Re: [PATCH v5 2/2] drm/bridge: add support for TI TDP158

[Robert Foss <rfoss@kernel.org>]

On Mon, Aug 12, 2024 at 4:51 PM Marc Gonzalez <mgonzalez@freebox.fr> wrote:
>
> TDP158 is an AC-coupled DVI / HDMI to TMDS level shifting Redriver.
> It supports DVI 1.0, HDMI 1.4b and 2.0b.
> It supports 4 TMDS channels, HPD, and a DDC interface.
> It supports dual power supply rails (1.1V on VDD, 3.3V on VCC)
> for power reduction. Several methods of power management are
> implemented to reduce overall power consumption.
> It supports fixed receiver EQ gain using I2C or pin strap to
> compensate for different lengths input cable or board traces.
>
> Features
>
> - AC-coupled TMDS or DisplayPort dual-mode physical layer input
> to HDMI 2.0b TMDS physical layer output supporting up to 6Gbps
> data rate, compatible with HDMI 2.0b electrical parameters
> - DisplayPort dual-mode standard version 1.1
> - Programmable fixed receiver equalizer up to 15.5dB
> - Global or independent high speed lane control, pre-emphasis
> and transmit swing, and slew rate control
> - I2C or pin strap programmable
> - Configurable as a DisplayPort redriver through I2C
> - Full lane swap on main lanes
> - Low power consumption (200 mW at 6Gbps, 8 mW in shutdown)
>
> https://www.ti.com/lit/ds/symlink/tdp158.pdf
>
> On our board, I2C_EN is pulled high.
> Thus, this code defines a module_i2c_driver.
>
> The default settings work fine for our use-case.
> So this basic driver doesn't need to tweak any I2C registers.
>
> Signed-off-by: Marc Gonzalez <mgonzalez@freebox.fr>
> ---
>  drivers/gpu/drm/bridge/Kconfig     |   7 +++
>  drivers/gpu/drm/bridge/Makefile    |   1 +
>  drivers/gpu/drm/bridge/ti-tdp158.c | 108 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 116 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index c621be1a99a89..c0ab5b620b57d 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -368,6 +368,13 @@ config DRM_TI_DLPC3433
>           It supports up to 720p resolution with 60 and 120 Hz refresh
>           rates.
>
> +config DRM_TI_TDP158
> +       tristate "TI TDP158 HDMI/TMDS bridge"
> +       depends on OF
> +       select DRM_PANEL_BRIDGE
> +       help
> +         Texas Instruments TDP158 HDMI/TMDS Bridge driver
> +
>  config DRM_TI_TFP410
>         tristate "TI TFP410 DVI/HDMI bridge"
>         depends on OF
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 7df87b582dca3..3daf803ce80b6 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -32,6 +32,7 @@ obj-$(CONFIG_DRM_I2C_ADV7511) += adv7511/
>  obj-$(CONFIG_DRM_TI_DLPC3433) += ti-dlpc3433.o
>  obj-$(CONFIG_DRM_TI_SN65DSI83) += ti-sn65dsi83.o
>  obj-$(CONFIG_DRM_TI_SN65DSI86) += ti-sn65dsi86.o
> +obj-$(CONFIG_DRM_TI_TDP158) += ti-tdp158.o
>  obj-$(CONFIG_DRM_TI_TFP410) += ti-tfp410.o
>  obj-$(CONFIG_DRM_TI_TPD12S015) += ti-tpd12s015.o
>  obj-$(CONFIG_DRM_NWL_MIPI_DSI) += nwl-dsi.o
> diff --git a/drivers/gpu/drm/bridge/ti-tdp158.c b/drivers/gpu/drm/bridge/ti-tdp158.c
> new file mode 100644
> index 0000000000000..4ee0ad29874de
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/ti-tdp158.c
> @@ -0,0 +1,108 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright 2024 Freebox SAS
> + */
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <linux/i2c.h>
> +
> +struct tdp158 {
> +       struct drm_bridge bridge;
> +       struct drm_bridge *next;
> +       struct gpio_desc *enable; // Operation Enable - pin 36
