NFC: trf7970a: Add ISO/IEC 15693 and Type 5 tag Support

Add support for ISO/IEC 15693 RF technology and Type 5 tags.
Note that Type 5 tags used to be referred to as Type V tags.

CC: Erick Macias <emacias@ti.com>
CC: Felipe Balbi <balbi@ti.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/nfc/trf7970a.c

@@ -85,10 +85,26 @@
  * Unfortunately, that means that the driver has to peek into tx frames
  * when the framing is 'NFC_DIGITAL_FRAMING_NFCA_T2T'.  This is done by
  * the trf7970a_per_cmd_config() routine.
+ *
+ * ISO/IEC 15693 frames specify whether to use single or double sub-carrier
+ * frequencies and whether to use low or high data rates in the flags byte
+ * of the frame.  This means that the driver has to peek at all 15693 frames
+ * to determine what speed to set the communication to.  In addition, write
+ * and lock commands use the OPTION flag to indicate that an EOF must be
+ * sent to the tag before it will send its response.  So the driver has to
+ * examine all frames for that reason too.
+ *
+ * It is unclear how long to wait before sending the EOF.  According to the
+ * Note under Table 1-1 in section 1.6 of
+ * http://www.ti.com/lit/ug/scbu011/scbu011.pdf, that wait should be at least
+ * 10 ms for TI Tag-it HF-I tags; however testing has shown that is not long
+ * enough.  For this reason, the driver waits 20 ms which seems to work
+ * reliably.
  */
 
 #define TRF7970A_SUPPORTED_PROTOCOLS \
-		(NFC_PROTO_MIFARE_MASK | NFC_PROTO_ISO14443_MASK)
+		(NFC_PROTO_MIFARE_MASK | NFC_PROTO_ISO14443_MASK |	\
+		 NFC_PROTO_ISO15693_MASK)
 
 /* TX data must be prefixed with a FIFO reset cmd, a cmd that depends
  * on what the current framing is, the address of the TX length byte 1
@@ -106,6 +122,7 @@
 
 #define TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT	5
 #define TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT	3
+#define TRF7970A_WAIT_TO_ISSUE_ISO15693_EOF	20
 
 /* Quirks */
 /* Erratum: When reading IRQ Status register on trf7970a, we must issue a
@@ -265,6 +282,36 @@
 /* NFC (ISO/IEC 14443A) Type 2 Tag commands */
 #define NFC_T2T_CMD_READ			0x30
 
+/* ISO 15693 commands codes */
+#define ISO15693_CMD_INVENTORY			0x01
+#define ISO15693_CMD_READ_SINGLE_BLOCK		0x20
+#define ISO15693_CMD_WRITE_SINGLE_BLOCK		0x21
+#define ISO15693_CMD_LOCK_BLOCK			0x22
+#define ISO15693_CMD_READ_MULTIPLE_BLOCK	0x23
+#define ISO15693_CMD_WRITE_MULTIPLE_BLOCK	0x24
+#define ISO15693_CMD_SELECT			0x25
+#define ISO15693_CMD_RESET_TO_READY		0x26
+#define ISO15693_CMD_WRITE_AFI			0x27
+#define ISO15693_CMD_LOCK_AFI			0x28
+#define ISO15693_CMD_WRITE_DSFID		0x29
+#define ISO15693_CMD_LOCK_DSFID			0x2a
+#define ISO15693_CMD_GET_SYSTEM_INFO		0x2b
+#define ISO15693_CMD_GET_MULTIPLE_BLOCK_SECURITY_STATUS	0x2c
+
+/* ISO 15693 request and response flags */
+#define ISO15693_REQ_FLAG_SUB_CARRIER		BIT(0)
+#define ISO15693_REQ_FLAG_DATA_RATE		BIT(1)
+#define ISO15693_REQ_FLAG_INVENTORY		BIT(2)
+#define ISO15693_REQ_FLAG_PROTOCOL_EXT		BIT(3)
+#define ISO15693_REQ_FLAG_SELECT		BIT(4)
+#define ISO15693_REQ_FLAG_AFI			BIT(4)
+#define ISO15693_REQ_FLAG_ADDRESS		BIT(5)
+#define ISO15693_REQ_FLAG_NB_SLOTS		BIT(5)
+#define ISO15693_REQ_FLAG_OPTION		BIT(6)
+
+#define ISO15693_REQ_FLAG_SPEED_MASK \
+		(ISO15693_REQ_FLAG_SUB_CARRIER | ISO15693_REQ_FLAG_DATA_RATE)
+
 enum trf7970a_state {
 	TRF7970A_ST_OFF,
 	TRF7970A_ST_IDLE,
@@ -272,6 +319,7 @@ enum trf7970a_state {
 	TRF7970A_ST_WAIT_FOR_TX_FIFO,
 	TRF7970A_ST_WAIT_FOR_RX_DATA,
 	TRF7970A_ST_WAIT_FOR_RX_DATA_CONT,
+	TRF7970A_ST_WAIT_TO_ISSUE_EOF,
 	TRF7970A_ST_MAX
 };
 
@@ -293,6 +341,7 @@ struct trf7970a {
 	int				technology;
 	int				framing;
 	u8				tx_cmd;
+	bool				issue_eof;
 	int				en2_gpio;
 	int				en_gpio;
 	struct mutex			lock;
@@ -454,8 +503,13 @@ static int trf7970a_transmit(struct trf7970a *trf, struct sk_buff *skb,
 		trf->state = TRF7970A_ST_WAIT_FOR_TX_FIFO;
 		timeout = TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT;
 	} else {
-		trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA;
-		timeout = trf->timeout;
+		if (trf->issue_eof) {
+			trf->state = TRF7970A_ST_WAIT_TO_ISSUE_EOF;
+			timeout = TRF7970A_WAIT_TO_ISSUE_ISO15693_EOF;
+		} else {
+			trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA;
+			timeout = trf->timeout;
+		}
 	}
 
 	dev_dbg(trf->dev, "Setting timeout for %d ms, state: %d\n", timeout,
@@ -631,6 +685,10 @@ static irqreturn_t trf7970a_irq(int irq, void *dev_id)
 			trf7970a_send_err_upstream(trf, -EIO);
 		}
 		break;
+	case TRF7970A_ST_WAIT_TO_ISSUE_EOF:
+		if (status != TRF7970A_IRQ_STATUS_TX)
+			trf7970a_send_err_upstream(trf, -EIO);
+		break;
 	default:
 		dev_err(trf->dev, "%s - Driver in invalid state: %d\n",
 				__func__, trf->state);
@@ -640,6 +698,29 @@ static irqreturn_t trf7970a_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static void trf7970a_issue_eof(struct trf7970a *trf)
+{
+	int ret;
+
+	dev_dbg(trf->dev, "Issuing EOF\n");
+
+	ret = trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
+	if (ret)
+		trf7970a_send_err_upstream(trf, ret);
+
+	ret = trf7970a_cmd(trf, TRF7970A_CMD_EOF);
+	if (ret)
+		trf7970a_send_err_upstream(trf, ret);
+
+	trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA;
+
+	dev_dbg(trf->dev, "Setting timeout for %d ms, state: %d\n",
+			trf->timeout, trf->state);
+
+	schedule_delayed_work(&trf->timeout_work,
+			msecs_to_jiffies(trf->timeout));
+}
+
 static void trf7970a_timeout_work_handler(struct work_struct *work)
 {
 	struct trf7970a *trf = container_of(work, struct trf7970a,
@@ -654,6 +735,8 @@ static void trf7970a_timeout_work_handler(struct work_struct *work)
 		trf->ignore_timeout = false;
 	else if (trf->state == TRF7970A_ST_WAIT_FOR_RX_DATA_CONT)
 		trf7970a_send_upstream(trf); /* No more rx data so send up */
+	else if (trf->state == TRF7970A_ST_WAIT_TO_ISSUE_EOF)
+		trf7970a_issue_eof(trf);
 	else
 		trf7970a_send_err_upstream(trf, -ETIMEDOUT);
 
@@ -801,6 +884,9 @@ static int trf7970a_config_rf_tech(struct trf7970a *trf, int tech)
 	case NFC_DIGITAL_RF_TECH_106A:
 		trf->iso_ctrl = TRF7970A_ISO_CTRL_14443A_106;
 		break;
+	case NFC_DIGITAL_RF_TECH_ISO15693:
+		trf->iso_ctrl = TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648;
+		break;
 	default:
 		dev_dbg(trf->dev, "Unsupported rf technology: %d\n", tech);
 		return -EINVAL;
@@ -823,6 +909,8 @@ static int trf7970a_config_framing(struct trf7970a *trf, int framing)
 		break;
 	case NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A:
 	case NFC_DIGITAL_FRAMING_NFCA_T4T:
+	case NFC_DIGITAL_FRAMING_ISO15693_INVENTORY:
+	case NFC_DIGITAL_FRAMING_ISO15693_T5T:
 		trf->tx_cmd = TRF7970A_CMD_TRANSMIT;
 		trf->iso_ctrl &= ~TRF7970A_ISO_CTRL_RX_CRC_N;
 		break;
@@ -873,15 +961,39 @@ static int trf7970a_in_configure_hw(struct nfc_digital_dev *ddev, int type,
 	return ret;
 }
 
