Re: [PATCH v4 3/4] drm/bridge: anx7625: Support reading edid through aux channel

From: Robert Foss
Date: Wed Jan 19 2022 - 10:08:22 EST

On Tue, 18 Jan 2022 at 10:20, Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx> wrote:
>
> Support reading edid through aux channel if panel is connected to aux
> bus. Extend anx7625_aux_dpcd_trans() to implement aux transfer function:
>
> 1. panel is populated in devm_of_dp_aux_populate_ep_devices(), so move
> anx7625_parse_dt() after.
> 2. Use pm runtime autosuspend since aux transfer function is called
> multiple times when reading edid.
> 3. No-op if aux transfer length is 0.
>
> Signed-off-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
> Reviewed-by: Xin Ji <xji@xxxxxxxxxxxxxxxx>
> ---
> v3->v4:
> rebase to latest drm-misc-next
> ---
> drivers/gpu/drm/bridge/analogix/anx7625.c | 120 ++++++++++++++++++----
> drivers/gpu/drm/bridge/analogix/anx7625.h | 1 +
> 2 files changed, 103 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index b7e3373994b480..50b9c98277f0d7 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -24,6 +24,7 @@
> #include <drm/drm_atomic_helper.h>
> #include <drm/drm_bridge.h>
> #include <drm/drm_crtc_helper.h>
> +#include <drm/drm_dp_aux_bus.h>

drivers/gpu/drm/bridge/analogix/anx7625.c:27:10: fatal error:
drm/drm_dp_aux_bus.h: No such file or directory
27 | #include <drm/drm_dp_aux_bus.h>

drm/dp/rm_dp_aux_bus.h is probably the correct path.

> #include <drm/dp/drm_dp_helper.h>
> #include <drm/drm_edid.h>
> #include <drm/drm_hdcp.h>
> @@ -231,19 +232,23 @@ static int wait_aux_op_finish(struct anx7625_data *ctx)
> return 0;
> }
>
> -static int anx7625_aux_dpcd_trans(struct anx7625_data *ctx, u8 op,
> - u32 address, u8 len, u8 *buf)
> +static int anx7625_aux_trans(struct anx7625_data *ctx, u8 op, u32 address,
> + u8 len, u8 *buf)
> {
> struct device *dev = &ctx->client->dev;
> int ret;
> u8 addrh, addrm, addrl;
> u8 cmd;
> + bool is_write = !(op & DP_AUX_I2C_READ);
>
> - if (len > MAX_DPCD_BUFFER_SIZE) {
> + if (len > DP_AUX_MAX_PAYLOAD_BYTES) {
> dev_err(dev, "exceed aux buffer len.\n");
> return -EINVAL;
> }
>
> + if (!len)
> + return len;
> +
> addrl = address & 0xFF;
> addrm = (address >> 8) & 0xFF;
> addrh = (address >> 16) & 0xFF;
> @@ -262,7 +267,7 @@ static int anx7625_aux_dpcd_trans(struct anx7625_data *ctx, u8 op,
> ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client,
> AP_AUX_ADDR_19_16, addrh);
>
> - if (op == DP_AUX_NATIVE_WRITE)
> + if (is_write)
> ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p0_client,
> AP_AUX_BUFF_START, len, buf);
> /* Enable aux access */
> @@ -275,14 +280,14 @@ static int anx7625_aux_dpcd_trans(struct anx7625_data *ctx, u8 op,
> }
>
> ret = wait_aux_op_finish(ctx);
> - if (ret) {
> + if (ret < 0) {
> dev_err(dev, "aux IO error: wait aux op finish.\n");
> return ret;
> }
>
> /* Write done */
> - if (op == DP_AUX_NATIVE_WRITE)
> - return 0;
> + if (is_write)
> + return len;
>
> /* Read done, read out dpcd data */
> ret = anx7625_reg_block_read(ctx, ctx->i2c.rx_p0_client,
> @@ -292,7 +297,7 @@ static int anx7625_aux_dpcd_trans(struct anx7625_data *ctx, u8 op,
> return -EIO;
> }
>
> - return 0;
> + return len;
> }
>
> static int anx7625_video_mute_control(struct anx7625_data *ctx,
> @@ -867,7 +872,7 @@ static int anx7625_hdcp_enable(struct anx7625_data *ctx)
> }
>
> /* Read downstream capability */
> - anx7625_aux_dpcd_trans(ctx, DP_AUX_NATIVE_READ, 0x68028, 1, &bcap);
> + anx7625_aux_trans(ctx, DP_AUX_NATIVE_READ, 0x68028, 1, &bcap);
> if (!(bcap & 0x01)) {
> pr_warn("downstream not support HDCP 1.4, cap(%x).\n", bcap);
> return 0;
> @@ -956,7 +961,7 @@ static void anx7625_dp_stop(struct anx7625_data *ctx)
> dev_dbg(dev, "notify downstream enter into standby\n");
> /* Downstream monitor enter into standby mode */
> data = 2;
> - ret |= anx7625_aux_dpcd_trans(ctx, DP_AUX_NATIVE_WRITE, 0x000600, 1, &data);
> + ret |= anx7625_aux_trans(ctx, DP_AUX_NATIVE_WRITE, 0x000600, 1, &data);
> if (ret < 0)
> DRM_DEV_ERROR(dev, "IO error : mute video fail\n");
>
> @@ -1655,11 +1660,56 @@ static int anx7625_parse_dt(struct device *dev,
> return 0;
> }
>
> +static bool anx7625_of_panel_on_aux_bus(struct device *dev)
> +{
> + struct device_node *bus, *panel;
> +
> + bus = of_get_child_by_name(dev->of_node, "aux-bus");
> + if (!bus)
> + return false;
> +
> + panel = of_get_child_by_name(bus, "panel");
> + of_node_put(bus);
> + if (!panel)
> + return false;
> + of_node_put(panel);
> +
> + return true;
> +}
> +
> static inline struct anx7625_data *bridge_to_anx7625(struct drm_bridge *bridge)
> {
> return container_of(bridge, struct anx7625_data, bridge);
> }
>
> +static ssize_t anx7625_aux_transfer(struct drm_dp_aux *aux,
> + struct drm_dp_aux_msg *msg)

