[PATCH v6 12/14] drm/bridge: imx: Add LDB support for i.MX8qxp
Robert Foss
robert.foss at linaro.org
Tue Mar 30 10:54:40 BST 2021
Hey Liu,
checkpatch --strict lists some nit and a warning. With those fixed
feel free to add my r-b.
On Wed, 17 Mar 2021 at 04:57, Liu Ying <victor.liu at nxp.com> wrote:
>
> This patch adds a drm bridge driver for i.MX8qxp LVDS display bridge(LDB)
> which is officially named as pixel mapper. The LDB has two channels.
> Each of them supports up to 24bpp parallel input color format and can map
> the input to VESA or JEIDA standards. The two channels cannot be used
> simultaneously, that is to say, the user should pick one of them to use.
> Two LDB channels from two LDB instances can work together in LDB split
> mode to support a dual link LVDS display. The channel indexes have to be
> different. Channel0 outputs odd pixels and channel1 outputs even pixels.
> This patch supports the LDB single mode and split mode.
>
> Signed-off-by: Liu Ying <victor.liu at nxp.com>
> ---
> Note that this patch depends on the patch 'phy: Add LVDS configuration options',
> which has already been sent with the following series to add Mixel combo PHY
> found in i.MX8qxp:
> https://www.spinics.net/lists/arm-kernel/msg879957.html
>
> v5->v6:
> * No change.
>
> v4->v5:
> * Link with the imx-ldb-helper object. (Robert)
> * Correspondingly, rename 'imx8qxp-ldb.c' to 'imx8qxp-ldb-drv.c'.
>
> v3->v4:
> * No change.
>
> v2->v3:
> * No change.
>
> v1->v2:
> * Drop unnecessary DT validation.
> * Use of_graph_get_endpoint_by_regs() and of_graph_get_remote_endpoint() to
> get the input remote endpoint in imx8qxp_ldb_set_di_id().
> * Avoid using companion_port OF node after putting it in
> imx8qxp_ldb_parse_dt_companion().
> * Mention i.MX8qxp LDB official name 'pixel mapper' in the bridge driver
> and Kconfig help message.
>
> drivers/gpu/drm/bridge/imx/Kconfig | 9 +
> drivers/gpu/drm/bridge/imx/Makefile | 3 +
> drivers/gpu/drm/bridge/imx/imx8qxp-ldb-drv.c | 720 +++++++++++++++++++++++++++
> 3 files changed, 732 insertions(+)
> create mode 100644 drivers/gpu/drm/bridge/imx/imx8qxp-ldb-drv.c
>
> diff --git a/drivers/gpu/drm/bridge/imx/Kconfig b/drivers/gpu/drm/bridge/imx/Kconfig
> index 1ea1ce7..94f8db4d 100644
> --- a/drivers/gpu/drm/bridge/imx/Kconfig
> +++ b/drivers/gpu/drm/bridge/imx/Kconfig
> @@ -1,3 +1,12 @@
> +config DRM_IMX8QXP_LDB
> + tristate "Freescale i.MX8QXP LVDS display bridge"
> + depends on OF
> + depends on COMMON_CLK
> + select DRM_KMS_HELPER
> + help
> + Choose this to enable the internal LVDS Display Bridge(LDB) found in
> + Freescale i.MX8qxp processor. Official name of LDB is pixel mapper.
