On 2020-03-09 20:51, Laurent Pinchart wrote:
> Replace the manual connector implementation based on drm_panel with the
> drm_panel_bridge helper. This simplifies the mxsfb driver by removing
> connector-related code, and standardizing all pipeline control
> operations on bridges.
>
> A hack is needed to get hold of the connector, as that's our only source
> of bus flags and formats for now. As soon as the bridge API provides us
> with that information this can be fixed.
This seems like a nice simplification.
I gave this a go applied on today's drm-misc-next using a Colibri iMX7
(imx7d-colibri-emmc-eval-v3.dts device tree). This device makes use of
the simple panel driver. I get this when booting:
[ 2.976698] [drm] Supports vblank timestamp caching Rev 2
(21.10.2013).
[ 2.983526] ------------[ cut here ]------------
[ 2.988180] WARNING: CPU: 0 PID: 1 at
drivers/gpu/drm/bridge/panel.c:267 devm_drm_panel_bridge_add+0x25/0x28
[ 2.998059] Modules linked in:
[ 3.001159] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
5.6.0-rc5-yocto-standard-01250-ga4ce5db7c9f1 #29
[ 3.010493] Hardware name: Freescale i.MX7 Dual (Device Tree)
[ 3.016281] [<c010f089>] (unwind_backtrace) from [<c010a9bb>]
(show_stack+0xb/0xc)
[ 3.023887] [<c010a9bb>] (show_stack) from [<c08b33cf>]
(dump_stack+0x63/0x70)
[ 3.031144] [<c08b33cf>] (dump_stack) from [<c0124385>]
(__warn+0x9d/0xb0)
[ 3.038047] [<c0124385>] (__warn) from [<c0124403>]
(warn_slowpath_fmt+0x6b/0x70)
[ 3.045564] [<c0124403>] (warn_slowpath_fmt) from [<c04ebf65>]
(devm_drm_panel_bridge_add+0x25/0x28)
[ 3.054736] [<c04ebf65>] (devm_drm_panel_bridge_add) from
[<c051fe7f>] (mxsfb_probe+0x197/0x2e0)
[ 3.063559] [<c051fe7f>] (mxsfb_probe) from [<c0532e91>]
(platform_drv_probe+0x2d/0x60)
[ 3.071598] [<c0532e91>] (platform_drv_probe) from [<c0531615>]
(really_probe+0x1dd/0x330)
[ 3.079897] [<c0531615>] (really_probe) from [<c05318b3>]
(driver_probe_device+0x4f/0x154)
[ 3.088195] [<c05318b3>] (driver_probe_device) from [<c0531b3f>]
(device_driver_attach+0x37/0x44)
[ 3.097101] [<c0531b3f>] (device_driver_attach) from [<c0531bc7>]
(__driver_attach+0x7b/0xec)
[ 3.105660] [<c0531bc7>] (__driver_attach) from [<c0530069>]
(bus_for_each_dev+0x3d/0x64)
[ 3.113870] [<c0530069>] (bus_for_each_dev) from [<c0530b9b>]
(bus_add_driver+0xef/0x160)
[ 3.122081] [<c0530b9b>] (bus_add_driver) from [<c053238d>]
(driver_register+0x35/0x9c)
[ 3.130119] [<c053238d>] (driver_register) from [<c0102de9>]
(do_one_initcall+0x3d/0x1e4)
[ 3.138333] [<c0102de9>] (do_one_initcall) from [<c1100d13>]
(kernel_init_freeable+0x1b3/0x1fc)
[ 3.147069] [<c1100d13>] (kernel_init_freeable) from [<c08c3f7b>]
(kernel_init+0x7/0xd0)
[ 3.155194] [<c08c3f7b>] (kernel_init) from [<c01010f9>]
(ret_from_fork+0x11/0x38)
[ 3.162789] Exception stack(0xec0e3fb0 to 0xec0e3ff8)
[ 3.167862] 3fa0: 00000000
00000000 00000000 00000000
[ 3.176071] 3fc0: 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000
[ 3.184278] 3fe0: 00000000 00000000 00000000 00000000 00000013
00000000
[ 3.191029] ---[ end trace b69e1f44de470959 ]---
[ 3.195671] mxsfb 30730000.lcdif: Cannot connect bridge: -19
Should we maybe use devm_drm_panel_bridge_add_typed?
Two more comments below.
