Re: [PATCH v5 6/7] phy: phy-mtk-dp: Add driver for DP phy

Vinod Koul
2021-10-22T05:12:50Z

On 21-10-21, 11:27, Markus Schneider-Pargmann wrote:
> This is a new driver that supports the integrated DisplayPort phy for
> mediatek SoCs, especially the mt8195. The phy is integrated into the
> DisplayPort controller and will be created by the mtk-dp driver. This
> driver expects a struct regmap to be able to work on the same registers
> as the DisplayPort controller. It sets the device data to be the struct
> phy so that the DisplayPort controller can easily work with it.
>
> The driver does not have any devicetree bindings because the datasheet
> does not list the controller and the phy as distinct units.
>
> The interaction with the controller can be covered by the configure
> callback of the phy framework and its displayport parameters.
>
> Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
> ---
>
> Notes:
> Changes v3 -> v4:
> - Split DP controller driver and phy driver into separate patches.
> - Add entry to MAINTAINERS for this phy driver
>
> MAINTAINERS | 1 +
> drivers/phy/mediatek/Kconfig | 8 ++
> drivers/phy/mediatek/Makefile | 1 +
> drivers/phy/mediatek/phy-mtk-dp.c | 219 ++++++++++++++++++++++++++++++
> 4 files changed, 229 insertions(+)
> create mode 100644 drivers/phy/mediatek/phy-mtk-dp.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index eeb4c70b3d5b..8a47eb628734 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6276,6 +6276,7 @@ L: linux-mediatek@lists.infradead.org (moderated for non-subscribers)
> S: Supported
> F: Documentation/devicetree/bindings/display/mediatek/
> F: drivers/gpu/drm/mediatek/
> +F: drivers/phy/mediatek/phy-mtk-dp.c
> F: drivers/phy/mediatek/phy-mtk-hdmi*
> F: drivers/phy/mediatek/phy-mtk-mipi*
>
> diff --git a/drivers/phy/mediatek/Kconfig b/drivers/phy/mediatek/Kconfig
> index 55f8e6c048ab..f7ec86059049 100644
> --- a/drivers/phy/mediatek/Kconfig
> +++ b/drivers/phy/mediatek/Kconfig
> @@ -55,3 +55,11 @@ config PHY_MTK_MIPI_DSI
> select GENERIC_PHY
> help
> Support MIPI DSI for Mediatek SoCs.
> +
> +config PHY_MTK_DP
> + tristate "MediaTek DP-PHY Driver"
> + depends on ARCH_MEDIATEK || COMPILE_TEST
> + depends on OF
> + select GENERIC_PHY
> + help
> + Support DisplayPort PHY for Mediatek SoCs.
> diff --git a/drivers/phy/mediatek/Makefile b/drivers/phy/mediatek/Makefile
> index ace660fbed3a..4ba1e0650434 100644
> --- a/drivers/phy/mediatek/Makefile
> +++ b/drivers/phy/mediatek/Makefile
> @@ -3,6 +3,7 @@
> # Makefile for the phy drivers.
> #
>
> +obj-$(CONFIG_PHY_MTK_DP) += phy-mtk-dp.o
> obj-$(CONFIG_PHY_MTK_TPHY) += phy-mtk-tphy.o
> obj-$(CONFIG_PHY_MTK_UFS) += phy-mtk-ufs.o
> obj-$(CONFIG_PHY_MTK_XSPHY) += phy-mtk-xsphy.o
> diff --git a/drivers/phy/mediatek/phy-mtk-dp.c b/drivers/phy/mediatek/phy-mtk-dp.c
> new file mode 100644
> index 000000000000..296203e319ac
> --- /dev/null
> +++ b/drivers/phy/mediatek/phy-mtk-dp.c
> @@ -0,0 +1,219 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2021 BayLibre
> + * Author: Markus Schneider-Pargmann <msp@baylibre.com>
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#define PHY_OFFSET 0x1000
> +
> +#define MTK_DP_PHY_DIG_PLL_CTL_1 (PHY_OFFSET + 0x014)
> +# define TPLL_SSC_EN BIT(3)
> +
> +#define MTK_DP_PHY_DIG_BIT_RATE (PHY_OFFSET + 0x03C)
> +# define BIT_RATE_RBR 0
> +# define BIT_RATE_HBR 1
> +# define BIT_RATE_HBR2 2
> +# define BIT_RATE_HBR3 3
> +
> +#define MTK_DP_PHY_DIG_SW_RST (PHY_OFFSET + 0x038)
> +# define DP_GLB_SW_RST_PHYD BIT(0)
> +
> +#define MTK_DP_LANE0_DRIVING_PARAM_3 (PHY_OFFSET + 0x138)
> +#define MTK_DP_LANE1_DRIVING_PARAM_3 (PHY_OFFSET + 0x238)
> +#define MTK_DP_LANE2_DRIVING_PARAM_3 (PHY_OFFSET + 0x338)
> +#define MTK_DP_LANE3_DRIVING_PARAM_3 (PHY_OFFSET + 0x438)
> +# 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)