> +
> 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..96d5d1e 100644
> --- a/drivers/gpu/drm/bridge/imx/Makefile
> +++ b/drivers/gpu/drm/bridge/imx/Makefile
> @@ -1,3 +1,6 @@
> +imx8qxp-ldb-objs := imx-ldb-helper.o imx8qxp-ldb-drv.o
> +obj-$(CONFIG_DRM_IMX8QXP_LDB) += imx8qxp-ldb.o
> +
> obj-$(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/imx8qxp-ldb-drv.c b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb-drv.c
> new file mode 100644
> index 00000000..d7f59c1
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb-drv.c
> @@ -0,0 +1,720 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +/*
> + * Copyright 2020 NXP
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_graph.h>
> +#include <linux/phy/phy.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +
> +#include <drm/drm_atomic_state_helper.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_connector.h>
> +#include <drm/drm_fourcc.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_print.h>
> +
> +#include "imx-ldb-helper.h"
> +
> +#define LDB_CH_SEL (1 << 28)
> +
> +#define SS_CTRL 0x20
> +#define CH_HSYNC_M(id) BIT(0 + ((id) * 2))
> +#define CH_VSYNC_M(id) BIT(1 + ((id) * 2))
> +#define CH_PHSYNC(id) BIT(0 + ((id) * 2))
> +#define CH_PVSYNC(id) BIT(1 + ((id) * 2))
> +
> +#define DRIVER_NAME "imx8qxp-ldb"
> +
> +struct imx8qxp_ldb_channel {
> + struct ldb_channel base;
> + struct phy *phy;
> + unsigned int di_id;
> +};
> +
> +struct imx8qxp_ldb {
> + struct ldb base;
> + struct device *dev;
> + struct imx8qxp_ldb_channel channel[MAX_LDB_CHAN_NUM];
> + struct clk *clk_pixel;
> + struct clk *clk_bypass;
> + struct drm_bridge *companion;
> + int active_chno;
> +};
> +
> +static inline struct imx8qxp_ldb_channel *
> +base_to_imx8qxp_ldb_channel(struct ldb_channel *base)
> +{
> + return container_of(base, struct imx8qxp_ldb_channel, base);
> +}
> +
> +static inline struct imx8qxp_ldb *base_to_imx8qxp_ldb(struct ldb *base)
> +{
> + return container_of(base, struct imx8qxp_ldb, base);
> +}
> +
> +static void imx8qxp_ldb_set_phy_cfg(struct imx8qxp_ldb *imx8qxp_ldb,
> + unsigned long di_clk, bool is_split,
> + struct phy_configure_opts_lvds *phy_cfg)
> +{
> + phy_cfg->bits_per_lane_and_dclk_cycle = 7;
> + phy_cfg->lanes = 4;
> +
> + if (is_split) {
> + phy_cfg->differential_clk_rate = di_clk / 2;
> + phy_cfg->is_slave = !imx8qxp_ldb->companion;
> + } else {
> + phy_cfg->differential_clk_rate = di_clk;
> + phy_cfg->is_slave = false;
> + }
> +}
> +
> +static int imx8qxp_ldb_bridge_atomic_check(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;
> + struct ldb *ldb = ldb_ch->ldb;
> + struct imx8qxp_ldb_channel *imx8qxp_ldb_ch =
> + base_to_imx8qxp_ldb_channel(ldb_ch);
> + struct imx8qxp_ldb *imx8qxp_ldb = base_to_imx8qxp_ldb(ldb);
> + struct drm_bridge *companion = imx8qxp_ldb->companion;
> + struct drm_display_mode *adj = &crtc_state->adjusted_mode;
> + unsigned long di_clk = adj->clock * 1000;
> + bool is_split = ldb_channel_is_split_link(ldb_ch);
> + union phy_configure_opts opts = { };
> + struct phy_configure_opts_lvds *phy_cfg = &opts.lvds;
> + int ret;
> +
> + ret = ldb_bridge_atomic_check_helper(bridge, bridge_state,
> + crtc_state, conn_state);
> + if (ret)
> + return ret;
> +
> + imx8qxp_ldb_set_phy_cfg(imx8qxp_ldb, di_clk, is_split, phy_cfg);
> + ret = phy_validate(imx8qxp_ldb_ch->phy, PHY_MODE_LVDS, 0, &opts);
> + if (ret < 0) {
> + DRM_DEV_DEBUG_DRIVER(imx8qxp_ldb->dev,
> + "failed to validate PHY: %d\n", ret);
> + return ret;
> + }
> +
> + if (is_split && companion) {
> + ret = companion->funcs->atomic_check(companion,
