On Tue, Aug 16, 2016 at 06:31:48PM -0400, Jaret Cantu wrote: > The TX settings can be calibrated for particular hardware. The > phy is reset by Linux, so this cannot be handled by the bootloader. > > The TRM mentions that the maximum resistance should be used for the > DN/DP calibration in order to pass USB certification. > > The values for the TX registers are poorly described in the TRM. > The meanings of the register values were taken from another > NXP-provided document: > https://community.nxp.com/message/566147#comment-566912 > > Signed-off-by: Jaret Cantu <jaret.cantu@xxxxxxxxxxx> > --- > v4. Corrected tx-d-cal register value by rounding up. > Changed Freescale web site reference to NXP. > > v3. Added unit suffix (-ohms) to tx-cal-45-d* > > v2. Copying devicetree list > Removed prettifying extra whitespace > Removed unnecessary register rewrite on resume > Use min and max constants for clarity > > .../devicetree/bindings/phy/mxs-usb-phy.txt | 10 ++++ > drivers/usb/phy/phy-mxs-usb.c | 61 ++++++++++++++++++++ > 2 files changed, 71 insertions(+) > > diff --git a/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt b/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt > index 379b84a..1d25b04 100644 > --- a/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt > +++ b/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt > @@ -12,6 +12,16 @@ Required properties: > - interrupts: Should contain phy interrupt > - fsl,anatop: phandle for anatop register, it is only for imx6 SoC series > > +Optional properties: > +- fsl,tx-cal-45-dn-ohms: Integer [30-55]. Resistance (in ohms) of switchable > + high-speed trimming resistor connected in parallel with the 45 ohm resistor > + that terminates the DN output signal. Default: 45 > +- fsl,tx-cal-45-dp-ohms: Integer [30-55]. Resistance (in ohms) of switchable > + high-speed trimming resistor connected in parallel with the 45 ohm resistor > + that terminates the DP output signal. Default: 45 > +- fsl,tx-d-cal: Integer [79-119]. Current trimming value (as a percentage) of > + the 17.78mA TX reference current. Default: 100 > + > Example: > usbphy1: usbphy@020c9000 { > compatible = "fsl,imx6q-usbphy", "fsl,imx23-usbphy"; > diff --git a/drivers/usb/phy/phy-mxs-usb.c b/drivers/usb/phy/phy-mxs-usb.c > index 00bfea0..0e2f1a3 100644 > --- a/drivers/usb/phy/phy-mxs-usb.c > +++ b/drivers/usb/phy/phy-mxs-usb.c > @@ -27,6 +27,7 @@ > #define DRIVER_NAME "mxs_phy" > > #define HW_USBPHY_PWD 0x00 > +#define HW_USBPHY_TX 0x10 > #define HW_USBPHY_CTRL 0x30 > #define HW_USBPHY_CTRL_SET 0x34 > #define HW_USBPHY_CTRL_CLR 0x38 > @@ -38,6 +39,10 @@ > #define HW_USBPHY_IP_SET 0x94 > #define HW_USBPHY_IP_CLR 0x98 > > +#define GM_USBPHY_TX_TXCAL45DP(x) (((x) & 0xf) << 16) > +#define GM_USBPHY_TX_TXCAL45DN(x) (((x) & 0xf) << 8) > +#define GM_USBPHY_TX_D_CAL(x) (((x) & 0xf) << 0) > + > #define BM_USBPHY_CTRL_SFTRST BIT(31) > #define BM_USBPHY_CTRL_CLKGATE BIT(30) > #define BM_USBPHY_CTRL_OTG_ID_VALUE BIT(27) > @@ -115,6 +120,12 @@ > */ > #define MXS_PHY_NEED_IP_FIX BIT(3) > > +/* Minimum and maximum values for device tree entries */ > +#define MXS_PHY_TX_CAL45_MIN 