diff options
Diffstat (limited to 'drivers/nfc/st-nci')
| -rw-r--r-- | drivers/nfc/st-nci/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/nfc/st-nci/Makefile | 3 | ||||
| -rw-r--r-- | drivers/nfc/st-nci/spi.c | 392 |
3 files changed, 406 insertions, 0 deletions
diff --git a/drivers/nfc/st-nci/Kconfig b/drivers/nfc/st-nci/Kconfig index fc3904c..e7c6db9 100644 --- a/drivers/nfc/st-nci/Kconfig +++ b/drivers/nfc/st-nci/Kconfig @@ -21,3 +21,14 @@ config NFC_ST_NCI_I2C If you choose to build a module, it'll be called st-nci_i2c. Say N if unsure. + +config NFC_ST_NCI_SPI + tristate "NFC ST NCI spi support" + depends on NFC_ST_NCI && SPI + ---help--- + This module adds support for an SPI interface to the + STMicroelectronics NFC NCI chips familly. + Select this if your platform is using the spi bus. + + If you choose to build a module, it'll be called st-nci_spi. + Say N if unsure. diff --git a/drivers/nfc/st-nci/Makefile b/drivers/nfc/st-nci/Makefile index 0df157d..348ce76 100644 --- a/drivers/nfc/st-nci/Makefile +++ b/drivers/nfc/st-nci/Makefile @@ -7,3 +7,6 @@ obj-$(CONFIG_NFC_ST_NCI) += st-nci.o st-nci_i2c-objs = i2c.o obj-$(CONFIG_NFC_ST_NCI_I2C) += st-nci_i2c.o + +st-nci_spi-objs = spi.o +obj-$(CONFIG_NFC_ST_NCI_SPI) += st-nci_spi.o diff --git a/drivers/nfc/st-nci/spi.c b/drivers/nfc/st-nci/spi.c new file mode 100644 index 0000000..598a58c --- /dev/null +++ b/drivers/nfc/st-nci/spi.c @@ -0,0 +1,392 @@ +/* + * SPI Link Layer for ST NCI based Driver + * Copyright (C) 2014-2015 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/spi/spi.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/st-nci.h> + +#include "ndlc.h" + +#define DRIVER_DESC "NCI NFC driver for ST_NCI" + +/* ndlc header */ +#define ST_NCI_FRAME_HEADROOM 1 +#define ST_NCI_FRAME_TAILROOM 0 + +#define ST_NCI_SPI_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */ +#define ST_NCI_SPI_MAX_SIZE 250 /* req 4.2.1 */ + +#define ST_NCI_SPI_DRIVER_NAME "st_nci_spi" + +static struct spi_device_id st_nci_spi_id_table[] = { + {ST_NCI_SPI_DRIVER_NAME, 0}, + {} +}; +MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table); + +struct st_nci_spi_phy { + struct spi_device *spi_dev; + struct llt_ndlc *ndlc; + + unsigned int gpio_reset; + unsigned int irq_polarity; +}; + +#define SPI_DUMP_SKB(info, skb) \ +do { \ + pr_debug("%s:\n", info); \ + print_hex_dump(KERN_DEBUG, "spi: ", DUMP_PREFIX_OFFSET, \ + 16, 1, (skb)->data, (skb)->len, 0); \ +} while (0) + +static int st_nci_spi_enable(void *phy_id) +{ + struct st_nci_spi_phy *phy = phy_id; + + gpio_set_value(phy->gpio_reset, 0); + usleep_range(10000, 15000); + gpio_set_value(phy->gpio_reset, 1); + usleep_range(80000, 85000); + + if (phy->ndlc->powered == 0) + enable_irq(phy->spi_dev->irq); + + return 0; +} + +static void st_nci_spi_disable(void *phy_id) +{ + struct st_nci_spi_phy *phy = phy_id; + + disable_irq_nosync(phy->spi_dev->irq); +} + +/* + * 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 st_nci_spi_write(void *phy_id, struct sk_buff *skb) +{ + int r; + struct st_nci_spi_phy *phy = phy_id; + struct spi_device *dev = phy->spi_dev; + struct sk_buff *skb_rx; + u8 buf[ST_NCI_SPI_MAX_SIZE]; + struct spi_transfer spi_xfer = { + .tx_buf = skb->data, + .rx_buf = buf, + .len = skb->len, + }; + + SPI_DUMP_SKB("st_nci_spi_write", skb); + + if (phy->ndlc->hard_fault != 0) + return phy->ndlc->hard_fault; + + r = spi_sync_transfer(dev, &spi_xfer, 1); + /* + * We may have received some valuable data on miso line. + * Send them back in the ndlc state machine. + */ + if (!r) { + skb_rx = alloc_skb(skb->len, GFP_KERNEL); + if (!skb_rx) { + r = -ENOMEM; + goto exit; + } + + skb_put(skb_rx, skb->len); + memcpy(skb_rx->data, buf, skb->len); + ndlc_recv(phy->ndlc, skb_rx); + } + +exit: + return r; +} + +/* + * Reads an ndlc frame and returns it in a newly allocated sk_buff. + * returns: + * 0 : if received frame is complete + * -EREMOTEIO : i2c read error (fatal) + * -EBADMSG : frame was incorrect and discarded + * -ENOMEM : cannot allocate skb, frame dropped + */ +static int st_nci_spi_read(struct st_nci_spi_phy *phy, + struct sk_buff **skb) +{ + int r; + u8 len; + u8 buf[ST_NCI_SPI_MAX_SIZE]; + struct spi_device *dev = phy->spi_dev; + struct spi_transfer spi_xfer = { + .rx_buf = buf, + .len = ST_NCI_SPI_MIN_SIZE, + }; + + r = spi_sync_transfer(dev, &spi_xfer, 1); + if (r < 0) + return -EREMOTEIO; + + len = be16_to_cpu(*(__be16 *) (buf + 2)); + if (len > ST_NCI_SPI_MAX_SIZE) { + nfc_err(&dev->dev, "invalid frame len\n"); + phy->ndlc->hard_fault = 1; + return -EBADMSG; + } + + *skb = alloc_skb(ST_NCI_SPI_MIN_SIZE + len, GFP_KERNEL); + if (*skb == NULL) + return -ENOMEM; + + skb_reserve(*skb, ST_NCI_SPI_MIN_SIZE); + skb_put(*skb, ST_NCI_SPI_MIN_SIZE); + memcpy((*skb)->data, buf, ST_NCI_SPI_MIN_SIZE); + + if (!len) + return 0; + + spi_xfer.len = len; + r = spi_sync_transfer(dev, &spi_xfer, 1); + if (r < 0) { + kfree_skb(*skb); + return -EREMOTEIO; + } + + skb_put(*skb, len); + memcpy((*skb)->data + ST_NCI_SPI_MIN_SIZE, buf, len); + + SPI_DUMP_SKB("spi 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 st_nci_irq_thread_fn(int irq, void *phy_id) +{ + struct st_nci_spi_phy *phy = phy_id; + struct spi_device *dev; + struct sk_buff *skb = NULL; + int r; + + if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) { + WARN_ON_ONCE(1); + return IRQ_NONE; + } + + dev = phy->spi_dev; + dev_dbg(&dev->dev, "IRQ\n"); + + if (phy->ndlc->hard_fault) + return IRQ_HANDLED; + + if (!phy->ndlc->powered) { + st_nci_spi_disable(phy); + return IRQ_HANDLED; + } + + r = st_nci_spi_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 spi_phy_ops = { + .write = st_nci_spi_write, + .enable = st_nci_spi_enable, + .disable = st_nci_spi_disable, +}; + +#ifdef CONFIG_OF +static int st_nci_spi_of_request_resources(struct spi_device *dev) +{ + struct st_nci_spi_phy *phy = spi_get_drvdata(dev); + struct device_node *pp; + int gpio; + int r; + + pp = dev->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(&dev->dev, + "Failed to