>
> Signed-off-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> ---
> drivers/gpu/drm/mxsfb/Makefile | 2 +-
> drivers/gpu/drm/mxsfb/mxsfb_drv.c | 105 ++++++++++++++----------------
> drivers/gpu/drm/mxsfb/mxsfb_drv.h | 5 +-
> drivers/gpu/drm/mxsfb/mxsfb_out.c | 99 ----------------------------
> 4 files changed, 53 insertions(+), 158 deletions(-)
> delete mode 100644 drivers/gpu/drm/mxsfb/mxsfb_out.c
>
> diff --git a/drivers/gpu/drm/mxsfb/Makefile b/drivers/gpu/drm/mxsfb/Makefile
> index ff6e358088fa..811584e54ad1 100644
> --- a/drivers/gpu/drm/mxsfb/Makefile
> +++ b/drivers/gpu/drm/mxsfb/Makefile
> @@ -1,3 +1,3 @@
> # SPDX-License-Identifier: GPL-2.0-only
> -mxsfb-y := mxsfb_drv.o mxsfb_crtc.o mxsfb_out.o
> +mxsfb-y := mxsfb_drv.o mxsfb_crtc.o
> obj-$(CONFIG_DRM_MXSFB) += mxsfb.o
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> index 2e6068d96034..cffc70257bd3 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> @@ -29,7 +29,6 @@
> #include <drm/drm_gem_framebuffer_helper.h>
> #include <drm/drm_irq.h>
> #include <drm/drm_of.h>
> -#include <drm/drm_panel.h>
> #include <drm/drm_probe_helper.h>
> #include <drm/drm_simple_kms_helper.h>
> #include <drm/drm_vblank.h>
> @@ -100,29 +99,11 @@ static void mxsfb_pipe_enable(struct
> drm_simple_display_pipe *pipe,
> struct drm_crtc_state *crtc_state,
> struct drm_plane_state *plane_state)
> {
> - struct drm_connector *connector;
> struct mxsfb_drm_private *mxsfb = drm_pipe_to_mxsfb_drm_private(pipe);
> struct drm_device *drm = pipe->plane.dev;
>
> - if (!mxsfb->connector) {
> - list_for_each_entry(connector,
> - &drm->mode_config.connector_list,
> - head)
> - if (connector->encoder == &mxsfb->pipe.encoder) {
> - mxsfb->connector = connector;
> - break;
> - }
> - }
> -
> - if (!mxsfb->connector) {
> - dev_warn(drm->dev, "No connector attached, using default\n");
> - mxsfb->connector = &mxsfb->panel_connector;
> - }
> -
> pm_runtime_get_sync(drm->dev);
> - drm_panel_prepare(mxsfb->panel);
> mxsfb_crtc_enable(mxsfb);
> - drm_panel_enable(mxsfb->panel);
> }
>
> static void mxsfb_pipe_disable(struct drm_simple_display_pipe *pipe)
> @@ -132,9 +113,7 @@ static void mxsfb_pipe_disable(struct
> drm_simple_display_pipe *pipe)
> struct drm_crtc *crtc = &pipe->crtc;
> struct drm_pending_vblank_event *event;
>
> - drm_panel_disable(mxsfb->panel);
> mxsfb_crtc_disable(mxsfb);
> - drm_panel_unprepare(mxsfb->panel);
> pm_runtime_put_sync(drm->dev);
>
> spin_lock_irq(&drm->event_lock);
> @@ -144,9 +123,6 @@ static void mxsfb_pipe_disable(struct
> drm_simple_display_pipe *pipe)
> drm_crtc_send_vblank_event(crtc, event);
> }
> spin_unlock_irq(&drm->event_lock);
> -
> - if (mxsfb->connector != &mxsfb->panel_connector)
> - mxsfb->connector = NULL;
> }
>
> static void mxsfb_pipe_update(struct drm_simple_display_pipe *pipe,
> @@ -190,6 +166,48 @@ static struct drm_simple_display_pipe_funcs mxsfb_funcs
> = {
> .disable_vblank = mxsfb_pipe_disable_vblank,
> };
>
> +static int mxsfb_attach_bridge(struct mxsfb_drm_private *mxsfb)
> +{
> + struct drm_device *drm = mxsfb->drm;
> + struct drm_connector_list_iter iter;
> + struct drm_panel *panel;
> + struct drm_bridge *bridge;
> + int ret;
> +
> + ret = drm_of_find_panel_or_bridge(drm->dev->of_node, 0, 0, &panel,
> + &bridge);
> + if (ret)
> + return ret;
> +
> + if (panel) {
> + bridge = devm_drm_panel_bridge_add(drm->dev, panel);
Do we need a select DRM_PANEL_BRIDGE in Kconfig maybe? From what I can
tell there is no devm_drm_panel_bridge_add() stub if DRM_PANEL_BRIDGE is
not selected.
