NFC: microread: Add i2c physical layer
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/nfc/microread/i2c.c b/drivers/nfc/microread/i2c.c
new file mode 100644
index 0000000..1010894
--- /dev/null
+++ b/drivers/nfc/microread/i2c.c
@@ -0,0 +1,340 @@
+/*
+ * HCI based Driver for Inside Secure microread NFC Chip - i2c layer
+ *
+ * Copyright (C) 2013 Intel Corporation. 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, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+
+#include <linux/nfc.h>
+#include <net/nfc/hci.h>
+#include <net/nfc/llc.h>
+
+#include "microread.h"
+
+#define MICROREAD_I2C_DRIVER_NAME "microread"
+
+#define MICROREAD_I2C_FRAME_HEADROOM 1
+#define MICROREAD_I2C_FRAME_TAILROOM 1
+
+/* framing in HCI mode */
+#define MICROREAD_I2C_LLC_LEN 1
+#define MICROREAD_I2C_LLC_CRC 1
+#define MICROREAD_I2C_LLC_LEN_CRC (MICROREAD_I2C_LLC_LEN + \
+ MICROREAD_I2C_LLC_CRC)
+#define MICROREAD_I2C_LLC_MIN_SIZE (1 + MICROREAD_I2C_LLC_LEN_CRC)
+#define MICROREAD_I2C_LLC_MAX_PAYLOAD 29
+#define MICROREAD_I2C_LLC_MAX_SIZE (MICROREAD_I2C_LLC_LEN_CRC + 1 + \
+ MICROREAD_I2C_LLC_MAX_PAYLOAD)
+
+struct microread_i2c_phy {
+ struct i2c_client *i2c_dev;
+ struct nfc_hci_dev *hdev;
+
+ int irq;
+
+ int hard_fault; /*
+ * < 0 if hardware error occured (e.g. i2c err)
+ * and prevents normal operation.
+ */
+};
+
+#define I2C_DUMP_SKB(info, skb) \
+do { \
+ pr_debug("%s:\n", info); \
+ print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
+ 16, 1, (skb)->data, (skb)->len, 0); \
+} while (0)
+
+static void microread_i2c_add_len_crc(struct sk_buff *skb)
+{
+ int i;
+ u8 crc = 0;
+ int len;
+
+ len = skb->len;
+ *skb_push(skb, 1) = len;
+
+ for (i = 0; i < skb->len; i++)
+ crc = crc ^ skb->data[i];
+
+ *skb_put(skb, 1) = crc;
+}
+
+static void microread_i2c_remove_len_crc(struct sk_buff *skb)
+{
+ skb_pull(skb, MICROREAD_I2C_FRAME_HEADROOM);
+ skb_trim(skb, MICROREAD_I2C_FRAME_TAILROOM);
+}
+
+static int check_crc(struct sk_buff *skb)
+{
+ int i;
+ u8 crc = 0;
+
+ for (i = 0; i < skb->len - 1; i++)
+ crc = crc ^ skb->data[i];
+
+ if (crc != skb->data[skb->len-1]) {
+ pr_err(MICROREAD_I2C_DRIVER_NAME
+ ": CRC error 0x%x != 0x%x\n",
+ crc, skb->data[skb->len-1]);
+
+ pr_info(DRIVER_DESC ": %s : BAD CRC\n", __func__);
+
+ return -EPERM;
+ }
+
+ return 0;
+}
+
+static int microread_i2c_enable(void *phy_id)
+{
+ return 0;
+}
+
+static void microread_i2c_disable(void *phy_id)
+{
+ return;
+}
+
+static int microread_i2c_write(void *phy_id, struct sk_buff *skb)
+{
+ int r;
+ struct microread_i2c_phy *phy = phy_id;
+ struct i2c_client *client = phy->i2c_dev;
+
+ if (phy->hard_fault != 0)
+ return phy->hard_fault;
+
+ usleep_range(3000, 6000);
+
+ microread_i2c_add_len_crc(skb);
+
+ I2C_DUMP_SKB("i2c frame written", skb);
+
+ r = i2c_master_send(client, skb->data, skb->len);
+
+ if (r == -EREMOTEIO) { /* Retry, chip was in standby */
+ usleep_range(6000, 10000);
+ r = i2c_master_send(client, skb->data, skb->len);
+ }
+
+ if (r >= 0) {
+ if (r != skb->len)
+ r = -EREMOTEIO;
+ else
+ r = 0;
+ }
+
+ microread_i2c_remove_len_crc(skb);
+
+ return r;
+}
+
+
+static int microread_i2c_read(struct microread_i2c_phy *phy,
+ struct sk_buff **skb)
+{
+ int r;
+ u8 len;
+ u8 tmp[MICROREAD_I2C_LLC_MAX_SIZE - 1];
+ struct i2c_client *client = phy->i2c_dev;
+
+ pr_debug("%s\n", __func__);
+
+ r = i2c_master_recv(client, &len, 1);
+ if (r != 1) {
+ dev_err(&client->dev, "cannot read len byte\n");
+ return -EREMOTEIO;
+ }
+
+ if ((len < MICROREAD_I2C_LLC_MIN_SIZE) ||
