SN65DSI84: How to set the output waveform of LVDS through registers

Hi,

You can't change the output waveform, you can only configure the DSI84 LVDS output common mode and SWING voltage.

Thanks

David 

Hi David,

Thanks for your reply, but we have two more questions as follows:

1) Which registers need to be set to modify the DSI84 LVDS outout common mode?

2) Which registers need to be set to modify the SWING voltage?

Best Regards,

Lumina

Lumina

Both common mode and SWING voltage are set through register 0x19, you can further adjust the common mode voltage through register 0x1B.

Thanks

David

Hi David,

Thanks a lot for your reply. But our customer still some questions as below:

Did the 0x1B register could be written? If yes, can u provide some suggestion for it? We have tried to set the value of the 0x1b register, but failed. The detais are as below.

To modify the void sn65dsi84_on(void) function, the code is as follows:

if (cmds && cmd_cnt > 0) {
int i, ret;
pr_err("====cmds && cmd_cnt > 0====\n");
for (i = 0; i < cmd_cnt; ++i) {
    struct sn65dsi_reg_hdr cmd = cmds[i];
    if(cmd.addr == 0x19)
        ret = sn65dsi84_reg_write(client, 0x19, 0x4f);
    else if(cmd.addr == 0x1b){
        ret = sn65dsi84_reg_write(client, 0x1b, 0x40);
        if (ret <= 0)
        pr_err("====%s: fail to write addr: 0x1b value: 0x40\n", __func__);
    else
        pr_err("====%s: success to write addr: 0x1b value: 0x40\n", __func__);
        }
else
    ret = sn65dsi84_reg_write(client, cmd.addr, cmd.value);
pr_err("====cmd.addr:0x%x cmd.value:0x%x====\n",cmd.addr,cmd.value);

From the printed log information, it shows that the value of the 0x1b register has been modified successfully.

01-16 19:41:38.186     0     0 E ====sn65dsi84_on: success to write addr: 0x1b value: 0x40

But when we use the i2c dump command to verify the result and noticed that the 0x19 register value have changed, but the 0x1b register value is still 0x00, which indicating that the 0x1b register is written fail.

Thanks,

Best Regards