3 files changed, 406 insertions, 0 deletions

diff --git a/drivers/nfc/st-nci/Kconfig b/drivers/nfc/st-nci/Kconfig
index fc3904c946ee..e7c6db9c5860 100644
--- a/drivers/nfc/st-nci/Kconfig
+++ b/drivers/nfc/st-nci/Kconfig
@@ -21,3 +21,14 @@ config NFC_ST_NCI_I2C
 
           If you choose to build a module, it'll be called st-nci_i2c.
           Say N if unsure.
+
+config NFC_ST_NCI_SPI
+        tristate "NFC ST NCI spi support"
+        depends on NFC_ST_NCI && SPI
+        ---help---
+          This module adds support for an SPI interface to the
+          STMicroelectronics NFC NCI chips familly.
+          Select this if your platform is using the spi bus.
+
+          If you choose to build a module, it'll be called st-nci_spi.
+          Say N if unsure.
diff --git a/drivers/nfc/st-nci/Makefile b/drivers/nfc/st-nci/Makefile
index 0df157df3a94..348ce76f2177 100644
--- a/drivers/nfc/st-nci/Makefile
+++ b/drivers/nfc/st-nci/Makefile
@@ -7,3 +7,6 @@ obj-$(CONFIG_NFC_ST_NCI)     += st-nci.o
 
 st-nci_i2c-objs = i2c.o
 obj-$(CONFIG_NFC_ST_NCI_I2C) += st-nci_i2c.o
+
+st-nci_spi-objs = spi.o
+obj-$(CONFIG_NFC_ST_NCI_SPI) += st-nci_spi.o
diff --git a/drivers/nfc/st-nci/spi.c b/drivers/nfc/st-nci/spi.c
new file mode 100644
index 000000000000..598a58c4d6d1
--- /dev/null
+++ b/drivers/nfc/st-nci/spi.c
@@ -0,0 +1,392 @@
+/*
+ * 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 <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];
+        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);