checkpatch --strict is unhappy about the above line not using as many
tabs as possible.

> +{
> + struct anx7625_data *ctx = container_of(aux, struct anx7625_data, aux);
> + struct device *dev = &ctx->client->dev;
> + u8 request = msg->request & ~DP_AUX_I2C_MOT;
> + int ret = 0;
> +
> + pm_runtime_get_sync(dev);
> + msg->reply = 0;
> + switch (request) {
> + case DP_AUX_NATIVE_WRITE:
> + case DP_AUX_I2C_WRITE:
> + case DP_AUX_NATIVE_READ:
> + case DP_AUX_I2C_READ:
> + break;
> + default:
> + ret = -EINVAL;
> + }
> + if (!ret)
> + ret = anx7625_aux_trans(ctx, msg->request, msg->address,
> + msg->size, msg->buffer);
> + pm_runtime_mark_last_busy(dev);
> + pm_runtime_put_autosuspend(dev);
> +
> + return ret;
> +}
> +
> static struct edid *anx7625_get_edid(struct anx7625_data *ctx)
> {
> struct device *dev = &ctx->client->dev;
> @@ -2066,6 +2116,13 @@ static int anx7625_bridge_attach(struct drm_bridge *bridge,
> return -ENODEV;
> }
>
> + ctx->aux.drm_dev = bridge->dev;
> + err = drm_dp_aux_register(&ctx->aux);
> + if (err) {
> + dev_err(dev, "failed to register aux channel: %d\n", err);
> + return err;
> + }
> +
> if (ctx->pdata.panel_bridge) {
> err = drm_bridge_attach(bridge->encoder,
> ctx->pdata.panel_bridge,
> @@ -2079,6 +2136,13 @@ static int anx7625_bridge_attach(struct drm_bridge *bridge,
> return 0;
> }
>
> +static void anx7625_bridge_detach(struct drm_bridge *bridge)
> +{
> + struct anx7625_data *ctx = bridge_to_anx7625(bridge);
> +
> + drm_dp_aux_unregister(&ctx->aux);
> +}
> +
> static enum drm_mode_status
> anx7625_bridge_mode_valid(struct drm_bridge *bridge,
> const struct drm_display_info *info,
> @@ -2344,6 +2408,7 @@ static struct edid *anx7625_bridge_get_edid(struct drm_bridge *bridge,
>
> static const struct drm_bridge_funcs anx7625_bridge_funcs = {
> .attach = anx7625_bridge_attach,
> + .detach = anx7625_bridge_detach,
> .mode_valid = anx7625_bridge_mode_valid,
> .mode_set = anx7625_bridge_mode_set,
> .atomic_check = anx7625_bridge_atomic_check,
> @@ -2501,6 +2566,12 @@ static const struct dev_pm_ops anx7625_pm_ops = {
> anx7625_runtime_pm_resume, NULL)
> };
>
> +static void anx7625_runtime_disable(void *data)
> +{
> + pm_runtime_dont_use_autosuspend(data);
> + pm_runtime_disable(data);
> +}
> +
> static int anx7625_i2c_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> @@ -2523,13 +2594,6 @@ static int anx7625_i2c_probe(struct i2c_client *client,
>
> pdata = &platform->pdata;
>
> - ret = anx7625_parse_dt(dev, pdata);
> - if (ret) {
> - if (ret != -EPROBE_DEFER)
> - DRM_DEV_ERROR(dev, "fail to parse DT : %d\n", ret);
> - return ret;
> - }
> -
> platform->client = client;
> i2c_set_clientdata(client, platform);
>
> @@ -2577,6 +2641,19 @@ static int anx7625_i2c_probe(struct i2c_client *client,
> }
> }
>
> + platform->aux.name = "anx7625-aux";
> + platform->aux.dev = dev;
> + platform->aux.transfer = anx7625_aux_transfer;
> + drm_dp_aux_init(&platform->aux);
> + devm_of_dp_aux_populate_ep_devices(&platform->aux);
> +
> + ret = anx7625_parse_dt(dev, pdata);
> + if (ret) {
> + if (ret != -EPROBE_DEFER)
> + DRM_DEV_ERROR(dev, "fail to parse DT : %d\n", ret);
> + return ret;
> + }
> +
> if (anx7625_register_i2c_dummy_clients(platform, client) != 0) {
> ret = -ENOMEM;
> DRM_DEV_ERROR(dev, "fail to reserve I2C bus.\n");
> @@ -2584,6 +2661,12 @@ static int anx7625_i2c_probe(struct i2c_client *client,
> }
>
> pm_runtime_enable(dev);
> + pm_runtime_set_autosuspend_delay(dev, 1000);
> + pm_runtime_use_autosuspend(dev);
> + pm_suspend_ignore_children(dev, true);
> + ret = devm_add_action_or_reset(dev, anx7625_runtime_disable, dev);
> + if (ret)
> + return ret;
>
> if (!platform->pdata.low_power_mode) {
> anx7625_disable_pd_protocol(platform);
> @@ -2596,7 +2679,8 @@ static int anx7625_i2c_probe(struct i2c_client *client,
>
> platform->bridge.funcs = &anx7625_bridge_funcs;
> platform->bridge.of_node = client->dev.of_node;
> - platform->bridge.ops = DRM_BRIDGE_OP_EDID;
> + if (!anx7625_of_panel_on_aux_bus(&client->dev))
> + platform->bridge.ops |= DRM_BRIDGE_OP_EDID;
> if (!platform->pdata.panel_bridge)
> platform->bridge.ops |= DRM_BRIDGE_OP_HPD |
> DRM_BRIDGE_OP_DETECT;
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h b/drivers/gpu/drm/bridge/analogix/anx7625.h
> index 64a8ab56529404..edbbfe410a56e8 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> @@ -472,6 +472,7 @@ struct anx7625_data {
> u8 bridge_attached;
> struct drm_connector *connector;
> struct mipi_dsi_device *dsi;
> + struct drm_dp_aux aux;
> };
>
> #endif /* __ANX7625_H__ */
> --
> 2.34.1.703.g22d0c6ccf7-goog
>