"I2C Master Interface Extended Read Mode" implements a segment pointer-based read operation using the Special Register configuration.
This patch fix https://patchwork.kernel.org/patch/7098101/ mentioned "The current implementation does not support "I2C Master Interface Extended Read Mode" to read data addressed by non-zero segment pointer, this means that if EDID has more than 1 extension blocks" With this patch,dw-hdmi can read EDID data with 1/2/4 blocks. Signed-off-by: Nickey Yang <nickey.y...@rock-chips.com> Reviewed-by: Douglas Anderson <diand...@chromium.org> --- drivers/gpu/drm/bridge/dw-hdmi.c | 38 ++++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c index 9a9ec27..3b93655 100644 --- a/drivers/gpu/drm/bridge/dw-hdmi.c +++ b/drivers/gpu/drm/bridge/dw-hdmi.c @@ -32,6 +32,7 @@ #include "dw-hdmi.h" #include "dw-hdmi-audio.h" +#define DDC_SEGMENT_ADDR 0x30 #define HDMI_EDID_LEN 512 #define RGB 0 @@ -111,6 +112,7 @@ struct dw_hdmi_i2c { u8 slave_reg; bool is_regaddr; + bool is_segment; }; struct dw_hdmi_phy_data { @@ -258,8 +260,12 @@ static int dw_hdmi_i2c_read(struct dw_hdmi *hdmi, reinit_completion(&i2c->cmp); hdmi_writeb(hdmi, i2c->slave_reg++, HDMI_I2CM_ADDRESS); - hdmi_writeb(hdmi, HDMI_I2CM_OPERATION_READ, - HDMI_I2CM_OPERATION); + if (i2c->is_segment) + hdmi_writeb(hdmi, HDMI_I2CM_OPERATION_READ_EXT, + HDMI_I2CM_OPERATION); + else + hdmi_writeb(hdmi, HDMI_I2CM_OPERATION_READ, + HDMI_I2CM_OPERATION); stat = wait_for_completion_timeout(&i2c->cmp, HZ / 10); if (!stat) @@ -271,6 +277,7 @@ static int dw_hdmi_i2c_read(struct dw_hdmi *hdmi, *buf++ = hdmi_readb(hdmi, HDMI_I2CM_DATAI); } + i2c->is_segment = false; return 0; } @@ -320,12 +327,6 @@ static int dw_hdmi_i2c_xfer(struct i2c_adapter *adap, dev_dbg(hdmi->dev, "xfer: num: %d, addr: %#x\n", num, addr); for (i = 0; i < num; i++) { - if (msgs[i].addr != addr) { - dev_warn(hdmi->dev, - "unsupported transfer, changed slave address\n"); - return -EOPNOTSUPP; - } - if (msgs[i].len == 0) { dev_dbg(hdmi->dev, "unsupported transfer %d/%d, no data\n", @@ -345,15 +346,24 @@ static int dw_hdmi_i2c_xfer(struct i2c_adapter *adap, /* Set slave device register address on transfer */ i2c->is_regaddr = false; + /* Set segment pointer for I2C extended read mode operation */ + i2c->is_segment = false; + for (i = 0; i < num; i++) { dev_dbg(hdmi->dev, "xfer: num: %d/%d, len: %d, flags: %#x\n", i + 1, num, msgs[i].len, msgs[i].flags); - - if (msgs[i].flags & I2C_M_RD) - ret = dw_hdmi_i2c_read(hdmi, msgs[i].buf, msgs[i].len); - else - ret = dw_hdmi_i2c_write(hdmi, msgs[i].buf, msgs[i].len); - + if (msgs[i].addr == DDC_SEGMENT_ADDR && msgs[i].len == 1) { + i2c->is_segment = true; + hdmi_writeb(hdmi, DDC_SEGMENT_ADDR, HDMI_I2CM_SEGADDR); + hdmi_writeb(hdmi, *msgs[i].buf, HDMI_I2CM_SEGPTR); + } else { + if (msgs[i].flags & I2C_M_RD) + ret = dw_hdmi_i2c_read(hdmi, msgs[i].buf, + msgs[i].len); + else + ret = dw_hdmi_i2c_write(hdmi, msgs[i].buf, + msgs[i].len); + } if (ret < 0) break; } -- 1.9.1
