1 files changed, 398 insertions, 0 deletions

diff --git a/kernel/drivers/nfc/st21nfcb/i2c.c b/kernel/drivers/nfc/st21nfcb/i2c.c
new file mode 100644
index 000000000..76a4cad41
--- /dev/null
+++ b/kernel/drivers/nfc/st21nfcb/i2c.c
@@ -0,0 +1,398 @@
+/*
+ * I2C Link Layer for ST21NFCB NCI based Driver
+ * Copyright (C) 2014  STMicroelectronics SAS. 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/>.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/nfc.h>
+#include <linux/platform_data/st21nfcb.h>
+
+#include "ndlc.h"
+
+#define DRIVER_DESC "NCI NFC driver for ST21NFCB"
+
+/* ndlc header */
+#define ST21NFCB_FRAME_HEADROOM	1
+#define ST21NFCB_FRAME_TAILROOM 0
+
+#define ST21NFCB_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
+#define ST21NFCB_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
+
+#define ST21NFCB_NCI_I2C_DRIVER_NAME "st21nfcb_nci_i2c"
+
+static struct i2c_device_id st21nfcb_nci_i2c_id_table[] = {
+	{ST21NFCB_NCI_DRIVER_NAME, 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, st21nfcb_nci_i2c_id_table);
+
+struct st21nfcb_i2c_phy {
+	struct i2c_client *i2c_dev;
+	struct llt_ndlc *ndlc;
+
+	unsigned int gpio_reset;
+	unsigned int irq_polarity;
+
+	int powered;
+};
+
+#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 int st21nfcb_nci_i2c_enable(void *phy_id)
+{
+	struct st21nfcb_i2c_phy *phy = phy_id;
+
+	gpio_set_value(phy->gpio_reset, 0);
+	usleep_range(10000, 15000);
+	gpio_set_value(phy->gpio_reset, 1);
+	phy->powered = 1;
+	usleep_range(80000, 85000);
+
+	return 0;
+}
+
+static void st21nfcb_nci_i2c_disable(void *phy_id)
+{
+	struct st21nfcb_i2c_phy *phy = phy_id;
+
+	phy->powered = 0;
+	/* reset chip in order to flush clf */
+	gpio_set_value(phy->gpio_reset, 0);
+	usleep_range(10000, 15000);
+	gpio_set_value(phy->gpio_reset, 1);
+}
+
+static void st21nfcb_nci_remove_header(struct sk_buff *skb)
+{
+	skb_pull(skb, ST21NFCB_FRAME_HEADROOM);
+}
+
+/*
+ * Writing a frame must not return the number of written bytes.
+ * It must return either zero for success, or <0 for error.
+ * In addition, it must not alter the skb
+ */
+static int st21nfcb_nci_i2c_write(void *phy_id, struct sk_buff *skb)
+{
+	int r = -1;
+	struct st21nfcb_i2c_phy *phy = phy_id;
+	struct i2c_client *client = phy->i2c_dev;
+
+	I2C_DUMP_SKB("st21nfcb_nci_i2c_write", skb);
+
+	if (phy->ndlc->hard_fault != 0)
+		return phy->ndlc->hard_fault;
+
+	r = i2c_master_send(client, skb->data, skb->len);
+	if (r < 0) {  /* Retry, chip was in standby */
+		usleep_range(1000, 4000);
+		r = i2c_master_send(client, skb->data, skb->len);
+	}
+
+	if (r >= 0) {
+		if (r != skb->len)
+			r = -EREMOTEIO;
+		else
+			r = 0;
+	}
+
+	st21nfcb_nci_remove_header(skb);
+
+	return r;
+}
+
+/*
+ * Reads an ndlc frame and returns it in a newly allocated sk_buff.
