Technologic Systems provides an IP compatible with the SJA1000,
instantiated in an FPGA. Because of some bus widths issue, access to
registers is made through a "window" that works like this:
base + 0x0: address to read/write
base + 0x2: 8-bit register value
This commit adds a new compatible device, "technologic,sja1000", with
read and write functions using the window mechanism.
Signed-off-by: Damien Riegel <damien.riegel@xxxxxxxxxxxxxxxxxxxx>
---
drivers/net/can/sja1000/sja1000_platform.c | 30 ++++++++++++++++++++++++++++--
1 file changed, 28 insertions(+), 2 deletions(-)
diff --git a/drivers/net/can/sja1000/sja1000_platform.c b/drivers/net/can/sja1000/sja1000_platform.c
index 0552ed4..6cbf251 100644
--- a/drivers/net/can/sja1000/sja1000_platform.c
+++ b/drivers/net/can/sja1000/sja1000_platform.c
@@ -70,6 +70,18 @@ static void sp_write_reg32(const struct sja1000_priv *priv, int reg, u8 val)
iowrite8(val, priv->reg_base + reg * 4);
}
+static u8 ts4800_read_reg16(const struct sja1000_priv *priv, int reg)
+{
+ sp_write_reg16(priv, 0, reg);
+ return sp_read_reg16(priv, 2);
+}
+
+static void ts4800_write_reg16(const struct sja1000_priv *priv, int reg, u8 val)
+{
+ sp_write_reg16(priv, 0, reg);
+ sp_write_reg16(priv, 2, val);
+}
+
static void sp_populate(struct sja1000_priv *priv,
struct sja1000_platform_data *pdata,
unsigned long resource_mem_flags)
@@ -98,21 +110,34 @@ static void sp_populate(struct sja1000_priv *priv,
static void sp_populate_of(struct sja1000_priv *priv, struct device_node *of)
{
+ int is_technologic;
int err;
u32 prop;
+ is_technologic = of_device_is_compatible(of, "technologic,sja1000");
+
err = of_property_read_u32(of, "reg-io-width", &prop);
if (err)
prop = 1; /* 8 bit is default */
+ if (is_technologic && prop != 2) {
+ netdev_warn(priv->dev, "forcing reg-io-width to 2\n");
+ prop = 2;
+ }
+
switch (prop) {
case 4:
priv->read_reg = sp_read_reg32;
priv->write_reg = sp_write_reg32;
break;
case 2:
- priv->read_reg = sp_read_reg16;
- priv->write_reg = sp_write_reg16;
+ if (is_technologic) {
+ priv->read_reg = ts4800_read_reg16;
+ priv->write_reg = ts4800_write_reg16;
+ } else {
+ priv->read_reg = sp_read_reg16;
+ priv->write_reg = sp_write_reg16;
+ }
break;
case 1: /* fallthrough */
default:
@@ -244,6 +269,7 @@ static int sp_remove(struct platform_device *pdev)
static const struct of_device_id sp_of_table[] = {
{.compatible = "nxp,sja1000"},
+ {.compatible = "technologic,sja1000"},
{},
};
MODULE_DEVICE_TABLE(of, sp_of_table);
--
2.5.0
--
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