> +       struct regulator *vcc; // 3.3V
> +       struct regulator *vdd; // 1.1V
> +       struct device *dev;
> +};
> +
> +static void tdp158_enable(struct drm_bridge *bridge, struct drm_bridge_state *prev)
> +{
> +       int err;
> +       struct tdp158 *tdp158 = bridge->driver_private;
> +
> +       err = regulator_enable(tdp158->vcc);
> +       if (err)
> +               dev_err(tdp158->dev, "failed to enable vcc: %d", err);
> +
> +       err = regulator_enable(tdp158->vdd);
> +       if (err)
> +               dev_err(tdp158->dev, "failed to enable vdd: %d", err);
> +
> +       gpiod_set_value_cansleep(tdp158->enable, 1);
> +}
> +
> +static void tdp158_disable(struct drm_bridge *bridge, struct drm_bridge_state *prev)
> +{
> +       struct tdp158 *tdp158 = bridge->driver_private;
> +
> +       gpiod_set_value_cansleep(tdp158->enable, 0);
> +       regulator_disable(tdp158->vdd);
> +       regulator_disable(tdp158->vcc);
> +}
> +
> +static int tdp158_attach(struct drm_bridge *bridge, enum drm_bridge_attach_flags flags)
> +{
> +       struct tdp158 *tdp158 = bridge->driver_private;
> +
> +       return drm_bridge_attach(bridge->encoder, tdp158->next, bridge, flags);
> +}
> +
> +static const struct drm_bridge_funcs tdp158_bridge_funcs = {
> +       .attach = tdp158_attach,
> +       .atomic_enable = tdp158_enable,
> +       .atomic_disable = tdp158_disable,
> +       .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> +       .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> +       .atomic_reset = drm_atomic_helper_bridge_reset,
> +};
> +
> +static int tdp158_probe(struct i2c_client *client)
> +{
> +       struct tdp158 *tdp158;
> +       struct device *dev = &client->dev;
> +
> +       tdp158 = devm_kzalloc(dev, sizeof(*tdp158), GFP_KERNEL);
> +       if (!tdp158)
> +               return -ENOMEM;
> +
> +       tdp158->next = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
> +       if (IS_ERR(tdp158->next))
> +               return dev_err_probe(dev, PTR_ERR(tdp158->next), "missing bridge");
> +
> +       tdp158->vcc = devm_regulator_get(dev, "vcc");
> +       if (IS_ERR(tdp158->vcc))
> +               return dev_err_probe(dev, PTR_ERR(tdp158->vcc), "vcc");
> +
> +       tdp158->vdd = devm_regulator_get(dev, "vdd");
> +       if (IS_ERR(tdp158->vdd))
> +               return dev_err_probe(dev, PTR_ERR(tdp158->vdd), "vdd");
> +
> +       tdp158->enable = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);
> +       if (IS_ERR(tdp158->enable))
> +               return dev_err_probe(dev, PTR_ERR(tdp158->enable), "enable");
> +
> +       tdp158->bridge.of_node = dev->of_node;
> +       tdp158->bridge.funcs = &tdp158_bridge_funcs;
> +       tdp158->bridge.driver_private = tdp158;
> +       tdp158->dev = dev;
> +
> +       return devm_drm_bridge_add(dev, &tdp158->bridge);
> +}
> +
> +static const struct of_device_id tdp158_match_table[] = {
> +       { .compatible = "ti,tdp158" },
> +       { }
> +};
> +MODULE_DEVICE_TABLE(of, tdp158_match_table);
> +
> +static struct i2c_driver tdp158_driver = {
> +       .probe = tdp158_probe,
> +       .driver = {
> +               .name = "tdp158",
> +               .of_match_table = tdp158_match_table,
> +       },
> +};
> +module_i2c_driver(tdp158_driver);
> +
> +MODULE_DESCRIPTION("TI TDP158 driver");
> +MODULE_LICENSE("GPL");
>
> --
> 2.34.1
>

Reviewed-by: Robert Foss <rfoss@kernel.org>