Messages in this thread Patch in this message | | | From | Marek Behún <> | Subject | [PATCH linux-phy 3/4] phy: marvell: phy-mvebu-a3700-comphy: Support changing tx amplitude for ethernet | Date | Wed, 17 Aug 2022 21:31:18 +0200 |
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Add support to set SerDes transmit amplitude if specified via the 'tx-p2p-microvolt' and 'tx-p2p-microvolt-names' device-tree properties.
This support is currently only for ethernet mode.
Signed-off-by: Marek Behún <kabel@kernel.org> --- drivers/phy/marvell/phy-mvebu-a3700-comphy.c | 109 ++++++++++++++++++- 1 file changed, 108 insertions(+), 1 deletion(-)
diff --git a/drivers/phy/marvell/phy-mvebu-a3700-comphy.c b/drivers/phy/marvell/phy-mvebu-a3700-comphy.c index a4d7d9bd100d..7fabd959ae0f 100644 --- a/drivers/phy/marvell/phy-mvebu-a3700-comphy.c +++ b/drivers/phy/marvell/phy-mvebu-a3700-comphy.c @@ -68,6 +68,16 @@ #define SPEED_PLL_MASK GENMASK(7, 2) #define SPEED_PLL_VALUE_16 FIELD_PREP(SPEED_PLL_MASK, 0x10) +#define COMPHY_GEN1_SET0 0x0d +#define COMPHY_GEN2_SET0 0x0f +#define COMPHY_GEN3_SET0 0x11 +#define COMPHY_GEN4_SET0 0x13 +#define COMPHY_GENx_SET0(x) (0x0d + (((x) & 3) - 1) * 2) +#define Gx_TX_AMP_MASK GENMASK(5, 1) +#define Gx_TX_AMP_VALUE(x) FIELD_PREP(Gx_TX_AMP_MASK, x) +#define Gx_TX_AMP_ADJ BIT(6) +#define Gx_TX_AMP_1025MV (Gx_TX_AMP_VALUE(0x12) | Gx_TX_AMP_ADJ) + #define COMPHY_DIG_LOOPBACK_EN 0x23 #define SEL_DATA_WIDTH_MASK GENMASK(11, 10) #define DATA_WIDTH_10BIT FIELD_PREP(SEL_DATA_WIDTH_MASK, 0x0) @@ -269,6 +279,7 @@ struct mvebu_a3700_comphy_priv { struct mvebu_a3700_comphy_lane { struct mvebu_a3700_comphy_priv *priv; struct device *dev; + struct phy *phy; unsigned int id; enum phy_mode mode; int submode; @@ -385,6 +396,15 @@ static inline void comphy_reg_set16(void __iomem *addr, u16 data, u16 mask) } /* Used for accessing lane 2 registers (SATA/USB3 PHY) */ +static u16 comphy_get_indirect(struct mvebu_a3700_comphy_priv *priv, u32 offset) +{ + writel(offset, + priv->lane2_phy_indirect + COMPHY_LANE2_INDIR_ADDR); + + /* We need to read the register with 32-bit read */ + return readl(priv->lane2_phy_indirect + COMPHY_LANE2_INDIR_DATA); +} + static void comphy_set_indirect(struct mvebu_a3700_comphy_priv *priv, u32 offset, u16 data, u16 mask) { @@ -394,6 +414,21 @@ static void comphy_set_indirect(struct mvebu_a3700_comphy_priv *priv, data, mask); } +static u16 comphy_lane_reg_get(struct mvebu_a3700_comphy_lane *lane, u16 reg) +{ + if (lane->id == 2) { + /* lane 2 PHY registers are accessed indirectly */ + return comphy_get_indirect(lane->priv, + reg + COMPHY_LANE2_REGS_BASE); + } else { + void __iomem *base = lane->id == 1 ? + lane->priv->lane1_phy_regs : + lane->priv->lane0_phy_regs; + + return readw(base + COMPHY_LANE_REG_DIRECT(reg)); + } +} + static void comphy_lane_reg_set(struct mvebu_a3700_comphy_lane *lane, u16 reg, u16 data, u16 mask) { @@ -624,10 +659,53 @@ static void comphy_gbe_phy_init(struct mvebu_a3700_comphy_lane *lane, } } +static u8 comphy_find_best_tx_amp(bool full_swing, u32 amp, u32 *true_amp) +{ + static const u32 half_swing_table[32] = { + 250, 270, 290, 310, 330, 345, 365, 380, + 400, 420, 435, 455, 470, 490, 505, 525, + 485, 520, 555, 590, 625, 660, 695, 730, + 765, 800, 830, 865, 900, 930, 965, 1000, + }; + static const u32 full_swing_table[22] = { + 470, 505, 540, 575, 610, 645, 680, 715, + 750, 785, 820, 850, 885, 915, 950, 980, + 900, 965, 1025, 1095, 1160, 1220, + }; + u32 diff, min_diff; + const u32 *table; + size_t len; + u8 res; + + if (full_swing) { + table = full_swing_table; + len = ARRAY_SIZE(full_swing_table); + } else { + table = half_swing_table; + len = ARRAY_SIZE(half_swing_table); + } + + res = 0; + min_diff = abs(amp - table[0]); + + for (size_t i = 1; i < len; ++i) { + diff = abs(amp - table[i]); + if (diff < min_diff) { + min_diff = diff; + res = i; + } + } + + if (true_amp) + *true_amp = table[res]; + + return res; +} + static int mvebu_a3700_comphy_ethernet_power_on(struct mvebu_a3700_comphy_lane *lane) { - u32 mask, data, speed_sel; + u32 mask, data, speed_sel, tx_amp_uv; int ret; /* Set selector */ @@ -746,6 +824,34 @@ mvebu_a3700_comphy_ethernet_power_on(struct mvebu_a3700_comphy_lane *lane) comphy_gbe_phy_init(lane, lane->submode != PHY_INTERFACE_MODE_2500BASEX); + /* + * Change transmit amplitude if specified in device-tree. + */ + if (!device_get_tx_p2p_amplitude(&lane->phy->dev, + phy_modes(lane->submode), + &tx_amp_uv)) { + u32 tx_amp_mv, true_tx_amp_mv; + bool full_swing; + u8 tx_amp; + u16 reg; + + reg = COMPHY_GENx_SET0(speed_sel + 1); + + data = comphy_lane_reg_get(lane, reg); + full_swing = data & Gx_TX_AMP_ADJ; + tx_amp_mv = DIV_ROUND_CLOSEST(tx_amp_uv, 1000); + tx_amp = comphy_find_best_tx_amp(tx_amp_mv, full_swing, + &true_tx_amp_mv); + + data = Gx_TX_AMP_VALUE(tx_amp); + mask = Gx_TX_AMP_MASK; + comphy_lane_reg_set(lane, reg, data, mask); + + dev_dbg(lane->dev, + "changed tx amplitude to %u mV (requested %u mV) on lane %d\n", + true_tx_amp_mv, tx_amp_mv, lane->id); + } + /* * 14. Check the PHY Polarity invert bit */ @@ -1382,6 +1488,7 @@ static int mvebu_a3700_comphy_probe(struct platform_device *pdev) lane->priv = priv; lane->dev = &pdev->dev; + lane->phy = phy; lane->mode = PHY_MODE_INVALID; lane->submode = PHY_INTERFACE_MODE_NA; lane->id = lane_id; -- 2.35.1
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