> + bridge_state, crtc_state, conn_state);
> + if (ret)
> + return ret;
> + }
> +
> + return ret;
> +}
> +
> +static void
> +imx8qxp_ldb_bridge_mode_set(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_channel *companion_ldb_ch;
> + struct ldb *ldb = ldb_ch->ldb;
> + struct imx8qxp_ldb_channel *imx8qxp_ldb_ch =
> + base_to_imx8qxp_ldb_channel(ldb_ch);
> + struct imx8qxp_ldb *imx8qxp_ldb = base_to_imx8qxp_ldb(ldb);
> + struct drm_bridge *companion = imx8qxp_ldb->companion;
> + struct device *dev = imx8qxp_ldb->dev;
> + unsigned long di_clk = adjusted_mode->clock * 1000;
> + bool is_split = ldb_channel_is_split_link(ldb_ch);
> + union phy_configure_opts opts = { };
> + struct phy_configure_opts_lvds *phy_cfg = &opts.lvds;
> + u32 chno = ldb_ch->chno;
> + int ret;
> +
> + ret = pm_runtime_get_sync(dev);
> + if (ret < 0)
> + DRM_DEV_ERROR(dev, "failed to get runtime PM sync: %d\n", ret);
> +
> + ret = phy_init(imx8qxp_ldb_ch->phy);
> + if (ret < 0)
> + DRM_DEV_ERROR(dev, "failed to initialize PHY: %d\n", ret);
> +
> + ret = phy_set_mode(imx8qxp_ldb_ch->phy, PHY_MODE_LVDS);
> + if (ret < 0)
> + DRM_DEV_ERROR(dev, "failed to set PHY mode: %d\n", ret);
> +
> + if (is_split && companion) {
> + companion_ldb_ch = bridge_to_ldb_ch(companion);
> +
> + companion_ldb_ch->in_bus_format = ldb_ch->in_bus_format;
> + companion_ldb_ch->out_bus_format = ldb_ch->out_bus_format;
> + }
> +
> + clk_set_rate(imx8qxp_ldb->clk_bypass, di_clk);
> + clk_set_rate(imx8qxp_ldb->clk_pixel, di_clk);
> +
> + imx8qxp_ldb_set_phy_cfg(imx8qxp_ldb, di_clk, is_split, phy_cfg);
> + ret = phy_configure(imx8qxp_ldb_ch->phy, &opts);
> + if (ret < 0)
> + DRM_DEV_ERROR(dev, "failed to configure PHY: %d\n", ret);
> +
> + if (chno == 0)
> + ldb->ldb_ctrl &= ~LDB_CH_SEL;
> + else
> + ldb->ldb_ctrl |= LDB_CH_SEL;
> +
> + /* input VSYNC signal from pixel link is active low */
> + if (imx8qxp_ldb_ch->di_id == 0)
> + ldb->ldb_ctrl |= LDB_DI0_VS_POL_ACT_LOW;
> + else
> + ldb->ldb_ctrl |= LDB_DI1_VS_POL_ACT_LOW;
> +
> + /*
> + * For split mode, settle input VSYNC signal polarity and
> + * channel selection down early.
> + */
> + if (is_split)
> + regmap_write(ldb->regmap, ldb->ctrl_reg, ldb->ldb_ctrl);
> +
> + ldb_bridge_mode_set_helper(bridge, mode, adjusted_mode);
> +
> + if (adjusted_mode->flags & DRM_MODE_FLAG_NVSYNC)
> + regmap_update_bits(ldb->regmap, SS_CTRL, CH_VSYNC_M(chno), 0);
> + else if (adjusted_mode->flags & DRM_MODE_FLAG_PVSYNC)
> + regmap_update_bits(ldb->regmap, SS_CTRL,
> + CH_VSYNC_M(chno), CH_PVSYNC(chno));
> +
> + if (adjusted_mode->flags & DRM_MODE_FLAG_NHSYNC)
> + regmap_update_bits(ldb->regmap, SS_CTRL, CH_HSYNC_M(chno), 0);
> + else if (adjusted_mode->flags & DRM_MODE_FLAG_PHSYNC)
> + regmap_update_bits(ldb->regmap, SS_CTRL,
> + CH_HSYNC_M(chno), CH_PHSYNC(chno));
> +
> + if (is_split && companion)
> + companion->funcs->mode_set(companion, mode, adjusted_mode);
> +}
> +
> +static void
> +imx8qxp_ldb_bridge_atomic_pre_enable(struct drm_bridge *bridge,
> + struct drm_bridge_state *old_bridge_state)
> +{
> + struct ldb_channel *ldb_ch = bridge->driver_private;
> + struct ldb *ldb = ldb_ch->ldb;
> + struct imx8qxp_ldb *imx8qxp_ldb = base_to_imx8qxp_ldb(ldb);
> + struct drm_bridge *companion = imx8qxp_ldb->companion;
> + bool is_split = ldb_channel_is_split_link(ldb_ch);
> +
> + clk_prepare_enable(imx8qxp_ldb->clk_pixel);
> + clk_prepare_enable(imx8qxp_ldb->clk_bypass);
> +
> + if (is_split && companion)
> + companion->funcs->atomic_pre_enable(companion, old_bridge_state);
> +}
> +
> +static void
