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Message-ID: <CAG3jFysTKXsmfx4x=XVdu3X0amE9EUOxN=bYo4eg+XjnqyFsVg@mail.gmail.com>
Date: Tue, 2 Mar 2021 15:22:43 +0100
From: Robert Foss <robert.foss@...aro.org>
To: Liu Ying <victor.liu@....com>
Cc: dri-devel <dri-devel@...ts.freedesktop.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>,
"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
<linux-arm-kernel@...ts.infradead.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
linux-media <linux-media@...r.kernel.org>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Rob Herring <robh+dt@...nel.org>, shawnguo@...nel.org,
s.hauer@...gutronix.de, kernel@...gutronix.de,
Fabio Estevam <festevam@...il.com>, linux-imx@....com,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Andrzej Hajda <a.hajda@...sung.com>,
Neil Armstrong <narmstrong@...libre.com>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>,
Jernej Skrabec <jernej.skrabec@...l.net>, kishon@...com,
Vinod Koul <vkoul@...nel.org>
Subject: Re: [PATCH v4 10/14] drm/bridge: imx: Add LDB driver helper support
Hey Liu,
Thanks for submitting this patch.
On Thu, 18 Feb 2021 at 04:59, Liu Ying <victor.liu@....com> wrote:
>
> This patch adds a helper to support LDB drm bridge drivers for
> i.MX SoCs. Helper functions exported from this driver should
> implement common logics for all LDB modules embedded in i.MX SoCs.
>
> Signed-off-by: Liu Ying <victor.liu@....com>
> ---
> v3->v4:
> * No change.
>
> v2->v3:
> * Call syscon_node_to_regmap() to get regmap instead of
> syscon_regmap_lookup_by_phandle().
>
> v1->v2:
> * No change.
>
> drivers/gpu/drm/bridge/imx/Kconfig | 8 +
> drivers/gpu/drm/bridge/imx/Makefile | 1 +
> drivers/gpu/drm/bridge/imx/imx-ldb-helper.c | 248 ++++++++++++++++++++++++++++
> include/drm/bridge/imx_ldb_helper.h | 98 +++++++++++
> 4 files changed, 355 insertions(+)
> create mode 100644 drivers/gpu/drm/bridge/imx/imx-ldb-helper.c
> create mode 100644 include/drm/bridge/imx_ldb_helper.h
>
> diff --git a/drivers/gpu/drm/bridge/imx/Kconfig b/drivers/gpu/drm/bridge/imx/Kconfig
> index 1ea1ce7..23e24fd 100644
> --- a/drivers/gpu/drm/bridge/imx/Kconfig
> +++ b/drivers/gpu/drm/bridge/imx/Kconfig
> @@ -1,3 +1,11 @@
> +config DRM_IMX_LVDS_BRIDGE_HELPER
> + tristate "Freescale i.MX LVDS display bridge helper"
> + depends on OF
> + select DRM_PANEL_BRIDGE
> + help
> + Helper to support Freescale i.MX LVDS Display Bridge(LDB).
> + This bridge is embedded in a SoC.
> +
> config DRM_IMX8QXP_PIXEL_COMBINER
> tristate "Freescale i.MX8QM/QXP pixel combiner"
> depends on OF
> diff --git a/drivers/gpu/drm/bridge/imx/Makefile b/drivers/gpu/drm/bridge/imx/Makefile
> index e74dd64..902b703 100644
> --- a/drivers/gpu/drm/bridge/imx/Makefile
> +++ b/drivers/gpu/drm/bridge/imx/Makefile
> @@ -1,3 +1,4 @@
> +obj-$(CONFIG_DRM_IMX_LVDS_BRIDGE_HELPER) += imx-ldb-helper.o
> obj-$(CONFIG_DRM_IMX8QXP_PIXEL_COMBINER) += imx8qxp-pixel-combiner.o
> obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK) += imx8qxp-pixel-link.o
> obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK_TO_DPI) += imx8qxp-pxl2dpi.o
> diff --git a/drivers/gpu/drm/bridge/imx/imx-ldb-helper.c b/drivers/gpu/drm/bridge/imx/imx-ldb-helper.c
> new file mode 100644
> index 00000000..94d7f9e
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/imx/imx-ldb-helper.c
> @@ -0,0 +1,248 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2012 Sascha Hauer, Pengutronix
> + * Copyright 2019,2020 NXP
> + */
> +
