From: Sascha Hauer Date: Tue, 28 Sep 2010 07:53:35 +0000 (+0200) Subject: can: mcp251x: allow to read two registers in one spi transfer X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f3a3ed3115d39463dc6672454bfbeaff46811a37;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git can: mcp251x: allow to read two registers in one spi transfer This patch bases on work done earlier by David Jander. Signed-off-by: Sascha Hauer Acked-by: David Jander Signed-off-by: Uwe Kleine-König Signed-off-by: Marc Kleine-Budde Acked-by: Wolfgang Grandegger --- diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c index fdea752f398f..9b3466aed06d 100644 --- a/drivers/net/can/mcp251x.c +++ b/drivers/net/can/mcp251x.c @@ -319,6 +319,20 @@ static u8 mcp251x_read_reg(struct spi_device *spi, uint8_t reg) return val; } +static void mcp251x_read_2regs(struct spi_device *spi, uint8_t reg, + uint8_t *v1, uint8_t *v2) +{ + struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); + + priv->spi_tx_buf[0] = INSTRUCTION_READ; + priv->spi_tx_buf[1] = reg; + + mcp251x_spi_trans(spi, 4); + + *v1 = priv->spi_rx_buf[2]; + *v2 = priv->spi_rx_buf[3]; +} + static void mcp251x_write_reg(struct spi_device *spi, u8 reg, uint8_t val) { struct mcp251x_priv *priv = dev_get_drvdata(&spi->dev); @@ -754,10 +768,11 @@ static irqreturn_t mcp251x_can_ist(int irq, void *dev_id) mutex_lock(&priv->mcp_lock); while (!priv->force_quit) { enum can_state new_state; - u8 intf = mcp251x_read_reg(spi, CANINTF); - u8 eflag; + u8 intf, eflag; int can_id = 0, data1 = 0; + mcp251x_read_2regs(spi, CANINTF, &intf, &eflag); + if (intf & CANINTF_RX0IF) { mcp251x_hw_rx(spi, 0); /* Free one buffer ASAP */ @@ -770,7 +785,6 @@ static irqreturn_t mcp251x_can_ist(int irq, void *dev_id) mcp251x_write_bits(spi, CANINTF, intf, 0x00); - eflag = mcp251x_read_reg(spi, EFLG); mcp251x_write_reg(spi, EFLG, 0x00); /* Update can state */