Pls use GENMASK() for this?

> +# 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 (PHY_OFFSET + 0x13C)
> +#define MTK_DP_LANE1_DRIVING_PARAM_4 (PHY_OFFSET + 0x23C)
> +#define MTK_DP_LANE2_DRIVING_PARAM_4 (PHY_OFFSET + 0x33C)
> +#define MTK_DP_LANE3_DRIVING_PARAM_4 (PHY_OFFSET + 0x43C)
> +# 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 (PHY_OFFSET + 0x140)
> +#define MTK_DP_LANE1_DRIVING_PARAM_5 (PHY_OFFSET + 0x240)
> +#define MTK_DP_LANE2_DRIVING_PARAM_5 (PHY_OFFSET + 0x340)
> +#define MTK_DP_LANE3_DRIVING_PARAM_5 (PHY_OFFSET + 0x440)
> +# 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 (PHY_OFFSET + 0x144)
> +#define MTK_DP_LANE1_DRIVING_PARAM_6 (PHY_OFFSET + 0x244)
> +#define MTK_DP_LANE2_DRIVING_PARAM_6 (PHY_OFFSET + 0x344)
> +#define MTK_DP_LANE3_DRIVING_PARAM_6 (PHY_OFFSET + 0x444)
> +# 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 (PHY_OFFSET + 0x148)
> +#define MTK_DP_LANE1_DRIVING_PARAM_7 (PHY_OFFSET + 0x248)
> +#define MTK_DP_LANE2_DRIVING_PARAM_7 (PHY_OFFSET + 0x348)
> +#define MTK_DP_LANE3_DRIVING_PARAM_7 (PHY_OFFSET + 0x448)
> +# 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 (PHY_OFFSET + 0x14C)
> +#define MTK_DP_LANE1_DRIVING_PARAM_8 (PHY_OFFSET + 0x24C)
> +#define MTK_DP_LANE2_DRIVING_PARAM_8 (PHY_OFFSET + 0x34C)
> +#define MTK_DP_LANE3_DRIVING_PARAM_8 (PHY_OFFSET + 0x44C)
> +# 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)
> +
> +struct mtk_dp_phy {
> + struct regmap *regs;
> +};
> +
> +static int mtk_dp_phy_init(struct phy *phy)
> +{
> + struct mtk_dp_phy *dp_phy = phy_get_drvdata(phy);
> + u32 driving_params[] = {
> + DRIVING_PARAM_3_DEFAULT,
> + DRIVING_PARAM_4_DEFAULT,
> + DRIVING_PARAM_5_DEFAULT,
> + DRIVING_PARAM_6_DEFAULT,
> + DRIVING_PARAM_7_DEFAULT,
> + DRIVING_PARAM_8_DEFAULT
> + };
> +
> + regmap_bulk_write(dp_phy->regs, MTK_DP_LANE0_DRIVING_PARAM_3,
> + driving_params, ARRAY_SIZE(driving_params));
> + regmap_bulk_write(dp_phy->regs, MTK_DP_LANE1_DRIVING_PARAM_3,
> + driving_params, ARRAY_SIZE(driving_params));
> + regmap_bulk_write(dp_phy->regs, MTK_DP_LANE2_DRIVING_PARAM_3,
> + driving_params, ARRAY_SIZE(driving_params));
> + regmap_bulk_write(dp_phy->regs, MTK_DP_LANE3_DRIVING_PARAM_3,
> + driving_params, ARRAY_SIZE(driving_params));
> +
> + return 0;
> +}
> +
> +static int mtk_dp_phy_configure(struct phy *phy, union phy_configure_opts *opts)
> +{
> + struct mtk_dp_phy *dp_phy = phy_get_drvdata(phy);
> + u32 val;
> +
> + if (opts->dp.set_rate) {
> + switch (opts->dp.link_rate) {
