[PATCH v1 6/6] drm/mediatek: Add mt8195 DisplayPort driver
Markus Schneider-Pargmann
msp at baylibre.com
Thu Sep 9 22:36:14 PDT 2021
Hi Chun-Kuang,
On Fri, Sep 10, 2021 at 07:37:50AM +0800, Chun-Kuang Hu wrote:
> Hi, Markus:
>
> Markus Schneider-Pargmann <msp at baylibre.com> 於 2021年9月7日 週二 上午3:37寫道：
> >
> > This patch adds a DisplayPort driver for the Mediatek mt8195 SoC.
> >
> > It supports both functional units on the mt8195, the embedded
> > DisplayPort as well as the external DisplayPort units. It offers
> > hot-plug-detection, audio up to 8 channels, and DisplayPort 1.4 with up
> > to 4 lanes.
> >
> > This driver is based on an initial version by
> > Jason-JH.Lin <jason-jh.lin at mediatek.com>.
> >
> > Signed-off-by: Markus Schneider-Pargmann <msp at baylibre.com>
> > ---
> >
> > Notes:
> > Changes RFC -> v1:
> > - Removed unused register definitions.
> > - Replaced workqueue with threaded irq.
> > - Removed connector code.
> > - Move to atomic_* drm functions.
> > - General cleanups of the code.
> > - Remove unused select GENERIC_PHY.
> >
> > drivers/gpu/drm/mediatek/Kconfig | 6 +
> > drivers/gpu/drm/mediatek/Makefile | 2 +
> > drivers/gpu/drm/mediatek/mtk_dp.c | 2881 +++++++++++++++++++++++++
> > drivers/gpu/drm/mediatek/mtk_dp_reg.h | 580 +++++
> > 4 files changed, 3469 insertions(+)
> > create mode 100644 drivers/gpu/drm/mediatek/mtk_dp.c
> > create mode 100644 drivers/gpu/drm/mediatek/mtk_dp_reg.h
> >
...
> > +#define TOP_OFFSET 0x2000
> > +#define ENC0_OFFSET 0x3000
> > +#define ENC1_OFFSET 0x3200
> > +#define TRANS_OFFSET 0x3400
> > +#define AUX_OFFSET 0x3600
> > +#define SEC_OFFSET 0x4000
...
> > +
> > +#define DP_PHY_DIG_PLL_CTL_1 0x1014
> > +# define TPLL_SSC_EN BIT(3)
>
> It seems that register 0x1000 ~ 0x1fff is to control phy and 0x2000 ~
> 0x4fff is to control non-phy part. For mipi and hdmi, the phy part is
> an independent device [1] and the phy driver is independent [2] , so I
> would like this phy to be an independent device.
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/mediatek/mt8173.dtsi?h=v5.14
> [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/phy/mediatek?h=v5.14
Thanks for your feedback. I looked into both mipi and hdmi phy drivers
that you referenced. It looks like both are really separate units in
their SoCs having their own registerspaces located at a completely
different range than the units using the phy.
For this displayport driver, the phy registers are listed as part of the
(e)DP_TX unit in the datasheet. Next to the phy registers all the other
parts are listed as well in the same overall register ranges (see
above), e.g. TOP_OFFSET, ENC_OFFSET or SEC_OFFSET. Also I would like to
avoid splitting it up into a separate unit in the devicetree as the
datasheet handles it as a single unit (including the phy registers).
>From a practical perspective there is also not much to these PHY
registers. The only things that would be done in the driver are:
- initializing the lane driving parameters with static values
- setup the bitrate
- enable/disable SSC
- do a reset
Exporting these four used functions over a driver boundary wouldn't help
clarity I think and the code probably can't be reused by any other
component anyways.
So I personally would prefer keeping it as part of the whole driver
because of the above mentioned reasons. What do you think?
Thanks,
Markus
>
> Regards,
> Chun-Kuang.
>
> > +
> > +#define DP_PHY_DIG_BIT_RATE 0x103C
> > +# define BIT_RATE_RBR 0
> > +# define BIT_RATE_HBR 1
> > +# define BIT_RATE_HBR2 2
> > +# define BIT_RATE_HBR3 3
> > +
> > +#define DP_PHY_DIG_SW_RST 0x1038
