413 lines
9.7 KiB
C
413 lines
9.7 KiB
C
/*
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* I2C Link Layer for ST21NFCB NCI based Driver
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* Copyright (C) 2014 STMicroelectronics SAS. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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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/i2c.h>
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#include <linux/gpio.h>
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#include <linux/of_irq.h>
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#include <linux/of_gpio.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/platform_data/st21nfcb.h>
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#include "ndlc.h"
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#define DRIVER_DESC "NCI NFC driver for ST21NFCB"
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/* ndlc header */
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#define ST21NFCB_FRAME_HEADROOM 1
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#define ST21NFCB_FRAME_TAILROOM 0
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#define ST21NFCB_NCI_I2C_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */
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#define ST21NFCB_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
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#define ST21NFCB_NCI_I2C_DRIVER_NAME "st21nfcb_nci_i2c"
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static struct i2c_device_id st21nfcb_nci_i2c_id_table[] = {
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{ST21NFCB_NCI_DRIVER_NAME, 0},
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{}
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};
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MODULE_DEVICE_TABLE(i2c, st21nfcb_nci_i2c_id_table);
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struct st21nfcb_i2c_phy {
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struct i2c_client *i2c_dev;
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struct llt_ndlc *ndlc;
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unsigned int gpio_irq;
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unsigned int gpio_reset;
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unsigned int irq_polarity;
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int powered;
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};
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#define I2C_DUMP_SKB(info, skb) \
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do { \
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pr_debug("%s:\n", info); \
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print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
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16, 1, (skb)->data, (skb)->len, 0); \
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} while (0)
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static int st21nfcb_nci_i2c_enable(void *phy_id)
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{
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struct st21nfcb_i2c_phy *phy = phy_id;
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gpio_set_value(phy->gpio_reset, 0);
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usleep_range(10000, 15000);
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gpio_set_value(phy->gpio_reset, 1);
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phy->powered = 1;
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usleep_range(80000, 85000);
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return 0;
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}
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static void st21nfcb_nci_i2c_disable(void *phy_id)
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{
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struct st21nfcb_i2c_phy *phy = phy_id;
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pr_info("\n");
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phy->powered = 0;
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/* reset chip in order to flush clf */
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gpio_set_value(phy->gpio_reset, 0);
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usleep_range(10000, 15000);
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gpio_set_value(phy->gpio_reset, 1);
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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 st21nfcb_nci_i2c_write(void *phy_id, struct sk_buff *skb)
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{
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int r = -1;
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struct st21nfcb_i2c_phy *phy = phy_id;
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struct i2c_client *client = phy->i2c_dev;
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I2C_DUMP_SKB("st21nfcb_nci_i2c_write", skb);
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if (phy->ndlc->hard_fault != 0)
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return phy->ndlc->hard_fault;
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r = i2c_master_send(client, skb->data, skb->len);
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if (r < 0) { /* Retry, chip was in standby */
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usleep_range(1000, 4000);
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r = i2c_master_send(client, skb->data, skb->len);
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}
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if (r >= 0) {
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if (r != skb->len)
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r = -EREMOTEIO;
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else
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r = 0;
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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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* frame size : if received frame is complete (find ST21NFCB_SOF_EOF at
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* end of read)
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* -EAGAIN : if received frame is incomplete (not find ST21NFCB_SOF_EOF
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* at end of read)
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* -EREMOTEIO : i2c read error (fatal)
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* -EBADMSG : frame was incorrect and discarded
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* (value returned from st21nfcb_nci_i2c_repack)
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* -EIO : if no ST21NFCB_SOF_EOF is found after reaching
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* the read length end sequence
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*/
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static int st21nfcb_nci_i2c_read(struct st21nfcb_i2c_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[ST21NFCB_NCI_I2C_MAX_SIZE];
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struct i2c_client *client = phy->i2c_dev;
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r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
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if (r < 0) { /* Retry, chip was in standby */
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usleep_range(1000, 4000);
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r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
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}
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if (r != ST21NFCB_NCI_I2C_MIN_SIZE)
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return -EREMOTEIO;
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len = be16_to_cpu(*(__be16 *) (buf + 2));
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if (len > ST21NFCB_NCI_I2C_MAX_SIZE) {
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nfc_err(&client->dev, "invalid frame len\n");
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return -EBADMSG;
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}
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*skb = alloc_skb(ST21NFCB_NCI_I2C_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, ST21NFCB_NCI_I2C_MIN_SIZE);
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skb_put(*skb, ST21NFCB_NCI_I2C_MIN_SIZE);
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memcpy((*skb)->data, buf, ST21NFCB_NCI_I2C_MIN_SIZE);
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if (!len)
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return 0;
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r = i2c_master_recv(client, buf, len);
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if (r != len) {
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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 + ST21NFCB_NCI_I2C_MIN_SIZE, buf, len);
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I2C_DUMP_SKB("i2c frame read", *skb);
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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 st21nfcb_nci_irq_thread_fn(int irq, void *phy_id)
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{
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struct st21nfcb_i2c_phy *phy = phy_id;
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struct i2c_client *client;
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struct sk_buff *skb = NULL;
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int r;
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if (!phy || irq != phy->i2c_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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client = phy->i2c_dev;
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dev_dbg(&client->dev, "IRQ\n");
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if (phy->ndlc->hard_fault)
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return IRQ_HANDLED;
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if (!phy->powered) {
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st21nfcb_nci_i2c_disable(phy);
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return IRQ_HANDLED;
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}
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r = st21nfcb_nci_i2c_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 struct nfc_phy_ops i2c_phy_ops = {
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.write = st21nfcb_nci_i2c_write,
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.enable = st21nfcb_nci_i2c_enable,
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.disable = st21nfcb_nci_i2c_disable,
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};
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#ifdef CONFIG_OF
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static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
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{
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struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
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struct device_node *pp;
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int gpio;
