diff options
Diffstat (limited to 'drivers/nfc/st21nfcb/i2c.c')
| -rw-r--r-- | drivers/nfc/st21nfcb/i2c.c | 388 |
1 files changed, 388 insertions, 0 deletions
diff --git a/drivers/nfc/st21nfcb/i2c.c b/drivers/nfc/st21nfcb/i2c.c new file mode 100644 index 000000000..c44f8cf53 --- /dev/null +++ b/drivers/nfc/st21nfcb/i2c.c @@ -0,0 +1,388 @@ +/* + * I2C Link Layer for ST21NFCB NCI based Driver + * Copyright (C) 2014 STMicroelectronics SAS. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * 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/>. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/gpio.h> +#include <linux/of_irq.h> +#include <linux/of_gpio.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/nfc.h> +#include <linux/platform_data/st21nfcb.h> + +#include "ndlc.h" + +#define DRIVER_DESC "NCI NFC driver for ST21NFCB" + +/* ndlc header */ +#define ST21NFCB_FRAME_HEADROOM 1 +#define ST21NFCB_FRAME_TAILROOM 0 + +#define ST21NFCB_NCI_I2C_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */ +#define ST21NFCB_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */ + +#define ST21NFCB_NCI_I2C_DRIVER_NAME "st21nfcb_nci_i2c" + +static struct i2c_device_id st21nfcb_nci_i2c_id_table[] = { + {ST21NFCB_NCI_DRIVER_NAME, 0}, + {} +}; +MODULE_DEVICE_TABLE(i2c, st21nfcb_nci_i2c_id_table); + +struct st21nfcb_i2c_phy { + struct i2c_client *i2c_dev; + struct llt_ndlc *ndlc; + + unsigned int gpio_reset; + unsigned int irq_polarity; + + int powered; +}; + +#define I2C_DUMP_SKB(info, skb) \ +do { \ + pr_debug("%s:\n", info); \ + print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \ + 16, 1, (skb)->data, (skb)->len, 0); \ +} while (0) + +static int st21nfcb_nci_i2c_enable(void *phy_id) +{ + struct st21nfcb_i2c_phy *phy = phy_id; + + gpio_set_value(phy->gpio_reset, 0); + usleep_range(10000, 15000); + gpio_set_value(phy->gpio_reset, 1); + phy->powered = 1; + usleep_range(80000, 85000); + + return 0; +} + +static void st21nfcb_nci_i2c_disable(void *phy_id) +{ + struct st21nfcb_i2c_phy *phy = phy_id; + + phy->powered = 0; + /* reset chip in order to flush clf */ + gpio_set_value(phy->gpio_reset, 0); + usleep_range(10000, 15000); + gpio_set_value(phy->gpio_reset, 1); +} + +/* + * Writing a frame must not return the number of written bytes. + * It must return either zero for success, or <0 for error. + * In addition, it must not alter the skb + */ +static int st21nfcb_nci_i2c_write(void *phy_id, struct sk_buff *skb) +{ + int r = -1; + struct st21nfcb_i2c_phy *phy = phy_id; + struct i2c_client *client = phy->i2c_dev; + + I2C_DUMP_SKB("st21nfcb_nci_i2c_write", skb); + + if (phy->ndlc->hard_fault != 0) + return phy->ndlc->hard_fault; + + r = i2c_master_send(client, skb->data, skb->len); + if (r < 0) { /* Retry, chip was in standby */ + usleep_range(1000, 4000); + r = i2c_master_send(client, skb->data, skb->len); + } + + if (r >= 0) { + if (r != skb->len) + r = -EREMOTEIO; + else + r = 0; + } + + return r; +} + +/* + * Reads an ndlc frame and returns it in a newly allocated sk_buff. + * returns: + * frame size : if received frame is complete (find ST21NFCB_SOF_EOF at + * end of read) + * -EAGAIN : if received frame is incomplete (not find ST21NFCB_SOF_EOF + * at end of read) + * -EREMOTEIO : i2c read error (fatal) + * -EBADMSG : frame was incorrect and discarded + * (value returned from st21nfcb_nci_i2c_repack) + * -EIO : if no ST21NFCB_SOF_EOF is found after reaching + * the read length end sequence + */ +static int st21nfcb_nci_i2c_read(struct st21nfcb_i2c_phy *phy, + struct sk_buff **skb) +{ + int r; + u8 len; + u8 buf[ST21NFCB_NCI_I2C_MAX_SIZE]; + struct i2c_client *client = phy->i2c_dev; + + r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE); + if (r < 0) { /* Retry, chip was in standby */ + usleep_range(1000, 4000); + r = i2c_master_recv(client, buf, ST21NFCB_NCI_I2C_MIN_SIZE); + } + + if (r != ST21NFCB_NCI_I2C_MIN_SIZE) + return -EREMOTEIO; + + len = be16_to_cpu(*(__be16 *) (buf + 2)); + if (len > ST21NFCB_NCI_I2C_MAX_SIZE) { + nfc_err(&client->dev, "invalid frame len\n"); + return -EBADMSG; + } + + *skb = alloc_skb(ST21NFCB_NCI_I2C_MIN_SIZE + len, GFP_KERNEL); + if (*skb == NULL) + return -ENOMEM; + + skb_reserve(*skb, ST21NFCB_NCI_I2C_MIN_SIZE); + skb_put(*skb, ST21NFCB_NCI_I2C_MIN_SIZE); + memcpy((*skb)->data, buf, ST21NFCB_NCI_I2C_MIN_SIZE); + + if (!len) + return 0; + + r = i2c_master_recv(client, buf, len); + if (r != len) { + kfree_skb(*skb); + return -EREMOTEIO; + } + + skb_put(*skb, len); + memcpy((*skb)->data + ST21NFCB_NCI_I2C_MIN_SIZE, buf, len); + + I2C_DUMP_SKB("i2c frame read", *skb); + + return 0; +} + +/* + * Reads