540000) {
+		writel(0x700, tcphy->base + TX_DIAG_TX_DRV(lane));
+		writel(0x13c, tcphy->base + TX_TXCC_CAL_SCLR_MULT(lane));
+	} else {
+		writel(0x128, tcphy->base + TX_TXCC_CAL_SCLR_MULT(lane));
+		writel(0x0400, tcphy->base + TX_DIAG_TX_DRV(lane));
+	}
+
+	val = readl(tcphy->base + XCVR_DIAG_PLLDRC_CTRL(lane));
+	val = val & 0x8fff;
+	switch (link_rate) {
+	case 162000:
+	case 270000:
+		val |= (6 << 12);
+		break;
+	case 540000:
+		val |= (4 << 12);
+		break;
+	}
+	writel(val, tcphy->base + XCVR_DIAG_PLLDRC_CTRL(lane));
 }
 
 static inline int property_enable(struct rockchip_typec_phy *tcphy,
@@ -709,30 +814,33 @@  static int tcphy_phy_init(struct rockchip_typec_phy *tcphy, u8 mode)
 	tcphy_cfg_24m(tcphy);
 
 	if (mode == MODE_DFP_DP) {
-		tcphy_cfg_dp_pll(tcphy);
+		tcphy_cfg_dp_pll(tcphy, DP_DEFAULT_RATE);
 		for (i = 0; i < 4; i++)
-			tcphy_dp_cfg_lane(tcphy, i);
+			tcphy_dp_cfg_lane(tcphy, DP_DEFAULT_RATE, 0, 0, i);
 
 		writel(PIN_ASSIGN_C_E, tcphy->base + PMA_LANE_CFG);
 	} else {
 		tcphy_cfg_usb3_pll(tcphy);
-		tcphy_cfg_dp_pll(tcphy);
+		tcphy_cfg_dp_pll(tcphy, DP_DEFAULT_RATE);
 		if (tcphy->flip) {
 			tcphy_tx_usb3_cfg_lane(tcphy, 3);
 			tcphy_rx_usb3_cfg_lane(tcphy, 2);
-			tcphy_dp_cfg_lane(tcphy, 0);
-			tcphy_dp_cfg_lane(tcphy, 1);
+			tcphy_dp_cfg_lane(tcphy, DP_DEFAULT_RATE, 0, 0, 0);
+			tcphy_dp_cfg_lane(tcphy, DP_DEFAULT_RATE, 0, 0, 1);
 		} else {
 			tcphy_tx_usb3_cfg_lane(tcphy, 0);
 			tcphy_rx_usb3_cfg_lane(tcphy, 1);
-			tcphy_dp_cfg_lane(tcphy, 2);
-			tcphy_dp_cfg_lane(tcphy, 3);
+			tcphy_dp_cfg_lane(tcphy, DP_DEFAULT_RATE, 0, 0, 2);
+			tcphy_dp_cfg_lane(tcphy, DP_DEFAULT_RATE, 0, 0, 3);
 		}
 
 		writel(PIN_ASSIGN_D_F, tcphy->base + PMA_LANE_CFG);
 	}
 
-	writel(DP_MODE_ENTER_A2, tcphy->base + DP_MODE_CTL);
+	val = readl(tcphy->base + DP_MODE_CTL);
+	val &= ~DP_MODE_MASK;
+	val |= DP_MODE_ENTER_A2 | DP_LINK_RESET_DEASSERTED;
+	writel(val, tcphy->base + DP_MODE_CTL);
 
 	reset_control_deassert(tcphy->uphy_rst);
 
@@ -945,7 +1053,7 @@  static int rockchip_dp_phy_power_on(struct phy *phy)
 	property_enable(tcphy, &cfg->uphy_dp_sel, 1);
 
 	ret = readx_poll_timeout(readl, tcphy->base + DP_MODE_CTL,
-				 val, val & DP_MODE_A2, 1000,
+				 val, val & DP_MODE_A2_ACK, 1000,
 				 PHY_MODE_SET_TIMEOUT);
 	if (ret < 0) {
 		dev_err(tcphy->dev, "failed to wait TCPHY enter A2\n");
@@ -954,13 +1062,19 @@  static int rockchip_dp_phy_power_on(struct phy *phy)
 
 	tcphy_dp_aux_calibration(tcphy);
 
