nfc: pn533: add UART phy driver (c656aa4c) · Commits · EulixOS / Software / Kernel

drivers/nfc/pn533/Kconfig

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		@@ -26,3 +26,14 @@ config NFC_PN533_I2C

		If you choose to build a module, it'll be called pn533_i2c.
		Say N if unsure.

		config NFC_PN532_UART
		tristate "NFC PN532 device support (UART)"
		depends on SERIAL_DEV_BUS
		select NFC_PN533
		---help---
		This module adds support for the NXP pn532 UART interface.
		Select this if your platform is using the UART bus.

		If you choose to build a module, it'll be called pn532_uart.
		Say N if unsure.

drivers/nfc/pn533/Makefile

+2 −0

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		@@ -4,7 +4,9 @@
		#
		pn533_usb-objs = usb.o
		pn533_i2c-objs = i2c.o
		pn532_uart-objs = uart.o

		obj-$(CONFIG_NFC_PN533) += pn533.o
		obj-$(CONFIG_NFC_PN533_USB) += pn533_usb.o
		obj-$(CONFIG_NFC_PN533_I2C) += pn533_i2c.o
		obj-$(CONFIG_NFC_PN532_UART) += pn532_uart.o

drivers/nfc/pn533/pn533.h

+8 −0

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		@@ -43,6 +43,11 @@

		/* Preamble (1), SoPC (2), ACK Code (2), Postamble (1) */
		#define PN533_STD_FRAME_ACK_SIZE 6
		/*
		* Preamble (1), SoPC (2), Packet Length (1), Packet Length Checksum (1),
		* Specific Application Level Error Code (1) , Postamble (1)
		*/
		#define PN533_STD_ERROR_FRAME_SIZE 8
		#define PN533_STD_FRAME_CHECKSUM(f) (f->data[f->datalen])
		#define PN533_STD_FRAME_POSTAMBLE(f) (f->data[f->datalen + 1])
		/* Half start code (3), LEN (4) should be 0xffff for extended frame */
		@@ -84,6 +89,9 @@
		#define PN533_CMD_MI_MASK 0x40
		#define PN533_CMD_RET_SUCCESS 0x00

		#define PN533_FRAME_DATALEN_ACK 0x00
		#define PN533_FRAME_DATALEN_ERROR 0x01
		#define PN533_FRAME_DATALEN_EXTENDED 0xFF

		enum pn533_protocol_type {
		PN533_PROTO_REQ_ACK_RESP = 0,

drivers/nfc/pn533/uart.c

0 → 100644

+323 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0+
		/*
		* Driver for NXP PN532 NFC Chip - UART transport layer
		*
		* Copyright (C) 2018 Lemonage Software GmbH
		* Author: Lars Pöschel <poeschel@lemonage.de>
		* All rights reserved.
		*/

		#include <linux/device.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/nfc.h>
		#include <linux/netdevice.h>
		#include <linux/of.h>
		#include <linux/serdev.h>
		#include "pn533.h"

		#define PN532_UART_SKB_BUFF_LEN (PN533_CMD_DATAEXCH_DATA_MAXLEN * 2)

		enum send_wakeup {
		PN532_SEND_NO_WAKEUP = 0,
		PN532_SEND_WAKEUP,
		PN532_SEND_LAST_WAKEUP,
		};


		struct pn532_uart_phy {
		struct serdev_device *serdev;
		struct sk_buff *recv_skb;
		struct pn533 *priv;
		/*
		* send_wakeup variable is used to control if we need to send a wakeup
		* request to the pn532 chip prior to our actual command. There is a
		* little propability of a race condition. We decided to not mutex the
		* variable as the worst that could happen is, that we send a wakeup
		* to the chip that is already awake. This does not hurt. It is a
		* no-op to the chip.
		*/
		enum send_wakeup send_wakeup;
		struct timer_list cmd_timeout;
		struct sk_buff *cur_out_buf;
		};

		static int pn532_uart_send_frame(struct pn533 *dev,
		struct sk_buff *out)
		{
		/* wakeup sequence and dummy bytes for waiting time */
		static const u8 wakeup[] = {
		0x55, 0x55, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
		struct pn532_uart_phy *pn532 = dev->phy;
		int err;

		print_hex_dump_debug("PN532_uart TX: ", DUMP_PREFIX_NONE, 16, 1,
		out->data, out->len, false);

