Re: [PATCH 2/2] drm/panel: add BOE tv101wum-ll2 panel driver

[Doug Anderson]

Hi,

On Tue, Jul 9, 2024 at 6:06 AM Neil Armstrong <neil.armstrong@xxxxxxxxxx> wrote:
>
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 5581387707c6..79c90894b6a4 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_DRM_PANEL_BOE_BF060Y8M_AJ0) += panel-boe-bf060y8m-aj0.o
>  obj-$(CONFIG_DRM_PANEL_BOE_HIMAX8279D) += panel-boe-himax8279d.o
>  obj-$(CONFIG_DRM_PANEL_BOE_TH101MB31UIG002_28A) += panel-boe-th101mb31ig002-28a.o
>  obj-$(CONFIG_DRM_PANEL_BOE_TV101WUM_NL6) += panel-boe-tv101wum-nl6.o
> +obj-$(CONFIG_DRM_PANEL_BOE_TV101WUM_LL2) += panel-boe-tv101wum-ll2.o

nit: please sort. L comes before N.


>  obj-$(CONFIG_DRM_PANEL_DSI_CM) += panel-dsi-cm.o
>  obj-$(CONFIG_DRM_PANEL_LVDS) += panel-lvds.o
>  obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
> diff --git a/drivers/gpu/drm/panel/panel-boe-tv101wum-ll2.c b/drivers/gpu/drm/panel/panel-boe-tv101wum-ll2.c
> new file mode 100644
> index 000000000000..5513cb48d949
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-boe-tv101wum-ll2.c
> @@ -0,0 +1,240 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +// Generated with linux-mdss-dsi-panel-driver-generator from vendor device tree:
> +//   Copyright (c) 2013, The Linux Foundation. All rights reserved.
> +//   Copyright (c) 2024, Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> +
> +#include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of.h>

nit: sort header files?

> +static int boe_tv101wum_ll2_prepare(struct drm_panel *panel)
> +{
> +       struct boe_tv101wum_ll2 *ctx = to_boe_tv101wum_ll2(panel);
> +       struct device *dev = &ctx->dsi->dev;
> +       int ret;
> +
> +       ret = regulator_bulk_enable(ARRAY_SIZE(ctx->supplies),
> +                                   ctx->supplies);
> +       if (ret < 0)
> +               return ret;
> +
> +       boe_tv101wum_ll2_reset(ctx);
> +
> +       ret = boe_tv101wum_ll2_on(ctx);
> +       if (ret < 0) {
> +               dev_err(dev, "Failed to initialize panel: %d\n", ret);

nit: Do you really need this error message? The "_multi" variants are
all chatty and print the error message, so we don't really need this
here...


> +               gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +               return ret;

Shouldn't you turn off the regulators?


> +static int boe_tv101wum_ll2_unprepare(struct drm_panel *panel)
> +{
> +       struct boe_tv101wum_ll2 *ctx = to_boe_tv101wum_ll2(panel);
> +       struct device *dev = &ctx->dsi->dev;
> +       int ret;
> +
> +       ret = boe_tv101wum_ll2_off(ctx);
> +       if (ret < 0)
> +               dev_err(dev, "Failed to un-initialize panel: %d\n", ret);

nit: Do you really need this error message? The "_multi" variants are
all chatty and print the error message, so we don't really need this
here...


> +
> +       gpiod_set_value_cansleep(ctx->reset_gpio, 1);
> +
> +       regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
> +
> +       return 0;

Maybe add a comment justifying why you don't return the error code
that boe_tv101wum_ll2_off() returned?


> +static int boe_tv101wum_ll2_get_modes(struct drm_panel *panel,
> +                                     struct drm_connector *connector)
> +{
> +       return drm_connector_helper_get_modes_fixed(connector, &boe_tv101wum_ll2_mode);

Random question for you: on panels that don't use the
drm_connector_helper the "bpc" gets set here. Is there a reason why
some panel drivers (like this one) don't set bpc?


> +static int boe_tv101wum_ll2_probe(struct mipi_dsi_device *dsi)
> +{
> +       struct device *dev = &dsi->dev;
> +       struct boe_tv101wum_ll2 *ctx;
> +       int ret;
> +
> +       ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
> +       if (!ctx)
> +               return -ENOMEM;
> +
> +       ctx->supplies[0].supply = "vsp";
> +       ctx->supplies[1].supply = "vsn";
> +
> +       ret = devm_regulator_bulk_get(&dsi->dev, ARRAY_SIZE(ctx->supplies),
> +                                     ctx->supplies);

Any chance I can convince you to use devm_regulator_bulk_get_const()?
Then you can list your supply structures as "static const" instead of
having to initialize them via code.


> +       if (ret < 0)
> +               return ret;
> +
> +       ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> +       if (IS_ERR(ctx->reset_gpio))
> +               return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
> +                                    "Failed to get reset-gpios\n");
> +
> +       ctx->dsi = dsi;
> +       mipi_dsi_set_drvdata(dsi, ctx);
> +
> +       dsi->lanes = 4;
> +       dsi->format = MIPI_DSI_FMT_RGB888;
> +       dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
> +                         MIPI_DSI_MODE_VIDEO_HSE;
> +
> +       drm_panel_init(&ctx->panel, dev, &boe_tv101wum_ll2_panel_funcs,
> +                      DRM_MODE_CONNECTOR_DSI);
> +       ctx->panel.prepare_prev_first = true;
> +
> +       ret = drm_panel_of_backlight(&ctx->panel);
> +       if (ret)
> +               return dev_err_probe(dev, ret, "Failed to get backlight\n");
> +
> +       drm_panel_add(&ctx->panel);

Any chance you could add devm_drm_panel_add() and then use it? Then
you can fully get rid of your remove and error handling since
devm_mipi_dsi_attach() already exists. Note that this would not change
object lifetimes at all since you're already calling
drm_panel_remove() in your remove code--it would just clean up the
code...


> +static struct mipi_dsi_driver boe_tv101wum_ll2_driver = {
> +       .probe = boe_tv101wum_ll2_probe,
> +       .remove = boe_tv101wum_ll2_remove,
> +       .driver = {
> +               .name = "panel-boe-tv101wum_ll2",
> +               .of_match_table = boe_tv101wum_ll2_of_match,
> +       },
> +};
> +module_mipi_dsi_driver(boe_tv101wum_ll2_driver);
> +
> +MODULE_DESCRIPTION("DRM driver for Boe TV101WUM-LL2 Panel");

Should "Boe" be "BOE" ?