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/regmap.h>
> +
> +#include <drm/bridge/imx_ldb_helper.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_print.h>
> +
> +bool ldb_channel_is_single_link(struct ldb_channel *ldb_ch)
> +{
> + return ldb_ch->link_type == LDB_CH_SINGLE_LINK;
> +}
> +EXPORT_SYMBOL_GPL(ldb_channel_is_single_link);
> +
> +bool ldb_channel_is_split_link(struct ldb_channel *ldb_ch)
> +{
> + return ldb_ch->link_type == LDB_CH_DUAL_LINK_EVEN_ODD_PIXELS ||
> + ldb_ch->link_type == LDB_CH_DUAL_LINK_ODD_EVEN_PIXELS;
> +}
> +EXPORT_SYMBOL_GPL(ldb_channel_is_split_link);
> +
> +int ldb_bridge_atomic_check_helper(struct drm_bridge *bridge,
> + struct drm_bridge_state *bridge_state,
> + struct drm_crtc_state *crtc_state,
> + struct drm_connector_state *conn_state)
> +{
> + struct ldb_channel *ldb_ch = bridge->driver_private;
> +
> + ldb_ch->in_bus_format = bridge_state->input_bus_cfg.format;
> + ldb_ch->out_bus_format = bridge_state->output_bus_cfg.format;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(ldb_bridge_atomic_check_helper);
> +
> +void ldb_bridge_mode_set_helper(struct drm_bridge *bridge,
> + const struct drm_display_mode *mode,
> + const struct drm_display_mode *adjusted_mode)
> +{
> + struct ldb_channel *ldb_ch = bridge->driver_private;
> + struct ldb *ldb = ldb_ch->ldb;
> + bool is_split = ldb_channel_is_split_link(ldb_ch);
> +
> + if (is_split)
> + ldb->ldb_ctrl |= LDB_SPLIT_MODE_EN;
> +
> + switch (ldb_ch->out_bus_format) {
> + case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
> + break;
> + case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
> + if (ldb_ch->chno == 0 || is_split)
> + ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH0_24;
> + if (ldb_ch->chno == 1 || is_split)
> + ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH1_24;
> + break;
> + case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
> + if (ldb_ch->chno == 0 || is_split)
> + ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH0_24 |
> + LDB_BIT_MAP_CH0_JEIDA;
> + if (ldb_ch->chno == 1 || is_split)
> + ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH1_24 |
> + LDB_BIT_MAP_CH1_JEIDA;
> + break;
> + }
> +}
> +EXPORT_SYMBOL_GPL(ldb_bridge_mode_set_helper);
> +
> +void ldb_bridge_enable_helper(struct drm_bridge *bridge)
> +{
> + struct ldb_channel *ldb_ch = bridge->driver_private;
> + struct ldb *ldb = ldb_ch->ldb;
> +
> + /*
> + * Platform specific bridge drivers should set ldb_ctrl properly
> + * for the enablement, so just write the ctrl_reg here.
> + */
> + regmap_write(ldb->regmap, ldb->ctrl_reg, ldb->ldb_ctrl);
> +}
> +EXPORT_SYMBOL_GPL(ldb_bridge_enable_helper);
> +
> +void ldb_bridge_disable_helper(struct drm_bridge *bridge)
> +{
> + struct ldb_channel *ldb_ch = bridge->driver_private;
> + struct ldb *ldb = ldb_ch->ldb;
> + bool is_split = ldb_channel_is_split_link(ldb_ch);
> +
> + if (ldb_ch->chno == 0 || is_split)
> + ldb->ldb_ctrl &= ~LDB_CH0_MODE_EN_MASK;
> + if (ldb_ch->chno == 1 || is_split)
> + ldb->ldb_ctrl &= ~LDB_CH1_MODE_EN_MASK;
> +
> + regmap_write(ldb->regmap, ldb->ctrl_reg, ldb->ldb_ctrl);
> +}
> +EXPORT_SYMBOL_GPL(ldb_bridge_disable_helper);
> +
> +int ldb_bridge_attach_helper(struct drm_bridge *bridge,
> + enum drm_bridge_attach_flags flags)
> +{
> + struct ldb_channel *ldb_ch = bridge->driver_private;
> + struct ldb *ldb = ldb_ch->ldb;
> +
> + if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
> + DRM_DEV_ERROR(ldb->dev,
> + "do not support creating a drm_connector\n");
