linux/drivers/nfc/st-nci/spi.c

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/*
* 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 "st-nci.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);