> + if (IS_ERR(bridge))
> + return PTR_ERR(bridge);
> + }
> +
> + if (!bridge)
> + return -ENODEV;
> +
> + ret = drm_simple_display_pipe_attach_bridge(&mxsfb->pipe, bridge);
> + if (ret) {
> + DRM_DEV_ERROR(drm->dev,
> + "failed to attach bridge: %d\n", ret);
> + return ret;
> + }
> +
> + mxsfb->bridge = bridge;
> +
> + /*
> + * Get hold of the connector. This is a bit of a hack, until the bridge
> + * API gives us bus flags and formats.
> + */
> + drm_connector_list_iter_begin(drm, &iter);
> + mxsfb->connector = drm_connector_list_iter_next(&iter);
> + drm_connector_list_iter_end(&iter);
Could we not just use drm_panel_bridge_connector() here?
--
Stefan
> +
> + return 0;
> +}
> +
> static int mxsfb_load(struct drm_device *drm, unsigned long flags)
> {
> struct platform_device *pdev = to_platform_device(drm->dev);
> @@ -201,6 +219,7 @@ static int mxsfb_load(struct drm_device *drm,
> unsigned long flags)
> if (!mxsfb)
> return -ENOMEM;
>
> + mxsfb->drm = drm;
> drm->dev_private = mxsfb;
> mxsfb->devdata = &mxsfb_devdata[pdev->id_entry->driver_data];
>
> @@ -236,41 +255,17 @@ static int mxsfb_load(struct drm_device *drm,
> unsigned long flags)
> /* Modeset init */
> drm_mode_config_init(drm);
>
> - ret = mxsfb_create_output(drm);
> - if (ret < 0) {
> - dev_err(drm->dev, "Failed to create outputs\n");
> - goto err_vblank;
> - }
> -
> ret = drm_simple_display_pipe_init(drm, &mxsfb->pipe, &mxsfb_funcs,
> - mxsfb_formats, ARRAY_SIZE(mxsfb_formats), NULL,
> - mxsfb->connector);
> + mxsfb_formats, ARRAY_SIZE(mxsfb_formats), NULL, NULL);
> if (ret < 0) {
> dev_err(drm->dev, "Cannot setup simple display pipe\n");
> goto err_vblank;
> }
>
> - /*
> - * Attach panel only if there is one.
> - * If there is no panel attach, it must be a bridge. In this case, we
> - * need a reference to its connector for a proper initialization.
> - * We will do this check in pipe->enable(), since the connector won't
> - * be attached to an encoder until then.
> - */
> -
> - if (mxsfb->panel) {
> - ret = drm_panel_attach(mxsfb->panel, mxsfb->connector);
> - if (ret) {
> - dev_err(drm->dev, "Cannot connect panel: %d\n", ret);
> - goto err_vblank;
> - }
> - } else if (mxsfb->bridge) {
> - ret = drm_simple_display_pipe_attach_bridge(&mxsfb->pipe,
> - mxsfb->bridge);
> - if (ret) {
> - dev_err(drm->dev, "Cannot connect bridge: %d\n", ret);
> - goto err_vblank;
> - }
> + ret = mxsfb_attach_bridge(mxsfb);
> + if (ret) {
> + dev_err(drm->dev, "Cannot connect bridge: %d\n", ret);
> + goto err_vblank;
> }
>
> drm->mode_config.min_width = MXSFB_MIN_XRES;
> @@ -288,7 +283,7 @@ static int mxsfb_load(struct drm_device *drm,
> unsigned long flags)
>
> if (ret < 0) {
> dev_err(drm->dev, "Failed to install IRQ handler\n");
> - goto err_irq;
> + goto err_vblank;
> }
>
> drm_kms_helper_poll_init(drm);
> @@ -299,8 +294,6 @@ static int mxsfb_load(struct drm_device *drm,
> unsigned long flags)
>
> return 0;
>
> -err_irq:
> - drm_panel_detach(mxsfb->panel);
> err_vblank:
> pm_runtime_disable(drm->dev);
>
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> b/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> index 0b65b5194a9c..0e3e5a63bbf9 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> @@ -8,6 +8,8 @@
> #ifndef __MXSFB_DRV_H__
> #define __MXSFB_DRV_H__
>
> +struct drm_device;
> +
> struct mxsfb_devdata {
> unsigned int transfer_count;
> unsigned int cur_buf;
> @@ -26,10 +28,9 @@ struct mxsfb_drm_private {