> + return -EINVAL;
> + }
> +
> + if (!bridge->encoder) {
> + DRM_DEV_ERROR(ldb->dev, "missing encoder\n");
> + return -ENODEV;
> + }
> +
> + return drm_bridge_attach(bridge->encoder,
> + ldb_ch->next_bridge, bridge,
> + DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +}
> +EXPORT_SYMBOL_GPL(ldb_bridge_attach_helper);
> +
> +int ldb_init_helper(struct ldb *ldb)
> +{
> + struct device *dev = ldb->dev;
> + struct device_node *np = dev->of_node;
> + struct device_node *child;
> + int ret;
> + u32 i;
> +
> + ldb->regmap = syscon_node_to_regmap(np->parent);
> + if (IS_ERR(ldb->regmap)) {
> + ret = PTR_ERR(ldb->regmap);
> + if (ret != -EPROBE_DEFER)
> + DRM_DEV_ERROR(dev, "failed to get regmap: %d\n", ret);
> + return ret;
> + }
> +
> + for_each_available_child_of_node(np, child) {
> + struct ldb_channel *ldb_ch;
> +
> + ret = of_property_read_u32(child, "reg", &i);
> + if (ret || i > MAX_LDB_CHAN_NUM - 1) {
> + ret = -EINVAL;
> + DRM_DEV_ERROR(dev,
> + "invalid channel node address: %u\n", i);
> + of_node_put(child);
> + return ret;
> + }
> +
> + ldb_ch = ldb->channel[i];
> + ldb_ch->ldb = ldb;
> + ldb_ch->chno = i;
> + ldb_ch->is_available = true;
> + ldb_ch->np = child;
> +
> + ldb->available_ch_cnt++;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(ldb_init_helper);
> +
> +int ldb_find_next_bridge_helper(struct ldb *ldb)
> +{
> + struct device *dev = ldb->dev;
> + struct ldb_channel *ldb_ch;
> + int ret, i;
> +
> + for (i = 0; i < MAX_LDB_CHAN_NUM; i++) {
> + ldb_ch = ldb->channel[i];
> +
> + if (!ldb_ch->is_available)
> + continue;
> +
> + ret = drm_of_find_panel_or_bridge(ldb_ch->np, 1, 0,
> + &ldb_ch->panel,
> + &ldb_ch->next_bridge);
> + if (ret) {
> + if (ret != -EPROBE_DEFER)
> + DRM_DEV_ERROR(dev,
> + "failed to find panel or bridge: %d\n",
> + ret);
> + return ret;
> + }
> +
> + if (ldb_ch->panel) {
> + ldb_ch->next_bridge = devm_drm_panel_bridge_add(dev,
> + ldb_ch->panel);
> + if (IS_ERR(ldb_ch->next_bridge)) {
> + ret = PTR_ERR(ldb_ch->next_bridge);
> + DRM_DEV_ERROR(dev,
> + "failed to add panel bridge: %d\n",
> + ret);
> + return ret;
> + }
> + }
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(ldb_find_next_bridge_helper);
> +
> +void ldb_add_bridge_helper(struct ldb *ldb,
> + const struct drm_bridge_funcs *bridge_funcs)
> +{
> + struct ldb_channel *ldb_ch;
> + int i;
> +
> + for (i = 0; i < MAX_LDB_CHAN_NUM; i++) {
> + ldb_ch = ldb->channel[i];
> +
> + if (!ldb_ch->is_available)
> + continue;
> +
> + ldb_ch->bridge.driver_private = ldb_ch;
> + ldb_ch->bridge.funcs = bridge_funcs;
> + ldb_ch->bridge.of_node = ldb_ch->np;
> +
> + drm_bridge_add(&ldb_ch->bridge);
> + }
> +}
> +EXPORT_SYMBOL_GPL(ldb_add_bridge_helper);
> +
> +void ldb_remove_bridge_helper(struct ldb *ldb)
> +{
> + struct ldb_channel *ldb_ch;
> + int i;
> +
> + for (i = 0; i < MAX_LDB_CHAN_NUM; i++) {
> + ldb_ch = ldb->channel[i];
> +
> + if (!ldb_ch->is_available)
> + continue;
> +
> + drm_bridge_remove(&ldb_ch->bridge);
> + }
> +}
> +EXPORT_SYMBOL_GPL(ldb_remove_bridge_helper);
> +
> +MODULE_DESCRIPTION("Freescale i.MX LVDS Display Bridge driver helper");
> +MODULE_AUTHOR("Liu Ying <victor.liu@....com>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:imx-ldb-helper");
I'm not entirely sure why this set of helper functions should be a
module. It's not a driver, but rather a toolbox for the LDB driver,
which is fine, but there is no situation I can see where this module
would be unloaded and the LDB driver would be loaded.
