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331 lines
7.9 KiB
331 lines
7.9 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Driver for NXP PN532 NFC Chip - UART transport layer |
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* |
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* Copyright (C) 2018 Lemonage Software GmbH |
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* Author: Lars Pöschel <[email protected]> |
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* All rights reserved. |
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*/ |
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#include <linux/device.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/nfc.h> |
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#include <linux/netdevice.h> |
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#include <linux/of.h> |
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#include <linux/serdev.h> |
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#include "pn533.h" |
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#define PN532_UART_SKB_BUFF_LEN (PN533_CMD_DATAEXCH_DATA_MAXLEN * 2) |
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enum send_wakeup { |
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PN532_SEND_NO_WAKEUP = 0, |
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PN532_SEND_WAKEUP, |
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PN532_SEND_LAST_WAKEUP, |
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}; |
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struct pn532_uart_phy { |
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struct serdev_device *serdev; |
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struct sk_buff *recv_skb; |
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struct pn533 *priv; |
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/* |
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* send_wakeup variable is used to control if we need to send a wakeup |
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* request to the pn532 chip prior to our actual command. There is a |
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* little propability of a race condition. We decided to not mutex the |
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* variable as the worst that could happen is, that we send a wakeup |
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* to the chip that is already awake. This does not hurt. It is a |
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* no-op to the chip. |
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*/ |
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enum send_wakeup send_wakeup; |
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struct timer_list cmd_timeout; |
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struct sk_buff *cur_out_buf; |
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}; |
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static int pn532_uart_send_frame(struct pn533 *dev, |
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struct sk_buff *out) |
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{ |
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/* wakeup sequence and dummy bytes for waiting time */ |
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static const u8 wakeup[] = { |
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0x55, 0x55, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; |
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struct pn532_uart_phy *pn532 = dev->phy; |
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int err; |
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print_hex_dump_debug("PN532_uart TX: ", DUMP_PREFIX_NONE, 16, 1, |
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out->data, out->len, false); |
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pn532->cur_out_buf = out; |
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if (pn532->send_wakeup) { |
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err = serdev_device_write(pn532->serdev, |
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wakeup, sizeof(wakeup), |
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MAX_SCHEDULE_TIMEOUT); |
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if (err < 0) |
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return err; |
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} |
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if (pn532->send_wakeup == PN532_SEND_LAST_WAKEUP) |
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pn532->send_wakeup = PN532_SEND_NO_WAKEUP; |
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err = serdev_device_write(pn532->serdev, out->data, out->len, |
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MAX_SCHEDULE_TIMEOUT); |
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if (err < 0) |
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return err; |
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mod_timer(&pn532->cmd_timeout, HZ / 40 + jiffies); |
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return 0; |
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} |
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static int pn532_uart_send_ack(struct pn533 *dev, gfp_t flags) |
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{ |
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/* spec 7.1.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */ |
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static const u8 ack[PN533_STD_FRAME_ACK_SIZE] = { |
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0x00, 0x00, 0xff, 0x00, 0xff, 0x00}; |
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struct pn532_uart_phy *pn532 = dev->phy; |
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int err; |
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err = serdev_device_write(pn532->serdev, ack, sizeof(ack), |
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MAX_SCHEDULE_TIMEOUT); |
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if (err < 0) |
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return err; |
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return 0; |
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} |
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static void pn532_uart_abort_cmd(struct pn533 *dev, gfp_t flags) |
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{ |
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/* An ack will cancel the last issued command */ |
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pn532_uart_send_ack(dev, flags); |
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/* schedule cmd_complete_work to finish current command execution */ |
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pn533_recv_frame(dev, NULL, -ENOENT); |
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} |
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static int pn532_dev_up(struct pn533 *dev) |
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{ |
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struct pn532_uart_phy *pn532 = dev->phy; |
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int ret = 0; |
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ret = serdev_device_open(pn532->serdev); |
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if (ret) |
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return ret; |
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pn532->send_wakeup = PN532_SEND_LAST_WAKEUP; |
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return ret; |
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} |
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static int pn532_dev_down(struct pn533 *dev) |
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{ |
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struct pn532_uart_phy *pn532 = dev->phy; |
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serdev_device_close(pn532->serdev); |
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pn532->send_wakeup = PN532_SEND_WAKEUP; |
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return 0; |
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} |
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static const struct pn533_phy_ops uart_phy_ops = { |
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.send_frame = pn532_uart_send_frame, |
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.send_ack = pn532_uart_send_ack, |
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.abort_cmd = pn532_uart_abort_cmd, |
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.dev_up = pn532_dev_up, |
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.dev_down = pn532_dev_down, |
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}; |
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static void pn532_cmd_timeout(struct timer_list *t) |
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{ |
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struct pn532_uart_phy *dev = from_timer(dev, t, cmd_timeout); |
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pn532_uart_send_frame(dev->priv, dev->cur_out_buf); |
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} |
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/* |
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* scans the buffer if it contains a pn532 frame. It is not checked if the |
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* frame is really valid. This is later done with pn533_rx_frame_is_valid. |
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* This is useful for malformed or errornous transmitted frames. Adjusts the |
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* bufferposition where the frame starts, since pn533_recv_frame expects a |
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* well formed frame. |
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*/ |
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static int pn532_uart_rx_is_frame(struct sk_buff *skb) |
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{ |
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struct pn533_std_frame *std; |
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struct pn533_ext_frame *ext; |
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u16 frame_len; |
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int i; |
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for (i = 0; i + PN533_STD_FRAME_ACK_SIZE <= skb->len; i++) { |
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std = (struct pn533_std_frame *)&skb->data[i]; |
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/* search start code */ |
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if (std->start_frame != cpu_to_be16(PN533_STD_FRAME_SOF)) |
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continue; |
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/* frame type */ |
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switch (std->datalen) { |
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case PN533_FRAME_DATALEN_ACK: |
