Linux-libre 4.3.2-gnu

1 files changed, 394 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..887d308c2
--- /dev/null
+++ b/drivers/nfc/st-nci/spi.c
@@ -0,0 +1,394 @@
+/*
+ * SPI Link Layer for ST NCI 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/spi/spi.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 <net/nfc/nci.h>
+#include <linux/platform_data/st-nci.h>
+
+#include "ndlc.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_SPI_DRIVER_NAME "st_nci_spi"
+
+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);
+
+struct st_nci_spi_phy {
+	struct spi_device *spi_dev;
+	struct llt_ndlc *ndlc;
+
+	unsigned int gpio_reset;
+	unsigned int irq_polarity;
+};
+
+#define SPI_DUMP_SKB(info, skb)					\
+do {								\
+	pr_debug("%s:\n", info);				\
+	print_hex_dump(KERN_DEBUG, "spi: ", DUMP_PREFIX_OFFSET,	\
+		       16, 1, (skb)->data, (skb)->len, 0);	\
+} while (0)
+
+static int st_nci_spi_enable(void *phy_id)
+{
+	struct st_nci_spi_phy *phy = phy_id;
+
+	gpio_set_value(phy->gpio_reset, 0);
+	usleep_range(10000, 15000);
+	gpio_set_value(phy->gpio_reset, 1);
+	usleep_range(80000, 85000);
+
+	if (phy->ndlc->powered == 0)
+		enable_irq(phy->spi_dev->irq);
+
+	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);
+}
+
+/*
+ * 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,
+	};
+
+	SPI_DUMP_SKB("st_nci_spi_write", skb);
+
+	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);
+
+	SPI_DUMP_SKB("spi 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 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,
+};
+
+#ifdef CONFIG_OF
+static int st_nci_spi_of_request_resources(struct spi_device *dev)
+{
+	struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
+	struct device_node *pp;
+	int gpio;
+	int r;
+
+	pp = dev->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(&dev->dev,
+			"Failed to retrieve reset-gpios from device tree\n");
+		return gpio;
+	}
+
+	/* GPIO request and configuration */
+	r = devm_gpio_request_one(&dev->dev, gpio,
+				GPIOF_OUT_INIT_HIGH, "clf_reset");
+	if (r) {
+		nfc_err(&dev->dev, "Failed to request reset pin\n");
+		return r;
+	}
+	phy->gpio_reset = gpio;
+
+	phy->irq_polarity = irq_get_trigger_type(dev->irq);
+
+	return 0;
+}
+#else
+static int st_nci_spi_of_request_resources(struct spi_device *dev)
+{
+	return -ENODEV;
+}
+#endif
+
+static int st_nci_spi_request_resources(struct spi_device *dev)
+{
+	struct st_nci_nfc_platform_data *pdata;
+	struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
+	int r;
+
+	pdata = dev->dev.platform_data;
+	if (pdata == NULL) {
+		nfc_err(&dev->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(&dev->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 st_nci_spi_probe(struct spi_device *dev)
+{
+	struct st_nci_spi_phy *phy;
+	struct st_nci_nfc_platform_data *pdata;
+	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);
+
+	pdata = dev->dev.platform_data;
+	if (!pdata && dev->dev.of_node) {
+		r = st_nci_spi_of_request_resources(dev);
+		if (r) {
+			nfc_err(&dev->dev, "No platform data\n");
+			return r;
+		}
+	} else if (pdata) {
+		r = st_nci_spi_request_resources(dev);
+		if (r) {
+			nfc_err(&dev->dev,
+				"Cannot get platform resources\n");
+			return r;
+		}
+	} else {
+		nfc_err(&dev->dev,
+			"st_nci platform resources not available\n");
+		return -ENODEV;
+	}
+
+	r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
+			ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
+			&phy->ndlc);
+	if (r < 0) {
+		nfc_err(&dev->dev, "Unable to register ndlc layer\n");
+		return r;
+	}
+
+	r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
+				st_nci_irq_thread_fn,
+				phy->irq_polarity | 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;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_st_nci_spi_match[] = {
+	{ .compatible = "st,st21nfcb-spi", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
+#endif
+
+static struct spi_driver st_nci_spi_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = ST_NCI_SPI_DRIVER_NAME,
+		.of_match_table = of_match_ptr(of_st_nci_spi_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);