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can: c_can: Wait for CONTROL_INIT to be cleared

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According to the documentation the CPU must wait for CONTROL_INIT to
be cleared before writing to the baudrate registers.

Signed-off-by: Benedikt Spranger <b.spranger@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Thomas Gleixner 2014-03-18 17:19:08 +00:00 committed by Marc Kleine-Budde
parent 130a5171da
commit 9fac1d1ab8
1 changed files with 23 additions and 3 deletions
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26
drivers/net/can/c_can/c_can.c
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@ -566,6 +566,21 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
return NETDEV_TX_OK;
}
static int c_can_wait_for_ctrl_init(struct net_device *dev,
struct c_can_priv *priv, u32 init)
{
int retry = 0;
while (init != (priv->read_reg(priv, C_CAN_CTRL_REG) & CONTROL_INIT)) {
udelay(10);
if (retry++ > 1000) {
netdev_err(dev, "CCTRL: set CONTROL_INIT failed\n");
return -EIO;
}
}
return 0;
}
static int c_can_set_bittiming(struct net_device *dev)
{
unsigned int reg_btr, reg_brpe, ctrl_save;
@ -573,6 +588,7 @@ static int c_can_set_bittiming(struct net_device *dev)
u32 ten_bit_brp;
struct c_can_priv *priv = netdev_priv(dev);
const struct can_bittiming *bt = &priv->can.bittiming;
int res;
/* c_can provides a 6-bit brp and 4-bit brpe fields */
ten_bit_brp = bt->brp - 1;
@ -590,13 +606,17 @@ static int c_can_set_bittiming(struct net_device *dev)
"setting BTR=%04x BRPE=%04x\n", reg_btr, reg_brpe);
ctrl_save = priv->read_reg(priv, C_CAN_CTRL_REG);
priv->write_reg(priv, C_CAN_CTRL_REG,
ctrl_save | CONTROL_CCE | CONTROL_INIT);
ctrl_save &= ~CONTROL_INIT;
priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_CCE | CONTROL_INIT);
res = c_can_wait_for_ctrl_init(dev, priv, CONTROL_INIT);
if (res)
return res;
priv->write_reg(priv, C_CAN_BTR_REG, reg_btr);
priv->write_reg(priv, C_CAN_BRPEXT_REG, reg_brpe);
priv->write_reg(priv, C_CAN_CTRL_REG, ctrl_save);
return 0;
return c_can_wait_for_ctrl_init(dev, priv, 0);
}
/*