		pn532->cur_out_buf = out;
		if (pn532->send_wakeup) {
		err = serdev_device_write(pn532->serdev,
		wakeup, sizeof(wakeup),
		MAX_SCHEDULE_TIMEOUT);
		if (err < 0)
		return err;
		}

		if (pn532->send_wakeup == PN532_SEND_LAST_WAKEUP)
		pn532->send_wakeup = PN532_SEND_NO_WAKEUP;

		err = serdev_device_write(pn532->serdev, out->data, out->len,
		MAX_SCHEDULE_TIMEOUT);
		if (err < 0)
		return err;

		mod_timer(&pn532->cmd_timeout, HZ / 40 + jiffies);
		return 0;
		}

		static int pn532_uart_send_ack(struct pn533 *dev, gfp_t flags)
		{
		/* spec 7.1.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */
		static const u8 ack[PN533_STD_FRAME_ACK_SIZE] = {
		0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
		struct pn532_uart_phy *pn532 = dev->phy;
		int err;

		err = serdev_device_write(pn532->serdev, ack, sizeof(ack),
		MAX_SCHEDULE_TIMEOUT);
		if (err < 0)
		return err;

		return 0;
		}

		static void pn532_uart_abort_cmd(struct pn533 *dev, gfp_t flags)
		{
		/* An ack will cancel the last issued command */
		pn532_uart_send_ack(dev, flags);
		/* schedule cmd_complete_work to finish current command execution */
		pn533_recv_frame(dev, NULL, -ENOENT);
		}

		static void pn532_dev_up(struct pn533 *dev)
		{
		struct pn532_uart_phy *pn532 = dev->phy;

		serdev_device_open(pn532->serdev);
		pn532->send_wakeup = PN532_SEND_LAST_WAKEUP;
		}

		static void pn532_dev_down(struct pn533 *dev)
		{
		struct pn532_uart_phy *pn532 = dev->phy;

		serdev_device_close(pn532->serdev);
		pn532->send_wakeup = PN532_SEND_WAKEUP;
		}

		static struct pn533_phy_ops uart_phy_ops = {
		.send_frame = pn532_uart_send_frame,
		.send_ack = pn532_uart_send_ack,
		.abort_cmd = pn532_uart_abort_cmd,
		.dev_up = pn532_dev_up,
		.dev_down = pn532_dev_down,
		};

		static void pn532_cmd_timeout(struct timer_list *t)
		{
		struct pn532_uart_phy *dev = from_timer(dev, t, cmd_timeout);

		pn532_uart_send_frame(dev->priv, dev->cur_out_buf);
		}

		/*
		* scans the buffer if it contains a pn532 frame. It is not checked if the
		* frame is really valid. This is later done with pn533_rx_frame_is_valid.
		* This is useful for malformed or errornous transmitted frames. Adjusts the
		* bufferposition where the frame starts, since pn533_recv_frame expects a
		* well formed frame.
		*/
		static int pn532_uart_rx_is_frame(struct sk_buff *skb)
		{
		struct pn533_std_frame *std;
		struct pn533_ext_frame *ext;
		u16 frame_len;
		int i;

		for (i = 0; i + PN533_STD_FRAME_ACK_SIZE <= skb->len; i++) {
		std = (struct pn533_std_frame *)&skb->data[i];
		/* search start code */
		if (std->start_frame != cpu_to_be16(PN533_STD_FRAME_SOF))
		continue;

		/* frame type */
		switch (std->datalen) {
		case PN533_FRAME_DATALEN_ACK:
		if (std->datalen_checksum == 0xff) {
		skb_pull(skb, i);
		return 1;
		}

		break;
		case PN533_FRAME_DATALEN_ERROR:
		if ((std->datalen_checksum == 0xff) &&
		(skb->len >=
		PN533_STD_ERROR_FRAME_SIZE)) {
		skb_pull(skb, i);
		return 1;
		}

		break;
		case PN533_FRAME_DATALEN_EXTENDED:
		ext = (struct pn533_ext_frame *)&skb->data[i];
		frame_len = be16_to_cpu(ext->datalen);
		if (skb->len >= frame_len +
		sizeof(struct pn533_ext_frame) +
		2 /* CKS + Postamble */) {
		skb_pull(skb, i);
		return 1;
		}