+ * returns:
+ * frame size : if received frame is complete (find ST21NFCB_SOF_EOF at
+ * end of read)
+ * -EAGAIN : if received frame is incomplete (not find ST21NFCB_SOF_EOF
+ * at end of read)
+ * -EREMOTEIO : i2c read error (fatal)
+ * -EBADMSG : frame was incorrect and discarded
+ * (value returned from st21nfcb_nci_i2c_repack)
+ * -EIO : if no ST21NFCB_SOF_EOF is found after reaching
+ * the read length end sequence
+ */
+static int st21nfcb_nci_i2c_read(struct st21nfcb_i2c_phy *phy,
+				 struct sk_buff **skb)
+{
+	int r;
+	u8 len;
+	u8 buf[ST21NFCB_NCI_I2C_MAX_SIZE];
+	struct i2c_client *client = phy->i2c_dev;
+
+	r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
+	if (r < 0) {  /* Retry, chip was in standby */
+		usleep_range(1000, 4000);
+		r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
+	}
+
+	if (r != ST21NFCB_NCI_I2C_MIN_SIZE)
+		return -EREMOTEIO;
+
+	len = be16_to_cpu(*(__be16 *) (buf + 2));
+	if (len > ST21NFCB_NCI_I2C_MAX_SIZE) {
+		nfc_err(&client->dev, "invalid frame len\n");
+		return -EBADMSG;
+	}
+
+	*skb = alloc_skb(ST21NFCB_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
+	if (*skb == NULL)
+		return -ENOMEM;
+
+	skb_reserve(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
+	skb_put(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
+	memcpy((*skb)->data, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
+
+	if (!len)
+		return 0;
+
+	r = i2c_master_recv(client, buf, len);
+	if (r != len) {
+		kfree_skb(*skb);
+		return -EREMOTEIO;
+	}
+
+	skb_put(*skb, len);
+	memcpy((*skb)->data + ST21NFCB_NCI_I2C_MIN_SIZE, buf, len);
+
+	I2C_DUMP_SKB("i2c frame read", *skb);
+
+	return 0;
+}
+
+/*
+ * Reads an ndlc frame from the chip.
+ *
+ * On ST21NFCB, IRQ goes in idle state when read starts.
+ */
+static irqreturn_t st21nfcb_nci_irq_thread_fn(int irq, void *phy_id)
+{
+	struct st21nfcb_i2c_phy *phy = phy_id;
+	struct i2c_client *client;
+	struct sk_buff *skb = NULL;
+	int r;
+
+	if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) {
+		WARN_ON_ONCE(1);
+		return IRQ_NONE;
+	}
+
+	client = phy->i2c_dev;
+	dev_dbg(&client->dev, "IRQ\n");
+
+	if (phy->ndlc->hard_fault)
+		return IRQ_HANDLED;
+
+	if (!phy->powered) {
+		st21nfcb_nci_i2c_disable(phy);
+		return IRQ_HANDLED;
+	}
+
+	r = st21nfcb_nci_i2c_read(phy, &skb);
+	if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
+		return IRQ_HANDLED;
+
+	ndlc_recv(phy->ndlc, skb);
+
+	return IRQ_HANDLED;
+}
+
+static struct nfc_phy_ops i2c_phy_ops = {
+	.write = st21nfcb_nci_i2c_write,
+	.enable = st21nfcb_nci_i2c_enable,
+	.disable = st21nfcb_nci_i2c_disable,
+};
+
+#ifdef CONFIG_OF
+static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
+{
+	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
+	struct device_node *pp;
+	int gpio;
+	int r;
+
+	pp = client->dev.of_node;
+	if (!pp)
+		return -ENODEV;
+
+	/* Get GPIO from device tree */
+	gpio = of_get_named_gpio(pp, "reset-gpios", 0);
+	if (gpio < 0) {
+		nfc_err(&client->dev,
+			"Failed to retrieve reset-gpios from device tree\n");
+		return gpio;
+	}
+
+	/* GPIO request and configuration */
+	r = devm_gpio_request_one(&client->dev, gpio,
+				GPIOF_OUT_INIT_HIGH, "clf_reset");
+	if (r) {
+		nfc_err(&client->dev, "Failed to request reset pin\n");
