NFC: nxp-nci_i2c: Add I2C support to NXP NCI driver

Add a module to the NXP-NCI driver to support NFC controllers with an
I2C control interface, such as the NPC100.

Signed-off-by: Clément Perrochaud <clement.perrochaud@effinnov.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

4 files changed, 464 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/net/nfc/nxp-nci.txt b/Documentation/devicetree/bindings/net/nfc/nxp-nci.txt
new file mode 100644
index 000000000000..5b6cd9b3f628
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/nfc/nxp-nci.txt
@@ -0,0 +1,35 @@
+* NXP Semiconductors NXP NCI NFC Controllers
+
+Required properties:
+- compatible: Should be "nxp,nxp-nci-i2c".
+- clock-frequency: I²C work frequency.
+- reg: address on the bus
+- interrupt-parent: phandle for the interrupt gpio controller
+- interrupts: GPIO interrupt to which the chip is connected
+- enable-gpios: Output GPIO pin used for enabling/disabling the chip
+- firmware-gpios: Output GPIO pin used to enter firmware download mode
+
+Optional SoC Specific Properties:
+- pinctrl-names: Contains only one value - "default".
+- pintctrl-0: Specifies the pin control groups used for this controller.
+
+Example (for ARM-based BeagleBone with NPC100 NFC controller on I2C2):
+
+&i2c2 {
+
+        status = "okay";
+
+        npc100: npc100@29 {
+
+                compatible = "nxp,nxp-nci-i2c";
+
+                reg = <0x29>;
+                clock-frequency = <100000>;
+
+                interrupt-parent = <&gpio1>;
+                interrupts = <29 GPIO_ACTIVE_HIGH>;
+
+                enable-gpios = <&gpio0 30 GPIO_ACTIVE_HIGH>;
+                firmware-gpios = <&gpio0 31 GPIO_ACTIVE_HIGH>;
+        };
+};
diff --git a/drivers/nfc/nxp-nci/Kconfig b/drivers/nfc/nxp-nci/Kconfig
index 5f60c7cf02e8..37b40612520d 100644
--- a/drivers/nfc/nxp-nci/Kconfig
+++ b/drivers/nfc/nxp-nci/Kconfig
@@ -11,3 +11,15 @@ config NFC_NXP_NCI
           To compile this driver as a module, choose m here. The module will
           be called nxp_nci.
           Say N if unsure.
+
+config NFC_NXP_NCI_I2C
+        tristate "NXP-NCI I2C support"
+        depends on NFC_NXP_NCI && I2C
+        ---help---
+          This module adds support for an I2C interface to the NXP NCI
+          chips.
+          Select this if your platform is using the I2C bus.
+
+          To compile this driver as a module, choose m here. The module will
+          be called nxp_nci_i2c.
+          Say Y if unsure.
diff --git a/drivers/nfc/nxp-nci/Makefile b/drivers/nfc/nxp-nci/Makefile
index 8f1e32826961..c008be30bb18 100644
--- a/drivers/nfc/nxp-nci/Makefile
+++ b/drivers/nfc/nxp-nci/Makefile
@@ -3,7 +3,9 @@
 #
 
 nxp-nci-objs = core.o firmware.o
+nxp-nci_i2c-objs = i2c.o
 
 obj-$(CONFIG_NFC_NXP_NCI) += nxp-nci.o
+obj-$(CONFIG_NFC_NXP_NCI_I2C) += nxp-nci_i2c.o
 
 ccflags-$(CONFIG_NFC_DEBUG) := -DDEBUG
diff --git a/drivers/nfc/nxp-nci/i2c.c b/drivers/nfc/nxp-nci/i2c.c
new file mode 100644
index 000000000000..17bd67dbebf0
--- /dev/null
+++ b/drivers/nfc/nxp-nci/i2c.c
@@ -0,0 +1,415 @@
+/*
+ * I2C link layer for the NXP NCI driver
+ *
+ * Copyright (C) 2014  NXP Semiconductors  All rights reserved.
