From: Raul E Rangel rrangel@chromium.org
If the device doesn't return a version that means the device is non-functional.
The dw_i2c_regs had invalid offsets for the version field. I got the correct value from the DesignWare databook. It also matches what the Picasso PPR says.
Signed-off-by: Raul E Rangel rrangel@chromium.org Reviewed-by: Simon Glass sjg@chromium.org Reviewed-by: Furquan Shaikh furquan@chromium.org Tested on chromebook_coral: Signed-off-by: Simon Glass sjg@chromium.org ---
drivers/i2c/designware_i2c.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c index ac170769f4..f7a48f6225 100644 --- a/drivers/i2c/designware_i2c.c +++ b/drivers/i2c/designware_i2c.c @@ -16,6 +16,12 @@ #include <dm/device_compat.h> #include <linux/err.h>
+/* + * This assigned unique hex value is constant and is derived from the two ASCII + * letters 'DW' followed by a 16-bit unsigned number + */ +#define DW_I2C_COMP_TYPE 0x44570140 + #ifdef CONFIG_SYS_I2C_DW_ENABLE_STATUS_UNSUPPORTED static int dw_i2c_enable(struct i2c_regs *i2c_base, bool enable) { @@ -764,6 +770,17 @@ int designware_i2c_ofdata_to_platdata(struct udevice *bus) int designware_i2c_probe(struct udevice *bus) { struct dw_i2c *priv = dev_get_priv(bus); + uint comp_type; + + comp_type = readl(&priv->regs->comp_type); + if (comp_type != DW_I2C_COMP_TYPE) { + log_err("I2C bus %s has unknown type %#x\n", bus->name, + comp_type); + return -ENXIO; + } + + log_info("I2C bus %s version %#x\n", bus->name, + readl(&priv->regs->comp_version));
return __dw_i2c_init(priv->regs, 0, 0); }