> +imx8qxp_ldb_bridge_atomic_enable(struct drm_bridge *bridge,
> + struct drm_bridge_state *old_bridge_state)
> +{
> + struct ldb_channel *ldb_ch = bridge->driver_private;
> + struct ldb *ldb = ldb_ch->ldb;
> + struct imx8qxp_ldb_channel *imx8qxp_ldb_ch =
> + base_to_imx8qxp_ldb_channel(ldb_ch);
> + struct imx8qxp_ldb *imx8qxp_ldb = base_to_imx8qxp_ldb(ldb);
> + struct drm_bridge *companion = imx8qxp_ldb->companion;
> + struct device *dev = imx8qxp_ldb->dev;
> + bool is_split = ldb_channel_is_split_link(ldb_ch);
> + int ret;
> +
> + if (ldb_ch->chno == 0 || is_split) {
> + ldb->ldb_ctrl &= ~LDB_CH0_MODE_EN_MASK;
> + ldb->ldb_ctrl |= imx8qxp_ldb_ch->di_id == 0 ?
> + LDB_CH0_MODE_EN_TO_DI0 : LDB_CH0_MODE_EN_TO_DI1;
> + }
> + if (ldb_ch->chno == 1 || is_split) {
> + ldb->ldb_ctrl &= ~LDB_CH1_MODE_EN_MASK;
> + ldb->ldb_ctrl |= imx8qxp_ldb_ch->di_id == 0 ?
> + LDB_CH1_MODE_EN_TO_DI0 : LDB_CH1_MODE_EN_TO_DI1;
> + }
> +
> + ldb_bridge_enable_helper(bridge);
> +
> + ret = phy_power_on(imx8qxp_ldb_ch->phy);
> + if (ret)
> + DRM_DEV_ERROR(dev, "failed to power on PHY: %d\n", ret);
> +
> + if (is_split && companion)
> + companion->funcs->atomic_enable(companion, old_bridge_state);
> +}
> +
> +static void
> +imx8qxp_ldb_bridge_atomic_disable(struct drm_bridge *bridge,
> + struct drm_bridge_state *old_bridge_state)
> +{
> + struct ldb_channel *ldb_ch = bridge->driver_private;
> + struct ldb *ldb = ldb_ch->ldb;
> + struct imx8qxp_ldb_channel *imx8qxp_ldb_ch =
> + base_to_imx8qxp_ldb_channel(ldb_ch);
> + struct imx8qxp_ldb *imx8qxp_ldb = base_to_imx8qxp_ldb(ldb);
> + struct drm_bridge *companion = imx8qxp_ldb->companion;
> + struct device *dev = imx8qxp_ldb->dev;
> + bool is_split = ldb_channel_is_split_link(ldb_ch);
> + int ret;
> +
> + ret = phy_power_off(imx8qxp_ldb_ch->phy);
> + if (ret)
> + DRM_DEV_ERROR(dev, "failed to power off PHY: %d\n", ret);
> +
> + ret = phy_exit(imx8qxp_ldb_ch->phy);
> + if (ret < 0)
> + DRM_DEV_ERROR(dev, "failed to teardown PHY: %d\n", ret);
> +
> + ldb_bridge_disable_helper(bridge);
> +
> + clk_disable_unprepare(imx8qxp_ldb->clk_bypass);
> + clk_disable_unprepare(imx8qxp_ldb->clk_pixel);
> +
> + if (is_split && companion)
> + companion->funcs->atomic_disable(companion, old_bridge_state);
> +
> + ret = pm_runtime_put(dev);
> + if (ret < 0)
> + DRM_DEV_ERROR(dev, "failed to put runtime PM: %d\n", ret);
> +}
> +
> +static const u32 imx8qxp_ldb_bus_output_fmts[] = {
> + MEDIA_BUS_FMT_RGB666_1X7X3_SPWG,
> + MEDIA_BUS_FMT_RGB888_1X7X4_SPWG,
> + MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA,
> + MEDIA_BUS_FMT_FIXED,
> +};
> +
> +static bool imx8qxp_ldb_bus_output_fmt_supported(u32 fmt)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(imx8qxp_ldb_bus_output_fmts); i++) {
> + if (imx8qxp_ldb_bus_output_fmts[i] == fmt)
> + return true;
> + }
> +
> + return false;
> +}
> +
> +static u32 *
> +imx8qxp_ldb_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> + struct drm_bridge_state *bridge_state,
> + struct drm_crtc_state *crtc_state,
> + struct drm_connector_state *conn_state,
> + u32 output_fmt,
> + unsigned int *num_input_fmts)
> +{
> + struct drm_display_info *di;
> + const struct drm_format_info *finfo;
> + u32 *input_fmts;
> +
> + if (!imx8qxp_ldb_bus_output_fmt_supported(output_fmt))
> + return NULL;
> +
> + *num_input_fmts = 1;
> +
> + input_fmts = kmalloc(sizeof(*input_fmts), GFP_KERNEL);
> + if (!input_fmts)
> + return NULL;
> +
> + switch (output_fmt) {
> + case MEDIA_BUS_FMT_FIXED:
> + di = &conn_state->connector->display_info;
> +
> + /*
> + * Look at the first bus format to determine input format.
