Hi,
On Thu, Jul 25, 2024 at 03:27:48PM +0200, Farouk Bouabid wrote:
> Theobroma Systems Mule is an MCU that emulates a set of I2C devices,
> among which an amc6821 and devices that are reachable through an I2C-mux.
> The devices on the mux can be selected by writing the appropriate device
> number to an I2C config register (amc6821 reg 0xff).
>
> This driver is expected to be probed as a platform device with amc6821
> as its parent i2c device.
>
> Add support for the mule-i2c-mux platform driver. The amc6821 driver
> support for the mux will be added in a later commit.
Seems like DT maintainers are happy with the approach. From the I2C
perspective, this seems suitable as well. Just a few minor comments. Can
be fixed incrementally, from my POV. But basically:
Reviewed-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
> +static inline int __mux_select(struct regmap *regmap, u32 dev)
> +{
> + return regmap_write(regmap, MUX_CONFIG_REG, dev);
> +}
Does this really need to be a seperate function? I'd vote for merging it
into 'mux_select'. Also the __-prefix often means unlocked versions of
some call, so it is also a bit misleading.
> +static int mule_i2c_mux_probe(struct platform_device *pdev)
> +{
> + struct device *mux_dev = &pdev->dev;
> + struct mule_i2c_reg_mux *priv;
> + struct i2c_client *client;
> + 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(mux_dev->of_node);
> + dev_dbg(mux_dev, "%d devices on the mux\n", ndev);
> +
> + client = to_i2c_client(mux_dev->parent);
> +
> + muxc = i2c_mux_alloc(client->adapter, mux_dev, ndev, sizeof(*priv),
> + I2C_MUX_LOCKED, mux_select, mux_deselect);
> + if (!muxc)
> + return dev_err_probe(mux_dev, -ENOMEM,
> + "Failed to allocate mux struct\n");
alloc_functions usually print something when failing.
> + ret = i2c_mux_add_adapter(muxc, 0, reg);
> + if (ret)
> + return dev_err_probe(mux_dev, ret,
> + "Failed to add i2c mux adapter %d\n", reg);
The 'add_adapter' functions for sure print something when failing.
Thanks!
Wolfram
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