Quoting Biju Das (2024-02-14 20:57:36) > Hi Sakari, > > > -----Original Message----- > > From: Biju Das > > Sent: Wednesday, February 14, 2024 8:55 PM > > Subject: RE: [PATCH 1/2] media: i2c: ov5645: Move the register 0x3008 from > > ov5645_global_init_setting > > > > Hi Sakari, > > > > Thanks for the feedback. > > > > > -----Original Message----- > > > From: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > > Sent: Wednesday, February 14, 2024 8:49 PM > > > To: Biju Das <biju.das.jz@xxxxxxxxxxxxxx> > > > Subject: Re: [PATCH 1/2] media: i2c: ov5645: Move the register 0x3008 > > > from ov5645_global_init_setting > > > > > > Hi Biju, > > > > > > On Wed, Feb 14, 2024 at 08:25:16PM +0000, Biju Das wrote: > > > > Hi Wolfram, > > > > > > > > Thanks for the feedback. > > > > > > > > > -----Original Message----- > > > > > From: Wolfram Sang <wsa@xxxxxxxxxx> > > > > > Sent: Wednesday, February 14, 2024 8:31 AM > > > > > Subject: Re: [PATCH 1/2] media: i2c: ov5645: Move the register > > > > > 0x3008 from ov5645_global_init_setting > > > > > > > > > > Hi Biju, > > > > > > > > > > > I think it is different here. That 1 msec is delay associated > > > > > > with applying hardware power see [1] > > > > > > > > > > Okay, ack. > > > > > > > > > > > I will restore it. > > > > > > > > > > Thanks! > > > > > > > > > > I had meanwhile another thought. What if we kind of merge the two > > > > > patches, so the outcome is basically this: > > > > > > > > > > In ov5645_set_register_array: > > > > > > > > > > If (settings->reg == 0x3008 && settings->val == 0x82) > > > > > usleep_range(1000, 2000) > > > > > > > > > > ? > > > > > > > > > > Then, we don't need to split the array and we are also future > > > > > proof if we ever need to set the reset bit again somewhere else. > > > > > > > > > > Bonus points for replacing 0x82 with a define :) Pulling up the datasheet OV5645-A66A v1.1 from the web: (a little google-fu++ got there, let me know if you need hints if you want to do a full clean up) 2.8 reset The OV5645 sensor includes a RESETB pin that forces a complete hardware reset when it is pulled low (GND). The OV5645 clears all registers and resets them to their default values when a hardware reset occurs. A reset can also be initiated through the SCCB interface by setting register 0x3008[7] to high. Manually applying a hard reset upon power up is required even though on-chip reset is included. The hard reset is active low with an asynchronized design. The reset pulse width should be greater than or equal to 1 ms. 2.9 hardware and software standby Two suspend modes are available for the OV5645: • hardware standby • SCCB software standby To initiate hardware standby mode, the PWDNB pin must be tied to low (while in MIPI mode, set register 0x300E[4:3] to 2’b11 before the PWDNB pin is set to low). When this occurs, the OV5645 internal device clock is halted and all internal counters are reset and registers are maintained. Executing a software standby through the SCCB interface suspends internal circuit activity but does not halt the device clock. All register content is maintained in standby mode. Address: 0x3008 RegName: SYSTEM_CTROL0 Default: 0x02 R/W: RW Description: System Control Bit[7]: Software reset Bit[6]: Software power down Then later in the datasheet it also describes: System Control Bit[7]: Software reset Bit[6]: Software power down Bit[5]: Debug mode Bit[4]: SRB clock sync enable Bit[3]: Isolation suspend select Bit[2]: MIPI reset mask Bit[1]: MIPI suspend mask Bit[0]: MIPI reset select > > > > > > > > > > What do you think? > > > > > > > > > > > > OK, this will do check for all other registers. > > > > > > > > But from your power down clue and checking ov5640.c Looks like there > > > > are 2 registers changes values after writing. > > > > > > > > [1] 0x3008, 0x82-->0x80 > > > > [2] 0x0601, 0x02-->0x00 > > > > > > > > I think [1] is soft reset based on ov5640. Since there is a gpio > > > > based hardware reset available, we can safely remove soft reset[1] > > > > and like ov5640.c, if there is no gpio for reset, then do the soft > > reset[1]. > > > > > > I guess that would work. My understanding is that hard reset control > > > is mandatory for the device, so there really should be no need for > > > soft reset in the driver. > > > > OK. > > > > > > > > > > > > > > > > > Then add 1msec delay for power down/up(0x3008: 0x42,0x02) and 0x0601 > > > > registers. > > > > > > > > With this looks like the Camera works ok @400kHz. > > > > > > > > The plans is to add a u8 variable for delay and enable delays for > > > > the above registers and add a check like below > > > > > > > > static int ov5645_set_register_array(struct ov5645 *ov5645, > > > > const struct reg_value *settings, > > > > unsigned int num_settings) > > > > { > > > > unsigned int i; > > > > int ret; > > > > > > > > for (i = 0; i < num_settings; ++i, ++settings) { > > > > ret = ov5645_write_reg(ov5645, settings->reg, settings->val); > > > > if (ret < 0) > > > > return ret; > > > > > > > > if (settings->delay_ms) > > > > usleep_range(1000 * settings->delay_ms, 2 * 1000 * > > > > settings->delay_ms); > > > > > > I'd prefer checking the register address in the write function instead > > > of this if you really need it. But it seems you don't. > > > > With delays in powerup/down registers (0x3008 : 0x42,0x02) it is not > > stable. > > Typo: without delays in powerup/down registers (0x3008 : 0x42,0x02) it is not > stable. > > You can see 0x42 followed by 0x02 which is an indication of power down/up procedure. > > Cheers, > Biju