linux/drivers/nfc/microread/i2c.c
Jeff Kirsher 98b32decc8 nfc: Fix FSF address in file headers
Several files refer to an old address for the Free Software Foundation
in the file header comment.  Resolve by replacing the address with
the URL <http://www.gnu.org/licenses/> so that we do not have to keep
updating the header comments anytime the address changes.

CC: linux-wireless@vger.kernel.org
CC: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
CC: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
CC: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2013-12-11 10:56:21 -05:00

329 lines
6.9 KiB
C

/*
* HCI based Driver for Inside Secure microread NFC Chip - i2c layer
*
* Copyright (C) 2013 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/module.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/nfc.h>
#include <net/nfc/hci.h>
#include <net/nfc/llc.h>
#include "microread.h"
#define MICROREAD_I2C_DRIVER_NAME "microread"
#define MICROREAD_I2C_FRAME_HEADROOM 1
#define MICROREAD_I2C_FRAME_TAILROOM 1
/* framing in HCI mode */
#define MICROREAD_I2C_LLC_LEN 1
#define MICROREAD_I2C_LLC_CRC 1
#define MICROREAD_I2C_LLC_LEN_CRC (MICROREAD_I2C_LLC_LEN + \
MICROREAD_I2C_LLC_CRC)
#define MICROREAD_I2C_LLC_MIN_SIZE (1 + MICROREAD_I2C_LLC_LEN_CRC)
#define MICROREAD_I2C_LLC_MAX_PAYLOAD 29
#define MICROREAD_I2C_LLC_MAX_SIZE (MICROREAD_I2C_LLC_LEN_CRC + 1 + \
MICROREAD_I2C_LLC_MAX_PAYLOAD)
struct microread_i2c_phy {
struct i2c_client *i2c_dev;
struct nfc_hci_dev *hdev;
int irq;
int hard_fault; /*
* < 0 if hardware error occured (e.g. i2c err)
* and prevents normal operation.
*/
};
#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 void microread_i2c_add_len_crc(struct sk_buff *skb)
{
int i;
u8 crc = 0;
int len;
len = skb->len;
*skb_push(skb, 1) = len;
for (i = 0; i < skb->len; i++)
crc = crc ^ skb->data[i];
*skb_put(skb, 1) = crc;
}
static void microread_i2c_remove_len_crc(struct sk_buff *skb)
{
skb_pull(skb, MICROREAD_I2C_FRAME_HEADROOM);
skb_trim(skb, MICROREAD_I2C_FRAME_TAILROOM);
}
static int check_crc(struct sk_buff *skb)
{
int i;
u8 crc = 0;
for (i = 0; i < skb->len - 1; i++)
crc = crc ^ skb->data[i];
if (crc != skb->data[skb->len-1]) {
pr_err("CRC error 0x%x != 0x%x\n", crc, skb->data[skb->len-1]);
pr_info("%s: BAD CRC\n", __func__);
return -EPERM;
}
return 0;
}
static int microread_i2c_enable(void *phy_id)
{
return 0;
}
static void microread_i2c_disable(void *phy_id)
{
return;
}
static int microread_i2c_write(void *phy_id, struct sk_buff *skb)
{
int r;
struct microread_i2c_phy *phy = phy_id;
struct i2c_client *client = phy->i2c_dev;
if (phy->hard_fault != 0)
return phy->hard_fault;
usleep_range(3000, 6000);
microread_i2c_add_len_crc(skb);
I2C_DUMP_SKB("i2c frame written", skb);
r = i2c_master_send(client, skb->data, skb->len);
if (r == -EREMOTEIO) { /* Retry, chip was in standby */
usleep_range(6000, 10000);
r = i2c_master_send(client, skb->data, skb->len);
}
if (r >= 0) {
if (r != skb->len)
r = -EREMOTEIO;
else
r = 0;
}
microread_i2c_remove_len_crc(skb);
return r;
}
static int microread_i2c_read(struct microread_i2c_phy *phy,
struct sk_buff **skb)
{
int r;
u8 len;
u8 tmp[MICROREAD_I2C_LLC_MAX_SIZE - 1];
struct i2c_client *client = phy->i2c_dev;