-	writel(DP_MODE_ENTER_A0, tcphy->base + DP_MODE_CTL);
+	/* enter A0 mode */
+	val = readl(tcphy->base + DP_MODE_CTL);
+	val &= ~DP_MODE_MASK;
+	val |= DP_MODE_ENTER_A0;
+	writel(val, tcphy->base + DP_MODE_CTL);
 
 	ret = readx_poll_timeout(readl, tcphy->base + DP_MODE_CTL,
-				 val, val & DP_MODE_A0, 1000,
+				 val, val & DP_MODE_A0_ACK, 1000,
 				 PHY_MODE_SET_TIMEOUT);
 	if (ret < 0) {
-		writel(DP_MODE_ENTER_A2, tcphy->base + DP_MODE_CTL);
+		val &= ~DP_MODE_MASK;
+		val |= DP_MODE_ENTER_A2;
+		writel(val, tcphy->base + DP_MODE_CTL);
 		dev_err(tcphy->dev, "failed to wait TCPHY enter A0\n");
 		goto power_on_finish;
 	}
@@ -978,6 +1092,7 @@  static int rockchip_dp_phy_power_on(struct phy *phy)
 static int rockchip_dp_phy_power_off(struct phy *phy)
 {
 	struct rockchip_typec_phy *tcphy = phy_get_drvdata(phy);
+	u32 val;
 
 	mutex_lock(&tcphy->lock);
 
@@ -986,7 +1101,10 @@  static int rockchip_dp_phy_power_off(struct phy *phy)
 
 	tcphy->mode &= ~MODE_DFP_DP;
 
-	writel(DP_MODE_ENTER_A2, tcphy->base + DP_MODE_CTL);
+	val = readl(tcphy->base + DP_MODE_CTL);
+	val &= ~DP_MODE_MASK;
+	val |= DP_MODE_ENTER_A2;
+	writel(val, tcphy->base + DP_MODE_CTL);
 
 	if (tcphy->mode == MODE_DISCONNECT)
 		tcphy_phy_deinit(tcphy);
@@ -1002,9 +1120,35 @@  static const struct phy_ops rockchip_dp_phy_ops = {
 	.owner		= THIS_MODULE,
 };
 
+static int typec_dp_phy_config(struct phy *phy, int link_rate,
+			 int lanes, u8 swing, u8 pre_emp)
+{
+	struct rockchip_typec_phy *tcphy = phy_get_drvdata(phy);
+	u8 i;
+
+	tcphy_cfg_dp_pll(tcphy, link_rate);
+
+	if (tcphy->mode == MODE_DFP_DP) {
+		for (i = 0; i < 4; i++)
+			tcphy_dp_cfg_lane(tcphy, link_rate, swing, pre_emp, i);
+	} else {
+		if (tcphy->flip) {
+			tcphy_dp_cfg_lane(tcphy, link_rate, swing, pre_emp, 0);
+			tcphy_dp_cfg_lane(tcphy, link_rate, swing, pre_emp, 1);
+		} else {
+			tcphy_dp_cfg_lane(tcphy, link_rate, swing, pre_emp, 2);
+			tcphy_dp_cfg_lane(tcphy, link_rate, swing, pre_emp, 3);
+		}
+	}
+
+	return 0;
+}
+
 static int tcphy_parse_dt(struct rockchip_typec_phy *tcphy,
 			  struct device *dev)
 {
+	int ret;
+
 	tcphy->grf_regs = syscon_regmap_lookup_by_phandle(dev->of_node,
 							  "rockchip,grf");
 	if (IS_ERR(tcphy->grf_regs)) {
@@ -1042,6 +1186,16 @@  static int tcphy_parse_dt(struct rockchip_typec_phy *tcphy,
 		return PTR_ERR(tcphy->tcphy_rst);
 	}
 
+	/*
+	 * check if phy_config pass from dts, if no,
+	 * use default phy config value.
+	 */
+	ret = of_property_read_u32_array(dev->of_node, "rockchip,phy-config",
+		(u32 *)tcphy->config, sizeof(tcphy->config) / sizeof(u32));
+	if (ret)
+		memcpy(tcphy->config, tcphy_default_config,
+		       sizeof(tcphy->config));
+
 	return 0;
 }
 
@@ -1126,6 +1280,7 @@  static int rockchip_typec_phy_probe(struct platform_device *pdev)
 		}
 	}
 
+	tcphy->typec_phy_config = typec_dp_phy_config;
 	pm_runtime_enable(dev);
 
 	for_each_available_child_of_node(np, child_np) {