NFC: Add STMicroelectronics ST95HF driver

This driver supports STMicroelectronics NFC Transceiver
"ST95HF", in in initiator role to read/write ISO14443 Type 4A,
ISO14443 Type 4B and ISO15693 Type5 tags.

The ST95HF datasheet is available here:
http://www.st.com/web/en/resource/technical/document/datasheet/DM00102056.pdf

Signed-off-by: Shikha Singh <shikha.singh@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 167 insertions, 0 deletions

diff --git a/drivers/nfc/st95hf/spi.c b/drivers/nfc/st95hf/spi.c
new file mode 100644
index 000000000000..e2d3bbcc8c34
--- /dev/null
+++ b/drivers/nfc/st95hf/spi.c
@@ -0,0 +1,167 @@
+/*
+ * ----------------------------------------------------------------------------
+ * drivers/nfc/st95hf/spi.c function definitions for SPI communication
+ * ----------------------------------------------------------------------------
+ * Copyright (C) 2015 STMicroelectronics Pvt. Ltd. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "spi.h"
+
+/* Function to send user provided buffer to ST95HF through SPI */
+int st95hf_spi_send(struct st95hf_spi_context *spicontext,
+		    unsigned char *buffertx,
+		    int datalen,
+		    enum req_type reqtype)
+{
+	struct spi_message m;
+	int result = 0;
+	struct spi_device *spidev = spicontext->spidev;
+	struct spi_transfer tx_transfer = {
+		.tx_buf = buffertx,
+		.len = datalen,
+	};
+
+	mutex_lock(&spicontext->spi_lock);
+
+	if (reqtype == SYNC) {
+		spicontext->req_issync = true;
+		reinit_completion(&spicontext->done);
+	} else {
+		spicontext->req_issync = false;
+	}
+
+	spi_message_init(&m);
+	spi_message_add_tail(&tx_transfer, &m);
+
+	result = spi_sync(spidev, &m);
+	if (result) {
+		dev_err(&spidev->dev, "error: sending cmd to st95hf using SPI = %d\n",
+			result);
+		mutex_unlock(&spicontext->spi_lock);
+		return result;
+	}
+
+	/* return for asynchronous or no-wait case */
+	if (reqtype == ASYNC) {
+		mutex_unlock(&spicontext->spi_lock);
+		return 0;
+	}
+
+	result = wait_for_completion_timeout(&spicontext->done,
+					     msecs_to_jiffies(1000));
+	/* check for timeout or success */
+	if (!result) {
+		dev_err(&spidev->dev, "error: response not ready timeout\n");
+		result = -ETIMEDOUT;
+	} else {
+		result = 0;
+	}
+
+	mutex_unlock(&spicontext->spi_lock);
+
+	return result;
+}
+EXPORT_SYMBOL_GPL(st95hf_spi_send);
+
+/* Function to Receive command Response */
+int st95hf_spi_recv_response(struct st95hf_spi_context *spicontext,
+			     unsigned char *receivebuff)
+{
+	int len = 0;
+	struct spi_transfer tx_takedata;
+	struct spi_message m;
+	struct spi_device *spidev = spicontext->spidev;
+	unsigned char readdata_cmd = ST95HF_COMMAND_RECEIVE;
+	struct spi_transfer t[2] = {
+		{.tx_buf = &readdata_cmd, .len = 1,},
+		{.rx_buf = receivebuff, .len = 2, .cs_change = 1,},
+	};
+
+	int ret = 0;
+
+	memset(&tx_takedata, 0x0, sizeof(struct spi_transfer));
+
+	mutex_lock(&spicontext->spi_lock);
+
+	/* First spi transfer to know the length of valid data */
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+
+	ret = spi_sync(spidev, &m);
+	if (ret) {
+		dev_err(&spidev->dev, "spi_recv_resp, data length error = %d\n",
+			ret);
+		mutex_unlock(&spicontext->spi_lock);
+		return ret;
+	}
+
+	/* As 2 bytes are already read */
+	len = 2;
+
+	/* Support of long frame */
+	if (receivebuff[0] & 0x60)
+		len += (((receivebuff[0] & 0x60) >> 5) << 8) | receivebuff[1];
+	else
+		len += receivebuff[1];
+
+	/* Now make a transfer to read only relevant bytes */
+	tx_takedata.rx_buf = &receivebuff[2];
+	tx_takedata.len = len - 2;
+
+	spi_message_init(&m);
+	spi_message_add_tail(&tx_takedata, &m);
+
+	ret = spi_sync(spidev, &m);
+
+	mutex_unlock(&spicontext->spi_lock);
+	if (ret) {
+		dev_err(&spidev->dev, "spi_recv_resp, data read error = %d\n",
+			ret);
+		return ret;
+	}
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(st95hf_spi_recv_response);
+
+int st95hf_spi_recv_echo_res(struct st95hf_spi_context *spicontext,
+			     unsigned char *receivebuff)
+{
+	unsigned char readdata_cmd = ST95HF_COMMAND_RECEIVE;
+	struct spi_transfer t[2] = {
+		{.tx_buf = &readdata_cmd, .len = 1,},
+		{.rx_buf = receivebuff, .len = 1,},
+	};
+	struct spi_message m;
+	struct spi_device *spidev = spicontext->spidev;
+	int ret = 0;
+
+	mutex_lock(&spicontext->spi_lock);
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+	ret = spi_sync(spidev, &m);
+
+	mutex_unlock(&spicontext->spi_lock);
+
+	if (ret)
+		dev_err(&spidev->dev, "recv_echo_res, data read error = %d\n",
+			ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(st95hf_spi_recv_echo_res);