--- /dev/null
+/*
+ * I2C Link Layer for ST21NFCB NCI based Driver
+ * Copyright (C) 2014 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.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/st21nfcb.h>
+
+#include "ndlc.h"
+
+#define DRIVER_DESC "NCI NFC driver for ST21NFCB"
+
+/* ndlc header */
+#define ST21NFCB_FRAME_HEADROOM 1
+#define ST21NFCB_FRAME_TAILROOM 0
+
+#define ST21NFCB_NCI_I2C_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */
+#define ST21NFCB_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
+
+#define ST21NFCB_NCI_I2C_DRIVER_NAME "st21nfcb_nci_i2c"
+
+static struct i2c_device_id st21nfcb_nci_i2c_id_table[] = {
+ {ST21NFCB_NCI_DRIVER_NAME, 0},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, st21nfcb_nci_i2c_id_table);
+
+struct st21nfcb_i2c_phy {
+ struct i2c_client *i2c_dev;
+ struct llt_ndlc *ndlc;
+
+ unsigned int gpio_reset;
+ unsigned int irq_polarity;
+
+ int powered;
+};
+
+#define I2C_DUMP_SKB(info, skb) \
+do { \
+ pr_debug("%s:\n", info); \
+ print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
+ 16, 1, (skb)->data, (skb)->len, 0); \
+} while (0)
+
+static int st21nfcb_nci_i2c_enable(void *phy_id)
+{
+ struct st21nfcb_i2c_phy *phy = phy_id;
+
+ gpio_set_value(phy->gpio_reset, 0);
+ usleep_range(10000, 15000);
+ gpio_set_value(phy->gpio_reset, 1);
+ phy->powered = 1;
+ usleep_range(80000, 85000);
+
+ return 0;
+}
+
+static void st21nfcb_nci_i2c_disable(void *phy_id)
+{
+ struct st21nfcb_i2c_phy *phy = phy_id;
+
+ phy->powered = 0;
+ /* reset chip in order to flush clf */
+ gpio_set_value(phy->gpio_reset, 0);
+ usleep_range(10000, 15000);
+ gpio_set_value(phy->gpio_reset, 1);
+}
+
+static void st21nfcb_nci_remove_header(struct sk_buff *skb)
+{
+ skb_pull(skb, ST21NFCB_FRAME_HEADROOM);
+}
+
+/*
+ * 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 st21nfcb_nci_i2c_write(void *phy_id, struct sk_buff *skb)
+{
+ int r = -1;
+ struct st21nfcb_i2c_phy *phy = phy_id;
+ struct i2c_client *client = phy->i2c_dev;
+
+ I2C_DUMP_SKB("st21nfcb_nci_i2c_write", skb);
+
+ 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;
+ }
+
+ st21nfcb_nci_remove_header(skb);
+
+ return r;
+}
+
+/*
+ * Reads an ndlc frame and returns it in a newly allocated sk_buff.
+ * returns:
+ * frame size : if received frame is complete (find ST21NFCB_SOF_EOF at
+ * end of read)
+ * -EAGAIN : if received frame is incomplete (not find ST21NFCB_SOF_EOF
+ * at end of read)
+ * -EREMOTEIO : i2c read error (fatal)
+ * -EBADMSG : frame was incorrect and discarded
+ * (value returned from st21nfcb_nci_i2c_repack)
+ * -EIO : if no ST21NFCB_SOF_EOF is found after reaching
+ * the read length end sequence
+ */
+static int st21nfcb_nci_i2c_read(struct st21nfcb_i2c_phy *phy,
+ struct sk_buff **skb)
+{
+ int r;
+ u8 len;
+ u8 buf[ST21NFCB_NCI_I2C_MAX_SIZE];
+ struct i2c_client *client = phy->i2c_dev;
+
+ r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
+ if (r < 0) { /* Retry, chip was in standby */
+ usleep_range(1000, 4000);
+ r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
+ }
+
+ if (r != ST21NFCB_NCI_I2C_MIN_SIZE)
+ return -EREMOTEIO;
+
+ len = be16_to_cpu(*(__be16 *) (buf + 2));
+ if (len > ST21NFCB_NCI_I2C_MAX_SIZE) {
+ nfc_err(&client->dev, "invalid frame len\n");
+ return -EBADMSG;
+ }
+
+ *skb = alloc_skb(ST21NFCB_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
+ if (*skb == NULL)
+ return -ENOMEM;
+
+ skb_reserve(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
+ skb_put(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
+ memcpy((*skb)->data, buf, ST21NFCB_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 + ST21NFCB_NCI_I2C_MIN_SIZE, buf, len);
+
+ I2C_DUMP_SKB("i2c 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 st21nfcb_nci_irq_thread_fn(int irq, void *phy_id)
