Hi Nickey, On 22-02-2017 07:45, Nickey Yang wrote: > "I2C Master Interface Extended Read Mode" implements a segment > pointer-based read operation using the Special Register configuration. > > This patch fix https://urldefense.proofpoint.com/v2/url?u=https-3A__patchwork.kernel.org_patch_7098101_&d=DwIBAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=yaVFU4TjGY0gVF8El1uKcisy6TPsyCl9uN7Wsis-qhY&m=GO5hTo1pTsXMTs-_YDONdmAGQyk8vf0XXA5s-P77fPo&s=cy1I1t3kDvC0ihSnmEqbDx-PiPvzXaksyM9G240RSmE&e= 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. Can't read an EDID with 3 extension blocks? Why? (I'm not reading the spec so I don't know if this is possible to exist. Maybe only an even number of blocks is allowed). > > Signed-off-by: Nickey Yang <nickey.yang@xxxxxxxxxxxxxx> > --- > 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..6ad7b87 100644 > --- a/drivers/gpu/drm/bridge/dw-hdmi.c > +++ b/drivers/gpu/drm/bridge/dw-hdmi.c > @@ -33,6 +33,7 @@ > #include "dw-hdmi-audio.h" > > #define HDMI_EDID_LEN 512 > +#define DDC_SEGMENT_ADDR 0x30 > > #define RGB 0 > #define YCBCR444 1 > @@ -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); Hmm, this does not match what I have here internally but I may have something wrong. You tested this using an EDID with how many extension blocks? Anyway, this is what I have: if(msgs[i].addr == DDC_SEGMENT_ADDR && msgs[i].len == 1) { hdmi_writeb(hdmi, msgs[i].buf[0], HDMI_I2CM_SEGADDR); [and segptr is 0x0] } I probably may have something wrong but I remember I tested this a long time ago using an HDMI 2.0 EDID and it worked fine. BUT, I have special cases for other addresses (0x50 and 0x54), I can't remember if these are for EDID or for SCDC. I can send you the code I have if you want. Best regards, Jose Miguel Abreu > + } 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; > } _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
