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From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date:   Tue, 5 Dec 2023 15:18:43 +0200
Message-ID: <CAA8EJpqrYpL8N4_nXW4BbJRuUR=zqmP88Ze6_xkoZRStso6ugA@mail.gmail.com>
Subject: Re: [v3 6/6] drm/vs: simple encoder
To:     Keith Zhao <keith.zhao@starfivetech.com>
Cc:     devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
        aou@eecs.berkeley.edu, suijingfeng@loongson.cn,
        tzimmermann@suse.de, paul.walmsley@sifive.com, mripard@kernel.org,
        xingyu.wu@starfivetech.com, jack.zhu@starfivetech.com,
        palmer@dabbelt.com, krzysztof.kozlowski+dt@linaro.org,
        william.qiu@starfivetech.com, shengyang.chen@starfivetech.com,
        changhuang.liang@starfivetech.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, 5 Dec 2023 at 15:14, Dmitry Baryshkov
<dmitry.baryshkov@linaro.org> wrote:
>
> On Mon, 4 Dec 2023 at 14:33, Keith Zhao <keith.zhao@starfivetech.com> wrote:
> >
> > add simple encoder for dsi bridge
>
> This doesn't look like a proper commit message.
>
> >
> > Signed-off-by: Keith Zhao <keith.zhao@starfivetech.com>
> > ---
> >  drivers/gpu/drm/verisilicon/Makefile        |   4 +-
> >  drivers/gpu/drm/verisilicon/vs_drv.c        |   2 +
> >  drivers/gpu/drm/verisilicon/vs_simple_enc.c | 195 ++++++++++++++++++++
> >  drivers/gpu/drm/verisilicon/vs_simple_enc.h |  23 +++
> >  4 files changed, 223 insertions(+), 1 deletion(-)
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_simple_enc.c
> >  create mode 100644 drivers/gpu/drm/verisilicon/vs_simple_enc.h
> >
> > diff --git a/drivers/gpu/drm/verisilicon/Makefile b/drivers/gpu/drm/verisilicon/Makefile
> > index 71fadafcee13..cd5d0a90bcfe 100644
> > --- a/drivers/gpu/drm/verisilicon/Makefile
> > +++ b/drivers/gpu/drm/verisilicon/Makefile
> > @@ -5,6 +5,8 @@ vs_drm-objs := vs_dc_hw.o \
> >                 vs_crtc.o \
> >                 vs_drv.o \
> >                 vs_modeset.o \
> > -               vs_plane.o
> > +               vs_plane.o \
> > +               vs_simple_enc.o
> > +
> >  vs_drm-$(CONFIG_DRM_VERISILICON_STARFIVE_HDMI) += starfive_hdmi.o
> >  obj-$(CONFIG_DRM_VERISILICON) += vs_drm.o
> > diff --git a/drivers/gpu/drm/verisilicon/vs_drv.c b/drivers/gpu/drm/verisilicon/vs_drv.c
> > index d7e5199fe293..946f137ab124 100644
> > --- a/drivers/gpu/drm/verisilicon/vs_drv.c
> > +++ b/drivers/gpu/drm/verisilicon/vs_drv.c
> > @@ -23,6 +23,7 @@
> >  #include "vs_drv.h"
> >  #include "vs_modeset.h"
> >  #include "vs_dc.h"
> > +#include "vs_simple_enc.h"
> >
> >  #define DRV_NAME       "verisilicon"
> >  #define DRV_DESC       "Verisilicon DRM driver"
> > @@ -217,6 +218,7 @@ static struct platform_driver *drm_sub_drivers[] = {
> >  #ifdef CONFIG_DRM_VERISILICON_STARFIVE_HDMI
> >         &starfive_hdmi_driver,
> >  #endif
> > +       &simple_encoder_driver,
> >  };
> >
> >  static struct component_match *vs_drm_match_add(struct device *dev)
> > diff --git a/drivers/gpu/drm/verisilicon/vs_simple_enc.c b/drivers/gpu/drm/verisilicon/vs_simple_enc.c
> > new file mode 100644
> > index 000000000000..c5a8d82bc469
> > --- /dev/null
> > +++ b/drivers/gpu/drm/verisilicon/vs_simple_enc.c
> > @@ -0,0 +1,195 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2020 VeriSilicon Holdings Co., Ltd.