> + default:
> + dev_err(&phy->dev,
> + "Implementation error, unknown linkrate %x\n",
> + opts->dp.link_rate);
> + return -EINVAL;
> + case 1620:
> + val = BIT_RATE_RBR;
> + break;
> + case 2700:
> + val = BIT_RATE_HBR;
> + break;
> + case 5400:
> + val = BIT_RATE_HBR2;
> + break;
> + case 8100:
> + val = BIT_RATE_HBR3;
> + break;
> + }
> + regmap_write(dp_phy->regs, MTK_DP_PHY_DIG_BIT_RATE, val);
> + }
> +
> + regmap_update_bits(dp_phy->regs, MTK_DP_PHY_DIG_BIT_RATE,
> + TPLL_SSC_EN, opts->dp.ssc ? TPLL_SSC_EN : 0);
> +
> + return 0;
> +}
> +
> +static int mtk_dp_phy_reset(struct phy *phy)
> +{
> + struct mtk_dp_phy *dp_phy = phy_get_drvdata(phy);
> +
> + regmap_update_bits(dp_phy->regs, MTK_DP_PHY_DIG_SW_RST,
> + DP_GLB_SW_RST_PHYD, 0);
> + usleep_range(50, 200);
> + regmap_update_bits(dp_phy->regs, MTK_DP_PHY_DIG_SW_RST,
> + DP_GLB_SW_RST_PHYD, 1);
> +
> + return 0;
> +}
> +
> +static const struct phy_ops mtk_dp_phy_dev_ops = {
> + .init = mtk_dp_phy_init,
> + .configure = mtk_dp_phy_configure,
> + .reset = mtk_dp_phy_reset,
> + .owner = THIS_MODULE,
> +};
> +
> +static int mtk_dp_phy_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct mtk_dp_phy *dp_phy;
> + struct phy *phy;
> +
> + dp_phy = devm_kzalloc(dev, sizeof(*dp_phy), GFP_KERNEL);
> + if (!dp_phy)
> + return -ENOMEM;
> +
> + dp_phy->regs = *(struct regmap **)dev->platform_data;
> + if (!dp_phy->regs) {
> + dev_err(dev, "No data passed, requires struct regmap**\n");
> + return -EINVAL;
> + }

is there a reason to do it this way? Why not set the IORESOURCE_MEM for
this device and let the driver map here?

NO clocks?

> +
> + phy = devm_phy_create(dev, NULL, &mtk_dp_phy_dev_ops);
> + if (IS_ERR(phy)) {
> + dev_err(dev, "Failed to create DP PHY: %ld\n", PTR_ERR(phy));
> + return PTR_ERR(phy);
> + }
> + phy_set_drvdata(phy, dp_phy);
> +
> + // Set device data to the phy so that mtk-dp can get it easily

pls change comment style

also why should mtk-dp do it this way, there is very nice API phy_get()
to do that, pls use that..

> + dev_set_drvdata(dev, phy);
> +
> + return 0;
> +}
> +
> +struct platform_driver mtk_dp_phy_driver = {

who creates this platform device?

> + .probe = mtk_dp_phy_probe,
> + .driver = {
> + .name = "mediatek-dp-phy",
> + },
> +};
> +module_platform_driver(mtk_dp_phy_driver);
> +
> +MODULE_AUTHOR("Markus Schneider-Pargmann <msp@baylibre.com>");
> +MODULE_DESCRIPTION("MediaTek DP PHY Driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.33.0

--
~Vinod