[PATCH v2 2/3] drm/bridge: anx7625: Support reading edid through aux channel

From: Hsin-Yi Wang
Date: Thu Jan 13 2022 - 02:32:15 EST


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>
---
v1->v2: Fix cmd for native read/write.

This patch is based on drm-misc-next and depends on
https://patchwork.freedesktop.org/patch/469081/
---
drivers/gpu/drm/bridge/analogix/anx7625.c | 127 +++++++++++++++++++---
drivers/gpu/drm/bridge/analogix/anx7625.h | 4 +
2 files changed, 113 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index dbe708eb3bcf11..24665bb93f9244 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>
#include <drm/drm_dp_helper.h>
#include <drm/drm_edid.h>
#include <drm/drm_hdcp.h>
@@ -231,19 +232,22 @@ 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;

- 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 +266,7 @@ 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 == DPCD_WRITE)
+ if (op == DPCD_WRITE || op == AP_AUX_WRITE)
ret |= anx7625_reg_block_write(ctx, ctx->i2c.rx_p0_client,
AP_AUX_BUFF_START, len, buf);
/* Enable aux access */
@@ -275,14 +279,14 @@ 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 == DPCD_WRITE)
- return 0;
+ if (op == DPCD_WRITE || op == AP_AUX_WRITE)
+ return len;

/* Read done, read out dpcd data */
ret = anx7625_reg_block_read(ctx, ctx->i2c.rx_p0_client,
@@ -292,7 +296,7 @@ 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 +871,7 @@ static int anx7625_hdcp_enable(struct anx7625_data *ctx)
}

/* Read downstream capability */
- anx7625_aux_dpcd_trans(ctx, DPCD_READ, 0x68028, 1, &bcap);
+ anx7625_aux_trans(ctx, DPCD_READ, 0x68028, 1, &bcap);
if (!(bcap & 0x01)) {
pr_warn("downstream not support HDCP 1.4, cap(%x).\n", bcap);
return 0;
@@ -956,7 +960,7 @@ 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, DPCD_WRITE, 0x000600, 1, &data);
+ ret |= anx7625_aux_trans(ctx, DPCD_WRITE, 0x000600, 1, &data);
if (ret < 0)
DRM_DEV_ERROR(dev, "IO error : mute video fail\n");

@@ -1655,11 +1659,64 @@ 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)
+{
+ 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, op;
+ int ret = 0;
+
+ pm_runtime_get_sync(dev);
+ msg->reply = 0;
+ switch (request) {
+ case DP_AUX_NATIVE_WRITE:
+ op = DPCD_WRITE;
+ break;
+ case DP_AUX_I2C_WRITE:
+ op = AP_AUX_WRITE;
+ break;
+ case DP_AUX_NATIVE_READ:
+ op = DPCD_READ;
+ break;
+ case DP_AUX_I2C_READ:
+ op = AP_AUX_READ;
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ if (!ret) {
+ ret = anx7625_aux_trans(ctx, op, 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 +2123,13 @@ 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 +2143,13 @@ 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 +2415,7 @@ 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 +2573,12 @@ 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 +2601,6 @@ 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 +2648,19 @@ 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 +2668,12 @@ 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 +2686,8 @@ 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 56165f5b254c14..cab19735c22e21 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.h
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
@@ -231,6 +231,9 @@
#define AP_AUX_ADDR_15_8 0x12
#define AP_AUX_ADDR_19_16 0x13

+#define AP_AUX_READ 0x1
+#define AP_AUX_WRITE 0x4
+
/* Bit[0:3] AUX status, bit 4 op_en, bit 5 address only */
#define AP_AUX_CTRL_STATUS 0x14
#define AP_AUX_CTRL_OP_EN 0x10
@@ -474,6 +477,7 @@ struct anx7625_data {
u8 bridge_attached;
struct drm_connector *connector;
struct mipi_dsi_device *dsi;
+ struct drm_dp_aux aux;
};

#endif /* __ANX7625_H__ */
--
2.34.1.575.g55b058a8bb-goog