		break;
		default: /* normal information frame */
		frame_len = std->datalen;
		if (skb->len >= frame_len +
		sizeof(struct pn533_std_frame) +
		2 /* CKS + Postamble */) {
		skb_pull(skb, i);
		return 1;
		}

		break;
		}
		}

		return 0;
		}

		static int pn532_receive_buf(struct serdev_device *serdev,
		const unsigned char *data, size_t count)
		{
		struct pn532_uart_phy *dev = serdev_device_get_drvdata(serdev);
		size_t i;

		del_timer(&dev->cmd_timeout);
		for (i = 0; i < count; i++) {
		skb_put_u8(dev->recv_skb, *data++);
		if (!pn532_uart_rx_is_frame(dev->recv_skb))
		continue;

		pn533_recv_frame(dev->priv, dev->recv_skb, 0);
		dev->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL);
		if (!dev->recv_skb)
		return 0;
		}

		return i;
		}

		static struct serdev_device_ops pn532_serdev_ops = {
		.receive_buf = pn532_receive_buf,
		.write_wakeup = serdev_device_write_wakeup,
		};

		static const struct of_device_id pn532_uart_of_match[] = {
		{ .compatible = "nxp,pn532", },
		{},
		};
		MODULE_DEVICE_TABLE(of, pn532_uart_of_match);

		static int pn532_uart_probe(struct serdev_device *serdev)
		{
		struct pn532_uart_phy *pn532;
		struct pn533 *priv;
		int err;

		err = -ENOMEM;
		pn532 = kzalloc(sizeof(*pn532), GFP_KERNEL);
		if (!pn532)
		goto err_exit;

		pn532->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL);
		if (!pn532->recv_skb)
		goto err_free;

		pn532->serdev = serdev;
		serdev_device_set_drvdata(serdev, pn532);
		serdev_device_set_client_ops(serdev, &pn532_serdev_ops);
		err = serdev_device_open(serdev);
		if (err) {
		dev_err(&serdev->dev, "Unable to open device\n");
		goto err_skb;
		}

		err = serdev_device_set_baudrate(serdev, 115200);
		if (err != 115200) {
		err = -EINVAL;
		goto err_serdev;
		}

		serdev_device_set_flow_control(serdev, false);
		pn532->send_wakeup = PN532_SEND_WAKEUP;
		timer_setup(&pn532->cmd_timeout, pn532_cmd_timeout, 0);
		priv = pn53x_common_init(PN533_DEVICE_PN532,
		PN533_PROTO_REQ_ACK_RESP,
		pn532, &uart_phy_ops, NULL,
		&pn532->serdev->dev);
		if (IS_ERR(priv)) {
		err = PTR_ERR(priv);
		goto err_serdev;
		}

		pn532->priv = priv;
		err = pn533_finalize_setup(pn532->priv);
		if (err)
		goto err_clean;

		serdev_device_close(serdev);
		err = pn53x_register_nfc(priv, PN533_NO_TYPE_B_PROTOCOLS, &serdev->dev);
		if (err) {
		pn53x_common_clean(pn532->priv);
		goto err_skb;
		}

		return err;

		err_clean:
		pn53x_common_clean(pn532->priv);
		err_serdev:
		serdev_device_close(serdev);
		err_skb:
		kfree_skb(pn532->recv_skb);
		err_free:
		kfree(pn532);
		err_exit:
		return err;
		}

		static void pn532_uart_remove(struct serdev_device *serdev)
		{
		struct pn532_uart_phy *pn532 = serdev_device_get_drvdata(serdev);

		pn53x_unregister_nfc(pn532->priv);
		serdev_device_close(serdev);
		pn53x_common_clean(pn532->priv);
		kfree_skb(pn532->recv_skb);
		kfree(pn532);
		}

		static struct serdev_device_driver pn532_uart_driver = {
		.probe = pn532_uart_probe,
		.remove = pn532_uart_remove,
		.driver = {
		.name = "pn532_uart",
		.of_match_table = of_match_ptr(pn532_uart_of_match),
		},
		};

		module_serdev_device_driver(pn532_uart_driver);

		MODULE_AUTHOR("Lars Pöschel <poeschel@lemonage.de>");
		MODULE_DESCRIPTION("PN532 UART driver");
		MODULE_LICENSE("GPL");