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Commit fb1f9020 authored by Hans de Goede's avatar Hans de Goede Committed by Mauro Carvalho Chehab
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V4L/DVB (13179): gspca_ov519: cache sensor regs to avoid unnecessary slow i2c reads / writes 



Cache sensor regs to avoid unnecessary slow i2c reads / writes, this speeds
up sd_start a bit with most bridges and a lot (from 5 seconds down to 0.3
seconds) with W996xCF cams, as this avoids very slow bit bang IO over
USB i2c reads.

Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent a511ba94

drivers/media/video/gspca/ov519.c

+43 −10
Original line number Original line Diff line number Diff line
@@ -103,6 +103,7 @@ struct sd { 
	u8 sensor_addr;

	u8 sensor_addr;

	int sensor_width;

	int sensor_width;

	int sensor_height;

	int sensor_height;

	int sensor_reg_cache[256];

};

};





/* Note this is a bit of a hack, but the w9968cf driver needs the code for all

/* Note this is a bit of a hack, but the w9968cf driver needs the code for all
@@ -2210,38 +2211,70 @@ static int ovfx2_i2c_r(struct sd *sd, __u8 reg) 




static int i2c_w(struct sd *sd, __u8 reg, __u8 value)

static int i2c_w(struct sd *sd, __u8 reg, __u8 value)

{

{

	int ret = -1;



	if (sd->sensor_reg_cache[reg] == value)

		return 0;



	switch (sd->bridge) {

	switch (sd->bridge) {

	case BRIDGE_OV511:

	case BRIDGE_OV511:

	case BRIDGE_OV511PLUS:

	case BRIDGE_OV511PLUS:

		return ov511_i2c_w(sd, reg, value);

		ret = ov511_i2c_w(sd, reg, value);

		break;

	case BRIDGE_OV518:

	case BRIDGE_OV518:

	case BRIDGE_OV518PLUS:

	case BRIDGE_OV518PLUS:

	case BRIDGE_OV519:

	case BRIDGE_OV519:

		return ov518_i2c_w(sd, reg, value);

		ret = ov518_i2c_w(sd, reg, value);

		break;

	case BRIDGE_OVFX2:

	case BRIDGE_OVFX2:

		return ovfx2_i2c_w(sd, reg, value);

		ret = ovfx2_i2c_w(sd, reg, value);

		break;

	case BRIDGE_W9968CF:

	case BRIDGE_W9968CF:

		return w9968cf_i2c_w(sd, reg, value);

		ret = w9968cf_i2c_w(sd, reg, value);

		break;

	}



	if (ret >= 0) {

		/* Up on sensor reset empty the register cache */

		if (reg == 0x12 && (value & 0x80))

			memset(sd->sensor_reg_cache, -1,

			       sizeof(sd->sensor_reg_cache));

		else

			sd->sensor_reg_cache[reg] = value;

	}

	}

	return -1; /* Should never happen */



	return ret;

}

}





static int i2c_r(struct sd *sd, __u8 reg)

static int i2c_r(struct sd *sd, __u8 reg)

{

{

	int ret;



	if (sd->sensor_reg_cache[reg] != -1)

		return sd->sensor_reg_cache[reg];



	switch (sd->bridge) {

	switch (sd->bridge) {

	case BRIDGE_OV511:

	case BRIDGE_OV511:

	case BRIDGE_OV511PLUS:

	case BRIDGE_OV511PLUS:

		return ov511_i2c_r(sd, reg);

		ret = ov511_i2c_r(sd, reg);

		break;

	case BRIDGE_OV518:

	case BRIDGE_OV518:

	case BRIDGE_OV518PLUS:

	case BRIDGE_OV518PLUS:

	case BRIDGE_OV519:

	case BRIDGE_OV519:

		return ov518_i2c_r(sd, reg);

		ret = ov518_i2c_r(sd, reg);

		break;

	case BRIDGE_OVFX2:

	case BRIDGE_OVFX2:

		return ovfx2_i2c_r(sd, reg);

		ret = ovfx2_i2c_r(sd, reg);

		break;

	case BRIDGE_W9968CF:

	case BRIDGE_W9968CF:

		return w9968cf_i2c_r(sd, reg);

		ret = w9968cf_i2c_r(sd, reg);

		break;

	}

	}

	return -1; /* Should never happen */



	if (ret >= 0)

		sd->sensor_reg_cache[reg] = ret;



	return ret;

}

}





/* Writes bits at positions specified by mask to an I2C reg. Bits that are in

/* Writes bits at positions specified by mask to an I2C reg. Bits that are in