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

From: Hsin-Yi Wang
Date: Thu Jan 13 2022 - 02:36:55 EST

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On Thu, Jan 13, 2022 at 11:40 AM Xin Ji <xji@xxxxxxxxxxxxxxxx> wrote:
>
> Hi Hsin-Yi, thanks for the patch! Please fix the follow comment, then
> add my id.
> Reviewed-by: Xin Ji <xji@xxxxxxxxxxxxxxxx>
>
> On Tue, Jan 11, 2022 at 07:27:00PM +0800, Hsin-Yi Wang 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>
> > ---
> > This patch is based on drm-misc-next and depends on
> > https://patchwork.freedesktop.org/patch/469081/
> > ---
> > drivers/gpu/drm/bridge/analogix/anx7625.c | 123 ++++++++++++++++++----
> > drivers/gpu/drm/bridge/analogix/anx7625.h | 4 +
> > 2 files changed, 109 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > index dbe708eb3bcf11..d60cfc058fbe7d 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;
>
> The native write command is 0x08, I2C Over aux write command is 0x04.
> The native read command is 0x09, I2C Over aux read command is 0x05.
Thanks for the review, the command for native read/write is updated.

v2 is sent.

>
> > }
> >
> > + 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 +1659,60 @@ 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:
> > + case DP_AUX_I2C_WRITE:
> > + op = AP_AUX_WRITE;
>
> The DPCD native write is different with I2C over aux write.
>
> > + break;
> > + case DP_AUX_NATIVE_READ:
> > + case DP_AUX_I2C_READ:
> > + op = AP_AUX_READ;
> The DPCD native read is different with I2C over 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 +2119,13 @@ 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 +2139,13 @@ 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 +2411,7 @@ 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 +2569,12 @@ 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 +2597,6 @@ 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 +2644,19 @@ 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 +2664,12 @@ 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 +2682,8 @@ 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

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In reply to: Xin Ji: "Re: [PATCH 2/3] drm/bridge: anx7625: Support reading edid through aux channel"
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