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

Luca Weiss
2023-10-13T11:38:29Z

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.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
---
drivers/usb/typec/mux/fsa4480.c | 81 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 81 insertions(+)

diff --git a/drivers/usb/typec/mux/fsa4480.c b/drivers/usb/typec/mux/fsa4480.c
index e0ee1f621abb..6ee467c96fb6 100644
--- a/drivers/usb/typec/mux/fsa4480.c
+++ b/drivers/usb/typec/mux/fsa4480.c
@@ -9,6 +9,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
+#include <linux/of_graph.h>
#include <linux/regmap.h>
#include <linux/usb/typec_dp.h>
#include <linux/usb/typec_mux.h>
@@ -60,6 +61,7 @@ struct fsa4480 {
unsigned int svid;

u8 cur_enable;
+ bool swap_sbu_lanes;
};

static const struct regmap_config fsa4480_regmap_config = {
@@ -76,6 +78,9 @@ 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 +184,84 @@ 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 device_node *ep;
+ u32 data_lanes[DATA_LANES_COUNT];
+ int ret, i, j;
+
+ ep = of_graph_get_next_endpoint(fsa->client->dev.of_node, NULL);
+ if (!ep)
+ return 0;
+
+ ret = of_property_count_u32_elems(ep, "data-lanes");
+ if (ret == -EINVAL)
+ /* Property isn't here, consider default mapping */
+ goto out_done;
+ if (ret < 0)
+ goto out_error;
+
+ if (ret != DATA_LANES_COUNT) {
+ dev_err(&fsa->client->dev, "expected 2 data lanes\n");
+ ret = -EINVAL;
+ goto out_error;
+ }
+
+ ret = of_property_read_u32_array(ep, "data-lanes", data_lanes, DATA_LANES_COUNT);
+ if (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;
+ dev_info(&fsa->client->dev, "using inverted data lanes mapping\n");
+ break;
+ default:
+ dev_err(&fsa->client->dev, "invalid data lanes mapping\n");
+ ret = -EINVAL;
+ goto out_error;
+ }
+
+out_done:
+ ret = 0;
+
+out_error:
+ of_node_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 +270,10 @@ 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