Re: [PATCH v2 2/3] usb: typec: fsa4480: Add support to swap SBU orientation

[Heikki Krogerus]

On Fri, Oct 20, 2023 at 11:33:19AM +0200, Luca Weiss wrote:
> On some hardware designs the AUX+/- lanes are connected reversed to
> SBU1/2 compared to the expected design by FSA4480.
> 
> Made more complicated, the otherwise compatible Orient-Chip OCP96011
> expects the lanes to be connected reversed compared to FSA4480.
> 
> * FSA4480 block diagram shows AUX+ connected to SBU2 and AUX- to SBU1.
> * OCP96011 block diagram shows AUX+ connected to SBU1 and AUX- to SBU2.
> 
> So if OCP96011 is used as drop-in for FSA4480 then the orientation
> handling in the driver needs to be reversed to match the expectation of
> the OCP96011 hardware.
> 
> Support parsing the data-lanes parameter in the endpoint node to swap
> this in the driver.
> 
> The parse_data_lanes_mapping function is mostly taken from nb7vpq904m.c.
> 
> Reviewed-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> Signed-off-by: Luca Weiss <luca.weiss@xxxxxxxxxxxxx>

Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

> ---
>  drivers/usb/typec/mux/fsa4480.c | 71 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 71 insertions(+)
> 
> diff --git a/drivers/usb/typec/mux/fsa4480.c b/drivers/usb/typec/mux/fsa4480.c
> index e0ee1f621abb..cb7cdf90cb0a 100644
> --- a/drivers/usb/typec/mux/fsa4480.c
> +++ b/drivers/usb/typec/mux/fsa4480.c
> @@ -60,6 +60,7 @@ struct fsa4480 {
>  	unsigned int svid;
>  
>  	u8 cur_enable;
> +	bool swap_sbu_lanes;
>  };
>  
>  static const struct regmap_config fsa4480_regmap_config = {
> @@ -76,6 +77,9 @@ static int fsa4480_set(struct fsa4480 *fsa)
>  	u8 enable = FSA4480_ENABLE_DEVICE;
>  	u8 sel = 0;
>  
> +	if (fsa->swap_sbu_lanes)
> +		reverse = !reverse;
> +
>  	/* USB Mode */
>  	if (fsa->mode < TYPEC_STATE_MODAL ||
>  	    (!fsa->svid && (fsa->mode == TYPEC_MODE_USB2 ||
> @@ -179,12 +183,75 @@ static int fsa4480_mux_set(struct typec_mux_dev *mux, struct typec_mux_state *st
>  	return ret;
>  }
>  
> +enum {
> +	NORMAL_LANE_MAPPING,
> +	INVERT_LANE_MAPPING,
> +};
> +
> +#define DATA_LANES_COUNT	2
> +
> +static const int supported_data_lane_mapping[][DATA_LANES_COUNT] = {
> +	[NORMAL_LANE_MAPPING] = { 0, 1 },
> +	[INVERT_LANE_MAPPING] = { 1, 0 },
> +};
> +
> +static int fsa4480_parse_data_lanes_mapping(struct fsa4480 *fsa)
> +{
> +	struct fwnode_handle *ep;
> +	u32 data_lanes[DATA_LANES_COUNT];
> +	int ret, i, j;
> +
> +	ep = fwnode_graph_get_next_endpoint(dev_fwnode(&fsa->client->dev), NULL);
> +	if (!ep)
> +		return 0;
> +
> +	ret = fwnode_property_read_u32_array(ep, "data-lanes", data_lanes, DATA_LANES_COUNT);
> +	if (ret == -EINVAL)
> +		/* Property isn't here, consider default mapping */
> +		goto out_done;
> +	if (ret) {
> +		dev_err(&fsa->client->dev, "invalid data-lanes property: %d\n", ret);
> +		goto out_error;
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(supported_data_lane_mapping); i++) {
> +		for (j = 0; j < DATA_LANES_COUNT; j++) {
> +			if (data_lanes[j] != supported_data_lane_mapping[i][j])
> +				break;
> +		}
> +
> +		if (j == DATA_LANES_COUNT)
> +			break;
> +	}
> +
> +	switch (i) {
> +	case NORMAL_LANE_MAPPING:
> +		break;
> +	case INVERT_LANE_MAPPING:
> +		fsa->swap_sbu_lanes = true;
> +		break;
> +	default:
> +		dev_err(&fsa->client->dev, "invalid data-lanes mapping\n");
> +		ret = -EINVAL;
> +		goto out_error;
> +	}
> +
> +out_done:
> +	ret = 0;
> +
> +out_error:
> +	fwnode_handle_put(ep);
> +
> +	return ret;
> +}
> +
>  static int fsa4480_probe(struct i2c_client *client)
>  {
>  	struct device *dev = &client->dev;
>  	struct typec_switch_desc sw_desc = { };
>  	struct typec_mux_desc mux_desc = { };
>  	struct fsa4480 *fsa;
> +	int ret;
>  
>  	fsa = devm_kzalloc(dev, sizeof(*fsa), GFP_KERNEL);
>  	if (!fsa)
> @@ -193,6 +260,10 @@ static int fsa4480_probe(struct i2c_client *client)
>  	fsa->client = client;
>  	mutex_init(&fsa->lock);
>  
> +	ret = fsa4480_parse_data_lanes_mapping(fsa);
> +	if (ret)
> +		return ret;
> +
>  	fsa->regmap = devm_regmap_init_i2c(client, &fsa4480_regmap_config);
>  	if (IS_ERR(fsa->regmap))
>  		return dev_err_probe(dev, PTR_ERR(fsa->regmap), "failed to initialize regmap\n");
> 
> -- 
> 2.42.0

-- 
heikki