+{
+ struct st21nfcb_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->powered) {
+ st21nfcb_nci_i2c_disable(phy);
+ return IRQ_HANDLED;
+ }
+
+ r = st21nfcb_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 = st21nfcb_nci_i2c_write,
+ .enable = st21nfcb_nci_i2c_enable,
+ .disable = st21nfcb_nci_i2c_disable,
+};
+
+#ifdef CONFIG_OF
+static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
+{
+ struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
+ struct device_node *pp;
+ int gpio;
+ int r;
+
+ pp = client->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(&client->dev,
+ "Failed to retrieve reset-gpios from device tree\n");
+ return gpio;
+ }
+
+ /* GPIO request and configuration */
+ r = devm_gpio_request_one(&client->dev, gpio,
+ GPIOF_OUT_INIT_HIGH, "clf_reset");
+ if (r) {
+ nfc_err(&client->dev, "Failed to request reset pin\n");
+ return r;
+ }
+ phy->gpio_reset = gpio;
+
+ phy->irq_polarity = irq_get_trigger_type(client->irq);
+
+ return 0;
+}
+#else
+static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
+{
+ return -ENODEV;
+}
+#endif
+
+static int st21nfcb_nci_i2c_request_resources(struct i2c_client *client)
+{
+ struct st21nfcb_nfc_platform_data *pdata;
+ struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
+ int r;
+
+ pdata = client->dev.platform_data;
+ if (pdata == NULL) {
+ nfc_err(&client->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(&client->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 st21nfcb_nci_i2c_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct st21nfcb_i2c_phy *phy;
+ struct st21nfcb_nfc_platform_data *pdata;
+ 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(&client->dev, sizeof(struct st21nfcb_i2c_phy),
+ GFP_KERNEL);
+ if (!phy)
+ return -ENOMEM;
+
+ phy->i2c_dev = client;
+
+ i2c_set_clientdata(client, phy);
+
+ pdata = client->dev.platform_data;
+ if (!pdata && client->dev.of_node) {
+ r = st21nfcb_nci_i2c_of_request_resources(client);
+ if (r) {
+ nfc_err(&client->dev, "No platform data\n");
+ return r;
+ }
+ } else if (pdata) {
+ r = st21nfcb_nci_i2c_request_resources(client);
+ if (r) {
+ nfc_err(&client->dev,
+ "Cannot get platform resources\n");
+ return r;
+ }
+ } else {
+ nfc_err(&client->dev,
+ "st21nfcb platform resources not available\n");
+ return -ENODEV;
+ }
+
+ r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
+ ST21NFCB_FRAME_HEADROOM, ST21NFCB_FRAME_TAILROOM,
+ &phy->ndlc);
+ if (r < 0) {
+ nfc_err(&client->dev, "Unable to register ndlc layer\n");
+ return r;
+ }
+
+ r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+ st21nfcb_nci_irq_thread_fn,
+ phy->irq_polarity | IRQF_ONESHOT,
+ ST21NFCB_NCI_DRIVER_NAME, phy);
+ if (r < 0)
+ nfc_err(&client->dev, "Unable to register IRQ handler\n");
+
+ return r;
+}
+
+static int st21nfcb_nci_i2c_remove(struct i2c_client *client)
+{
+ struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
+
+ dev_dbg(&client->dev, "%s\n", __func__);
+
+ ndlc_remove(phy->ndlc);
+
+ if (phy->powered)
+ st21nfcb_nci_i2c_disable(phy);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_st21nfcb_i2c_match[] = {
+ { .compatible = "st,st21nfcb-i2c", },
+ { .compatible = "st,st21nfcb_i2c", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, of_st21nfcb_i2c_match);
+#endif
+
+static struct i2c_driver st21nfcb_nci_i2c_driver = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = ST21NFCB_NCI_I2C_DRIVER_NAME,
+ .of_match_table = of_match_ptr(of_st21nfcb_i2c_match),
+ },
+ .probe = st21nfcb_nci_i2c_probe,
+ .id_table = st21nfcb_nci_i2c_id_table,
+ .remove = st21nfcb_nci_i2c_remove,
+};
+
+module_i2c_driver(st21nfcb_nci_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);
Code Review / kvmfornfv.git / blobdiff