an ndlc frame from the chip. + * + * On ST21NFCB, IRQ goes in idle state when read starts. + */ +static irqreturn_t st21nfcb_nci_irq_thread_fn(int irq, void *phy_id) +{ + struct st21nfcb_i2c_phy *phy = phy_id; + struct i2c_client *client; + struct sk_buff *skb = NULL; + int r; + + if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) { + WARN_ON_ONCE(1); + return IRQ_NONE; + } + + client = phy->i2c_dev; + dev_dbg(&client->dev, "IRQ\n"); + + if (phy->ndlc->hard_fault) + return IRQ_HANDLED; + + if (!phy->powered) { + st21nfcb_nci_i2c_disable(phy); + return IRQ_HANDLED; + } + + r = st21nfcb_nci_i2c_read(phy, &skb); + if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG) + return IRQ_HANDLED; + + ndlc_recv(phy->ndlc, skb); + + return IRQ_HANDLED; +} + +static struct nfc_phy_ops i2c_phy_ops = { + .write = st21nfcb_nci_i2c_write, + .enable = st21nfcb_nci_i2c_enable, + .disable = st21nfcb_nci_i2c_disable, +}; + +#ifdef CONFIG_OF +static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client) +{ + struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client); + struct device_node *pp; + int gpio; + int r; + + pp = client->dev.of_node; + if (!pp) + return -ENODEV; + + /* Get GPIO from device tree */ + gpio = of_get_named_gpio(pp, "reset-gpios", 0); + if (gpio < 0) { + nfc_err(&client->dev, + "Failed to retrieve reset-gpios from device tree\n"); + return gpio; + } + + /* GPIO request and configuration */ + r = devm_gpio_request_one(&client->dev, gpio, + GPIOF_OUT_INIT_HIGH, "clf_reset"); + if (r) { + nfc_err(&client->dev, "Failed to request reset pin\n"); + return r; + } + phy->gpio_reset = gpio; + + phy->irq_polarity = irq_get_trigger_type(client->irq); + + return 0; +} +#else +static int st21nfcb_nci_i2c_of_request_resources(struct i2c_client *client) +{ + return -ENODEV; +} +#endif + +static int st21nfcb_nci_i2c_request_resources(struct i2c_client *client) +{ + struct st21nfcb_nfc_platform_data *pdata; + struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client); + int r; + + pdata = client->dev.platform_data; + if (pdata == NULL) { + nfc_err(&client->dev, "No platform data\n"); + return -EINVAL; + } + + /* store for later use */ + phy->gpio_reset = pdata->gpio_reset; + phy->irq_polarity = pdata->irq_polarity; + + r = devm_gpio_request_one(&client->dev, + phy->gpio_reset, GPIOF_OUT_INIT_HIGH, "clf_reset"); + if (r) { + pr_err("%s : reset gpio_request failed\n", __FILE__); + return r; + } + + return 0; +} + +static int st21nfcb_nci_i2c_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct st21nfcb_i2c_phy *phy; + struct st21nfcb_nfc_platform_data *pdata; + int r; + + 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 st21nfcb_i2c_phy), + GFP_KERNEL); + if (!phy) + return -ENOMEM; + + phy->i2c_dev = client; + + i2c_set_clientdata(client, phy); + + pdata = client->dev.platform_data; + if (!pdata && client->dev.of_node) { + r = st21nfcb_nci_i2c_of_request_resources(client); + if (r) { + nfc_err(&client->dev, "No platform data\n"); + return r; + } + } else if (pdata) { + r = st21nfcb_nci_i2c_request_resources(client); + if (r) { + nfc_err(&client->dev, + "Cannot get platform resources\n"); + return r; + } + } else { + nfc_err(&client->dev, + "st21nfcb platform resources not available\n"); + return -ENODEV; + } + + r = ndlc_probe(phy, &i2c_phy_ops, &client->dev, + ST21NFCB_FRAME_HEADROOM, ST21NFCB_FRAME_TAILROOM, + &phy->ndlc); + if (r < 0) { + nfc_err(&client->dev, "Unable to register ndlc layer\n"); + return r; + } + + r = devm_request_threaded_irq(&client->dev, client->irq, NULL, + st21nfcb_nci_irq_thread_fn, + phy->irq_polarity | IRQF_ONESHOT, + ST21NFCB_NCI_DRIVER_NAME, phy); + if (r < 0) + nfc_err(&client->dev, "Unable to register IRQ handler\n"); + + return r; +} + +static int st21nfcb_nci_i2c_remove(struct i2c_client *client) +{ + struct st21nfcb_i2c_phy *phy = i2c_get_clientdata(client); + + dev_dbg(&client->dev, "%s\n", __func__); + + ndlc_remove(phy->ndlc); + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id of_st21nfcb_i2c_match[] = { + { .compatible = "st,st21nfcb-i2c", }, + { .compatible = "st,st21nfcb_i2c", }, + {} +}; +MODULE_DEVICE_TABLE(of, of_st21nfcb_i2c_match); +#endif + +static struct i2c_driver st21nfcb_nci_i2c_driver = { + .driver = { + .owner = THIS_MODULE, + .name = ST21NFCB_NCI_I2C_DRIVER_NAME, + .of_match_table = of_match_ptr(of_st21nfcb_i2c_match), + }, + .probe = st21nfcb_nci_i2c_probe, + .id_table = st21nfcb_nci_i2c_id_table, + .remove = st21nfcb_nci_i2c_remove, +}; + +module_i2c_driver(st21nfcb_nci_i2c_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION(DRIVER_DESC); |