diff options
| author | Marc Kleine-Budde <mkl@pengutronix.de> | 2010-09-28 12:18:34 +0400 |
|---|---|---|
| committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2010-10-18 13:19:42 +0400 |
| commit | d3cd15657516141adce387810be8cb377baf020e (patch) | |
| tree | f85a4b2ab4b8bd7f532ccf93e56dc1cade87eb6e /drivers/net | |
| parent | 7e15de3a73899903f33975b1ce57cf59c616d1d9 (diff) | |
| download | linux-d3cd15657516141adce387810be8cb377baf020e.tar.xz | |
can: mcp251x: write intf only when needed
This patch introduces a variable "clear_intf" that hold the bits that
should be cleared. Only read-modify-write register if "clear_intf"
is set.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/can/mcp251x.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c index 7e2f951002a5..f5e2edd09ce4 100644 --- a/drivers/net/can/mcp251x.c +++ b/drivers/net/can/mcp251x.c @@ -125,6 +125,8 @@ # define CANINTF_TX0IF 0x04 # define CANINTF_RX1IF 0x02 # define CANINTF_RX0IF 0x01 +# define CANINTF_ERR_TX \ + (CANINTF_ERRIF | CANINTF_TX2IF | CANINTF_TX1IF | CANINTF_TX0IF) #define EFLG 0x2d # define EFLG_EWARN 0x01 # define EFLG_RXWAR 0x02 @@ -769,10 +771,12 @@ static irqreturn_t mcp251x_can_ist(int irq, void *dev_id) while (!priv->force_quit) { enum can_state new_state; u8 intf, eflag; + u8 clear_intf = 0; int can_id = 0, data1 = 0; mcp251x_read_2regs(spi, CANINTF, &intf, &eflag); + /* receive buffer 0 */ if (intf & CANINTF_RX0IF) { mcp251x_hw_rx(spi, 0); /* Free one buffer ASAP */ @@ -780,10 +784,17 @@ static irqreturn_t mcp251x_can_ist(int irq, void *dev_id) 0x00); } - if (intf & CANINTF_RX1IF) + /* receive buffer 1 */ + if (intf & CANINTF_RX1IF) { mcp251x_hw_rx(spi, 1); + clear_intf |= CANINTF_RX1IF; + } - mcp251x_write_bits(spi, CANINTF, intf, 0x00); + /* any error or tx interrupt we need to clear? */ + if (intf & CANINTF_ERR_TX) + clear_intf |= intf & CANINTF_ERR_TX; + if (clear_intf) + mcp251x_write_bits(spi, CANINTF, clear_intf, 0x00); if (eflag) mcp251x_write_bits(spi, EFLG, eflag, 0x00); |