> > +# define DP_GLB_SW_RST_PHYD BIT(0)
> > +
> > +#define MTK_DP_LANE0_DRIVING_PARAM_3 0x1138
> > +#define MTK_DP_LANE1_DRIVING_PARAM_3 0x1238
> > +#define MTK_DP_LANE2_DRIVING_PARAM_3 0x1338
> > +#define MTK_DP_LANE3_DRIVING_PARAM_3 0x1438
> > +# define XTP_LN_TX_LCTXC0_SW0_PRE0_DEFAULT 0x10
> > +# define XTP_LN_TX_LCTXC0_SW0_PRE1_DEFAULT (0x14 << 8)
> > +# define XTP_LN_TX_LCTXC0_SW0_PRE2_DEFAULT (0x18 << 16)
> > +# define XTP_LN_TX_LCTXC0_SW0_PRE3_DEFAULT (0x20 << 24)
> > +# define DRIVING_PARAM_3_DEFAULT (XTP_LN_TX_LCTXC0_SW0_PRE0_DEFAULT | \
> > + XTP_LN_TX_LCTXC0_SW0_PRE1_DEFAULT | \
> > + XTP_LN_TX_LCTXC0_SW0_PRE2_DEFAULT | \
> > + XTP_LN_TX_LCTXC0_SW0_PRE3_DEFAULT)
> > +
> > +#define MTK_DP_LANE0_DRIVING_PARAM_4 0x113C
> > +#define MTK_DP_LANE1_DRIVING_PARAM_4 0x123C
> > +#define MTK_DP_LANE2_DRIVING_PARAM_4 0x133C
> > +#define MTK_DP_LANE3_DRIVING_PARAM_4 0x143C
> > +# define XTP_LN_TX_LCTXC0_SW1_PRE0_DEFAULT 0x18
> > +# define XTP_LN_TX_LCTXC0_SW1_PRE1_DEFAULT (0x1e << 8)
> > +# define XTP_LN_TX_LCTXC0_SW1_PRE2_DEFAULT (0x24 << 16)
> > +# define XTP_LN_TX_LCTXC0_SW2_PRE0_DEFAULT (0x20 << 24)
> > +# define DRIVING_PARAM_4_DEFAULT (XTP_LN_TX_LCTXC0_SW1_PRE0_DEFAULT | \
> > + XTP_LN_TX_LCTXC0_SW1_PRE1_DEFAULT | \
> > + XTP_LN_TX_LCTXC0_SW1_PRE2_DEFAULT | \
> > + XTP_LN_TX_LCTXC0_SW2_PRE0_DEFAULT)
> > +
> > +#define MTK_DP_LANE0_DRIVING_PARAM_5 0x1140
> > +#define MTK_DP_LANE1_DRIVING_PARAM_5 0x1240
> > +#define MTK_DP_LANE2_DRIVING_PARAM_5 0x1340
> > +#define MTK_DP_LANE3_DRIVING_PARAM_5 0x1440
> > +# define XTP_LN_TX_LCTXC0_SW2_PRE1_DEFAULT 0x28
> > +# define XTP_LN_TX_LCTXC0_SW3_PRE0_DEFAULT (0x30 << 8)
> > +# define DRIVING_PARAM_5_DEFAULT (XTP_LN_TX_LCTXC0_SW2_PRE1_DEFAULT | \
> > + XTP_LN_TX_LCTXC0_SW3_PRE0_DEFAULT)
> > +
> > +#define MTK_DP_LANE0_DRIVING_PARAM_6 0x1144
> > +#define MTK_DP_LANE1_DRIVING_PARAM_6 0x1244
> > +#define MTK_DP_LANE2_DRIVING_PARAM_6 0x1344
> > +#define MTK_DP_LANE3_DRIVING_PARAM_6 0x1444
> > +# define XTP_LN_TX_LCTXCP1_SW0_PRE0_DEFAULT 0x00
> > +# define XTP_LN_TX_LCTXCP1_SW0_PRE1_DEFAULT (0x04 << 8)
> > +# define XTP_LN_TX_LCTXCP1_SW0_PRE2_DEFAULT (0x08 << 16)
> > +# define XTP_LN_TX_LCTXCP1_SW0_PRE3_DEFAULT (0x10 << 24)
> > +# define DRIVING_PARAM_6_DEFAULT (XTP_LN_TX_LCTXCP1_SW0_PRE0_DEFAULT | \
> > + XTP_LN_TX_LCTXCP1_SW0_PRE1_DEFAULT | \
> > + XTP_LN_TX_LCTXCP1_SW0_PRE2_DEFAULT | \
> > + XTP_LN_TX_LCTXCP1_SW0_PRE3_DEFAULT)
> > +
> > +#define MTK_DP_LANE0_DRIVING_PARAM_7 0x1148
> > +#define MTK_DP_LANE1_DRIVING_PARAM_7 0x1248
> > +#define MTK_DP_LANE2_DRIVING_PARAM_7 0x1348
> > +#define MTK_DP_LANE3_DRIVING_PARAM_7 0x1448
> > +# define XTP_LN_TX_LCTXCP1_SW1_PRE0_DEFAULT 0x00
> > +# define XTP_LN_TX_LCTXCP1_SW1_PRE1_DEFAULT (0x06 << 8)
> > +# define XTP_LN_TX_LCTXCP1_SW1_PRE2_DEFAULT (0x0c << 16)
> > +# define XTP_LN_TX_LCTXCP1_SW2_PRE0_DEFAULT (0x00 << 24)
> > +# define DRIVING_PARAM_7_DEFAULT (XTP_LN_TX_LCTXCP1_SW1_PRE0_DEFAULT | \
> > + XTP_LN_TX_LCTXCP1_SW1_PRE1_DEFAULT | \
> > + XTP_LN_TX_LCTXCP1_SW1_PRE2_DEFAULT | \
> > + XTP_LN_TX_LCTXCP1_SW2_PRE0_DEFAULT)
> > +
> > +#define MTK_DP_LANE0_DRIVING_PARAM_8 0x114C
> > +#define MTK_DP_LANE1_DRIVING_PARAM_8 0x124C
> > +#define MTK_DP_LANE2_DRIVING_PARAM_8 0x134C
> > +#define MTK_DP_LANE3_DRIVING_PARAM_8 0x144C
> > +# define XTP_LN_TX_LCTXCP1_SW2_PRE1_DEFAULT 0x08
> > +# define XTP_LN_TX_LCTXCP1_SW3_PRE0_DEFAULT (0x00 << 8)
> > +# define DRIVING_PARAM_8_DEFAULT (XTP_LN_TX_LCTXCP1_SW2_PRE1_DEFAULT | \
> > + XTP_LN_TX_LCTXCP1_SW3_PRE0_DEFAULT)
> > +
> > +#endif /*_MTK_DP_REG_H_*/
> > --
> > 2.33.0
> >
More information about the Linux-mediatek
mailing list