> struct clk *clk_axi;
> struct clk *clk_disp_axi;
>
> + struct drm_device *drm;
> struct drm_simple_display_pipe pipe;
> - struct drm_connector panel_connector;
> struct drm_connector *connector;
> - struct drm_panel *panel;
> struct drm_bridge *bridge;
> };
>
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_out.c
> b/drivers/gpu/drm/mxsfb/mxsfb_out.c
> deleted file mode 100644
> index 9eca1605d11d..000000000000
> --- a/drivers/gpu/drm/mxsfb/mxsfb_out.c
> +++ /dev/null
> @@ -1,99 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-or-later
> -/*
> - * Copyright (C) 2016 Marek Vasut <ma...@denx.de>
> - */
> -
> -#include <linux/of_graph.h>
> -
> -#include <drm/drm_atomic.h>
> -#include <drm/drm_atomic_helper.h>
> -#include <drm/drm_crtc.h>
> -#include <drm/drm_fb_cma_helper.h>
> -#include <drm/drm_gem_cma_helper.h>
> -#include <drm/drm_of.h>
> -#include <drm/drm_panel.h>
> -#include <drm/drm_plane_helper.h>
> -#include <drm/drm_probe_helper.h>
> -#include <drm/drm_simple_kms_helper.h>
> -
> -#include "mxsfb_drv.h"
> -
> -static struct mxsfb_drm_private *
> -drm_connector_to_mxsfb_drm_private(struct drm_connector *connector)
> -{
> - return container_of(connector, struct mxsfb_drm_private,
> - panel_connector);
> -}
> -
> -static int mxsfb_panel_get_modes(struct drm_connector *connector)
> -{
> - struct mxsfb_drm_private *mxsfb =
> - drm_connector_to_mxsfb_drm_private(connector);
> -
> - if (mxsfb->panel)
> - return drm_panel_get_modes(mxsfb->panel, connector);
> -
> - return 0;
> -}
> -
> -static const struct
> -drm_connector_helper_funcs mxsfb_panel_connector_helper_funcs = {
> - .get_modes = mxsfb_panel_get_modes,
> -};
> -
> -static enum drm_connector_status
> -mxsfb_panel_connector_detect(struct drm_connector *connector, bool force)
> -{
> - struct mxsfb_drm_private *mxsfb =
> - drm_connector_to_mxsfb_drm_private(connector);
> -
> - if (mxsfb->panel)
> - return connector_status_connected;
> -
> - return connector_status_disconnected;
> -}
> -
> -static void mxsfb_panel_connector_destroy(struct drm_connector *connector)
> -{
> - struct mxsfb_drm_private *mxsfb =
> - drm_connector_to_mxsfb_drm_private(connector);
> -
> - if (mxsfb->panel)
> - drm_panel_detach(mxsfb->panel);
> -
> - drm_connector_unregister(connector);
> - drm_connector_cleanup(connector);
> -}
> -
> -static const struct drm_connector_funcs mxsfb_panel_connector_funcs = {
> - .detect = mxsfb_panel_connector_detect,
> - .fill_modes = drm_helper_probe_single_connector_modes,
> - .destroy = mxsfb_panel_connector_destroy,
> - .reset = drm_atomic_helper_connector_reset,
> - .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> - .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> -};
> -
> -int mxsfb_create_output(struct drm_device *drm)
> -{
> - struct mxsfb_drm_private *mxsfb = drm->dev_private;
> - int ret;
> -
> - ret = drm_of_find_panel_or_bridge(drm->dev->of_node, 0, 0,
> - &mxsfb->panel, &mxsfb->bridge);
> - if (ret)
> - return ret;
> -
> - if (mxsfb->panel) {
> - mxsfb->connector = &mxsfb->panel_connector;
> - mxsfb->connector->dpms = DRM_MODE_DPMS_OFF;
> - mxsfb->connector->polled = 0;
> - drm_connector_helper_add(mxsfb->connector,
> - &mxsfb_panel_connector_helper_funcs);
> - ret = drm_connector_init(drm, mxsfb->connector,
> - &mxsfb_panel_connector_funcs,
> - DRM_MODE_CONNECTOR_Unknown);
> - }
> -
> - return ret;
> -}
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