Re: (EXT) [PATCH v8 09/14] drm/bridge: imx: Add LDB driver helper support

Liu Ying
2022-06-10T03:01:45Z

On Thu, 2022-06-09 at 09:47 +0200, Alexander Stein wrote:
> Am Donnerstag, 9. Juni 2022, 08:49:26 CEST schrieb Liu Ying:
> > This patch adds a helper to support LDB drm bridge drivers for
> > i.MX SoCs. Helper functions supported by this helper should
> > implement common logics for all LDB modules embedded in i.MX SoCs.
> >
> > Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> # Colibri
> > iMX8X,
> > LT170410-2WHC, LP156WF1 Reviewed-by: Robert Foss <
> > robert.foss@linaro.org>
> > Signed-off-by: Liu Ying <victor.liu@nxp.com>
> > ---
>
> Hi,

Hi,

>
> reading this I got reminded of fsl-ldb [1], which is accepted
> already. At a
> first glance reading the RM the LDB peripheral are similar, although
> not
> identical. Is it worth merging them into one driver (at some point)?

fsl-ldb is for i.MX8mp LDB. It couples the lvds phy(LVDS_CTRL register)
with LDB(LDB_CTRL register) hardly.

Eventually, I think there would be separate LDB bridge drivers for
i.MX8mp/qxp/qm LDBs, as they are far or less different(LVDS PHY IPs,
clocks, ways of dual link usage...). So, maybe, the question is that
can fsl-ldb use this LDB helper driver. AFAICS, the different DT
bindings between i.MX8mp LDB and i.MX8qxp/qm LDB make this difficult.
This LDB helper takes each LDB child node(channel node) of i.MX8qxp/qm
as a bridge, while i.MX8mp LDB bindings put input and output ports in
'ports' node. Like i.MX8qxp/qm LDB, i.MX6 LDB
binding(Documentation/devicetree/bindings/display/imx/ldb.txt) also
uses 'channel' nodes, though i.MX6 LDB has a separate encoder driver.
I think the 'channel' node better reflects HW design.
So, maybe, fsl-ldb for i.MX8mp won't use this LDB helper.

Regards,
Liu Ying

>
> Best regards,
> Alexander
>
> [1]
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.freedesktop.org%2Fpatch%2Fmsgid%2F20220426193645.244792-2-marex%40denx.de&amp;data=05%7C01%7Cvictor.liu%40nxp.com%7Ca4ee326b3f314cf48a3408da49ec5a33%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637903576722519563%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=yJhovCeB7Dx2eWJqKohZskA7fX3NLwqmW1GxeQlDe40%3D&amp;reserved=0
>
> > Marcel, I add your T-b tag from v6, let me know if you want me to
> > drop it,
> > as the checkpatch fix in v7 and the rebase in v8 are trivial.
> >
> > v7->v8:
> > * Use devm_drm_of_get_bridge() due to the rebase upon v5.19-rc1.
> >
> > v6->v7:
> > * Fix below complaints from 'checkpatch.pl --strict'. (Robert)
> > - 'Alignment should match open parenthesis'
> > - 'Prefer using the BIT macro'
> > * Add Marcel's T-b tag.
> > * Add Robert's R-b tag.
> >
> > v5->v6:
> > * No change.
> >
> > v4->v5:
> > * Make imx-ldb-helper be a pure object to be linked with i.MX8qxp
> > LDB bridge
> > driver and i.MX8qm LDB bridge driver. (Robert)
> > * Move 'imx_ldb_helper.h' to 'drivers/gpu/drm/bridge/imx/imx-ldb-
> > helper.h'.
> > (Robert)
> > * s/__FSL_IMX_LDB__/__IMX_LDB_HELPER__/ for 'imx-ldb-helper.h'.
> >
> > 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/imx-ldb-helper.c | 220
> > ++++++++++++++++++++
> > drivers/gpu/drm/bridge/imx/imx-ldb-helper.h | 96 +++++++++
> > 2 files changed, 316 insertions(+)
> > create mode 100644 drivers/gpu/drm/bridge/imx/imx-ldb-helper.c
> > create mode 100644 drivers/gpu/drm/bridge/imx/imx-ldb-helper.h
> >
> > 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 000000000000..e85eb9ab5947
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/imx/imx-ldb-helper.c
> > @@ -0,0 +1,220 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (C) 2012 Sascha Hauer, Pengutronix
> > + * Copyright 2019,2020,2022 NXP
> > + */
> > +
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/of.h>
> > +#include <linux/regmap.h>
> > +
> > +#include <drm/drm_bridge.h>
> > +#include <drm/drm_of.h>
> > +#include <drm/drm_print.h>
> > +
> > +#include "imx-ldb-helper.h"
> > +
> > +bool ldb_channel_is_single_link(struct ldb_channel *ldb_ch)
> > +{
> > + return ldb_ch->link_type == LDB_CH_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;
> > +}
> > +
> > +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;
> > +}
> > +
> > +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;
> > + }
> > +}
> > +
> > +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);
> > +}
> > +
> > +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);
> > +}
> > +
> > +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);
> > +}
> > +
> > +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;
> > +}
> > +
> > +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;
> > +
> > + ldb_ch->next_bridge = devm_drm_of_get_bridge(dev,
>
> ldb_ch->np,
> > +
>
> 1, 0);
> > + if (IS_ERR(ldb_ch->next_bridge)) {
> > + ret = PTR_ERR(ldb_ch->next_bridge);
> > + if (ret != -EPROBE_DEFER)
> > + DRM_DEV_ERROR(dev,
> > + "failed to get
>
> next bridge: %d\n",
> > + ret);
> > + return ret;
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +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);
> > + }
> > +}
> > +
> > +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);
> > + }
> > +}
> > diff --git a/drivers/gpu/drm/bridge/imx/imx-ldb-helper.h
> > b/drivers/gpu/drm/bridge/imx/imx-ldb-helper.h new file mode 100644
> > index 000000000000..a0a5cde27fbc
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/imx/imx-ldb-helper.h
> > @@ -0,0 +1,96 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ */
> > +
> > +/*
> > + * Copyright 2019,2020,2022 NXP
> > + */
> > +
> > +#ifndef __IMX_LDB_HELPER__
> > +#define __IMX_LDB_HELPER__
> > +
> > +#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>
> > +
> > +#define LDB_CH0_MODE_EN_TO_DI0 BIT(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 BIT(2)
> > +#define LDB_CH1_MODE_EN_TO_DI1 (3 << 2)
> > +#define LDB_CH1_MODE_EN_MASK (3 << 2)
> > +#define LDB_SPLIT_MODE_EN BIT(4)
> > +#define LDB_DATA_WIDTH_CH0_24 BIT(5)
> > +#define LDB_BIT_MAP_CH0_JEIDA BIT(6)
> > +#define LDB_DATA_WIDTH_CH1_24 BIT(7)
> > +#define LDB_BIT_MAP_CH1_JEIDA BIT(8)
> > +#define LDB_DI0_VS_POL_ACT_LOW BIT(9)
> > +#define LDB_DI1_VS_POL_ACT_LOW BIT(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_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 /* __IMX_LDB_HELPER__ */
>
>
>
>