+static int trf7970a_is_iso15693_write_or_lock(u8 cmd)
+{
+	switch (cmd) {
+	case ISO15693_CMD_WRITE_SINGLE_BLOCK:
+	case ISO15693_CMD_LOCK_BLOCK:
+	case ISO15693_CMD_WRITE_MULTIPLE_BLOCK:
+	case ISO15693_CMD_WRITE_AFI:
+	case ISO15693_CMD_LOCK_AFI:
+	case ISO15693_CMD_WRITE_DSFID:
+	case ISO15693_CMD_LOCK_DSFID:
+		return 1;
+		break;
+	default:
+		return 0;
+	}
+}
+
 static int trf7970a_per_cmd_config(struct trf7970a *trf, struct sk_buff *skb)
 {
 	u8 *req = skb->data;
-	u8 special_fcn_reg1;
+	u8 special_fcn_reg1, iso_ctrl;
 	int ret;
 
+	trf->issue_eof = false;
+
 	/* When issuing Type 2 read command, make sure the '4_bit_RX' bit in
 	 * special functions register 1 is cleared; otherwise, its a write or
 	 * sector select command and '4_bit_RX' must be set.
+	 *
+	 * When issuing an ISO 15693 command, inspect the flags byte to see
+	 * what speed to use.  Also, remember if the OPTION flag is set on
+	 * a Type 5 write or lock command so the driver will know that it
+	 * has to send an EOF in order to get a response.
 	 */
 	if ((trf->technology == NFC_DIGITAL_RF_TECH_106A) &&
 			(trf->framing == NFC_DIGITAL_FRAMING_NFCA_T2T)) {
@@ -898,6 +1010,37 @@ static int trf7970a_per_cmd_config(struct trf7970a *trf, struct sk_buff *skb)
 
 			trf->special_fcn_reg1 = special_fcn_reg1;
 		}
+	} else if (trf->technology == NFC_DIGITAL_RF_TECH_ISO15693) {
+		iso_ctrl = trf->iso_ctrl & ~TRF7970A_ISO_CTRL_RFID_SPEED_MASK;
+
+		switch (req[0] & ISO15693_REQ_FLAG_SPEED_MASK) {
+		case 0x00:
+			iso_ctrl |= TRF7970A_ISO_CTRL_15693_SGL_1OF4_662;
+			break;
+		case ISO15693_REQ_FLAG_SUB_CARRIER:
+			iso_ctrl |= TRF7970A_ISO_CTRL_15693_DBL_1OF4_667a;
+			break;
+		case ISO15693_REQ_FLAG_DATA_RATE:
+			iso_ctrl |= TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648;
+			break;
+		case (ISO15693_REQ_FLAG_SUB_CARRIER |
+				ISO15693_REQ_FLAG_DATA_RATE):
+			iso_ctrl |= TRF7970A_ISO_CTRL_15693_DBL_1OF4_2669;
+			break;
+		}
+
+		if (iso_ctrl != trf->iso_ctrl) {
+			ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl);
+			if (ret)
+				return ret;
+
+			trf->iso_ctrl = iso_ctrl;
+		}
+
+		if ((trf->framing == NFC_DIGITAL_FRAMING_ISO15693_T5T) &&
+				trf7970a_is_iso15693_write_or_lock(req[1]) &&
+				(req[0] & ISO15693_REQ_FLAG_OPTION))
+			trf->issue_eof = true;
 	}
 
 	return 0;
@@ -1185,6 +1328,7 @@ static int trf7970a_remove(struct spi_device *spi)
 	case TRF7970A_ST_WAIT_FOR_TX_FIFO:
 	case TRF7970A_ST_WAIT_FOR_RX_DATA:
 	case TRF7970A_ST_WAIT_FOR_RX_DATA_CONT:
+	case TRF7970A_ST_WAIT_TO_ISSUE_EOF:
 		trf7970a_send_err_upstream(trf, -ECANCELED);
 		break;
 	default: