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Subject[PATCH 1/2] can: D_CAN: perform a sofware reset on open
Date
When the C_CAN interface is closed it is put in power down mode, but
does not reset the error counters / state. So reset the D_CAN on open,
so the reported state and the actual state match.

According to [1], the C_CAN module doesn't have the software reset.

[1] http://www.bosch-semiconductors.com/media/ip_modules/pdf_2/c_can_fd8/users_manual_c_can_fd8_r210_1.pdf

Signed-off-by: Jeroen Hofstee <jhofstee@victronenergy.com>
---
drivers/net/can/c_can/c_can.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index 606b7d8ffe13..502a181d02e7 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -52,6 +52,7 @@
#define CONTROL_EX_PDR BIT(8)

/* control register */
+#define CONTROL_SWR BIT(15)
#define CONTROL_TEST BIT(7)
#define CONTROL_CCE BIT(6)
#define CONTROL_DISABLE_AR BIT(5)
@@ -569,6 +570,26 @@ static void c_can_configure_msg_objects(struct net_device *dev)
IF_MCONT_RCV_EOB);
}

+static int software_reset(struct net_device *dev)
+{
+ struct c_can_priv *priv = netdev_priv(dev);
+ int retry = 0;
+
+ if (priv->type != BOSCH_D_CAN)
+ return 0;
+
+ priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_SWR | CONTROL_INIT);
+ while (priv->read_reg(priv, C_CAN_CTRL_REG) & CONTROL_SWR) {
+ msleep(20);
+ if (retry++ > 100) {
+ netdev_err(dev, "CCTRL: software reset failed\n");
+ return -EIO;
+ }
+ }
+
+ return 0;
+}
+
/*
* Configure C_CAN chip:
* - enable/disable auto-retransmission
@@ -578,6 +599,11 @@ static void c_can_configure_msg_objects(struct net_device *dev)
static int c_can_chip_config(struct net_device *dev)
{
struct c_can_priv *priv = netdev_priv(dev);
+ int err;
+
+ err = software_reset(dev);
+ if (err)
+ return err;

/* enable automatic retransmission */
priv->write_reg(priv, C_CAN_CTRL_REG, CONTROL_ENABLE_AR);
--
2.17.1
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