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drivers: i2c_nrfx_twim: Use concatenation buffer by default

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Issue an error logging message when the i2c_nrfx_twim driver lacks
a concatenation buffer big enough to properly handle a call to
i2c_burst_write() function, to give the user a hint what is wrong.

Also use by default a 16-bytes long concatenation buffer for every
instance of the i2c_nrfx_twim driver. Such value should cover most
of the simple uses of the i2c_burst_write() function, like those
in the stmemsc sensor drivers, and when a longer buffer is needed,
the user will be provided with the above message pointing to the
property that should be adjusted.

Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>
This commit is contained in:
Andrzej Głąbek 2021-09-20 11:31:01 +02:00 • committed by Carles Cufí
commit 99ce264df7
2 changed files with 24 additions and 17 deletions
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29
drivers/i2c/i2c_nrfx_twim.c
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@ -65,17 +65,17 @@ static int i2c_nrfx_twim_transfer(const struct device *dev,
break;
}
/* Merge this fragment with the next if we have a buffer, this
* isn't the last fragment, it doesn't end a bus transaction,
* the next one doesn't start a bus transaction, and the
* direction of the next fragment is the same as this one.
/* This fragment needs to be merged with the next one if:
* - it is not the last fragment
* - it does not end a bus transaction
* - the next fragment does not start a bus transaction
* - the direction of the next fragment is the same as this one
*/
bool concat_next = (concat_buf_size > 0)
&& ((i + 1) < num_msgs)
&& !(msgs[i].flags & I2C_MSG_STOP)
&& !(msgs[i + 1].flags & I2C_MSG_RESTART)
&& ((msgs[i].flags & I2C_MSG_READ)
== (msgs[i + 1].flags & I2C_MSG_READ));
bool concat_next = ((i + 1) < num_msgs)
&& !(msgs[i].flags & I2C_MSG_STOP)
&& !(msgs[i + 1].flags & I2C_MSG_RESTART)
&& ((msgs[i].flags & I2C_MSG_READ)
== (msgs[i + 1].flags & I2C_MSG_READ));
/* If we need to concatenate the next message, or we've
* already committed to concatenate this message, add it to
@ -83,8 +83,13 @@ static int i2c_nrfx_twim_transfer(const struct device *dev,
*/
if (concat_next || (concat_len != 0)) {
if ((concat_len + msgs[i].len) > concat_buf_size) {
LOG_ERR("concat-buf overflow: %u + %u > %u",
concat_len, msgs[i].len, concat_buf_size);
LOG_ERR("Need to use concatenation buffer and "
"provided size is insufficient "
"(%u + %u > %u). "
"Adjust the zephyr,concat-buf-size "
"property in the \"%s\" node.",
concat_len, msgs[i].len,
concat_buf_size, dev->name);
ret = -ENOSPC;
break;
}