> diff --git a/include/drm/bridge/imx_ldb_helper.h b/include/drm/bridge/imx_ldb_helper.h
> new file mode 100644
> index 00000000..2a7ba97
> --- /dev/null
> +++ b/include/drm/bridge/imx_ldb_helper.h
This header is specific to this driver, and I would expect it to not
be useful to other drivers. Additionally the filename has a different
format than the .c file it corresponds to. I would change the name and
path to "drivers/gpu/drm/bridge/imx/imx-ldb-helper.h".
> @@ -0,0 +1,98 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +
> +/*
> + * Copyright 2019,2020 NXP
> + */
> +
> +#ifndef __FSL_IMX_LDB__
> +#define __FSL_IMX_LDB__
> +
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/of.h>
> +#include <linux/regmap.h>
> +
> +#include <drm/drm_atomic.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_device.h>
> +#include <drm/drm_encoder.h>
> +#include <drm/drm_modeset_helper_vtables.h>
> +#include <drm/drm_panel.h>
> +
> +#define LDB_CH0_MODE_EN_TO_DI0 (1 << 0)
> +#define LDB_CH0_MODE_EN_TO_DI1 (3 << 0)
> +#define LDB_CH0_MODE_EN_MASK (3 << 0)
> +#define LDB_CH1_MODE_EN_TO_DI0 (1 << 2)
> +#define LDB_CH1_MODE_EN_TO_DI1 (3 << 2)
> +#define LDB_CH1_MODE_EN_MASK (3 << 2)
> +#define LDB_SPLIT_MODE_EN (1 << 4)
> +#define LDB_DATA_WIDTH_CH0_24 (1 << 5)
> +#define LDB_BIT_MAP_CH0_JEIDA (1 << 6)
> +#define LDB_DATA_WIDTH_CH1_24 (1 << 7)
> +#define LDB_BIT_MAP_CH1_JEIDA (1 << 8)
> +#define LDB_DI0_VS_POL_ACT_LOW (1 << 9)
> +#define LDB_DI1_VS_POL_ACT_LOW (1 << 10)
> +
> +#define MAX_LDB_CHAN_NUM 2
> +
> +enum ldb_channel_link_type {
> + LDB_CH_SINGLE_LINK,
> + LDB_CH_DUAL_LINK_EVEN_ODD_PIXELS,
> + LDB_CH_DUAL_LINK_ODD_EVEN_PIXELS,
> +};
> +
> +struct ldb;
> +
> +struct ldb_channel {
> + struct ldb *ldb;
> + struct drm_bridge bridge;
> + struct drm_panel *panel;
> + struct drm_bridge *next_bridge;
> + struct device_node *np;
> + u32 chno;
> + bool is_available;
> + u32 in_bus_format;
> + u32 out_bus_format;
> + enum ldb_channel_link_type link_type;
> +};
> +
> +struct ldb {
> + struct regmap *regmap;
> + struct device *dev;
> + struct ldb_channel *channel[MAX_LDB_CHAN_NUM];
> + unsigned int ctrl_reg;
> + u32 ldb_ctrl;
> + unsigned int available_ch_cnt;
> +};
> +
> +#define bridge_to_ldb_ch(b) container_of(b, struct ldb_channel, bridge)
> +
> +bool ldb_channel_is_single_link(struct ldb_channel *ldb_ch);
> +bool ldb_channel_is_split_link(struct ldb_channel *ldb_ch);
> +
> +int ldb_bridge_atomic_check_helper(struct drm_bridge *bridge,
> + struct drm_bridge_state *bridge_state,
> + struct drm_crtc_state *crtc_state,
> + struct drm_connector_state *conn_state);
> +
> +void ldb_bridge_mode_set_helper(struct drm_bridge *bridge,
> + const struct drm_display_mode *mode,
> + const struct drm_display_mode *adjusted_mode);
> +
> +void ldb_bridge_enable_helper(struct drm_bridge *bridge);
> +
> +void ldb_bridge_disable_helper(struct drm_bridge *bridge);
> +
> +int ldb_bridge_attach_helper(struct drm_bridge *bridge,
> + enum drm_bridge_attach_flags flags);
> +
> +int ldb_init_helper(struct ldb *ldb);
> +
> +int ldb_find_next_bridge_helper(struct ldb *ldb);
> +
> +void ldb_add_bridge_helper(struct ldb *ldb,
> + const struct drm_bridge_funcs *bridge_funcs);
> +
> +void ldb_remove_bridge_helper(struct ldb *ldb);
> +
> +#endif /* __FSL_IMX_LDB__ */
> --
> 2.7.4
>
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