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nrf52: Add a static copy buffer for i2c

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Signed-off-by: Brennan Ashton <bashton@brennanashton.com>
This commit is contained in:
Brennan Ashton 2021-01-17 14:18:12 -08:00 committed by Xiang Xiao
parent 4693857b2c
commit b6fbcb649c
2 changed files with 38 additions and 5 deletions
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19
arch/arm/src/nrf52/Kconfig
View File

@ -632,5 +632,24 @@ menu "I2C Master Configuration"
config NRF52_I2C_MASTER_DISABLE_NOSTART
bool "Disable the I2C Master NOSTART flag support"
default n
---help---
To combine two i2c messages that are part of a
single transaction (NO_STOP-NO_START) the nrf52
hardware requires these be joined into a single
transfer. This can be expensive and some devices
can get away with multi-part transfers as separate
transfers. Enable this at your own risk!
config NRF52_I2C_MASTER_COPY_BUF_SIZE
int "Static buffer size for NOSTART flag support"
depends on !NRF52_I2C_MASTER_DISABLE_NOSTART
default 4
---help---
To combine two i2c messages that are part of a
single transaction (NO_STOP-NO_START) the nrf52
hardware requires these be joined into a single
transfer. This static buffer will be used if the
transaction will fit otherwise it will fall back
on malloc.
endmenu

24
arch/arm/src/nrf52/nrf52_i2c.c
View File

@ -68,6 +68,11 @@ struct nrf52_i2c_priv_s
uint8_t msgc; /* Message count */
struct i2c_msg_s *msgv; /* Message list */
uint8_t *ptr; /* Current message buffer */
#ifdef CONFIG_NRF52_I2C_MASTER_COPY_BUF_SIZE
/* Static buffer used for continued messages */
uint8_t copy_buf[CONFIG_NRF52_I2C_MASTER_COPY_BUF_SIZE];
#endif
uint32_t freq; /* Current I2C frequency */
int dcnt; /* Current message length */
uint16_t flags; /* Current message flags */
@ -308,11 +313,20 @@ static int nrf52_i2c_transfer(FAR struct i2c_master_s *dev,
/* Combine buffers */
pack_buf = kmm_malloc(priv->msgv[0].length +
priv->msgv[1].length);
if (pack_buf == NULL)
if ((priv->msgv[0].length +
priv->msgv[1].length) <=
CONFIG_NRF52_I2C_MASTER_COPY_BUF_SIZE)
{
return -1;
pack_buf = priv->copy_buf;
}
else
{
pack_buf = kmm_malloc(priv->msgv[0].length +
priv->msgv[1].length);
if (pack_buf == NULL)
{
return -ENOMEM;
}
}
/* Combine messages */
@ -496,7 +510,7 @@ static int nrf52_i2c_transfer(FAR struct i2c_master_s *dev,
errout:
#ifndef CONFIG_NRF52_I2C_MASTER_DISABLE_NOSTART
if (pack_buf != NULL)
if (pack_buf != NULL && pack_buf != priv->copy_buf)
{
kmm_free(pack_buf);
}