1 files changed, 316 insertions, 0 deletions
diff --git a/drivers/nfc/st-nci/i2c.c b/drivers/nfc/st-nci/i2c.c
new file mode 100644
index 000000000..f9525ef87
--- /dev/null
+++ b/drivers/nfc/st-nci/i2c.c
@@ -0,0 +1,316 @@
+/*
+ * I2C Link Layer for ST NCI NFC controller familly based Driver
+ * Copyright (C) 2014-2015 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/consumer.h>
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/nfc.h>
+#include <linux/of.h>
+
+#include "st-nci.h"
+
+#define DRIVER_DESC "NCI NFC driver for ST_NCI"
+
+/* ndlc header */
+#define ST_NCI_FRAME_HEADROOM 1
+#define ST_NCI_FRAME_TAILROOM 0
+
+#define ST_NCI_I2C_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
+#define ST_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
+
+#define ST_NCI_DRIVER_NAME "st_nci"
+#define ST_NCI_I2C_DRIVER_NAME "st_nci_i2c"
+
+struct st_nci_i2c_phy {
+	struct i2c_client *i2c_dev;
+	struct llt_ndlc *ndlc;
+
+	bool irq_active;
+
+	struct gpio_desc *gpiod_reset;
+
+	struct st_nci_se_status se_status;
+};
+
+static int st_nci_i2c_enable(void *phy_id)
+{
+	struct st_nci_i2c_phy *phy = phy_id;
+
+	gpiod_set_value(phy->gpiod_reset, 0);
+	usleep_range(10000, 15000);
+	gpiod_set_value(phy->gpiod_reset, 1);
+	usleep_range(80000, 85000);
+
+	if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
+		enable_irq(phy->i2c_dev->irq);
+		phy->irq_active = true;
+	}
+
+	return 0;
+}
+
+static void st_nci_i2c_disable(void *phy_id)
+{
+	struct st_nci_i2c_phy *phy = phy_id;
+
+	disable_irq_nosync(phy->i2c_dev->irq);
+	phy->irq_active = false;
+}
+
+/*
+ * 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 st_nci_i2c_write(void *phy_id, struct sk_buff *skb)
+{
+	int r = -1;
+	struct st_nci_i2c_phy *phy = phy_id;
+	struct i2c_client *client = phy->i2c_dev;
+
+	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;
+	}
+
+	return r;
+}
+
+/*
+ * Reads an ndlc frame and returns it in a newly allocated sk_buff.
+ * returns:
+ * 0 : if received frame is complete
+ * -EREMOTEIO : i2c read error (fatal)
+ * -EBADMSG : frame was incorrect and discarded
+ * -ENOMEM : cannot allocate skb, frame dropped
+ */
+static int st_nci_i2c_read(struct st_nci_i2c_phy *phy,
+				 struct sk_buff **skb)
+{
+	int r;
+	u8 len;
+	u8 buf[ST_NCI_I2C_MAX_SIZE];
+	struct i2c_client *client = phy->i2c_dev;
+
+	r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
+	if (r < 0) {  /* Retry, chip was in standby */
+		usleep_range(1000, 4000);
+		r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
+	}
+
+	if (r != ST_NCI_I2C_MIN_SIZE)
+		return -EREMOTEIO;
+
+	len = be16_to_cpu(*(__be16 *) (buf + 2));
+	if (len > ST_NCI_I2C_MAX_SIZE) {
+		nfc_err(&client->dev, "invalid frame len\n");
+		return -EBADMSG;
+	}
+
+	*skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
+	if (*skb == NULL)
+		return -ENOMEM;
+
+	skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE);
+	skb_put(*skb, ST_NCI_I2C_MIN_SIZE);
+	memcpy((*skb)->data, buf, ST_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 + ST_NCI_I2C_MIN_SIZE, buf, len);
+
+	return 0;
+}
+
+/*
+ * Reads an ndlc frame from the chip.
+ *
+ * On ST_NCI, IRQ goes in idle state when read starts.
+ */
+static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
+{
+	struct st_nci_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->ndlc->powered) {
+		st_nci_i2c_disable(phy);
+		return IRQ_HANDLED;
+	}
+
+	r = st_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 = st_nci_i2c_write,
+	.enable = st_nci_i2c_enable,
+	.disable = st_nci_i2c_disable,
+};
+
+static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
+
+static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
+	{ "reset-gpios", &reset_gpios, 1 },
+	{},
+};
+
+static int st_nci_i2c_probe(struct i2c_client *client,
+				  const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct st_nci_i2c_phy *phy;
+	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(dev, sizeof(struct st_nci_i2c_phy), GFP_KERNEL);
+	if (!phy)
+		return -ENOMEM;
+
+	phy->i2c_dev = client;
+
+	i2c_set_clientdata(client, phy);
+
+	r = devm_acpi_dev_add_driver_gpios(dev, acpi_st_nci_gpios);
+	if (r)
+		dev_dbg(dev, "Unable to add GPIO mapping table\n");
+
+	/* Get RESET GPIO */
+	phy->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(phy->gpiod_reset)) {
+		nfc_err(dev, "Unable to get RESET GPIO\n");
+		return -ENODEV;
+	}
+
+	phy->se_status.is_ese_present =
+				device_property_read_bool(dev, "ese-present");
+	phy->se_status.is_uicc_present =
+				device_property_read_bool(dev, "uicc-present");
+
+	r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
+			ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
+			&phy->ndlc, &phy->se_status);
+	if (r < 0) {
+		nfc_err(&client->dev, "Unable to register ndlc layer\n");
+		return r;
+	}
+
+	phy->irq_active = true;
+	r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+				st_nci_irq_thread_fn,
+				IRQF_ONESHOT,
+				ST_NCI_DRIVER_NAME, phy);
+	if (r < 0)
+		nfc_err(&client->dev, "Unable to register IRQ handler\n");
+
+	return r;
+}
+
+static int st_nci_i2c_remove(struct i2c_client *client)
+{
+	struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
+
+	dev_dbg(&client->dev, "%s\n", __func__);
+
+	ndlc_remove(phy->ndlc);
+
+	return 0;
+}
+
+static const struct i2c_device_id st_nci_i2c_id_table[] = {
+	{ST_NCI_DRIVER_NAME, 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table);
+
+static const struct acpi_device_id st_nci_i2c_acpi_match[] = {
+	{"SMO2101"},
+	{"SMO2102"},
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, st_nci_i2c_acpi_match);
+
+static const struct of_device_id of_st_nci_i2c_match[] = {
+	{ .compatible = "st,st21nfcb-i2c", },
+	{ .compatible = "st,st21nfcb_i2c", },
+	{ .compatible = "st,st21nfcc-i2c", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match);
+
+static struct i2c_driver st_nci_i2c_driver = {
+	.driver = {
+		.name = ST_NCI_I2C_DRIVER_NAME,
+		.of_match_table = of_match_ptr(of_st_nci_i2c_match),
+		.acpi_match_table = ACPI_PTR(st_nci_i2c_acpi_match),
+	},
+	.probe = st_nci_i2c_probe,
+	.id_table = st_nci_i2c_id_table,
+	.remove = st_nci_i2c_remove,
+};
+module_i2c_driver(st_nci_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);