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vf_i2c: update I2C controller logic
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Update the I2C controller logic to be more consistent with the
newer version of the controller reference manual.
This makes it work better on modern LS/LX platforms and avoids
unnecessary delays.  Also fixes a lock leak.

MFC after:	7 days
Tested by:	bz (LS1088a FDT), Pierre-Luc Drouin (Honeycomb, ACPI)
Differential Revision:	https://reviews.freebsd.org/D44021
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@pldrouin @bsdjhb
pldrouin authored and bsdjhb committed Aug 6, 2024
2 parents c13dd76 + 4484711 commit 4a45049
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Showing 4 changed files with 65 additions and 92 deletions.
148 changes: 59 additions & 89 deletions sys/dev/iicbus/controller/vybrid/vf_i2c.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,8 @@

/*
* Vybrid Family Inter-Integrated Circuit (I2C)
* Chapter 48, Vybrid Reference Manual, Rev. 5, 07/2013
* Originally based on Chapter 48, Vybrid Reference Manual, Rev. 5, 07/2013
* Currently based on Chapter 21, LX2160A Reference Manual, Rev. 1, 10/2021
*
* The current implementation is based on the original driver by Ruslan Bukin,
* later modified by Dawid Górecki, and split into FDT and ACPI drivers by Val
Expand Down Expand Up @@ -184,6 +185,7 @@ vf_i2c_attach_common(device_t dev)
mtx_unlock(&sc->mutex);

sc->iicbus = device_add_child(dev, "iicbus", -1);

if (sc->iicbus == NULL) {
device_printf(dev, "could not add iicbus child");
mtx_destroy(&sc->mutex);
Expand Down Expand Up @@ -233,24 +235,6 @@ i2c_detach(device_t dev)
return (0);
}

/* Wait for transfer interrupt flag */
static int
wait_for_iif(struct vf_i2c_softc *sc)
{
int retry;

retry = 1000;
while (retry --) {
if (READ1(sc, I2C_IBSR) & IBSR_IBIF) {
WRITE1(sc, I2C_IBSR, IBSR_IBIF);
return (IIC_NOERR);
}
DELAY(10);
}

return (IIC_ETIMEOUT);
}

/* Wait for free bus */
static int
wait_for_nibb(struct vf_i2c_softc *sc)
Expand All @@ -272,14 +256,24 @@ static int
wait_for_icf(struct vf_i2c_softc *sc)
{
int retry;
uint8_t ibsr;

vf_i2c_dbg(sc, "i2c wait for transfer complete + interrupt flag\n");

retry = 1000;
while (retry --) {
if (READ1(sc, I2C_IBSR) & IBSR_TCF) {
if (READ1(sc, I2C_IBSR) & IBSR_IBIF) {
WRITE1(sc, I2C_IBSR, IBSR_IBIF);
return (IIC_NOERR);
ibsr = READ1(sc, I2C_IBSR);

if (ibsr & IBSR_IBIF) {
WRITE1(sc, I2C_IBSR, IBSR_IBIF);

if (ibsr & IBSR_IBAL) {
WRITE1(sc, I2C_IBSR, IBSR_IBAL);
return (IIC_EBUSBSY);
}

if (ibsr & IBSR_TCF)
return (IIC_NOERR);
}
DELAY(10);
}
Expand Down Expand Up @@ -309,30 +303,24 @@ i2c_repeated_start(device_t dev, u_char slave, int timeout)

mtx_lock(&sc->mutex);

WRITE1(sc, I2C_IBAD, slave);

if ((READ1(sc, I2C_IBSR) & IBSR_IBB) == 0) {
vf_i2c_dbg(sc, "cant i2c repeat start: bus is no longer busy\n");
mtx_unlock(&sc->mutex);
return (IIC_EBUSERR);
}

/* Set repeated start condition */
DELAY(10);

reg = READ1(sc, I2C_IBCR);
reg |= (IBCR_RSTA | IBCR_IBIE);
WRITE1(sc, I2C_IBCR, reg);

DELAY(10);

/* Write target address - LSB is R/W bit */
WRITE1(sc, I2C_IBDR, slave);

error = wait_for_iif(sc);
error = wait_for_icf(sc);

if (!tx_acked(sc)) {
vf_i2c_dbg(sc,
"cant i2c start: missing ACK after slave addres\n");
mtx_unlock(&sc->mutex);
vf_i2c_dbg(sc, "cant i2c repeat start: missing ACK after slave address\n");
return (IIC_ENOACK);
}

Expand All @@ -357,27 +345,32 @@ i2c_start(device_t dev, u_char slave, int timeout)

mtx_lock(&sc->mutex);

WRITE1(sc, I2C_IBAD, slave);
error = wait_for_nibb(sc);

if (READ1(sc, I2C_IBSR) & IBSR_IBB) {
/* Reset controller if bus is still busy. */
if (error == IIC_ETIMEOUT) {
WRITE1(sc, I2C_IBCR, IBCR_MDIS);
DELAY(1000);
WRITE1(sc, I2C_IBCR, IBCR_NOACK);
error = wait_for_nibb(sc);
}

if (error != 0) {
mtx_unlock(&sc->mutex);
vf_i2c_dbg(sc, "cant i2c start: IIC_EBUSBSY\n");
return (IIC_EBUSERR);
vf_i2c_dbg(sc, "cant i2c start: %i\n", error);
return (error);
}

/* Set start condition */
reg = (IBCR_MSSL | IBCR_NOACK | IBCR_IBIE);
reg = (IBCR_MSSL | IBCR_NOACK | IBCR_IBIE | IBCR_TXRX);
WRITE1(sc, I2C_IBCR, reg);

DELAY(100);

reg |= (IBCR_TXRX);
WRITE1(sc, I2C_IBCR, reg);
WRITE1(sc, I2C_IBSR, IBSR_IBIF);

/* Write target address - LSB is R/W bit */
WRITE1(sc, I2C_IBDR, slave);

error = wait_for_iif(sc);
error = wait_for_icf(sc);
if (error != 0) {
mtx_unlock(&sc->mutex);
vf_i2c_dbg(sc, "cant i2c start: iif error\n");
Expand All @@ -386,8 +379,7 @@ i2c_start(device_t dev, u_char slave, int timeout)
mtx_unlock(&sc->mutex);

if (!tx_acked(sc)) {
vf_i2c_dbg(sc,
"cant i2c start: missing QACK after slave addres\n");
vf_i2c_dbg(sc, "cant i2c start: missing ACK after slave address\n");
return (IIC_ENOACK);
}

Expand All @@ -405,16 +397,9 @@ i2c_stop(device_t dev)

mtx_lock(&sc->mutex);

WRITE1(sc, I2C_IBCR, IBCR_NOACK | IBCR_IBIE);

DELAY(100);
if ((READ1(sc, I2C_IBCR) & IBCR_MSSL) != 0)
WRITE1(sc, I2C_IBCR, IBCR_NOACK | IBCR_IBIE);

/* Reset controller if bus still busy after STOP */
if (wait_for_nibb(sc) == IIC_ETIMEOUT) {
WRITE1(sc, I2C_IBCR, IBCR_MDIS);
DELAY(1000);
WRITE1(sc, I2C_IBCR, IBCR_NOACK);
}
mtx_unlock(&sc->mutex);

return (IIC_NOERR);
Expand Down Expand Up @@ -469,27 +454,14 @@ i2c_reset(device_t dev, u_char speed, u_char addr, u_char *oldadr)
div_reg = i2c_get_div_val(dev);
vf_i2c_dbg(sc, "i2c reset\n");

switch (speed) {
case IIC_FAST:
case IIC_SLOW:
case IIC_UNKNOWN:
case IIC_FASTEST:
default:
break;
}

mtx_lock(&sc->mutex);
WRITE1(sc, I2C_IBCR, IBCR_MDIS);

