From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
Enable additional features based on DT settings and unconditionally
release the shared interrupt pin after 1.6 seconds and allow to use
it as reset.
These features aren't enabled by default & its up to board designer
to enable the same as it may have unexpected side effects.
These should be validated for proper functioning & detection of devices
in secondary bus as sometimes it can cause secondary bus being disabled.
Signed-off-by: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
Signed-off-by: Naresh Solanki <naresh.solanki@xxxxxxxxxxxxx>
---
Changes in V4:
- Drop max7358
- Update #define
- Move conf variable
- Print warning when I2C_FUNC_SMBUS_WRITE_BYTE_DATA isn't supported
Changes in V3:
- Delete unused #define
- Update pca954x_init
- Update commit message
Changes in V2:
- Update comments
- Update check for DT properties
---
drivers/i2c/muxes/i2c-mux-pca954x.c | 44 ++++++++++++++++++++++++++++-
1 file changed, 43 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 2219062104fb..f37ce332078c 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -57,6 +57,20 @@
#define PCA954X_IRQ_OFFSET 4
+/*
+ * MAX7357's configuration register is writeable after POR, but
+ * can be locked by setting the basic mode bit. MAX7358 configuration
+ * register is locked by default and needs to be unlocked first.
+ * The configuration register holds the following settings:
+ */
+#define MAX7357_CONF_INT_ENABLE BIT(0)
+#define MAX7357_CONF_FLUSH_OUT BIT(1)
+#define MAX7357_CONF_RELEASE_INT BIT(2)
+#define MAX7357_CONF_DISCON_SINGLE_CHAN BIT(4)
+#define MAX7357_CONF_PRECONNECT_TEST BIT(7)
+
+#define MAX7357_POR_DEFAULT_CONF MAX7357_CONF_INT_ENABLE
+
enum pca_type {
max_7356,
max_7357,
@@ -470,7 +484,35 @@ static int pca954x_init(struct i2c_client *client, struct pca954x *data)
else
data->last_chan = 0; /* Disconnect multiplexer */
- ret = i2c_smbus_write_byte(client, data->last_chan);
+ if (device_is_compatible(&client->dev, "maxim,max7357")) {
+ if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
+ u8 conf = MAX7357_POR_DEFAULT_CONF;
+ /*
+ * The interrupt signal is shared with the reset pin. Release the
+ * interrupt after 1.6 seconds to allow using the pin as reset.
+ * The interrupt isn't serviced yet.
+ */
+ conf |= MAX7357_CONF_RELEASE_INT;
+
+ if (device_property_read_bool(&client->dev, "maxim,isolate-stuck-channel"))
+ conf |= MAX7357_CONF_DISCON_SINGLE_CHAN;
+ if (device_property_read_bool(&client->dev,
+ "maxim,send-flush-out-sequence"))
+ conf |= MAX7357_CONF_FLUSH_OUT;
+ if (device_property_read_bool(&client->dev,
+ "maxim,preconnection-wiggle-test-enable"))
+ conf |= MAX7357_CONF_PRECONNECT_TEST;
+
+ ret = i2c_smbus_write_byte_data(client, data->last_chan, conf);
+ } else {
+ dev_warn(&client->dev,
+ "Write byte not supported. Cannot enable enhanced mode features");
+ ret = i2c_smbus_write_byte(client, data->last_chan);
+ }
+ } else {
+ ret = i2c_smbus_write_byte(client, data->last_chan);
+ }
+
if (ret < 0)
data->last_chan = 0;
--
2.41.0