> + * Default to MEDIA_BUS_FMT_RGB888_1X24, if no match.
> + */
> + if (di->num_bus_formats) {
> + finfo = drm_format_info(di->bus_formats[0]);
> +
> + input_fmts[0] = finfo->depth == 18 ?
> + MEDIA_BUS_FMT_RGB666_1X24_CPADHI :
> + MEDIA_BUS_FMT_RGB888_1X24;
> + } else {
> + input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> + }
> + break;
> + case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
> + input_fmts[0] = MEDIA_BUS_FMT_RGB666_1X24_CPADHI;
> + break;
> + case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
> + case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
> + input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> + break;
> + default:
> + kfree(input_fmts);
> + input_fmts = NULL;
> + break;
> + }
> +
> + return input_fmts;
> +}
> +
> +static u32 *
> +imx8qxp_ldb_bridge_atomic_get_output_bus_fmts(struct drm_bridge *bridge,
> + struct drm_bridge_state *bridge_state,
> + struct drm_crtc_state *crtc_state,
> + struct drm_connector_state *conn_state,
> + unsigned int *num_output_fmts)
> +{
> + *num_output_fmts = ARRAY_SIZE(imx8qxp_ldb_bus_output_fmts);
> + return kmemdup(imx8qxp_ldb_bus_output_fmts,
> + sizeof(imx8qxp_ldb_bus_output_fmts), GFP_KERNEL);
> +}
> +
> +static enum drm_mode_status
> +imx8qxp_ldb_bridge_mode_valid(struct drm_bridge *bridge,
> + const struct drm_display_info *info,
> + const struct drm_display_mode *mode)
> +{
> + struct ldb_channel *ldb_ch = bridge->driver_private;
> + bool is_single = ldb_channel_is_single_link(ldb_ch);
> +
> + if (mode->clock > 170000)
> + return MODE_CLOCK_HIGH;
> +
> + if (mode->clock > 150000 && is_single)
> + return MODE_CLOCK_HIGH;
> +
> + return MODE_OK;
> +}
> +
> +static const struct drm_bridge_funcs imx8qxp_ldb_bridge_funcs = {
> + .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> + .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> + .atomic_reset = drm_atomic_helper_bridge_reset,
> + .mode_valid = imx8qxp_ldb_bridge_mode_valid,
> + .attach = ldb_bridge_attach_helper,
> + .atomic_check = imx8qxp_ldb_bridge_atomic_check,
> + .mode_set = imx8qxp_ldb_bridge_mode_set,
> + .atomic_pre_enable = imx8qxp_ldb_bridge_atomic_pre_enable,
> + .atomic_enable = imx8qxp_ldb_bridge_atomic_enable,
> + .atomic_disable = imx8qxp_ldb_bridge_atomic_disable,
> + .atomic_get_input_bus_fmts =
> + imx8qxp_ldb_bridge_atomic_get_input_bus_fmts,
> + .atomic_get_output_bus_fmts =
> + imx8qxp_ldb_bridge_atomic_get_output_bus_fmts,
> +};
> +
> +static int imx8qxp_ldb_set_di_id(struct imx8qxp_ldb *imx8qxp_ldb)
> +{
> + struct imx8qxp_ldb_channel *imx8qxp_ldb_ch =
> + &imx8qxp_ldb->channel[imx8qxp_ldb->active_chno];
> + struct ldb_channel *ldb_ch = &imx8qxp_ldb_ch->base;
> + struct device_node *ep, *remote;
> + struct device *dev = imx8qxp_ldb->dev;
> + struct of_endpoint endpoint;
> + int ret;
> +
> + ep = of_graph_get_endpoint_by_regs(ldb_ch->np, 0, -1);
> + if (!ep) {
> + DRM_DEV_ERROR(dev, "failed to get port0 endpoint\n");
> + return -EINVAL;