+ *
+ * Authors: Clément Perrochaud <clement.perrochaud@nxp.com>
+ *
+ * Derived from PN544 device driver:
+ * Copyright (C) 2012  Intel Corporation. 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/delay.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/nfc.h>
+#include <linux/of_gpio.h>
+#include <linux/of_irq.h>
+#include <linux/platform_data/nxp-nci.h>
+#include <linux/unaligned/access_ok.h>
+
+#include <net/nfc/nfc.h>
+
+#include "nxp-nci.h"
+
+#define NXP_NCI_I2C_DRIVER_NAME "nxp-nci_i2c"
+
+#define NXP_NCI_I2C_MAX_PAYLOAD 32
+
+struct nxp_nci_i2c_phy {
+        struct i2c_client *i2c_dev;
+        struct nci_dev *ndev;
+
+        unsigned int gpio_en;
+        unsigned int gpio_fw;
+
+        int hard_fault; /*
+                         * < 0 if hardware error occurred (e.g. i2c err)
+                         * and prevents normal operation.
+                         */
+};
+
+static int nxp_nci_i2c_set_mode(void *phy_id,
+                                    enum nxp_nci_mode mode)
+{
+        struct nxp_nci_i2c_phy *phy = (struct nxp_nci_i2c_phy *) phy_id;
+
+        gpio_set_value(phy->gpio_fw, (mode == NXP_NCI_MODE_FW) ? 1 : 0);
+        gpio_set_value(phy->gpio_en, (mode != NXP_NCI_MODE_COLD) ? 1 : 0);
+        usleep_range(10000, 15000);
+
+        if (mode == NXP_NCI_MODE_COLD)
+                phy->hard_fault = 0;
+
+        return 0;
+}
+
+static int nxp_nci_i2c_write(void *phy_id, struct sk_buff *skb)
+{
+        int r;
+        struct nxp_nci_i2c_phy *phy = phy_id;
+        struct i2c_client *client = phy->i2c_dev;
+
+        if (phy->hard_fault != 0)
+                return phy->hard_fault;
+
+        r = i2c_master_send(client, skb->data, skb->len);
+        if (r == -EREMOTEIO) {
+                /* Retry, chip was in standby */
+                usleep_range(110000, 120000);
+                r = i2c_master_send(client, skb->data, skb->len);
+        }
+
+        if (r < 0) {
+                nfc_err(&client->dev, "Error %d on I2C send\n", r);
+        } else if (r != skb->len) {
+                nfc_err(&client->dev,
+                        "Invalid length sent: %u (expected %u)\n",
+                        r, skb->len);
+                r = -EREMOTEIO;
+        } else {
+                /* Success but return 0 and not number of bytes */
+                r = 0;
+        }
+
+        return r;
+}
+
+static struct nxp_nci_phy_ops i2c_phy_ops = {
+        .set_mode = nxp_nci_i2c_set_mode,
+        .write = nxp_nci_i2c_write,
+};
+
+static int nxp_nci_i2c_fw_read(struct nxp_nci_i2c_phy *phy,
+                               struct sk_buff **skb)
+{
+        struct i2c_client *client = phy->i2c_dev;
+        u16 header;
+        size_t frame_len;
+        int r;
+
+        r = i2c_master_recv(client, (u8 *) &header, NXP_NCI_FW_HDR_LEN);
+        if (r < 0) {
+                goto fw_read_exit;
+        } else if (r != NXP_NCI_FW_HDR_LEN) {
+                nfc_err(&client->dev, "Incorrect header length: %u\n", r);
+                r = -EBADMSG;
+                goto fw_read_exit;
+        }
+
+        frame_len = (get_unaligned_be16(&header) & NXP_NCI_FW_FRAME_LEN_MASK) +
+                    NXP_NCI_FW_CRC_LEN;
+
+        *skb = alloc_skb(NXP_NCI_FW_HDR_LEN + frame_len, GFP_KERNEL);
+        if (*skb == NULL) {
+                r = -ENOMEM;
+                goto fw_read_exit;
+        }
+
+        memcpy(skb_put(*skb, NXP_NCI_FW_HDR_LEN), &header, NXP_NCI_FW_HDR_LEN);
+
+        r = i2c_master_recv(client, skb_put(*skb, frame_len), frame_len);
+        if (r != frame_len) {
+                nfc_err(&client->dev,
+                        "Invalid frame length: %u (expected %zu)\n",
+                        r, frame_len);
+                r = -EBADMSG;
+                goto fw_read_exit_free_skb;
+        }
+
+        return 0;
+
+fw_read_exit_free_skb:
+        kfree_skb(*skb);
+fw_read_exit:
+        return r;
+}
+
+static int nxp_nci_i2c_nci_read(struct nxp_nci_i2c_phy *phy,
+                                struct sk_buff **skb)
+{
+        struct nci_ctrl_hdr header; /* May actually be a data header */
+        struct i2c_client *client = phy->i2c_dev;
+        int r;
+
+        r = i2c_master_recv(client, (u8 *) &header, NCI_CTRL_HDR_SIZE);
+        if (r < 0) {
+                goto nci_read_exit;
+        } else if (r != NCI_CTRL_HDR_SIZE) {
+                nfc_err(&client->dev, "Incorrect header length: %u\n", r);
+                r = -EBADMSG;
+                goto nci_read_exit;
+        }
+
+        *skb = alloc_skb(NCI_CTRL_HDR_SIZE + header.plen, GFP_KERNEL);
+        if (*skb == NULL) {
+                r = -ENOMEM;
+                goto nci_read_exit;
+        }
+
+        memcpy(skb_put(*skb, NCI_CTRL_HDR_SIZE), (void *) &header,
+               NCI_CTRL_HDR_SIZE);
+
+        r = i2c_master_recv(client, skb_put(*skb, header.plen), header.plen);
+        if (r != header.plen) {
+                nfc_err(&client->dev,
+                        "Invalid frame payload length: %u (expected %u)\n",
+                        r, header.plen);
+                r = -EBADMSG;
+                goto nci_read_exit_free_skb;
+        }
+
+        return 0;
+
+nci_read_exit_free_skb:
+        kfree_skb(*skb);
+nci_read_exit:
+        return r;
+}
+
+static irqreturn_t nxp_nci_i2c_irq_thread_fn(int irq, void *phy_id)
+{
+        struct nxp_nci_i2c_phy *phy = phy_id;
+        struct i2c_client *client;
+        struct nxp_nci_info *info;
+
+        struct sk_buff *skb = NULL;
+        int r = 0;
+
+        if (!phy || !phy->ndev)
+                goto exit_irq_none;
+
+        client = phy->i2c_dev;
+
+        if (!client || irq != client->irq)
+                goto exit_irq_none;
+
+        info = nci_get_drvdata(phy->ndev);
+
+        if (!info)
+                goto exit_irq_none;
+
+        mutex_lock(&info->info_lock);
+
+        if (phy->hard_fault != 0)
+                goto exit_irq_handled;
+
+        switch (info->mode) {
+        case NXP_NCI_MODE_NCI:
+                r = nxp_nci_i2c_nci_read(phy, &skb);
+                break;
+        case NXP_NCI_MODE_FW:
+                r = nxp_nci_i2c_fw_read(phy, &skb);
+                break;
+        case NXP_NCI_MODE_COLD:
+                r = -EREMOTEIO;
+                break;
+        }
+
+        if (r == -EREMOTEIO) {
+                phy->hard_fault = r;
+                skb = NULL;
+        } else if (r < 0) {
+                nfc_err(&client->dev, "Read failed with error %d\n", r);
+                goto exit_irq_handled;
+        }
+
+        switch (info->mode) {
+        case NXP_NCI_MODE_NCI:
+                nci_recv_frame(phy->ndev, skb);
+                break;
+        case NXP_NCI_MODE_FW:
+                nxp_nci_fw_recv_frame(phy->ndev, skb);
+                break;
+        case NXP_NCI_MODE_COLD:
+                break;
+        }
+
+exit_irq_handled:
+        mutex_unlock(&info->info_lock);
+        return IRQ_HANDLED;
+exit_irq_none:
+        WARN_ON_ONCE(1);
+        return IRQ_NONE;
+}
+
+#ifdef CONFIG_OF
+
+static int nxp_nci_i2c_parse_devtree(struct i2c_client *client)
+{
+        struct nxp_nci_i2c_phy *phy = i2c_get_clientdata(client);
+        struct device_node *pp;
+        int r;
+
+        pp = client->dev.of_node;
+        if (!pp)
+                return -ENODEV;
+
+        r = of_get_named_gpio(pp, "enable-gpios", 0);
+        if (r == -EPROBE_DEFER)
+                r = of_get_named_gpio(pp, "enable-gpios", 0);
+        if (r < 0) {
+                nfc_err(&client->dev, "Failed to get EN gpio, error: %d\n", r);
+                return r;
+        }
+        phy->gpio_en = r;
+
+        r = of_get_named_gpio(pp, "firmware-gpios", 0);
+        if (r == -EPROBE_DEFER)
+                r = of_get_named_gpio(pp, "firmware-gpios", 0);
+        if (r < 0) {
+                nfc_err(&client->dev, "Failed to get FW gpio, error: %d\n", r);
