306 lines
6.9 KiB
C
306 lines
6.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* SPI Link Layer for ST NCI based Driver
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* Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/spi/spi.h>
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#include <linux/gpio/consumer.h>
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#include <linux/acpi.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/nfc.h>
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#include <linux/of.h>
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#include <net/nfc/nci.h>
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#include "st-nci.h"
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#define DRIVER_DESC "NCI NFC driver for ST_NCI"
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/* ndlc header */
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#define ST_NCI_FRAME_HEADROOM 1
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#define ST_NCI_FRAME_TAILROOM 0
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#define ST_NCI_SPI_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */
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#define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */
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#define ST_NCI_DRIVER_NAME "st_nci"
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#define ST_NCI_SPI_DRIVER_NAME "st_nci_spi"
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struct st_nci_spi_phy {
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struct spi_device *spi_dev;
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struct llt_ndlc *ndlc;
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bool irq_active;
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struct gpio_desc *gpiod_reset;
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struct st_nci_se_status se_status;
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};
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static int st_nci_spi_enable(void *phy_id)
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{
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struct st_nci_spi_phy *phy = phy_id;
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gpiod_set_value(phy->gpiod_reset, 0);
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usleep_range(10000, 15000);
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gpiod_set_value(phy->gpiod_reset, 1);
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usleep_range(80000, 85000);
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if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
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enable_irq(phy->spi_dev->irq);
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phy->irq_active = true;
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}
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return 0;
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}
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static void st_nci_spi_disable(void *phy_id)
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{
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struct st_nci_spi_phy *phy = phy_id;
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disable_irq_nosync(phy->spi_dev->irq);
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phy->irq_active = false;
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}
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/*
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* Writing a frame must not return the number of written bytes.
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* It must return either zero for success, or <0 for error.
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* In addition, it must not alter the skb
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*/
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static int st_nci_spi_write(void *phy_id, struct sk_buff *skb)
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{
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int r;
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struct st_nci_spi_phy *phy = phy_id;
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struct spi_device *dev = phy->spi_dev;
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struct sk_buff *skb_rx;
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u8 buf[ST_NCI_SPI_MAX_SIZE + NCI_DATA_HDR_SIZE +
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ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM];
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struct spi_transfer spi_xfer = {
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.tx_buf = skb->data,
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.rx_buf = buf,
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.len = skb->len,
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};
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if (phy->ndlc->hard_fault != 0)
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return phy->ndlc->hard_fault;
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r = spi_sync_transfer(dev, &spi_xfer, 1);
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/*
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* We may have received some valuable data on miso line.
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* Send them back in the ndlc state machine.
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*/
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if (!r) {
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skb_rx = alloc_skb(skb->len, GFP_KERNEL);
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if (!skb_rx)
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return -ENOMEM;
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skb_put(skb_rx, skb->len);
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memcpy(skb_rx->data, buf, skb->len);
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ndlc_recv(phy->ndlc, skb_rx);
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}
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return r;
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}
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/*
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* Reads an ndlc frame and returns it in a newly allocated sk_buff.
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* returns:
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* 0 : if received frame is complete
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* -EREMOTEIO : i2c read error (fatal)
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* -EBADMSG : frame was incorrect and discarded
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* -ENOMEM : cannot allocate skb, frame dropped
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*/
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static int st_nci_spi_read(struct st_nci_spi_phy *phy,
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struct sk_buff **skb)
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{
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int r;
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u8 len;
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u8 buf[ST_NCI_SPI_MAX_SIZE];
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struct spi_device *dev = phy->spi_dev;
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struct spi_transfer spi_xfer = {
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.rx_buf = buf,
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.len = ST_NCI_SPI_MIN_SIZE,
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};
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r = spi_sync_transfer(dev, &spi_xfer, 1);
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if (r < 0)
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return -EREMOTEIO;
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len = be16_to_cpu(*(__be16 *) (buf + 2));
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if (len > ST_NCI_SPI_MAX_SIZE) {
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nfc_err(&dev->dev, "invalid frame len\n");
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phy->ndlc->hard_fault = 1;
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return -EBADMSG;
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}
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*skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL);
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if (*skb == NULL)
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return -ENOMEM;
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skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE);
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skb_put(*skb, ST_NCI_SPI_MIN_SIZE);
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memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE);
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if (!len)
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return 0;
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spi_xfer.len = len;
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r = spi_sync_transfer(dev, &spi_xfer, 1);
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if (r < 0) {
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kfree_skb(*skb);
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return -EREMOTEIO;
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}
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skb_put(*skb, len);
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memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len);
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return 0;
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}
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/*
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* Reads an ndlc frame from the chip.