> + }
> +
> + remote = of_graph_get_remote_endpoint(ep);
> + of_node_put(ep);
> + if (!remote) {
> + DRM_DEV_ERROR(dev, "failed to get port0 remote endpoint\n");
> + return -EINVAL;
> + }
> +
> + ret = of_graph_parse_endpoint(remote, &endpoint);
> + of_node_put(remote);
> + if (ret) {
> + DRM_DEV_ERROR(dev, "failed to parse port0 remote endpoint: %d\n",
> + ret);
> + return ret;
> + }
> +
> + imx8qxp_ldb_ch->di_id = endpoint.id;
> +
> + return 0;
> +}
> +
> +static int
> +imx8qxp_ldb_check_chno_and_dual_link(struct ldb_channel *ldb_ch, int link)
> +{
> + if ((link == DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS && ldb_ch->chno != 0) ||
> + (link == DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS && ldb_ch->chno != 1))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static int imx8qxp_ldb_parse_dt_companion(struct imx8qxp_ldb *imx8qxp_ldb)
> +{
> + struct imx8qxp_ldb_channel *imx8qxp_ldb_ch =
> + &imx8qxp_ldb->channel[imx8qxp_ldb->active_chno];
> + struct ldb_channel *ldb_ch = &imx8qxp_ldb_ch->base;
> + struct ldb_channel *companion_ldb_ch;
> + struct device_node *companion;
> + struct device_node *child;
> + struct device_node *companion_port = NULL;
> + struct device_node *port1, *port2;
> + struct device *dev = imx8qxp_ldb->dev;
> + const struct of_device_id *match;
> + u32 i;
> + int dual_link;
> + int ret;
> +
> + /* Locate the companion LDB for dual-link operation, if any. */
> + companion = of_parse_phandle(dev->of_node, "fsl,companion-ldb", 0);
> + if (!companion)
> + return 0;
> +
> + if (!of_device_is_available(companion)) {
> + DRM_DEV_ERROR(dev, "companion LDB is not available\n");
> + ret = -ENODEV;
> + goto out;
> + }
> +
> + /*
> + * Sanity check: the companion bridge must have the same compatible
> + * string.
> + */
> + match = of_match_device(dev->driver->of_match_table, dev);
> + if (!of_device_is_compatible(companion, match->compatible)) {
> + DRM_DEV_ERROR(dev, "companion LDB is incompatible\n");
> + ret = -ENXIO;
> + goto out;
> + }
> +
> + for_each_available_child_of_node(companion, child) {
> + ret = of_property_read_u32(child, "reg", &i);
> + if (ret || i > MAX_LDB_CHAN_NUM - 1) {
> + DRM_DEV_ERROR(dev,
> + "invalid channel node address: %u\n", i);
> + ret = -EINVAL;
> + of_node_put(child);
> + goto out;
> + }
> +
> + /*
> + * Channel numbers have to be different, because channel0
> + * transmits odd pixels and channel1 transmits even pixels.
> + */
> + if (i == (ldb_ch->chno ^ 0x1)) {
> + companion_port = child;
> + break;
> + }
> + }
> +
> + if (companion_port == NULL) {
> + DRM_DEV_ERROR(dev,
> + "failed to find companion LDB channel port\n");
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + /*
> + * We need to work out if the sink is expecting us to function in
> + * dual-link mode. We do this by looking at the DT port nodes we are
> + * connected to. If they are marked as expecting odd pixels and
> + * even pixels than we need to enable LDB split mode.