retrieve reset-gpios from device tree\n"); + return gpio; + } + + /* GPIO request and configuration */ + r = devm_gpio_request_one(&dev->dev, gpio, + GPIOF_OUT_INIT_HIGH, "clf_reset"); + if (r) { + nfc_err(&dev->dev, "Failed to request reset pin\n"); + return r; + } + phy->gpio_reset = gpio; + + phy->irq_polarity = irq_get_trigger_type(dev->irq); + + return 0; +} +#else +static int st_nci_spi_of_request_resources(struct spi_device *dev) +{ + return -ENODEV; +} +#endif + +static int st_nci_spi_request_resources(struct spi_device *dev) +{ + struct st_nci_nfc_platform_data *pdata; + struct st_nci_spi_phy *phy = spi_get_drvdata(dev); + int r; + + pdata = dev->dev.platform_data; + if (pdata == NULL) { + nfc_err(&dev->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(&dev->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 st_nci_spi_probe(struct spi_device *dev) +{ + struct st_nci_spi_phy *phy; + struct st_nci_nfc_platform_data *pdata; + int r; + + dev_dbg(&dev->dev, "%s\n", __func__); + dev_dbg(&dev->dev, "IRQ: %d\n", dev->irq); + + /* Check SPI platform functionnalities */ + if (!dev) { + pr_debug("%s: dev is NULL. Device is not accessible.\n", + __func__); + return -ENODEV; + } + + phy = devm_kzalloc(&dev->dev, sizeof(struct st_nci_spi_phy), + GFP_KERNEL); + if (!phy) + return -ENOMEM; + + phy->spi_dev = dev; + + spi_set_drvdata(dev, phy); + + pdata = dev->dev.platform_data; + if (!pdata && dev->dev.of_node) { + r = st_nci_spi_of_request_resources(dev); + if (r) { + nfc_err(&dev->dev, "No platform data\n"); + return r; + } + } else if (pdata) { + r = st_nci_spi_request_resources(dev); + if (r) { + nfc_err(&dev->dev, + "Cannot get platform resources\n"); + return r; + } + } else { + nfc_err(&dev->dev, + "st_nci platform resources not available\n"); + return -ENODEV; + } + + r = ndlc_probe(phy, &spi_phy_ops, &dev->dev, + ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, + &phy->ndlc); + if (r < 0) { + nfc_err(&dev->dev, "Unable to register ndlc layer\n"); + return r; + } + + r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL, + st_nci_irq_thread_fn, + phy->irq_polarity | IRQF_ONESHOT, + ST_NCI_SPI_DRIVER_NAME, phy); + if (r < 0) + nfc_err(&dev->dev, "Unable to register IRQ handler\n"); + + return r; +} + +static int st_nci_spi_remove(struct spi_device *dev) +{ + struct st_nci_spi_phy *phy = spi_get_drvdata(dev); + + dev_dbg(&dev->dev, "%s\n", __func__); + + ndlc_remove(phy->ndlc); + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id of_st_nci_spi_match[] = { + { .compatible = "st,st21nfcb-spi", }, + {} +}; +MODULE_DEVICE_TABLE(of, of_st_nci_spi_match); +#endif + +static struct spi_driver st_nci_spi_driver = { + .driver = { + .owner = THIS_MODULE, + .name = ST_NCI_SPI_DRIVER_NAME, + .of_match_table = of_match_ptr(of_st_nci_spi_match), + }, + .probe = st_nci_spi_probe, + .id_table = st_nci_spi_id_table, + .remove = st_nci_spi_remove, +}; + +module_spi_driver(st_nci_spi_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION(DRIVER_DESC); |