> > + */
> > +#include <linux/component.h>
> > +#include <linux/of_device.h>
> > +#include <linux/module.h>
> > +
> > +#include <drm/drm_atomic_helper.h>
> > +#include <drm/drm_bridge.h>
> > +#include <drm/drm_crtc_helper.h>
> > +#include <drm/drm_of.h>
> > +#include <linux/regmap.h>
> > +#include <linux/media-bus-format.h>
> > +#include <linux/mfd/syscon.h>
> > +
> > +#include "vs_crtc.h"
> > +#include "vs_simple_enc.h"
> > +
> > +static const struct simple_encoder_priv dsi_priv = {
>
> Please use proper prefix for all the struct and function names.
> vs_simple_encoder sounds better. Or vs_dsi_encoder.
>
> > +       .encoder_type = DRM_MODE_ENCODER_DSI
> > +};
> > +
> > +static inline struct simple_encoder *to_simple_encoder(struct drm_encoder *enc)
> > +{
> > +       return container_of(enc, struct simple_encoder, encoder);
> > +}
> > +
> > +static int encoder_parse_dt(struct device *dev)
> > +{
> > +       struct simple_encoder *simple = dev_get_drvdata(dev);
> > +       unsigned int args[2];
> > +
> > +       simple->dss_regmap = syscon_regmap_lookup_by_phandle_args(dev->of_node,
> > +                                                                 "starfive,syscon",
> > +                                                                 2, args);
> > +
> > +       if (IS_ERR(simple->dss_regmap)) {
> > +               return dev_err_probe(dev, PTR_ERR(simple->dss_regmap),
> > +                                    "getting the regmap failed\n");
> > +       }
> > +
> > +       simple->offset = args[0];
> > +       simple->mask = args[1];
> > +
> > +       return 0;
> > +}
> > +
> > +void encoder_atomic_enable(struct drm_encoder *encoder,
> > +                          struct drm_atomic_state *state)
> > +{
> > +       struct simple_encoder *simple = to_simple_encoder(encoder);
> > +
> > +       regmap_update_bits(simple->dss_regmap, simple->offset, simple->mask,
> > +                          simple->mask);
> > +}
> > +
> > +int encoder_atomic_check(struct drm_encoder *encoder,
> > +                        struct drm_crtc_state *crtc_state,
> > +                        struct drm_connector_state *conn_state)
> > +{
> > +       struct vs_crtc_state *vs_crtc_state = to_vs_crtc_state(crtc_state);
> > +       struct drm_connector *connector = conn_state->connector;
> > +       int ret = 0;
> > +
> > +       struct drm_bridge *first_bridge = drm_bridge_chain_get_first_bridge(encoder);
> > +       struct drm_bridge_state *bridge_state = ERR_PTR(-EINVAL);
> > +
> > +       vs_crtc_state->encoder_type = encoder->encoder_type;
> > +
> > +       if (first_bridge && first_bridge->funcs->atomic_duplicate_state)
> > +               bridge_state = drm_atomic_get_bridge_state(crtc_state->state, first_bridge);
>
> Please don't poke into others' playground. This should go into your
> DSI bridge's atomic_check() instead.

Hmm. And you can not use vs_crtc_state from your bridge. Actually this
design makes me wonder, how does your hardware work? Is it possible to
send the DSI commands to the panel?

>
> > +
> > +       if (IS_ERR(bridge_state)) {
> > +               if (connector->display_info.num_bus_formats)
> > +                       vs_crtc_state->output_fmt = connector->display_info.bus_formats[0];
> > +               else
> > +                       vs_crtc_state->output_fmt = MEDIA_BUS_FMT_FIXED;
> > +       } else {
> > +               vs_crtc_state->output_fmt = bridge_state->input_bus_cfg.format;
> > +       }
> > +
> > +       switch (vs_crtc_state->output_fmt) {
> > +       case MEDIA_BUS_FMT_FIXED:
> > +       case MEDIA_BUS_FMT_RGB565_1X16:
> > +       case MEDIA_BUS_FMT_RGB666_1X18:
> > +       case MEDIA_BUS_FMT_RGB888_1X24:
> > +       case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
> > +       case MEDIA_BUS_FMT_RGB101010_1X30:
> > +       case MEDIA_BUS_FMT_UYYVYY8_0_5X24:
> > +       case MEDIA_BUS_FMT_UYVY8_1X16:
> > +       case MEDIA_BUS_FMT_YUV8_1X24:
> > +       case MEDIA_BUS_FMT_UYYVYY10_0_5X30:
> > +       case MEDIA_BUS_FMT_UYVY10_1X20:
> > +       case MEDIA_BUS_FMT_YUV10_1X30:
> > +               ret = 0;