> + */
> + port1 = of_graph_get_port_by_id(ldb_ch->np, 1);
> + port2 = of_graph_get_port_by_id(companion_port, 1);
> + dual_link = drm_of_lvds_get_dual_link_pixel_order(port1, port2);
> + of_node_put(port1);
> + of_node_put(port2);
> +
> + switch (dual_link) {
> + case DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS:
> + ldb_ch->link_type = LDB_CH_DUAL_LINK_ODD_EVEN_PIXELS;
> + break;
> + case DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS:
> + ldb_ch->link_type = LDB_CH_DUAL_LINK_EVEN_ODD_PIXELS;
> + break;
> + default:
> + ret = dual_link;
> + DRM_DEV_ERROR(dev,
> + "failed to get dual link pixel order: %d\n", ret);
> + goto out;
> + }
> +
> + ret = imx8qxp_ldb_check_chno_and_dual_link(ldb_ch, dual_link);
> + if (ret < 0) {
> + DRM_DEV_ERROR(dev,
> + "unmatched channel number(%u) vs dual link(%d)\n",
> + ldb_ch->chno, dual_link);
> + goto out;
> + }
> +
> + imx8qxp_ldb->companion = of_drm_find_bridge(companion_port);
> + if (!imx8qxp_ldb->companion) {
> + ret = -EPROBE_DEFER;
> + DRM_DEV_DEBUG_DRIVER(dev,
> + "failed to find bridge for companion bridge: %d\n", ret);
> + goto out;
> + }
> +
> + DRM_DEV_DEBUG_DRIVER(dev,
> + "dual-link configuration detected (companion bridge %pOF)\n",
> + companion);
> +
> + companion_ldb_ch = bridge_to_ldb_ch(imx8qxp_ldb->companion);
> + companion_ldb_ch->link_type = ldb_ch->link_type;
> +out:
> + of_node_put(companion_port);
> + of_node_put(companion);
> + return ret;
> +}
> +
> +static int imx8qxp_ldb_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct imx8qxp_ldb *imx8qxp_ldb;
> + struct imx8qxp_ldb_channel *imx8qxp_ldb_ch;
> + struct ldb *ldb;
> + struct ldb_channel *ldb_ch;
> + int ret, i;
> +
> + imx8qxp_ldb = devm_kzalloc(dev, sizeof(*imx8qxp_ldb), GFP_KERNEL);
> + if (!imx8qxp_ldb)
> + return -ENOMEM;
> +
> + imx8qxp_ldb->clk_pixel = devm_clk_get(dev, "pixel");
> + if (IS_ERR(imx8qxp_ldb->clk_pixel)) {
> + ret = PTR_ERR(imx8qxp_ldb->clk_pixel);
> + if (ret != -EPROBE_DEFER)
> + DRM_DEV_ERROR(dev,
> + "failed to get pixel clock: %d\n", ret);
> + return ret;
> + }
> +
> + imx8qxp_ldb->clk_bypass = devm_clk_get(dev, "bypass");
> + if (IS_ERR(imx8qxp_ldb->clk_bypass)) {
> + ret = PTR_ERR(imx8qxp_ldb->clk_bypass);
> + if (ret != -EPROBE_DEFER)
> + DRM_DEV_ERROR(dev,
> + "failed to get bypass clock: %d\n", ret);
> + return ret;
> + }
> +
> + imx8qxp_ldb->dev = dev;
> +
> + ldb = &imx8qxp_ldb->base;
> + ldb->dev = dev;
> + ldb->ctrl_reg = 0xe0;
> +
> + for (i = 0; i < MAX_LDB_CHAN_NUM; i++)
> + ldb->channel[i] = &imx8qxp_ldb->channel[i].base;
> +
> + ret = ldb_init_helper(ldb);
> + if (ret)
> + return ret;
> +
> + if (ldb->available_ch_cnt == 0) {
> + DRM_DEV_DEBUG_DRIVER(dev, "no available channel\n");
> + return 0;
> + } else if (ldb->available_ch_cnt > 1) {
> + DRM_DEV_ERROR(dev, "invalid available channel number(%u)\n",
> + ldb->available_ch_cnt);
> + return -ENOTSUPP;
> + }
WARNING: ENOTSUPP is not a SUSV4 error code, prefer EOPNOTSUPP
#683: FILE: drivers/gpu/drm/bridge/imx/imx8qxp-ldb-drv.c:625:
+ return -ENOTSUPP;
Maybe -EINVAL is a better return value.
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