Le 11/06/2024 à 13:43, Farouk Bouabid a écrit :
Mule is an MCU that emulates a set of I2C devices which are reachable
through an I2C-mux.
The emulated devices share a single I2C address with the mux itself
where the requested register is what determines which logic is executed
(mux logic or device logic):
1- The devices on the mux can be selected (mux function) by writing the
appropriate device number to an I2C config register (0xff) that is not
used by any device logic.
2- Any access to a register other than the config register will be
handled by the previously selected device.
Signed-off-by: Farouk Bouabid <farouk.bouabid@xxxxxxxxx>
---
Hi,
...
+static int mule_i2c_mux_probe(struct i2c_client *client)
+{
+ struct i2c_adapter *adap = client->adapter;
+ struct mule_i2c_reg_mux *priv;
+ struct i2c_mux_core *muxc;
+ struct device_node *dev;
+ unsigned int readback;
+ int ndev, ret;
+ bool old_fw;
+
+ /* Count devices on the mux */
+ ndev = of_get_child_count(client->dev.of_node);
+ dev_dbg(&client->dev, "%u devices on the mux\n", ndev);
Should this be %d?
+
+ muxc = i2c_mux_alloc(adap, &client->dev,
+ ndev, sizeof(*priv),
+ I2C_MUX_LOCKED,
+ mux_select, mux_deselect);
Nitpick: this could be written with less lines.
+ if (!muxc)
+ return -ENOMEM;
+
+ muxc->share_addr_with_children = 1;
+ priv = i2c_mux_priv(muxc);
+
+ priv->regmap = devm_regmap_init_i2c(client, &mule_regmap_config);
+ if (IS_ERR(priv->regmap))
+ return dev_err_probe(&client->dev, PTR_ERR(priv->regmap),
+ "Failed to allocate i2c register map\n");
+
+ i2c_set_clientdata(client, muxc);
+
+ /*
+ * Mux 0 is guaranteed to exist on all old and new mule fw.
+ * mule fw without mux support will accept write ops to the
+ * config register, but readback returns 0xff (register not updated).
+ */
+ ret = mux_select(muxc, 0);
Should this 0 be MUX_DEFAULT_DEV (for consistency)?
+ if (ret)
+ return ret;
+
+ ret = regmap_read(priv->regmap, MUX_CONFIG_REG, &readback);
+ if (ret)
+ return ret;
+
+ old_fw = (readback != 0);
+
+ ret = devm_add_action_or_reset(&client->dev, mux_remove, muxc);
+ if (ret)
+ return ret;
+
+ /* Create device adapters */
+ for_each_child_of_node(client->dev.of_node, dev) {
+ u32 reg;
+
+ ret = of_property_read_u32(dev, "reg", ®);
+ if (ret) {
+ dev_err(&client->dev, "No reg property found for %s: %d\n",
+ of_node_full_name(dev), ret);
return dev_err_probe() as above?
+ return ret;
+ }
+
+ if (old_fw && reg != 0) {
+ dev_warn(&client->dev,
+ "Mux %d not supported, please update Mule FW\n", reg);
+ continue;
+ }
+
+ ret = mux_select(muxc, reg);
+ if (ret) {
+ dev_warn(&client->dev,
+ "Mux %d not supported, please update Mule FW\n", reg);
+ continue;
+ }
+
+ ret = i2c_mux_add_adapter(muxc, 0, reg, 0);
+ if (ret) {
+ dev_err(&client->dev, "Failed to add i2c mux adapter %d: %d\n", reg, ret);
return dev_err_probe() as above?
+ return ret;
+ }
+ }
+
+ mux_deselect(muxc, MUX_DEFAULT_DEV);
+
+ return 0;
+}
...
