Merge branch 'for-6.8/mcp2221' into for-linus

- several assorted functional fixes for mcp2221 driver (Hamish Martin)

drivers/hid/hid-mcp2221.c

@@ -49,6 +49,7 @@ enum {
 	MCP2221_I2C_MASK_ADDR_NACK = 0x40,
 	MCP2221_I2C_WRADDRL_SEND = 0x21,
 	MCP2221_I2C_ADDR_NACK = 0x25,
+	MCP2221_I2C_READ_PARTIAL = 0x54,
 	MCP2221_I2C_READ_COMPL = 0x55,
 	MCP2221_ALT_F_NOT_GPIOV = 0xEE,
 	MCP2221_ALT_F_NOT_GPIOD = 0xEF,
@@ -187,6 +188,25 @@ static int mcp_cancel_last_cmd(struct mcp2221 *mcp)
 	return mcp_send_data_req_status(mcp, mcp->txbuf, 8);
 }
 
+/* Check if the last command succeeded or failed and return the result.
+ * If the command did fail, cancel that command which will free the i2c bus.
+ */
+static int mcp_chk_last_cmd_status_free_bus(struct mcp2221 *mcp)
+{
+	int ret;
+
+	ret = mcp_chk_last_cmd_status(mcp);
+	if (ret) {
+		/* The last command was a failure.
+		 * Send a cancel which will also free the bus.
+		 */
+		usleep_range(980, 1000);
+		mcp_cancel_last_cmd(mcp);
+	}
+
+	return ret;
+}
+
 static int mcp_set_i2c_speed(struct mcp2221 *mcp)
 {
 	int ret;
@@ -241,7 +261,7 @@ static int mcp_i2c_write(struct mcp2221 *mcp,
 		usleep_range(980, 1000);
 
 		if (last_status) {
-			ret = mcp_chk_last_cmd_status(mcp);
+			ret = mcp_chk_last_cmd_status_free_bus(mcp);
 			if (ret)
 				return ret;
 		}
@@ -278,6 +298,7 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp,
 {
 	int ret;
 	u16 total_len;
+	int retries = 0;
 
 	mcp->txbuf[0] = type;
 	if (msg) {
@@ -301,20 +322,31 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp,
 	mcp->rxbuf_idx = 0;
 
 	do {
+		/* Wait for the data to be read by the device */
+		usleep_range(980, 1000);
+
 		memset(mcp->txbuf, 0, 4);
 		mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
 
 		ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
-		if (ret)
-			return ret;
-
-		ret = mcp_chk_last_cmd_status(mcp);
-		if (ret)
-			return ret;
-
-		usleep_range(980, 1000);
+		if (ret) {
+			if (retries < 5) {
+				/* The data wasn't ready to read.
+				 * Wait a bit longer and try again.
+				 */
+				usleep_range(90, 100);
+				retries++;
+			} else {
+				return ret;
+			}
+		} else {
+			retries = 0;
+		}
 	} while (mcp->rxbuf_idx < total_len);
 
+	usleep_range(980, 1000);
+	ret = mcp_chk_last_cmd_status_free_bus(mcp);
+
 	return ret;
 }
 
@@ -328,11 +360,6 @@ static int mcp_i2c_xfer(struct i2c_adapter *adapter,
 
 	mutex_lock(&mcp->lock);
 
-	/* Setting speed before every transaction is required for mcp2221 */
-	ret = mcp_set_i2c_speed(mcp);
-	if (ret)
-		goto exit;
-
 	if (num == 1) {
 		if (msgs->flags & I2C_M_RD) {
 			ret = mcp_i2c_smbus_read(mcp, msgs, MCP2221_I2C_RD_DATA,
@@ -417,9 +444,7 @@ static int mcp_smbus_write(struct mcp2221 *mcp, u16 addr,
 	if (last_status) {
 		usleep_range(980, 1000);
 
-		ret = mcp_chk_last_cmd_status(mcp);
-		if (ret)
-			return ret;
+		ret = mcp_chk_last_cmd_status_free_bus(mcp);
 	}
 
 	return ret;
@@ -437,10 +462,6 @@ static int mcp_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
 
 	mutex_lock(&mcp->lock);
 
-	ret = mcp_set_i2c_speed(mcp);
-	if (ret)
-		goto exit;
-
 	switch (size) {
 
 	case I2C_SMBUS_QUICK:
@@ -791,7 +812,8 @@ static int mcp2221_raw_event(struct hid_device *hdev,
 				mcp->status = -EIO;
 				break;
 			}
-			if (data[2] == MCP2221_I2C_READ_COMPL) {
+			if (data[2] == MCP2221_I2C_READ_COMPL ||
+			    data[2] == MCP2221_I2C_READ_PARTIAL) {
 				buf = mcp->rxbuf;
 				memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]);
 				mcp->rxbuf_idx = mcp->rxbuf_idx + data[3];
@@ -1150,12 +1172,18 @@ static int mcp2221_probe(struct hid_device *hdev,
 	if (i2c_clk_freq < 50)
 		i2c_clk_freq = 50;
 	mcp->cur_i2c_clk_div = (12000000 / (i2c_clk_freq * 1000)) - 3;
+	ret = mcp_set_i2c_speed(mcp);
+	if (ret) {
+		hid_err(hdev, "can't set i2c speed: %d\n", ret);
+		return ret;
+	}
 
 	mcp->adapter.owner = THIS_MODULE;
 	mcp->adapter.class = I2C_CLASS_HWMON;
 	mcp->adapter.algo = &mcp_i2c_algo;
 	mcp->adapter.retries = 1;
 	mcp->adapter.dev.parent = &hdev->dev;
+	ACPI_COMPANION_SET(&mcp->adapter.dev, ACPI_COMPANION(hdev->dev.parent));
 	snprintf(mcp->adapter.name, sizeof(mcp->adapter.name),
 			"MCP2221 usb-i2c bridge");