Hi!
2024-09-03 at 17:13, Andi Shyti wrote:
> Hi Farouk,
>
> Before jumping into the review, who is going to take this and the
> previous patch?
>
> Peter shall I take it?
Please do. Thanks, and as always, sorry for my low bandwidth...
>
> Now to the review :-)
>
> On Mon, Sep 02, 2024 at 06:38:15PM GMT, 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
>
> Along the driver I expressed some concern about the prefixes.
>
> You should avoid prefixes such as mux_* or MUX_* because they
> don't belong to your driver. You should always use your driver's
> name:
>
> 1. mule_*
> 2. mule_mux_*
> 3. mule_i2c_mux_*
>
> You have used the 3rd, I'd rather prefer the 1st. Because when
> you are in i2c/muxex/ it's implied that you are an i2c mux
> device. But it's a matter of personal taste.
>
> Other than this, there is still, one major error down below.
>
>> support for the mux will be added in a later commit.
>>
>> Reviewed-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Farouk Bouabid <farouk.bouabid@xxxxxxxxx>
>
> ...
>
>> +#include <linux/i2c-mux.h>
>> +#include <linux/i2c.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/property.h>
>> +#include <linux/regmap.h>
>> +
>> +#define MUX_CONFIG_REG 0xff
>> +#define MUX_DEFAULT_DEV 0x0
>
> Please define these as MULE_I2C_MUX_*
>
>> +
>> +struct mule_i2c_reg_mux {
>> + struct regmap *regmap;
>> +};
>> +
>> +static int mux_select(struct i2c_mux_core *muxc, u32 dev)
>> +{
>> + struct mule_i2c_reg_mux *mux = muxc->priv;
>> +
>> + return regmap_write(mux->regmap, MUX_CONFIG_REG, dev);
>> +}
>> +
>> +static int mux_deselect(struct i2c_mux_core *muxc, u32 dev)
>> +{
>> + return mux_select(muxc, MUX_DEFAULT_DEV);
>> +}
>> +
>> +static void mux_remove(void *data)
>
> Please call these mule_i2c_mux_*(), the mux_ prefix doesn't
> belong to this driver.
>
>> +{
>> + struct i2c_mux_core *muxc = data;
>> +
>> + i2c_mux_del_adapters(muxc);
>> +
>> + mux_deselect(muxc, MUX_DEFAULT_DEV);
>> +}
>
> ...
>
>> + /* Create device adapters */
>> + for_each_child_of_node(mux_dev->of_node, dev) {
>> + u32 reg;
>> +
>> + ret = of_property_read_u32(dev, "reg", ®);
>> + if (ret)
>> + return dev_err_probe(mux_dev, ret,
>> + "No reg property found for %s\n",
>> + of_node_full_name(dev));
>> +
>> + if (old_fw && reg != 0) {
>> + dev_warn(mux_dev,
>> + "Mux is not supported, please update Mule FW\n");
>> + continue;
>> + }
>> +
>> + ret = mux_select(muxc, reg);
>> + if (ret) {
>> + dev_warn(mux_dev,
>> + "Device %d not supported, please update Mule FW\n", reg);
>> + continue;
>> + }
>> +
>> + ret = i2c_mux_add_adapter(muxc, 0, reg);
>> + if (ret)
>> + return ret;
>
> do we need to delete the adapters we added in previous cycles?
Yes, nicely spotted. A call to i2c_mux_del_adapters(muxc) is needed
on failure if any i2c_mux_add_adapter() call has succeeded (but it's
safe to call it on any i2c_mux_add_adapter() failure).
Cheers,
Peter
>
>> + }
>> +
>> + mux_deselect(muxc, MUX_DEFAULT_DEV);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id mule_i2c_mux_of_match[] = {
>> + {.compatible = "tsd,mule-i2c-mux",},
>
> if you are going to resend, can you leave one space after the
> '{' and before the '}'
>
>> + {},
>> +};
>> +MODULE_DEVICE_TABLE(of, mule_i2c_mux_of_match);
>> +
>> +static struct platform_driver mule_i2c_mux_driver = {
>> + .driver = {
>
> I don't see the need for this '\t' here, the alignment is too
> far. It just looks bad. Your choice, though.
>
> Thanks,
> Andi
>
>> + .name = "mule-i2c-mux",
>> + .of_match_table = mule_i2c_mux_of_match,
>> + },
>> + .probe = mule_i2c_mux_probe,
>> +};
>> +
>> +module_platform_driver(mule_i2c_mux_driver);
>> +
>> +MODULE_AUTHOR("Farouk Bouabid <farouk.bouabid@xxxxxxxxx>");
>> +MODULE_DESCRIPTION("I2C mux driver for Theobroma Systems Mule");
>> +MODULE_LICENSE("GPL");
>>
>> --
>> 2.34.1
>>
