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drivers: can: flexcan: disable self-reception and support listen-only

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Add work-around for the NXP MCUxpresso SDK not exposing APIs for
setting the listen-only (LOM) bit of the FlexCAN MCR register and the
self-reception disable (SRXDIS) bit of the CTRL1 register.

These bits can only be written when the FlexCAN module is in freeze
mode. Add a set of simplified functions (not supporting errata 9595) for
entering/exiting freeze mode.

This work-around can be removed again once the NXP MCUxpresso SDK
exposes the needed functionality.

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>
This commit is contained in:
Henrik Brix Andersen 2019-09-13 21:19:16 +02:00 • committed by Maureen Helm
commit 8940c25145
1 changed files with 47 additions and 1 deletions
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48
drivers/can/can_mcux_flexcan.c
View file

@ -88,6 +88,39 @@ struct mcux_flexcan_data {
struct mcux_flexcan_tx_callback tx_cbs[MCUX_FLEXCAN_MAX_TX];
};
#if (!defined(FSL_FEATURE_FLEXCAN_HAS_ERRATA_9595) || \
!FSL_FEATURE_FLEXCAN_HAS_ERRATA_9595)
static void mcux_flexcan_freeze(struct device *dev)
{
const struct mcux_flexcan_config *config = dev->config->config_info;
/*
* Simple freeze implementation without support for
* FSL_FEATURE_FLEXCAN_HAS_ERRATA_9595.
*
* This can be removed once the MCUX FlexCAN driver supports
* setting the MCR->LOM and CTRL1->SRXDIS bits or exposes its
* internal freeze/unfreeze functions through the API.
*/
config->base->MCR |= CAN_MCR_FRZ_MASK;
config->base->MCR |= CAN_MCR_HALT_MASK;
while ((config->base->MCR & CAN_MCR_FRZACK_MASK) == 0U) {
}
}
static void mcux_flexcan_thaw(struct device *dev)
{
const struct mcux_flexcan_config *config = dev->config->config_info;
config->base->MCR &= ~CAN_MCR_HALT_MASK;
config->base->MCR &= ~CAN_MCR_FRZ_MASK;
while ((config->base->MCR & CAN_MCR_FRZACK_MASK) != 0U) {
}
}
#endif
static int mcux_flexcan_configure(struct device *dev, enum can_mode mode,
u32_t bitrate)
{
@ -96,10 +129,12 @@ static int mcux_flexcan_configure(struct device *dev, enum can_mode mode,
struct device *clock_dev;
u32_t clock_freq;
/* TODO: support silent mode */
#if (defined(FSL_FEATURE_FLEXCAN_HAS_ERRATA_9595) && \
FSL_FEATURE_FLEXCAN_HAS_ERRATA_9595)
if (mode == CAN_SILENT_MODE || mode == CAN_SILENT_LOOPBACK_MODE) {
return -ENOTSUP;
}
#endif
clock_dev = device_get_binding(config->clock_name);
if (clock_dev == NULL) {
@ -124,6 +159,17 @@ static int mcux_flexcan_configure(struct device *dev, enum can_mode mode,
FLEXCAN_Init(config->base, &flexcan_config, clock_freq);
#if (!defined(FSL_FEATURE_FLEXCAN_HAS_ERRATA_9595) || \
!FSL_FEATURE_FLEXCAN_HAS_ERRATA_9595)
mcux_flexcan_freeze(dev);
if (mode == CAN_SILENT_MODE || mode == CAN_SILENT_LOOPBACK_MODE) {
config->base->CTRL1 |= CAN_CTRL1_LOM(1);
}
/* Disable self reception */
config->base->MCR |= CAN_MCR_SRXDIS(1);
mcux_flexcan_thaw(dev);
#endif
return 0;
}