+ (len > MICROREAD_I2C_LLC_MAX_SIZE)) {
+ dev_err(&client->dev, "invalid len byte\n");
+ pr_err("invalid len byte\n");
+ r = -EBADMSG;
+ goto flush;
+ }
+
+ *skb = alloc_skb(1 + len, GFP_KERNEL);
+ if (*skb == NULL) {
+ r = -ENOMEM;
+ goto flush;
+ }
+
+ *skb_put(*skb, 1) = len;
+
+ r = i2c_master_recv(client, skb_put(*skb, len), len);
+ if (r != len) {
+ kfree_skb(*skb);
+ return -EREMOTEIO;
+ }
+
+ I2C_DUMP_SKB("cc frame read", *skb);
+
+ r = check_crc(*skb);
+ if (r != 0) {
+ kfree_skb(*skb);
+ r = -EBADMSG;
+ goto flush;
+ }
+
+ skb_pull(*skb, 1);
+ skb_trim(*skb, (*skb)->len - MICROREAD_I2C_FRAME_TAILROOM);
+
+ usleep_range(3000, 6000);
+
+ return 0;
+
+flush:
+ if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
+ r = -EREMOTEIO;
+
+ usleep_range(3000, 6000);
+
+ return r;
+}
+
+static irqreturn_t microread_i2c_irq_thread_fn(int irq, void *phy_id)
+{
+ struct microread_i2c_phy *phy = phy_id;
+ struct i2c_client *client;
+ struct sk_buff *skb = NULL;
+ int r;
+
+ if (!phy || irq != phy->i2c_dev->irq) {
+ WARN_ON_ONCE(1);
+ return IRQ_NONE;
+ }
+
+ client = phy->i2c_dev;
+ dev_dbg(&client->dev, "IRQ\n");
+
+ if (phy->hard_fault != 0)
+ return IRQ_HANDLED;
+
+ r = microread_i2c_read(phy, &skb);
+ if (r == -EREMOTEIO) {
+ phy->hard_fault = r;
+
+ nfc_hci_recv_frame(phy->hdev, NULL);
+
+ return IRQ_HANDLED;
+ } else if ((r == -ENOMEM) || (r == -EBADMSG)) {
+ return IRQ_HANDLED;
+ }
+
+ nfc_hci_recv_frame(phy->hdev, skb);
+
+ return IRQ_HANDLED;
+}
+
+static struct nfc_phy_ops i2c_phy_ops = {
+ .write = microread_i2c_write,
+ .enable = microread_i2c_enable,
+ .disable = microread_i2c_disable,
+};
+
+static int microread_i2c_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct microread_i2c_phy *phy;
+ struct microread_nfc_platform_data *pdata =
+ dev_get_platdata(&client->dev);
+ int r;
+
+ dev_dbg(&client->dev, "client %p", client);
+
+ if (!pdata) {
+ dev_err(&client->dev, "client %p: missing platform data",
+ client);
+ return -EINVAL;
+ }
+
+ phy = devm_kzalloc(&client->dev, sizeof(struct microread_i2c_phy),
+ GFP_KERNEL);
+ if (!phy) {
+ dev_err(&client->dev, "Can't allocate microread phy");
+ return -ENOMEM;
+ }
+
+ i2c_set_clientdata(client, phy);
+ phy->i2c_dev = client;
+
+ r = request_threaded_irq(client->irq, NULL, microread_i2c_irq_thread_fn,
+ IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+ MICROREAD_I2C_DRIVER_NAME, phy);
+ if (r) {
+ dev_err(&client->dev, "Unable to register IRQ handler");
+ return r;
+ }
+
+ r = microread_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
+ MICROREAD_I2C_FRAME_HEADROOM,
+ MICROREAD_I2C_FRAME_TAILROOM,
+ MICROREAD_I2C_LLC_MAX_PAYLOAD, &phy->hdev);
+ if (r < 0)
+ goto err_irq;
+
+ dev_info(&client->dev, "Probed");
+
+ return 0;
+
+err_irq:
+ free_irq(client->irq, phy);
+
+ return r;
+}
+
+static int microread_i2c_remove(struct i2c_client *client)
+{
+ struct microread_i2c_phy *phy = i2c_get_clientdata(client);
+
+ dev_dbg(&client->dev, "%s\n", __func__);
+
+ microread_remove(phy->hdev);
+
+ free_irq(client->irq, phy);
+
+ return 0;
+}
+
+static struct i2c_device_id microread_i2c_id[] = {
+ { MICROREAD_I2C_DRIVER_NAME, 0},
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, microread_i2c_id);
+
+static struct i2c_driver microread_i2c_driver = {
+ .driver = {
+ .name = MICROREAD_I2C_DRIVER_NAME,
+ },
+ .probe = microread_i2c_probe,
+ .remove = microread_i2c_remove,
+ .id_table = microread_i2c_id,
+};
+
+module_i2c_driver(microread_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);