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drivers: i2c: sam0: Continue write/read if next message allows it #38482

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Merged
merged 1 commit into from
Sep 27, 2021
Merged

drivers: i2c: sam0: Continue write/read if next message allows it #38482

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60 changes: 40 additions & 20 deletions drivers/i2c/i2c_sam0.c
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,8 @@ struct i2c_sam0_msg {
struct i2c_sam0_dev_data {
struct k_sem sem;
struct i2c_sam0_msg msg;
struct i2c_msg *msgs;
uint8_t num_msgs;
};

#define DEV_NAME(dev) ((dev)->name)
Expand Down Expand Up @@ -137,6 +139,18 @@ static void i2c_sam0_isr(const struct device *dev)
return;
}

/*
* Directly send/receive next message if it is in the same direction and
* the current message has no stop flag and the next message has no
* restart flag.
*/
const bool continue_next = (data->msg.size == 1) && (data->num_msgs > 1) &&
((data->msgs[0].flags & I2C_MSG_RW_MASK) ==
(data->msgs[1].flags & I2C_MSG_RW_MASK)) &&
!(data->msgs[0].flags & I2C_MSG_STOP) &&
!(data->msgs[1].flags & I2C_MSG_RESTART) &&
((status & (SERCOM_I2CM_INTFLAG_MB | SERCOM_I2CM_INTFLAG_SB)));

if (status & SERCOM_I2CM_INTFLAG_MB) {
if (!data->msg.size) {
i2c->INTENCLR.reg = SERCOM_I2CM_INTENCLR_MASK;
Expand All @@ -147,12 +161,8 @@ static void i2c_sam0_isr(const struct device *dev)
i2c->DATA.reg = *data->msg.buffer;
data->msg.buffer++;
data->msg.size--;

return;
}

if (status & SERCOM_I2CM_INTFLAG_SB) {
if (data->msg.size == 1) {
} else if (status & SERCOM_I2CM_INTFLAG_SB) {
if (!continue_next) {
/*
* If this is the last byte, then prepare for an auto
* NACK before doing the actual read. This does not
Expand All @@ -165,12 +175,20 @@ static void i2c_sam0_isr(const struct device *dev)
data->msg.buffer++;
data->msg.size--;

if (!data->msg.size) {
if (!continue_next) {
i2c->INTENCLR.reg = SERCOM_I2CM_INTENCLR_MASK;
k_sem_give(&data->sem);
return;
}
return;
}

if (continue_next) {
data->msgs++;
data->num_msgs--;

data->msg.buffer = data->msgs->buf;
data->msg.size = data->msgs->len;
data->msg.status = 0;
}
}

Expand Down Expand Up @@ -373,10 +391,12 @@ static int i2c_sam0_transfer(const struct device *dev, struct i2c_msg *msgs,
if (!num_msgs) {
return 0;
}
data->num_msgs = num_msgs;
data->msgs = msgs;

for (; num_msgs > 0;) {
if (!msgs->len) {
if ((msgs->flags & I2C_MSG_RW_MASK) == I2C_MSG_READ) {
for (; data->num_msgs > 0;) {
if (!data->msgs->len) {
if ((data->msgs->flags & I2C_MSG_RW_MASK) == I2C_MSG_READ) {
return -EINVAL;
}
}
Expand All @@ -392,20 +412,20 @@ static int i2c_sam0_transfer(const struct device *dev, struct i2c_msg *msgs,
SERCOM_I2CM_STATUS_BUSERR;
wait_synchronization(i2c);

data->msg.buffer = msgs->buf;
data->msg.size = msgs->len;
data->msg.buffer = data->msgs->buf;
data->msg.size = data->msgs->len;
data->msg.status = 0;

addr_reg = addr << 1U;
if ((msgs->flags & I2C_MSG_RW_MASK) == I2C_MSG_READ) {
if ((data->msgs->flags & I2C_MSG_RW_MASK) == I2C_MSG_READ) {
addr_reg |= 1U;

/* Set to auto ACK */
i2c->CTRLB.bit.ACKACT = 0;
wait_synchronization(i2c);
}

if (msgs->flags & I2C_MSG_ADDR_10_BITS) {
if (data->msgs->flags & I2C_MSG_ADDR_10_BITS) {
#ifdef SERCOM_I2CM_ADDR_TENBITEN
addr_reg |= SERCOM_I2CM_ADDR_TENBITEN;
#else
Expand All @@ -432,7 +452,7 @@ static int i2c_sam0_transfer(const struct device *dev, struct i2c_msg *msgs,
i2c->INTENSET.reg = SERCOM_I2CM_INTENSET_ERROR;
#endif

if ((msgs->flags & I2C_MSG_RW_MASK) == I2C_MSG_READ) {
if ((data->msgs->flags & I2C_MSG_RW_MASK) == I2C_MSG_READ) {
/*
* Always set MB even when reading, since that's how
* some errors are indicated.
Expand Down Expand Up @@ -472,9 +492,9 @@ static int i2c_sam0_transfer(const struct device *dev, struct i2c_msg *msgs,
return -EIO;
}

if (msgs->flags & I2C_MSG_STOP) {
if (data->msgs->flags & I2C_MSG_STOP) {
i2c->CTRLB.bit.CMD = 3;
} else if ((msgs->flags & I2C_MSG_RESTART) && num_msgs > 1) {
} else if ((data->msgs->flags & I2C_MSG_RESTART) && data->num_msgs > 1) {
/*
* No action, since we do this automatically if we
* don't send an explicit stop
Expand All @@ -487,8 +507,8 @@ static int i2c_sam0_transfer(const struct device *dev, struct i2c_msg *msgs,
i2c->CTRLB.bit.CMD = 3;
}

num_msgs--;
msgs++;
data->num_msgs--;
data->msgs++;
}

return 0;
Expand Down