DELAY(1000);

if(div_reg != DIV_REG_UNSET)
WRITE1(sc, I2C_IBFD, div_reg);

WRITE1(sc, I2C_IBCR, 0x0); /* Enable i2c */

DELAY(1000);

mtx_unlock(&sc->mutex);

return (IIC_NOERR);
Expand All @@ -511,36 +483,34 @@ i2c_read(device_t dev, char *buf, int len, int *read, int last, int delay)

if (len) {
if (len == 1)
WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL | \
IBCR_NOACK);
WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL | IBCR_NOACK);
else
WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL);

/* dummy read */
READ1(sc, I2C_IBDR);
DELAY(1000);
}

while (*read < len) {
error = wait_for_icf(sc);
if (error != 0) {
mtx_unlock(&sc->mutex);
return (error);
}
while (*read < len) {
error = wait_for_icf(sc);
if (error != 0) {
mtx_unlock(&sc->mutex);
return (error);
}

if ((*read == len - 2) && last) {
/* NO ACK on last byte */
WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL | \
IBCR_NOACK);
}
if (last) {
if (*read == len - 2) {
/* NO ACK on last byte */
WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_MSSL | IBCR_NOACK);

if ((*read == len - 1) && last) {
/* Transfer done, remove master bit */
WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_NOACK);
}
} else if (*read == len - 1) {
/* Transfer done, remove master bit */
WRITE1(sc, I2C_IBCR, IBCR_IBIE | IBCR_NOACK);
}
}

*buf++ = READ1(sc, I2C_IBDR);
(*read)++;
*buf++ = READ1(sc, I2C_IBDR);
(*read)++;
}
}
mtx_unlock(&sc->mutex);

Expand All @@ -563,7 +533,7 @@ i2c_write(device_t dev, const char *buf, int len, int *sent, int timeout)
while (*sent < len) {
WRITE1(sc, I2C_IBDR, *buf++);

error = wait_for_iif(sc);
error = wait_for_icf(sc);
if (error != 0) {
mtx_unlock(&sc->mutex);
return (error);
Expand Down
3 changes: 2 additions & 1 deletion sys/dev/iicbus/controller/vybrid/vf_i2c.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,8 @@

/*
* Vybrid Family Inter-Integrated Circuit (I2C)
* Chapter 48, Vybrid Reference Manual, Rev. 5, 07/2013
* Originally based on Chapter 48, Vybrid Reference Manual, Rev. 5, 07/2013
* Currently based on Chapter 21, LX2160A Reference Manual, Rev. 1, 10/2021
*
* The current implementation is based on the original driver by Ruslan Bukin,
* later modified by Dawid Górecki, and split into FDT and ACPI drivers by Val
Expand Down
3 changes: 2 additions & 1 deletion sys/dev/iicbus/controller/vybrid/vf_i2c_acpi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,8 @@

/*
* Vybrid Family Inter-Integrated Circuit (I2C)
* Chapter 48, Vybrid Reference Manual, Rev. 5, 07/2013
* Originally based on Chapter 48, Vybrid Reference Manual, Rev. 5, 07/2013
* Currently based on Chapter 21, LX2160A Reference Manual, Rev. 1, 10/2021
*
* The current implementation is based on the original driver by Ruslan Bukin,
* later modified by Dawid Górecki, and split into FDT and ACPI drivers by Val
Expand Down
3 changes: 2 additions & 1 deletion sys/dev/iicbus/controller/vybrid/vf_i2c_fdt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,8 @@

/*
* Vybrid Family Inter-Integrated Circuit (I2C)
* Chapter 48, Vybrid Reference Manual, Rev. 5, 07/2013
* Originally based on Chapter 48, Vybrid Reference Manual, Rev. 5, 07/2013
* Currently based on Chapter 21, LX2160A Reference Manual, Rev. 1, 10/2021
*
* The current implementation is based on the original driver by Ruslan Bukin,
* later modified by Dawid Górecki, and split into FDT and ACPI drivers by Val
Expand Down

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