1 files changed, 318 insertions, 0 deletions
diff --git a/drivers/nfc/st-nci/spi.c b/drivers/nfc/st-nci/spi.c
new file mode 100644
index 000000000..8db323ade
--- /dev/null
+++ b/drivers/nfc/st-nci/spi.c
@@ -0,0 +1,318 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SPI Link Layer for ST NCI based Driver
+ * Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/spi/spi.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 <net/nfc/nci.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_SPI_MIN_SIZE 4   /* PCB(1) + NCI Packet header(3) */
+#define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
+
+#define ST_NCI_DRIVER_NAME "st_nci"
+#define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
+
+struct st_nci_spi_phy {
+	struct spi_device *spi_dev;
+	struct llt_ndlc *ndlc;
+
+	bool irq_active;
+
+	struct gpio_desc *gpiod_reset;
+
+	struct st_nci_se_status se_status;
+};
+
+static int st_nci_spi_enable(void *phy_id)
+{
+	struct st_nci_spi_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->spi_dev->irq);
+		phy->irq_active = true;
+	}
+
+	return 0;
+}
+
+static void st_nci_spi_disable(void *phy_id)
+{
+	struct st_nci_spi_phy *phy = phy_id;
+
+	disable_irq_nosync(phy->spi_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_spi_write(void *phy_id, struct sk_buff *skb)
+{
+	int r;
+	struct st_nci_spi_phy *phy = phy_id;
+	struct spi_device *dev = phy->spi_dev;
+	struct sk_buff *skb_rx;
+	u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
+	       ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
+	struct spi_transfer spi_xfer = {
+		.tx_buf = skb->data,
+		.rx_buf = buf,
+		.len = skb->len,
+	};
+
+	if (phy->ndlc->hard_fault != 0)
+		return phy->ndlc->hard_fault;
+
+	r = spi_sync_transfer(dev, &spi_xfer, 1);
+	/*
+	 * We may have received some valuable data on miso line.
+	 * Send them back in the ndlc state machine.
+	 */
+	if (!r) {
+		skb_rx = alloc_skb(skb->len, GFP_KERNEL);
+		if (!skb_rx) {
+			r = -ENOMEM;
+			goto exit;
+		}
+
+		skb_put(skb_rx, skb->len);
+		memcpy(skb_rx->data, buf, skb->len);
+		ndlc_recv(phy->ndlc, skb_rx);
+	}
+
+exit:
+	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_spi_read(struct st_nci_spi_phy *phy,
+			struct sk_buff **skb)
+{
+	int r;
+	u8 len;
+	u8 buf[ST_NCI_SPI_MAX_SIZE];
+	struct spi_device *dev = phy->spi_dev;
+	struct spi_transfer spi_xfer = {
+		.rx_buf = buf,
+		.len = ST_NCI_SPI_MIN_SIZE,
+	};
+
+	r = spi_sync_transfer(dev, &spi_xfer, 1);
+	if (r < 0)
+		return -EREMOTEIO;
+
+	len = be16_to_cpu(*(__be16 *) (buf + 2));
+	if (len > ST_NCI_SPI_MAX_SIZE) {
+		nfc_err(&dev->dev, "invalid frame len\n");
+		phy->ndlc->hard_fault = 1;
+		return -EBADMSG;
+	}
+
+	*skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
+	if (*skb == NULL)
+		return -ENOMEM;
+
+	skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
+	skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
+	memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
+
+	if (!len)
+		return 0;
+
+	spi_xfer.len = len;
+	r = spi_sync_transfer(dev, &spi_xfer, 1);
+	if (r < 0) {
+		kfree_skb(*skb);
+		return -EREMOTEIO;
+	}
+
+	skb_put(*skb, len);
+	memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
+
+	return 0;
+}
+
+/*
+ * Reads an ndlc frame from the chip.
+ *
+ * On ST21NFCB, IRQ goes in idle state when read starts.
+ */
+static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
+{
+	struct st_nci_spi_phy *phy = phy_id;
+	struct spi_device *dev;
+	struct sk_buff *skb = NULL;
+	int r;
+
+	if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
+		WARN_ON_ONCE(1);
+		return IRQ_NONE;
+	}
+
+	dev = phy->spi_dev;
+	dev_dbg(&dev->dev, "IRQ\n");
+
+	if (phy->ndlc->hard_fault)
+		return IRQ_HANDLED;
+
+	if (!phy->ndlc->powered) {
+		st_nci_spi_disable(phy);
+		return IRQ_HANDLED;
+	}
+
+	r = st_nci_spi_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 spi_phy_ops = {
+	.write = st_nci_spi_write,
+	.enable = st_nci_spi_enable,
+	.disable = st_nci_spi_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_spi_probe(struct spi_device *dev)
+{
+	struct st_nci_spi_phy *phy;
+	int r;
+
+	dev_dbg(&dev->dev, "%s\n", __func__);
+	dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq);
+
+	/* Check SPI platform functionnalities */
+	if (!dev) {
+		pr_debug("%s: dev is NULL. Device is not accessible.\n",
+			__func__);
+		return -ENODEV;
+	}
+
+	phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
+			   GFP_KERNEL);
+	if (!phy)
+		return -ENOMEM;
+
+	phy->spi_dev = dev;
+
+	spi_set_drvdata(dev, phy);
+
+	r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios);
+	if (r)
+		dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n");
+
+	/* Get RESET GPIO */
+	phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(phy->gpiod_reset)) {
+		nfc_err(&dev->dev, "Unable to get RESET GPIO\n");
+		return PTR_ERR(phy->gpiod_reset);
+	}
+
+	phy->se_status.is_ese_present =
+			device_property_read_bool(&dev->dev, "ese-present");
+	phy->se_status.is_uicc_present =
+			device_property_read_bool(&dev->dev, "uicc-present");
+
+	r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
+			ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
+			&phy->ndlc, &phy->se_status);
+	if (r < 0) {
+		nfc_err(&dev->dev, "Unable to register ndlc layer\n");
+		return r;
+	}
+
+	phy->irq_active = true;
+	r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
+				st_nci_irq_thread_fn,
+				IRQF_ONESHOT,
+				ST_NCI_SPI_DRIVER_NAME, phy);
+	if (r < 0)
+		nfc_err(&dev->dev, "Unable to register IRQ handler\n");
+
+	return r;
+}
+
+static int st_nci_spi_remove(struct spi_device *dev)
+{
+	struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
+
+	dev_dbg(&dev->dev, "%s\n", __func__);
+
+	ndlc_remove(phy->ndlc);
+
+	return 0;
+}
+
+static struct spi_device_id st_nci_spi_id_table[] = {
+	{ST_NCI_SPI_DRIVER_NAME, 0},
+	{}
+};
+MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
+
+static const struct acpi_device_id st_nci_spi_acpi_match[] = {
+	{"SMO2101", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);
+
+static const struct of_device_id of_st_nci_spi_match[] = {
+	{ .compatible = "st,st21nfcb-spi", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
+
+static struct spi_driver st_nci_spi_driver = {
+	.driver = {
+		.name = ST_NCI_SPI_DRIVER_NAME,
+		.of_match_table = of_match_ptr(of_st_nci_spi_match),
+		.acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
+	},
+	.probe = st_nci_spi_probe,
+	.id_table = st_nci_spi_id_table,
+	.remove = st_nci_spi_remove,
+};
+module_spi_driver(st_nci_spi_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);