--- /dev/null
+/*
+ * 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);
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff