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SubjectRe: [RFC 4/4] NFC: pn533: add I2C phy driver
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Hi Michael,

I know this is an old patch already applied, but I noticed the following:

On 25-03-16 15:46, Michael Thalmeier wrote:
> This adds the I2C phy interface for the pn533 driver. This way the driver can
> be used to interact with I2C connected pn532.
>
> Signed-off-by: Michael Thalmeier <michael.thalmeier@hale.at>
> ---
> drivers/nfc/pn533/Kconfig | 11 ++
> drivers/nfc/pn533/Makefile | 2 +
> drivers/nfc/pn533/i2c.c | 277 +++++++++++++++++++++++++++++++++++++++++++++
> drivers/nfc/pn533/pn533.c | 29 +++++
> drivers/nfc/pn533/pn533.h | 2 +
> 5 files changed, 321 insertions(+)
> create mode 100644 drivers/nfc/pn533/i2c.c
>
> diff --git a/drivers/nfc/pn533/Kconfig b/drivers/nfc/pn533/Kconfig
> index b5a926e..d94122d 100644
> --- a/drivers/nfc/pn533/Kconfig
> +++ b/drivers/nfc/pn533/Kconfig
> @@ -14,3 +14,14 @@ config NFC_PN533_USB
>
> If you choose to build a module, it'll be called pn533_usb.
> Say N if unsure.
> +
> +config NFC_PN533_I2C
> + tristate "NFC PN533 device support (I2C)"
> + depends on I2C
> + select NFC_PN533
> + ---help---
> + This module adds support for the NXP pn533 I2C interface.
> + Select this if your platform is using the I2C bus.
> +
> + If you choose to build a module, it'll be called pn533_i2c.
> + Say N if unsure.
> diff --git a/drivers/nfc/pn533/Makefile b/drivers/nfc/pn533/Makefile
> index 12c6be4..51d24c6 100644
> --- a/drivers/nfc/pn533/Makefile
> +++ b/drivers/nfc/pn533/Makefile
> @@ -2,6 +2,8 @@
> # Makefile for PN533 NFC driver
> #
> pn533_usb-objs = usb.o
> +pn533_i2c-objs = i2c.o
>
> obj-$(CONFIG_NFC_PN533) += pn533.o
> obj-$(CONFIG_NFC_PN533_USB) += pn533_usb.o
> +obj-$(CONFIG_NFC_PN533_I2C) += pn533_i2c.o
> diff --git a/drivers/nfc/pn533/i2c.c b/drivers/nfc/pn533/i2c.c
> new file mode 100644
> index 0000000..35066b30
> --- /dev/null
> +++ b/drivers/nfc/pn533/i2c.c
> @@ -0,0 +1,277 @@
> +/*
> + * Driver for NXP PN533 NFC Chip - I2C transport layer
> + *
> + * Copyright (C) 2011 Instituto Nokia de Tecnologia
> + * Copyright (C) 2012-2013 Tieto Poland
> + * Copyright (C) 2016 HALE electronic
> + *
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * 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/>.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/i2c.h>
> +#include <linux/nfc.h>
> +#include <linux/netdevice.h>
> +#include <linux/interrupt.h>
> +#include <net/nfc/nfc.h>
> +#include "pn533.h"
> +
> +#define VERSION "0.1"
> +
> +#define PN533_I2C_DRIVER_NAME "pn533_i2c"
> +
> +struct pn533_i2c_phy {
> + struct i2c_client *i2c_dev;
> + struct pn533 *priv;
> +
> + int hard_fault; /*
> + * < 0 if hardware error occured (e.g. i2c err)
> + * and prevents normal operation.
> + */
> +};
> +
> +static int pn533_i2c_send_ack(struct pn533 *dev, gfp_t flags)
> +{
> + struct pn533_i2c_phy *phy = dev->phy;
> + struct i2c_client *client = phy->i2c_dev;
> + u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
> + /* spec 6.2.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */
> + int rc;
> +
> + rc = i2c_master_send(client, ack, 6);
> +
> + return rc;
> +}
> +
> +static int pn533_i2c_send_frame(struct pn533 *dev,
> + struct sk_buff *out)
> +{
> + struct pn533_i2c_phy *phy = dev->phy;
> + struct i2c_client *client = phy->i2c_dev;
> + int rc;
> +
> + if (phy->hard_fault != 0)
> + return phy->hard_fault;
> +
> + if (phy->priv == NULL)
> + phy->priv = dev;
> +
> + print_hex_dump_debug("PN533_i2c TX: ", DUMP_PREFIX_NONE, 16, 1,
> + out->data, out->len, false);
> +
> + rc = i2c_master_send(client, out->data, out->len);
> +
> + if (rc == -EREMOTEIO) { /* Retry, chip was in power down */
> + usleep_range(6000, 10000);
> + rc = i2c_master_send(client, out->data, out->len);
> + }
> +
> + if (rc >= 0) {
> + if (rc != out->len)
> + rc = -EREMOTEIO;
> + else
> + rc = 0;
> + }
> +
> + return rc;
> +}
> +
> +static void pn533_i2c_abort_cmd(struct pn533 *dev, gfp_t flags)
> +{
> + /* An ack will cancel the last issued command */
> + pn533_i2c_send_ack(dev, flags);
> +
> + /* schedule cmd_complete_work to finish current command execution */
> + if (dev->cmd != NULL)
> + dev->cmd->status = -ENOENT;
> + queue_work(dev->wq, &dev->cmd_complete_work);
> +}
> +
> +static int pn533_i2c_read(struct pn533_i2c_phy *phy, struct sk_buff **skb)
> +{
> + struct i2c_client *client = phy->i2c_dev;
> + int len = PN533_EXT_FRAME_HEADER_LEN +
> + PN533_STD_FRAME_MAX_PAYLOAD_LEN +
> + PN533_STD_FRAME_TAIL_LEN + 1;
> + int r;
> +
> + *skb = alloc_skb(len, GFP_KERNEL);
> + if (*skb == NULL)
> + return -ENOMEM;
> +
> + r = i2c_master_recv(client, skb_put(*skb, len), len);
> + if (r != len) {
> + nfc_err(&client->dev, "cannot read. r=%d len=%d\n", r, len);
> + kfree_skb(*skb);
> + return -EREMOTEIO;
> + }
> +
> + if (!((*skb)->data[0] & 0x01)) {
> + nfc_err(&client->dev, "READY flag not set");
> + kfree_skb(*skb);
> + return -EBUSY;
> + }
> +
> + /* remove READY byte */
> + skb_pull(*skb, 1);
> + /* trim to frame size */
> + skb_trim(*skb, phy->priv->ops->rx_frame_size((*skb)->data));
> +
> + return 0;
> +}
> +
> +static irqreturn_t pn533_i2c_irq_thread_fn(int irq, void *data)
> +{
> + struct pn533_i2c_phy *phy = data;
> + struct i2c_client *client;
> + struct sk_buff *skb = NULL;
> + int r;
> +
> + if (!phy || irq != phy->i2c_dev->irq) {
> + WARN_ON_ONCE(1);
> + return IRQ_NONE;
> + }
> +
> + client = phy->i2c_dev;
> + dev_dbg(&client->dev, "IRQ\n");
> +
> + if (phy->hard_fault != 0)
> + return IRQ_HANDLED;
> +
> + r = pn533_i2c_read(phy, &skb);
> + if (r == -EREMOTEIO) {
> + phy->hard_fault = r;
> +
> + pn533_recv_frame(phy->priv, NULL, -EREMOTEIO);
> +
> + return IRQ_HANDLED;
> + } else if ((r == -ENOMEM) || (r == -EBADMSG) || (r == -EBUSY)) {
> + return IRQ_HANDLED;
> + }
This logic seems a bit odd and could be written cleaner no?

> +
> + pn533_recv_frame(phy->priv, skb, 0);
> +
> + return IRQ_HANDLED;
> +
> +#if 0
> +#endif
But mostly, this shouldn't be here :)

> +}
> +
> +static struct pn533_phy_ops i2c_phy_ops = {
> + .send_frame = pn533_i2c_send_frame,
> + .send_ack = pn533_i2c_send_ack,
> + .abort_cmd = pn533_i2c_abort_cmd,
> +};
> +
> +
> +static int pn533_i2c_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct pn533_i2c_phy *phy;
> + struct pn533 *priv;
> + int r = 0;
> +
> + dev_dbg(&client->dev, "%s\n", __func__);
> + dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
> +
> + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
> + nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
> + return -ENODEV;
> + }
> +
> + phy = devm_kzalloc(&client->dev, sizeof(struct pn533_i2c_phy),
> + GFP_KERNEL);
> + if (!phy) {
> + nfc_err(&client->dev,
> + "Cannot allocate memory for pn533 i2c phy.\n");
> + return -ENOMEM;
> + }
> +
> + phy->i2c_dev = client;
> + i2c_set_clientdata(client, phy);
> +
> + r = request_threaded_irq(client->irq, NULL, pn533_i2c_irq_thread_fn,
> + IRQF_TRIGGER_FALLING | IRQF_SHARED | IRQF_ONESHOT,
> + PN533_I2C_DRIVER_NAME, phy);
Are we allowed to call this if client->irq is 0?
> +
> + if (r < 0) {
> + nfc_err(&client->dev, "Unable to register IRQ handler\n");
> + }
Because then this won't cause an error. The IRQ is fully optional on the
hardware for i2c is it not?
> +
> + priv = pn533_register_device(PN533_DEVICE_PN532,
> + PN533_NO_TYPE_B_PROTOCOLS,
> + PN533_PROTO_REQ_ACK_RESP,
> + phy, &i2c_phy_ops, NULL,
> + &phy->i2c_dev->dev);
Currently, this hangs, and i'll let you know why in a follow up.

> +
> + if (IS_ERR(priv)) {
> + r = PTR_ERR(priv);
> + goto err_register;
> + }
> +
> + phy->priv = priv;
> +
> + return 0;
> +
> +err_register:
> + free_irq(client->irq, phy);
> +
> + return r;
> +}
> +
> +static int pn533_i2c_remove(struct i2c_client *client)
> +{
> + struct pn533_i2c_phy *phy = i2c_get_clientdata(client);
> +
> + dev_dbg(&client->dev, "%s\n", __func__);
> +
> + pn533_unregister_device(phy->priv);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id of_pn533_i2c_match[] = {
> + { .compatible = "nxp,pn533-i2c", },
> + { .compatible = "nxp,pn532-i2c", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, of_pn533_i2c_match);
> +
> +static struct i2c_device_id pn533_i2c_id_table[] = {
> + { PN533_I2C_DRIVER_NAME, 0 },
> + {}
> +};
> +MODULE_DEVICE_TABLE(i2c, pn533_i2c_id_table);
> +
> +static struct i2c_driver pn533_i2c_driver = {
> + .driver = {
> + .name = PN533_I2C_DRIVER_NAME,
> + .owner = THIS_MODULE,
> + .of_match_table = of_match_ptr(of_pn533_i2c_match),
> + },
> + .probe = pn533_i2c_probe,
> + .id_table = pn533_i2c_id_table,
> + .remove = pn533_i2c_remove,
> +};
> +
> +module_i2c_driver(pn533_i2c_driver);
> +
> +MODULE_AUTHOR("Michael Thalmeier <michael.thalmeier@hale.at>");
> +MODULE_DESCRIPTION("PN533 I2C driver ver " VERSION);
> +MODULE_VERSION(VERSION);
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/nfc/pn533/pn533.c b/drivers/nfc/pn533/pn533.c
> index 4468284..3d286a7 100644
> --- a/drivers/nfc/pn533/pn533.c
> +++ b/drivers/nfc/pn533/pn533.c
> @@ -2435,8 +2435,35 @@ static int pn533_rf_field(struct nfc_dev *nfc_dev, u8 rf)
> return rc;
> }
>
> +static int pn532_sam_configuration(struct nfc_dev *nfc_dev)
> +{
> + struct pn533 *dev = nfc_get_drvdata(nfc_dev);
> + struct sk_buff *skb;
> + struct sk_buff *resp;
> +
> + skb = pn533_alloc_skb(dev, 1);
> + if (!skb)
> + return -ENOMEM;
> +
> + *skb_put(skb, 1) = 0x01;
> +
> + resp = pn533_send_cmd_sync(dev, PN533_CMD_SAM_CONFIGURATION, skb);
> + if (IS_ERR(resp))
> + return PTR_ERR(resp);
> +
> + dev_kfree_skb(resp);
> + return 0;
> +}
> +
> static int pn533_dev_up(struct nfc_dev *nfc_dev)
> {
> + struct pn533 *dev = nfc_get_drvdata(nfc_dev);
> + if (dev->device_type == PN533_DEVICE_PN532) {
> + int rc = pn532_sam_configuration(nfc_dev);
> + if (rc)
> + return rc;
> + }
> +
> return pn533_rf_field(nfc_dev, 1);
> }
>
> @@ -2469,6 +2496,7 @@ static int pn533_setup(struct pn533 *dev)
> case PN533_DEVICE_STD:
> case PN533_DEVICE_PASORI:
> case PN533_DEVICE_ACR122U:
> + case PN533_DEVICE_PN532:
> max_retries.mx_rty_atr = 0x2;
> max_retries.mx_rty_psl = 0x1;
> max_retries.mx_rty_passive_act =
> @@ -2504,6 +2532,7 @@ static int pn533_setup(struct pn533 *dev)
>
> switch (dev->device_type) {
> case PN533_DEVICE_STD:
> + case PN533_DEVICE_PN532:
> break;
>
> case PN533_DEVICE_PASORI:
> diff --git a/drivers/nfc/pn533/pn533.h b/drivers/nfc/pn533/pn533.h
> index 0958c653..61c5d6a 100644
> --- a/drivers/nfc/pn533/pn533.h
> +++ b/drivers/nfc/pn533/pn533.h
> @@ -21,6 +21,7 @@
> #define PN533_DEVICE_STD 0x1
> #define PN533_DEVICE_PASORI 0x2
> #define PN533_DEVICE_ACR122U 0x3
> +#define PN533_DEVICE_PN532 0x4
>
> #define PN533_ALL_PROTOCOLS (NFC_PROTO_JEWEL_MASK | NFC_PROTO_MIFARE_MASK |\
> NFC_PROTO_FELICA_MASK | NFC_PROTO_ISO14443_MASK |\
> @@ -72,6 +73,7 @@
> #define PN533_FRAME_CMD(f) (f->data[1])
>
> #define PN533_CMD_GET_FIRMWARE_VERSION 0x02
> +#define PN533_CMD_SAM_CONFIGURATION 0x14
> #define PN533_CMD_RF_CONFIGURATION 0x32
> #define PN533_CMD_IN_DATA_EXCHANGE 0x40
> #define PN533_CMD_IN_COMM_THRU 0x42
>

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