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int r;
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pp = client->dev.of_node;
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if (!pp)
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return -ENODEV;
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/* Get GPIO from device tree */
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gpio = of_get_named_gpio(pp, "reset-gpios", 0);
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if (gpio < 0) {
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nfc_err(&client->dev,
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"Failed to retrieve reset-gpios from device tree\n");
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return gpio;
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}
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/* GPIO request and configuration */
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r = devm_gpio_request_one(&client->dev, gpio,
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GPIOF_OUT_INIT_HIGH, "clf_reset");
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if (r) {
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nfc_err(&client->dev, "Failed to request reset pin\n");
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return -ENODEV;
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}
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phy->gpio_reset = gpio;
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/* IRQ */
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r = irq_of_parse_and_map(pp, 0);
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if (r < 0) {
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nfc_err(&client->dev, "Unable to get irq, error: %d\n", r);
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return r;
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}
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phy->irq_polarity = irq_get_trigger_type(r);
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client->irq = r;
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return 0;
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}
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#else
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static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client)
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{
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return -ENODEV;
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}
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#endif
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static int st21nfcb_nci_i2c_request_resources(struct i2c_client *client)
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{
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struct st21nfcb_nfc_platform_data *pdata;
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struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
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int r;
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int irq;
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pdata = client->dev.platform_data;
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if (pdata == NULL) {
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nfc_err(&client->dev, "No platform data\n");
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return -EINVAL;
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}
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/* store for later use */
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phy->gpio_irq = pdata->gpio_irq;
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phy->gpio_reset = pdata->gpio_reset;
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phy->irq_polarity = pdata->irq_polarity;
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r = devm_gpio_request_one(&client->dev, phy->gpio_irq,
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GPIOF_IN, "clf_irq");
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if (r) {
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pr_err("%s : gpio_request failed\n", __FILE__);
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return -ENODEV;
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}
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r = devm_gpio_request_one(&client->dev,
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phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset");
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if (r) {
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pr_err("%s : reset gpio_request failed\n", __FILE__);
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return -ENODEV;
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}
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/* IRQ */
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irq = gpio_to_irq(phy->gpio_irq);
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if (irq < 0) {
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nfc_err(&client->dev,
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"Unable to get irq number for GPIO %d error %d\n",
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phy->gpio_irq, r);
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return -ENODEV;
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}
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client->irq = irq;
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return 0;
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}
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static int st21nfcb_nci_i2c_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct st21nfcb_i2c_phy *phy;
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struct st21nfcb_nfc_platform_data *pdata;
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int r;
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dev_dbg(&client->dev, "%s\n", __func__);
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dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
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nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
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return -ENODEV;
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}
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phy = devm_kzalloc(&client->dev, sizeof(struct st21nfcb_i2c_phy),
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GFP_KERNEL);
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if (!phy) {
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nfc_err(&client->dev,
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"Cannot allocate memory for st21nfcb i2c phy.\n");
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return -ENOMEM;
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}
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phy->i2c_dev = client;
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i2c_set_clientdata(client, phy);
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pdata = client->dev.platform_data;
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if (!pdata && client->dev.of_node) {
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r = st21nfcb_nci_i2c_of_request_resources(client);
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if (r) {
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nfc_err(&client->dev, "No platform data\n");
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return r;
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}
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} else if (pdata) {
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r = st21nfcb_nci_i2c_request_resources(client);
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if (r) {
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nfc_err(&client->dev,
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"Cannot get platform resources\n");
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return r;
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}
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} else {
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nfc_err(&client->dev,
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"st21nfcb platform resources not available\n");
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return -ENODEV;
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}
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r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
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st21nfcb_nci_irq_thread_fn,
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phy->irq_polarity | IRQF_ONESHOT,
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ST21NFCB_NCI_DRIVER_NAME, phy);
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if (r < 0) {
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nfc_err(&client->dev, "Unable to register IRQ handler\n");
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return r;
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}
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return ndlc_probe(phy, &i2c_phy_ops, &client->dev,
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ST21NFCB_FRAME_HEADROOM, ST21NFCB_FRAME_TAILROOM,
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&phy->ndlc);
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}
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static int st21nfcb_nci_i2c_remove(struct i2c_client *client)
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{
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struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client);
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dev_dbg(&client->dev, "%s\n", __func__);
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ndlc_remove(phy->ndlc);
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return 0;
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}
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static const struct of_device_id of_st21nfcb_i2c_match[] = {
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{ .compatible = "st,st21nfcb_i2c", },
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{}
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};
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static struct i2c_driver st21nfcb_nci_i2c_driver = {
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.driver = {
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.owner = THIS_MODULE,
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.name = ST21NFCB_NCI_I2C_DRIVER_NAME,
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.of_match_table = of_match_ptr(of_st21nfcb_i2c_match),
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},
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.probe = st21nfcb_nci_i2c_probe,
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.id_table = st21nfcb_nci_i2c_id_table,
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.remove = st21nfcb_nci_i2c_remove,
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};
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module_i2c_driver(st21nfcb_nci_i2c_driver);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION(DRIVER_DESC);
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