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if (std->datalen_checksum == 0xff) { |
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skb_pull(skb, i); |
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return 1; |
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} |
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break; |
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case PN533_FRAME_DATALEN_ERROR: |
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if ((std->datalen_checksum == 0xff) && |
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(skb->len >= |
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PN533_STD_ERROR_FRAME_SIZE)) { |
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skb_pull(skb, i); |
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return 1; |
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} |
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break; |
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case PN533_FRAME_DATALEN_EXTENDED: |
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ext = (struct pn533_ext_frame *)&skb->data[i]; |
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frame_len = be16_to_cpu(ext->datalen); |
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if (skb->len >= frame_len + |
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sizeof(struct pn533_ext_frame) + |
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2 /* CKS + Postamble */) { |
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skb_pull(skb, i); |
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return 1; |
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} |
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break; |
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default: /* normal information frame */ |
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frame_len = std->datalen; |
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if (skb->len >= frame_len + |
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sizeof(struct pn533_std_frame) + |
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2 /* CKS + Postamble */) { |
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skb_pull(skb, i); |
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return 1; |
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} |
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break; |
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} |
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} |
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return 0; |
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} |
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static int pn532_receive_buf(struct serdev_device *serdev, |
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const unsigned char *data, size_t count) |
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{ |
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struct pn532_uart_phy *dev = serdev_device_get_drvdata(serdev); |
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size_t i; |
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del_timer(&dev->cmd_timeout); |
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for (i = 0; i < count; i++) { |
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skb_put_u8(dev->recv_skb, *data++); |
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if (!pn532_uart_rx_is_frame(dev->recv_skb)) |
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continue; |
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pn533_recv_frame(dev->priv, dev->recv_skb, 0); |
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dev->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL); |
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if (!dev->recv_skb) |
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return 0; |
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} |
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return i; |
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} |
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static const struct serdev_device_ops pn532_serdev_ops = { |
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.receive_buf = pn532_receive_buf, |
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.write_wakeup = serdev_device_write_wakeup, |
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}; |
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static const struct of_device_id pn532_uart_of_match[] = { |
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{ .compatible = "nxp,pn532", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, pn532_uart_of_match); |
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static int pn532_uart_probe(struct serdev_device *serdev) |
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{ |
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struct pn532_uart_phy *pn532; |
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struct pn533 *priv; |
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int err; |
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err = -ENOMEM; |
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pn532 = kzalloc(sizeof(*pn532), GFP_KERNEL); |
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if (!pn532) |
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goto err_exit; |
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pn532->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL); |
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if (!pn532->recv_skb) |
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goto err_free; |
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pn532->serdev = serdev; |
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serdev_device_set_drvdata(serdev, pn532); |
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serdev_device_set_client_ops(serdev, &pn532_serdev_ops); |
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err = serdev_device_open(serdev); |
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if (err) { |
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dev_err(&serdev->dev, "Unable to open device\n"); |
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goto err_skb; |
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} |
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err = serdev_device_set_baudrate(serdev, 115200); |
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if (err != 115200) { |
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err = -EINVAL; |
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goto err_serdev; |
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} |
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serdev_device_set_flow_control(serdev, false); |
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pn532->send_wakeup = PN532_SEND_WAKEUP; |
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timer_setup(&pn532->cmd_timeout, pn532_cmd_timeout, 0); |
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priv = pn53x_common_init(PN533_DEVICE_PN532_AUTOPOLL, |
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PN533_PROTO_REQ_ACK_RESP, |
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pn532, &uart_phy_ops, NULL, |
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&pn532->serdev->dev); |
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if (IS_ERR(priv)) { |
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err = PTR_ERR(priv); |
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goto err_serdev; |
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} |
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pn532->priv = priv; |
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err = pn533_finalize_setup(pn532->priv); |
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if (err) |
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goto err_clean; |
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serdev_device_close(serdev); |
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err = pn53x_register_nfc(priv, PN533_NO_TYPE_B_PROTOCOLS, &serdev->dev); |
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if (err) { |
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pn53x_common_clean(pn532->priv); |
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goto err_skb; |
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} |
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return err; |
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err_clean: |
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pn53x_common_clean(pn532->priv); |
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err_serdev: |
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serdev_device_close(serdev); |
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err_skb: |
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kfree_skb(pn532->recv_skb); |
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err_free: |
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kfree(pn532); |
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err_exit: |
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return err; |
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} |
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static void pn532_uart_remove(struct serdev_device *serdev) |
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{ |
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struct pn532_uart_phy *pn532 = serdev_device_get_drvdata(serdev); |
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pn53x_unregister_nfc(pn532->priv); |
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serdev_device_close(serdev); |
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pn53x_common_clean(pn532->priv); |
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del_timer_sync(&pn532->cmd_timeout); |
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kfree_skb(pn532->recv_skb); |
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kfree(pn532); |
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} |
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static struct serdev_device_driver pn532_uart_driver = { |
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.probe = pn532_uart_probe, |
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.remove = pn532_uart_remove, |
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.driver = { |
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.name = "pn532_uart", |
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.of_match_table = pn532_uart_of_match, |
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}, |
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}; |
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module_serdev_device_driver(pn532_uart_driver); |
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MODULE_AUTHOR("Lars Pöschel <[email protected]>"); |
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MODULE_DESCRIPTION("PN532 UART driver"); |
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MODULE_LICENSE("GPL");
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