+                return r;
+        }
+        phy->gpio_fw = r;
+
+        r = irq_of_parse_and_map(pp, 0);
+        if (r < 0) {
+                nfc_err(&client->dev, "Unable to get irq, error: %d\n", r);
+                return r;
+        }
+        client->irq = r;
+
+        return 0;
+}
+
+#else
+
+static int nxp_nci_i2c_parse_devtree(struct i2c_client *client)
+{
+        return -ENODEV;
+}
+
+#endif
+
+static int nxp_nci_i2c_probe(struct i2c_client *client,
+                            const struct i2c_device_id *id)
+{
+        struct nxp_nci_i2c_phy *phy;
+        struct nxp_nci_nfc_platform_data *pdata;
+        int r;
+
+        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+                nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
+                r = -ENODEV;
+                goto probe_exit;
+        }
+
+        phy = devm_kzalloc(&client->dev, sizeof(struct nxp_nci_i2c_phy),
+                           GFP_KERNEL);
+        if (!phy) {
+                r = -ENOMEM;
+                goto probe_exit;
+        }
+
+        phy->i2c_dev = client;
+        i2c_set_clientdata(client, phy);
+
+        pdata = client->dev.platform_data;
+
+        if (!pdata && client->dev.of_node) {
+                r = nxp_nci_i2c_parse_devtree(client);
+                if (r < 0) {
+                        nfc_err(&client->dev, "Failed to get DT data\n");
+                        goto probe_exit;
+                }
+        } else if (pdata) {
+                phy->gpio_en = pdata->gpio_en;
+                phy->gpio_fw = pdata->gpio_fw;
+                client->irq = pdata->irq;
+        } else {
+                nfc_err(&client->dev, "No platform data\n");
+                r = -EINVAL;
+                goto probe_exit;
+        }
+
+        r = devm_gpio_request_one(&phy->i2c_dev->dev, phy->gpio_en,
+                                  GPIOF_OUT_INIT_LOW, "nxp_nci_en");
+        if (r < 0)
+                goto probe_exit;
+
+        r = devm_gpio_request_one(&phy->i2c_dev->dev, phy->gpio_fw,
+                                  GPIOF_OUT_INIT_LOW, "nxp_nci_fw");
+        if (r < 0)
+                goto probe_exit;
+
+        r = nxp_nci_probe(phy, &client->dev, &i2c_phy_ops,
+                          NXP_NCI_I2C_MAX_PAYLOAD, &phy->ndev);
+        if (r < 0)
+                goto probe_exit;
+
+        r = request_threaded_irq(client->irq, NULL,
+                                 nxp_nci_i2c_irq_thread_fn,
+                                 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+                                 NXP_NCI_I2C_DRIVER_NAME, phy);
+        if (r < 0)
+                nfc_err(&client->dev, "Unable to register IRQ handler\n");
+
+probe_exit:
+        return r;
+}
+
+static int nxp_nci_i2c_remove(struct i2c_client *client)
+{
+        struct nxp_nci_i2c_phy *phy = i2c_get_clientdata(client);
+
+        nxp_nci_remove(phy->ndev);
+        free_irq(client->irq, phy);
+
+        return 0;
+}
+
+static struct i2c_device_id nxp_nci_i2c_id_table[] = {
+        {"nxp-nci_i2c", 0},
+        {}
+};
+MODULE_DEVICE_TABLE(i2c, nxp_nci_i2c_id_table);
+
+static const struct of_device_id of_nxp_nci_i2c_match[] = {
+        { .compatible = "nxp,nxp-nci-i2c", },
+        {},
+};
+MODULE_DEVICE_TABLE(of, of_nxp_nci_i2c_match);
+
+static struct i2c_driver nxp_nci_i2c_driver = {
+        .driver = {
+                   .name = NXP_NCI_I2C_DRIVER_NAME,
+                   .owner  = THIS_MODULE,
+                   .of_match_table = of_match_ptr(of_nxp_nci_i2c_match),
+                  },
+        .probe = nxp_nci_i2c_probe,
+        .id_table = nxp_nci_i2c_id_table,
+        .remove = nxp_nci_i2c_remove,
+};
+
+module_i2c_driver(nxp_nci_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("I2C driver for NXP NCI NFC controllers");
+MODULE_AUTHOR("Clément Perrochaud <clement.perrochaud@nxp.com>");