r = i2c_master_recv(client, &len, 1);
if (r != 1) {
nfc_err(&client->dev, "cannot read len byte\n");
return -EREMOTEIO;
}
if ((len < MICROREAD_I2C_LLC_MIN_SIZE) ||
(len > MICROREAD_I2C_LLC_MAX_SIZE)) {
nfc_err(&client->dev, "invalid len byte\n");
r = -EBADMSG;
goto flush;
}
*skb = alloc_skb(1 + len, GFP_KERNEL);
if (*skb == NULL) {
r = -ENOMEM;
goto flush;
}
*skb_put(*skb, 1) = len;
r = i2c_master_recv(client, skb_put(*skb, len), len);
if (r != len) {
kfree_skb(*skb);
return -EREMOTEIO;
}
I2C_DUMP_SKB("cc frame read", *skb);
r = check_crc(*skb);
if (r != 0) {
kfree_skb(*skb);
r = -EBADMSG;
goto flush;
}
skb_pull(*skb, 1);
skb_trim(*skb, (*skb)->len - MICROREAD_I2C_FRAME_TAILROOM);
usleep_range(3000, 6000);
return 0;
flush:
if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
r = -EREMOTEIO;
usleep_range(3000, 6000);
return r;
}
static irqreturn_t microread_i2c_irq_thread_fn(int irq, void *phy_id)
{
struct microread_i2c_phy *phy = phy_id;
struct i2c_client *client;
struct sk_buff *skb = NULL;
int r;
if (!phy || irq != phy->i2c_dev->irq) {
WARN_ON_ONCE(1);
return IRQ_NONE;
}
client = phy->i2c_dev;
if (phy->hard_fault != 0)
return IRQ_HANDLED;
r = microread_i2c_read(phy, &skb);
if (r == -EREMOTEIO) {
phy->hard_fault = r;
nfc_hci_recv_frame(phy->hdev, NULL);
return IRQ_HANDLED;
} else if ((r == -ENOMEM) || (r == -EBADMSG)) {
return IRQ_HANDLED;
}
nfc_hci_recv_frame(phy->hdev, skb);
return IRQ_HANDLED;
}
static struct nfc_phy_ops i2c_phy_ops = {
.write = microread_i2c_write,
.enable = microread_i2c_enable,
.disable = microread_i2c_disable,
};
static int microread_i2c_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct microread_i2c_phy *phy;
struct microread_nfc_platform_data *pdata =
dev_get_platdata(&client->dev);
int r;
dev_dbg(&client->dev, "client %p\n", client);
if (!pdata) {
nfc_err(&client->dev, "client %p: missing platform data\n",
client);
return -EINVAL;
}
phy = devm_kzalloc(&client->dev, sizeof(struct microread_i2c_phy),
GFP_KERNEL);
if (!phy)
return -ENOMEM;
i2c_set_clientdata(client, phy);
phy->i2c_dev = client;
r = request_threaded_irq(client->irq, NULL, microread_i2c_irq_thread_fn,
IRQF_TRIGGER_RISING | IRQF_ONESHOT,
MICROREAD_I2C_DRIVER_NAME, phy);
if (r) {
nfc_err(&client->dev, "Unable to register IRQ handler\n");
return r;
}
r = microread_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
MICROREAD_I2C_FRAME_HEADROOM,
MICROREAD_I2C_FRAME_TAILROOM,
MICROREAD_I2C_LLC_MAX_PAYLOAD, &phy->hdev);
if (r < 0)
goto err_irq;
nfc_info(&client->dev, "Probed");
return 0;
err_irq:
free_irq(client->irq, phy);
return r;
}
static int microread_i2c_remove(struct i2c_client *client)
{
struct microread_i2c_phy *phy = i2c_get_clientdata(client);
microread_remove(phy->hdev);
free_irq(client->irq, phy);
return 0;
}
static struct i2c_device_id microread_i2c_id[] = {
{ MICROREAD_I2C_DRIVER_NAME, 0},
{ }
};
MODULE_DEVICE_TABLE(i2c, microread_i2c_id);
static struct i2c_driver microread_i2c_driver = {
.driver = {
.name = MICROREAD_I2C_DRIVER_NAME,
},
.probe = microread_i2c_probe,
.remove = microread_i2c_remove,
.id_table = microread_i2c_id,
};
module_i2c_driver(microread_i2c_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(DRIVER_DESC);