Re: [PATCH v3 13/19] usb: dwc3: add tx demphasis quirk

[Bjorn Helgaas <bhelgaas@google.com>]

On Tue, Oct 28, 2014 at 5:54 AM, Huang Rui <ray.huang@amd.com> wrote:
> This patch adds Tx demphasis quirk, and the Tx demphasis value is

"demphasis" (above and in subject) should be "de-emphasis" as used in
the code and comments below.

> configurable according to PIPE3 specification.
>
> Value           Description
> 0               -6dB de-emphasis
> 1               -3.5dB de-emphasis
> 2               No de-emphasis
> 3               Reserved
>
> It can be configured on DT or platform data.
>
> Signed-off-by: Huang Rui <ray.huang@amd.com>
> ---
>  drivers/usb/dwc3/core.c          | 17 +++++++++++++++++
>  drivers/usb/dwc3/core.h          | 11 +++++++++++
>  drivers/usb/dwc3/platform_data.h |  3 +++
>  3 files changed, 31 insertions(+)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 19019dc..e36fcd0 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -392,6 +392,9 @@ static void dwc3_phy_setup(struct dwc3 *dwc)
>         if (dwc->rx_detect_poll_quirk)
>                 reg |= DWC3_GUSB3PIPECTL_RX_DETOPOLL;
>
> +       if (dwc->tx_deemph_quirk)
> +               reg |= DWC3_GUSB3PIPECTL_TX_DEEPH(dwc->tx_deemph);
> +
>         dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(0), reg);
>
>         mdelay(100);
> @@ -691,6 +694,7 @@ static int dwc3_probe(struct platform_device *pdev)
>         struct resource         *res;
>         struct dwc3             *dwc;
>         u8                      lpm_nyet_thres;
> +       u8                      tx_deemph;
>
>         int                     ret;
>
> @@ -749,6 +753,9 @@ static int dwc3_probe(struct platform_device *pdev)
>         /* default to highest possible threshold */
>         lpm_nyet_thres = 0xff;
>
> +       /* default to -3.5dB de-emphasis */
> +       tx_deemph = 1;
> +
>         if (node) {
>                 dwc->maximum_speed = of_usb_get_maximum_speed(node);
>                 dwc->has_lpm_erratum = of_property_read_bool(node,
> @@ -776,6 +783,11 @@ static int dwc3_probe(struct platform_device *pdev)
>                                 "snps,lfps_filter_quirk");
>                 dwc->rx_detect_poll_quirk = of_property_read_bool(node,
>                                 "snps,rx_detect_poll_quirk");
> +
> +               dwc->tx_deemph_quirk = of_property_read_bool(node,
> +                               "snps,tx_deemph_quirk");
> +               of_property_read_u8(node, "snps,tx_deemph",
> +                               &tx_deemph);
>         } else if (pdata) {
>                 dwc->maximum_speed = pdata->maximum_speed;
>                 dwc->has_lpm_erratum = pdata->has_lpm_erratum;
> @@ -793,6 +805,10 @@ static int dwc3_probe(struct platform_device *pdev)
>                 dwc->del_phy_power_chg_quirk = pdata->del_phy_power_chg_quirk;
>                 dwc->lfps_filter_quirk = pdata->lfps_filter_quirk;
>                 dwc->rx_detect_poll_quirk = pdata->rx_detect_poll_quirk;
> +
> +               dwc->tx_deemph_quirk = pdata->tx_deemph_quirk;
> +               if (pdata->tx_deemph)
> +                       tx_deemph = pdata->tx_deemph;
>         }
>
>         /* default to superspeed if no maximum_speed passed */
> @@ -800,6 +816,7 @@ static int dwc3_probe(struct platform_device *pdev)
>                 dwc->maximum_speed = USB_SPEED_SUPER;
>
>         dwc->lpm_nyet_thres = lpm_nyet_thres;
> +       dwc->tx_deemph = tx_deemph;
>
>         ret = dwc3_core_get_phy(dwc);
>         if (ret)
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 57a203a..1277dcf 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -185,6 +185,8 @@
>  #define DWC3_GUSB3PIPECTL_SUSPHY       (1 << 17)
>  #define DWC3_GUSB3PIPECTL_LFPSFILT     (1 << 9)
>  #define DWC3_GUSB3PIPECTL_RX_DETOPOLL  (1 << 8)
> +#define DWC3_GUSB3PIPECTL_TX_DEEPH_MASK        DWC3_GUSB3PIPECTL_TX_DEEPH(3)
> +#define DWC3_GUSB3PIPECTL_TX_DEEPH(n)  ((n) << 1)
>
>  /* Global TX Fifo Size Register */
>  #define DWC3_GTXFIFOSIZ_TXFDEF(n)      ((n) & 0xffff)
> @@ -695,6 +697,12 @@ struct dwc3_scratchpad_array {
>   * @del_phy_power_chg_quirk: set if we enable delay phy power change quirk
>   * @lfps_filter_quirk: set if we enable LFPS filter quirk
>   * @rx_detect_poll_quirk: set if we enable rx_detect to polling lfps quirk
> + * @tx_deemph_quirk: set if we enable Tx deemphasis quirk
> + * @tx_deemph: Tx deemphasis value
> + *     0       - -6dB de-emphasis
> + *     1       - -3.5dB de-emphasis
> + *     2       - No de-emphasis
> + *     3       - Reserved
>   */
>  struct dwc3 {
>         struct usb_ctrlrequest  *ctrl_req;
> @@ -810,6 +818,9 @@ struct dwc3 {
>         unsigned                del_phy_power_chg_quirk:1;
>         unsigned                lfps_filter_quirk:1;
>         unsigned                rx_detect_poll_quirk:1;
> +
> +       unsigned                tx_deemph_quirk:1;
> +       unsigned                tx_deemph:2;
>  };
>
>  /* -------------------------------------------------------------------------- */
> diff --git a/drivers/usb/dwc3/platform_data.h b/drivers/usb/dwc3/platform_data.h
> index 9776764..ea631dc 100644
> --- a/drivers/usb/dwc3/platform_data.h
> +++ b/drivers/usb/dwc3/platform_data.h
> @@ -35,4 +35,7 @@ struct dwc3_platform_data {
>         unsigned del_phy_power_chg_quirk:1;
>         unsigned lfps_filter_quirk:1;
>         unsigned rx_detect_poll_quirk:1;
> +
> +       unsigned tx_deemph_quirk:1;
> +       unsigned tx_deemph:2;
>  };
> --
> 1.9.1
>