> > +               break;
> > +       default:
> > +               ret = -EINVAL;
> > +               break;
> > +       }
> > +
> > +       /* If MEDIA_BUS_FMT_FIXED, set it to default value */
> > +       if (vs_crtc_state->output_fmt == MEDIA_BUS_FMT_FIXED)
> > +               vs_crtc_state->output_fmt = MEDIA_BUS_FMT_RGB888_1X24;
> > +
> > +       return ret;
> > +}
> > +
> > +static const struct drm_encoder_helper_funcs encoder_helper_funcs = {
> > +       .atomic_check = encoder_atomic_check,
> > +       .atomic_enable = encoder_atomic_enable,
> > +};
> > +
> > +static int encoder_bind(struct device *dev, struct device *master, void *data)
> > +{
> > +       struct drm_device *drm_dev = data;
> > +       struct simple_encoder *simple = dev_get_drvdata(dev);
> > +       struct drm_encoder *encoder;
> > +       struct drm_bridge *bridge;
> > +       int ret;
> > +
> > +       encoder = &simple->encoder;
> > +
> > +       ret = drmm_encoder_init(drm_dev, encoder, NULL, simple->priv->encoder_type, NULL);
> > +       if (ret)
> > +               return ret;
> > +
> > +       drm_encoder_helper_add(encoder, &encoder_helper_funcs);
> > +
> > +       encoder->possible_crtcs =
> > +                       drm_of_find_possible_crtcs(drm_dev, dev->of_node);
> > +
> > +       /* output port is port1*/
> > +       bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
> > +       if (IS_ERR(bridge))
> > +               return 0;
> > +
> > +       return drm_bridge_attach(encoder, bridge, NULL, 0);
> > +}
> > +
> > +static const struct component_ops encoder_component_ops = {
> > +       .bind = encoder_bind,
> > +};
> > +
> > +static const struct of_device_id simple_encoder_dt_match[] = {
> > +       { .compatible = "starfive,dsi-encoder", .data = &dsi_priv},
> > +       {},
> > +};
> > +MODULE_DEVICE_TABLE(of, simple_encoder_dt_match);
> > +
> > +static int encoder_probe(struct platform_device *pdev)
> > +{
> > +       struct device *dev = &pdev->dev;
> > +       struct simple_encoder *simple;
> > +       int ret;
> > +
> > +       simple = devm_kzalloc(dev, sizeof(*simple), GFP_KERNEL);
> > +       if (!simple)
> > +               return -ENOMEM;
> > +
> > +       simple->priv = of_device_get_match_data(dev);
> > +
> > +       simple->dev = dev;
> > +
> > +       dev_set_drvdata(dev, simple);
> > +
> > +       ret = encoder_parse_dt(dev);
> > +       if (ret)
> > +               return ret;
> > +
> > +       return component_add(dev, &encoder_component_ops);
> > +}
> > +
> > +static int encoder_remove(struct platform_device *pdev)
> > +{
> > +       struct device *dev = &pdev->dev;
> > +
> > +       component_del(dev, &encoder_component_ops);
> > +       dev_set_drvdata(dev, NULL);
> > +
> > +       return 0;
> > +}
> > +
> > +struct platform_driver simple_encoder_driver = {
> > +       .probe = encoder_probe,
> > +       .remove = encoder_remove,
> > +       .driver = {
> > +               .name = "vs-simple-encoder",
> > +               .of_match_table = of_match_ptr(simple_encoder_dt_match),
> > +       },
> > +};
> > +
> > +MODULE_DESCRIPTION("Simple Encoder Driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/gpu/drm/verisilicon/vs_simple_enc.h b/drivers/gpu/drm/verisilicon/vs_simple_enc.h
> > new file mode 100644
> > index 000000000000..fb33ca9e18d6
> > --- /dev/null
> > +++ b/drivers/gpu/drm/verisilicon/vs_simple_enc.h
> > @@ -0,0 +1,23 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2022 VeriSilicon Holdings Co., Ltd.
> > + */
> > +
> > +#ifndef __VS_SIMPLE_ENC_H_
> > +#define __VS_SIMPLE_ENC_H_
> > +
> > +struct simple_encoder_priv {
> > +       unsigned char encoder_type;
> > +};
> > +
> > +struct simple_encoder {
> > +       struct drm_encoder encoder;
> > +       struct device *dev;
> > +       const struct simple_encoder_priv *priv;
> > +       struct regmap *dss_regmap;
> > +       unsigned int offset;
> > +       unsigned int mask;
> > +};
> > +
> > +extern struct platform_driver simple_encoder_driver;
> > +#endif /* __VS_SIMPLE_ENC_H_ */
> > --
> > 2.34.1
> >
>
>
> --
> With best wishes
> Dmitry


-- 
With best wishes
Dmitry