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*
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* On ST21NFCB, IRQ goes in idle state when read starts.
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*/
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static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
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{
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struct st_nci_spi_phy *phy = phy_id;
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struct sk_buff *skb = NULL;
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int r;
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if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) {
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WARN_ON_ONCE(1);
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return IRQ_NONE;
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}
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if (phy->ndlc->hard_fault)
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return IRQ_HANDLED;
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if (!phy->ndlc->powered) {
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st_nci_spi_disable(phy);
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return IRQ_HANDLED;
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}
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r = st_nci_spi_read(phy, &skb);
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if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
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return IRQ_HANDLED;
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ndlc_recv(phy->ndlc, skb);
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return IRQ_HANDLED;
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}
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static const struct nfc_phy_ops spi_phy_ops = {
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.write = st_nci_spi_write,
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.enable = st_nci_spi_enable,
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.disable = st_nci_spi_disable,
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};
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static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
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static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
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{ "reset-gpios", &reset_gpios, 1 },
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{},
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};
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static int st_nci_spi_probe(struct spi_device *dev)
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{
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struct st_nci_spi_phy *phy;
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int r;
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/* Check SPI platform functionnalities */
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if (!dev) {
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pr_debug("%s: dev is NULL. Device is not accessible.\n",
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__func__);
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return -ENODEV;
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}
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phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy),
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GFP_KERNEL);
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if (!phy)
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return -ENOMEM;
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phy->spi_dev = dev;
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spi_set_drvdata(dev, phy);
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r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios);
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if (r)
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dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n");
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/* Get RESET GPIO */
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phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH);
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if (IS_ERR(phy->gpiod_reset)) {
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nfc_err(&dev->dev, "Unable to get RESET GPIO\n");
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return PTR_ERR(phy->gpiod_reset);
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}
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phy->se_status.is_ese_present =
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device_property_read_bool(&dev->dev, "ese-present");
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phy->se_status.is_uicc_present =
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device_property_read_bool(&dev->dev, "uicc-present");
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r = ndlc_probe(phy, &spi_phy_ops, &dev->dev,
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ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
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&phy->ndlc, &phy->se_status);
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if (r < 0) {
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nfc_err(&dev->dev, "Unable to register ndlc layer\n");
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return r;
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}
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phy->irq_active = true;
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r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL,
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st_nci_irq_thread_fn,
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IRQF_ONESHOT,
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ST_NCI_SPI_DRIVER_NAME, phy);
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if (r < 0)
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nfc_err(&dev->dev, "Unable to register IRQ handler\n");
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return r;
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}
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static void st_nci_spi_remove(struct spi_device *dev)
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{
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struct st_nci_spi_phy *phy = spi_get_drvdata(dev);
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ndlc_remove(phy->ndlc);
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}
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static struct spi_device_id st_nci_spi_id_table[] = {
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{ST_NCI_SPI_DRIVER_NAME, 0},
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{"st21nfcb-spi", 0},
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{}
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};
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MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table);
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static const struct acpi_device_id st_nci_spi_acpi_match[] __maybe_unused = {
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{"SMO2101", 0},
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{}
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};
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MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match);
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static const struct of_device_id of_st_nci_spi_match[] __maybe_unused = {
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{ .compatible = "st,st21nfcb-spi", },
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{}
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};
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MODULE_DEVICE_TABLE(of, of_st_nci_spi_match);
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static struct spi_driver st_nci_spi_driver = {
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.driver = {
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.name = ST_NCI_SPI_DRIVER_NAME,
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.of_match_table = of_match_ptr(of_st_nci_spi_match),
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.acpi_match_table = ACPI_PTR(st_nci_spi_acpi_match),
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},
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.probe = st_nci_spi_probe,
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.id_table = st_nci_spi_id_table,
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.remove = st_nci_spi_remove,
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};
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module_spi_driver(st_nci_spi_driver);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION(DRIVER_DESC);
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