30 > +#define MXS_PHY_TX_CAL45_MAX 55 > +#define MXS_PHY_TX_D_CAL_MIN 79 > +#define MXS_PHY_TX_D_CAL_MAX 119 > + > struct mxs_phy_data { > unsigned int flags; > }; > @@ -164,6 +175,8 @@ struct mxs_phy { > const struct mxs_phy_data *data; > struct regmap *regmap_anatop; > int port_id; > + u32 tx_reg_set; > + u32 tx_reg_mask; > }; > > static inline bool is_imx6q_phy(struct mxs_phy *mxs_phy) > @@ -185,6 +198,20 @@ static void mxs_phy_clock_switch_delay(void) > usleep_range(300, 400); > } > > +static void mxs_phy_tx_init(struct mxs_phy *mxs_phy) > +{ > + void __iomem *base = mxs_phy->phy.io_priv; > + u32 phytx; > + > + /* Update TX register if there is anything to write */ > + if (mxs_phy->tx_reg_mask) { > + phytx = readl(base + HW_USBPHY_TX); > + phytx &= ~mxs_phy->tx_reg_mask; > + phytx |= mxs_phy->tx_reg_set; > + writel(phytx, base + HW_USBPHY_TX); > + } > +} > + > static int mxs_phy_hw_init(struct mxs_phy *mxs_phy) > { > int ret; > @@ -214,6 +241,8 @@ static int mxs_phy_hw_init(struct mxs_phy *mxs_phy) > if (mxs_phy->data->flags & MXS_PHY_NEED_IP_FIX) > writel(BM_USBPHY_IP_FIX, base + HW_USBPHY_IP_SET); > > + mxs_phy_tx_init(mxs_phy); > + > return 0; > } > > @@ -459,6 +488,7 @@ static int mxs_phy_probe(struct platform_device *pdev) > int ret; > const struct of_device_id *of_id; > struct device_node *np = pdev->dev.of_node; > + u32 val; > > of_id = of_match_device(mxs_phy_dt_ids, &pdev->dev); > if (!of_id) > @@ -491,6 +521,37 @@ static int mxs_phy_probe(struct platform_device *pdev) > } > } > > + /* Precompute which bits of the TX register are to be updated, if any */ > + if (!of_property_read_u32(np, "fsl,tx-cal-45-dn-ohms", &val) && > + val >= MXS_PHY_TX_CAL45_MIN && val <= MXS_PHY_TX_CAL45_MAX) { > + /* Scale to a 4-bit value */ > + val = (MXS_PHY_TX_CAL45_MAX - val) * 0xF > + / (MXS_PHY_TX_CAL45_MAX - MXS_PHY_TX_CAL45_MIN); > + mxs_phy->tx_reg_mask |= GM_USBPHY_TX_TXCAL45DN(~0); > + mxs_phy->tx_reg_set |= GM_USBPHY_TX_TXCAL45DN(val); > + } > + > + if (!of_property_read_u32(np, "fsl,tx-cal-45-dp-ohms", &val) && > + val >= MXS_PHY_TX_CAL45_MIN && val <= MXS_PHY_TX_CAL45_MAX) { > + /* Scale to a 4-bit value. */ > + val = (MXS_PHY_TX_CAL45_MAX - val) * 0xF > + / (MXS_PHY_TX_CAL45_MAX - MXS_PHY_TX_CAL45_MIN); > + mxs_phy->tx_reg_mask |= GM_USBPHY_TX_TXCAL45DP(~0); > + mxs_phy->tx_reg_set |= GM_USBPHY_TX_TXCAL45DP(val); > + } > + > + if (!of_property_read_u32(np, "fsl,tx-d-cal", &val) && > + val >= MXS_PHY_TX_D_CAL_MIN && val <= MXS_PHY_TX_D_CAL_MAX) { > + /* Scale to a 4-bit value. Round up the values and heavily > + * weight the rounding by adding 2/3 of the denominator. > + */ > + val = ((MXS_PHY_TX_D_CAL_MAX - val) * 0xF > + + (MXS_PHY_TX_D_CAL_MAX - MXS_PHY_TX_D_CAL_MIN) * 2/3) > + / (MXS_PHY_TX_D_CAL_MAX - MXS_PHY_TX_D_CAL_MIN); > + mxs_phy->tx_reg_mask |= GM_USBPHY_TX_D_CAL(~0); > + mxs_phy->tx_reg_set |= GM_USBPHY_TX_D_CAL(val); > + } > + > ret = of_alias_get_id(np, "usbphy"); > if (ret < 0) > dev_dbg(&pdev->dev, "failed to get alias id, errno %d\n", ret); > -- Acked-by: Peter Chen <peter.chen@xxxxxxx> -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
