I borrowed this code from LinCAN project. It helped me a lot by investigating
the problem with memory access. I don't know if it is worth committing it to
the repository, but it was nice to use it.
Yegor
diff --git a/drivers/net/can/sja1000/sja1000.c
b/drivers/net/can/sja1000/sja1000.c
index 145b1a7..86ef501 100644
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -229,6 +229,8 @@ static int sja1000_get_berr_counter(const struct net_device
*dev,
static void chipset_init(struct net_device *dev)
{
struct sja1000_priv *priv = netdev_priv(dev);
+ int i;
+ unsigned char n, r;
/* set clock divider and output control register */
priv->write_reg(priv, REG_CDR, priv->cdr | CDR_PELICAN);
@@ -245,6 +247,18 @@ static void chipset_init(struct net_device *dev)
priv->write_reg(priv, REG_ACCM3, 0xFF);
priv->write_reg(priv, REG_OCR, priv->ocr | OCR_MODE_NORMAL);
+
+ /* Simple check for chip presence */
+ for (i=0, n=0x5a; i<8; i++, n+=0xf) {
+ priv->write_reg(priv, REG_ACCC0 + i, n);
+ }
+ for (i=0, n=0x5a; i<8; i++, n+=0xf) {
+ r = n ^ priv->read_reg(priv, REG_ACCC0 + i);
+ if (r) {
+ printk("sja1000p_chip_config: chip connection broken,"
+ " readback differ 0x%02x\n", r);
+ }
+ }
}
/*
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