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// SPDX-License-Identifier: GPL-2.0-only
/*
* SPI Link Layer for ST NCI based Driver
* Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/gpio/consumer.h>
#include <linux/acpi.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/nfc.h>
#include <linux/of.h>
#include <net/nfc/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_DRIVER_NAME "st_nci"
#define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
struct st_nci_spi_phy {
struct spi_device *spi_dev;
struct llt_ndlc *ndlc;
bool irq_active;
struct gpio_desc *gpiod_reset;
struct st_nci_se_status se_status;
};
static int st_nci_spi_enable(void *phy_id)
{
struct st_nci_spi_phy *phy = phy_id;
gpiod_set_value(phy->gpiod_reset, 0);
usleep_range(10000, 15000);
gpiod_set_value(phy->gpiod_reset, 1);
usleep_range(80000, 85000);
if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
enable_irq(phy->spi_dev->irq);
phy->irq_active = true;
}
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);
phy->irq_active = false;
}
/*
* 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 + NCI_DATA_HDR_SIZE +
ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
struct spi_transfer spi_xfer = {
.tx_buf = skb->data,
.rx_buf = buf,
.len = skb->len,
};
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);
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,
};
static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
{ "reset-gpios", &reset_gpios, 1 },
{},
};
static int st_nci_spi_probe(struct spi_device *dev)
{
struct st_nci_spi_phy *phy;
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);
r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios);
if (r)
dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n");
/* Get RESET GPIO */
phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(phy->gpiod_reset)) {
nfc_err(&dev->dev, "Unable to get RESET GPIO\n");
return PTR_ERR(phy->gpiod_reset);
}
phy->se_status.is_ese_present =
device_property_read_bool(&dev->dev, "ese-present");
phy->se_status.is_uicc_present =
device_property_read_bool(&dev->dev, "uicc-present");
r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
&phy->ndlc, &phy->se_status);
if (r < 0) {
nfc_err(&dev->dev, "Unable to register ndlc layer\n");
return r;
}
phy->irq_active = true;
r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
st_nci_irq_thread_fn,
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;
}
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);
static const struct acpi_device_id st_nci_spi_acpi_match[] = {
{"SMO2101", 0},
{}
};
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