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drivers: CAN: MCP2515: Read INT GPIO pin to check interrupt status

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Faster than the 3 byte SPI read operation when no interrupt flags are
expected to be set.

Signed-off-by: Nick Ward <nix.ward@gmail.com>
This commit is contained in:
Nick Ward 2019-07-21 22:41:16 +10:00 • committed by Jukka Rissanen
commit a64f998645
1 changed files with 26 additions and 6 deletions
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32
drivers/can/can_mcp2515.c
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@ -533,11 +533,26 @@ static void mcp2515_recover(struct device *dev, s32_t timeout)
static void mcp2515_handle_interrupts(struct device *dev)
{
const struct mcp2515_config *dev_cfg = DEV_CFG(dev);
struct mcp2515_data *dev_data = DEV_DATA(dev);
u32_t pin;
int ret;
u8_t canintf;
mcp2515_cmd_read_reg(dev, MCP2515_ADDR_CANINTF, &canintf, 1);
/* Loop until INT pin is high (all interrupt flags handled) */
while (1) {
ret = mcp2515_cmd_read_reg(dev, MCP2515_ADDR_CANINTF,
&canintf, 1);
if (ret != 0) {
LOG_ERR("Couldn't read INTF register %d", ret);
continue;
}
if (canintf == 0) {
/* No interrupt flags set */
break;
}
while (canintf != 0) {
if (canintf & MCP2515_CANINTF_RX0IF) {
mcp2515_rx(dev, 0);
}
@ -566,9 +581,14 @@ static void mcp2515_handle_interrupts(struct device *dev)
mcp2515_cmd_bit_modify(dev, MCP2515_ADDR_CANINTF, canintf,
~canintf);
/* check that no new interrupts happened while clearing known
* ones */
mcp2515_cmd_read_reg(dev, MCP2515_ADDR_CANINTF, &canintf, 1);
/* Break from loop if INT pin is no longer low */
ret = gpio_pin_read(dev_data->int_gpio, dev_cfg->int_pin, &pin);
if (ret != 0) {
LOG_ERR("Couldn't read INT pin");
} else if (pin != 0) {
/* All interrupt flags handled */
break;
}
}
}
@ -610,7 +630,7 @@ static int mcp2515_init(struct device *dev)
struct mcp2515_data *dev_data = DEV_DATA(dev);
int ret;
k_sem_init(&dev_data->int_sem, 0, UINT_MAX);
k_sem_init(&dev_data->int_sem, 0, 1);
k_mutex_init(&dev_data->mutex);
k_sem_init(&dev_data->tx_sem, 3, 3);
k_sem_init(&dev_data->tx_cb[0].sem, 0, 1);