+		return r;
+	}
+	phy->gpio_reset = gpio;
+
+	phy->irq_polarity = irq_get_trigger_type(client->irq);
+
+	return 0;
+}
+#else
+static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
+{
+	return -ENODEV;
+}
+#endif
+
+static int st21nfcb_nci_i2c_request_resources(struct i2c_client *client)
+{
+	struct st21nfcb_nfc_platform_data *pdata;
+	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
+	int r;
+
+	pdata = client->dev.platform_data;
+	if (pdata == NULL) {
+		nfc_err(&client->dev, "No platform data\n");
+		return -EINVAL;
+	}
+
+	/* store for later use */
+	phy->gpio_reset = pdata->gpio_reset;
+	phy->irq_polarity = pdata->irq_polarity;
+
+	r = devm_gpio_request_one(&client->dev,
+			phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset");
+	if (r) {
+		pr_err("%s : reset gpio_request failed\n", __FILE__);
+		return r;
+	}
+
+	return 0;
+}
+
+static int st21nfcb_nci_i2c_probe(struct i2c_client *client,
+				  const struct i2c_device_id *id)
+{
+	struct st21nfcb_i2c_phy *phy;
+	struct st21nfcb_nfc_platform_data *pdata;
+	int r;
+
+	dev_dbg(&client->dev, "%s\n", __func__);
+	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
+		return -ENODEV;
+	}
+
+	phy = devm_kzalloc(&client->dev, sizeof(struct st21nfcb_i2c_phy),
+			   GFP_KERNEL);
+	if (!phy)
+		return -ENOMEM;
+
+	phy->i2c_dev = client;
+
+	i2c_set_clientdata(client, phy);
+
+	pdata = client->dev.platform_data;
+	if (!pdata && client->dev.of_node) {
+		r = st21nfcb_nci_i2c_of_request_resources(client);
+		if (r) {
+			nfc_err(&client->dev, "No platform data\n");
+			return r;
+		}
+	} else if (pdata) {
+		r = st21nfcb_nci_i2c_request_resources(client);
+		if (r) {
+			nfc_err(&client->dev,
+				"Cannot get platform resources\n");
+			return r;
+		}
+	} else {
+		nfc_err(&client->dev,
+			"st21nfcb platform resources not available\n");
+		return -ENODEV;
+	}
+
+	r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
+			ST21NFCB_FRAME_HEADROOM, ST21NFCB_FRAME_TAILROOM,
+			&phy->ndlc);
+	if (r < 0) {
+		nfc_err(&client->dev, "Unable to register ndlc layer\n");
+		return r;
+	}
+
+	r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+				st21nfcb_nci_irq_thread_fn,
+				phy->irq_polarity | IRQF_ONESHOT,
+				ST21NFCB_NCI_DRIVER_NAME, phy);
+	if (r < 0)
+		nfc_err(&client->dev, "Unable to register IRQ handler\n");
+
+	return r;
+}
+
+static int st21nfcb_nci_i2c_remove(struct i2c_client *client)
+{
+	struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
+
+	dev_dbg(&client->dev, "%s\n", __func__);
+
+	ndlc_remove(phy->ndlc);
+
+	if (phy->powered)
+		st21nfcb_nci_i2c_disable(phy);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_st21nfcb_i2c_match[] = {
+	{ .compatible = "st,st21nfcb-i2c", },
+	{ .compatible = "st,st21nfcb_i2c", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_st21nfcb_i2c_match);
+#endif
+
+static struct i2c_driver st21nfcb_nci_i2c_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = ST21NFCB_NCI_I2C_DRIVER_NAME,
+		.of_match_table = of_match_ptr(of_st21nfcb_i2c_match),
+	},
+	.probe = st21nfcb_nci_i2c_probe,
+	.id_table = st21nfcb_nci_i2c_id_table,
+	.remove = st21nfcb_nci_i2c_remove,
+};
+
+module_i2c_driver(st21nfcb_nci_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);