diff options
Diffstat (limited to 'drivers/nfc/st-nci/spi.c')
| -rw-r--r-- | drivers/nfc/st-nci/spi.c | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/drivers/nfc/st-nci/spi.c b/drivers/nfc/st-nci/spi.c new file mode 100644 index 0000000000..169eacc0a3 --- /dev/null +++ b/drivers/nfc/st-nci/spi.c @@ -0,0 +1,305 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * SPI Link Layer for ST NCI based Driver + * Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/spi/spi.h> +#include <linux/gpio/consumer.h> +#include <linux/acpi.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/nfc.h> +#include <linux/of.h> +#include <net/nfc/nci.h> + +#include "st-nci.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_DRIVER_NAME "st_nci" +#define ST_NCI_SPI_DRIVER_NAME "st_nci_spi" + +struct st_nci_spi_phy { + struct spi_device *spi_dev; + struct llt_ndlc *ndlc; + + bool irq_active; + + struct gpio_desc *gpiod_reset; + + struct st_nci_se_status se_status; +}; + +static int st_nci_spi_enable(void *phy_id) +{ + struct st_nci_spi_phy *phy = phy_id; + + gpiod_set_value(phy->gpiod_reset, 0); + usleep_range(10000, 15000); + gpiod_set_value(phy->gpiod_reset, 1); + usleep_range(80000, 85000); + + if (phy->ndlc->powered == 0 && phy->irq_active == 0) { + enable_irq(phy->spi_dev->irq); + phy->irq_active = true; + } + + 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); + phy->irq_active = false; +} + +/* + * 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 + NCI_DATA_HDR_SIZE + + ST_NCI_FRAME_HEADROOM + ST_NCI_FRAME_TAILROOM]; + struct spi_transfer spi_xfer = { + .tx_buf = skb->data, + .rx_buf = buf, + .len = skb->len, + }; + + 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) + return -ENOMEM; + + skb_put(skb_rx, skb->len); + memcpy(skb_rx->data, buf, skb->len); + ndlc_recv(phy->ndlc, skb_rx); + } + + 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); + + 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 sk_buff *skb = NULL; + int r; + + if (!phy || !phy->ndlc || irq != phy->spi_dev->irq) { + WARN_ON_ONCE(1); + return IRQ_NONE; + } + + 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 const struct nfc_phy_ops spi_phy_ops = { + .write = st_nci_spi_write, + .enable = st_nci_spi_enable, + .disable = st_nci_spi_disable, +}; + +static const struct acpi_gpio_params reset_gpios = { 1, 0, false }; + +static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = { + { "reset-gpios", &reset_gpios, 1 }, + {}, +}; + +static int st_nci_spi_probe(struct spi_device *dev) +{ + struct st_nci_spi_phy *phy; + int r; + + /* 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); + + r = devm_acpi_dev_add_driver_gpios(&dev->dev, acpi_st_nci_gpios); + if (r) + dev_dbg(&dev->dev, "Unable to add GPIO mapping table\n"); + + /* Get RESET GPIO */ + phy->gpiod_reset = devm_gpiod_get(&dev->dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(phy->gpiod_reset)) { + nfc_err(&dev->dev, "Unable to get RESET GPIO\n"); + return PTR_ERR(phy->gpiod_reset); + } + + phy->se_status.is_ese_present = + device_property_read_bool(&dev->dev, "ese-present"); + phy->se_status.is_uicc_present = + device_property_read_bool(&dev->dev, "uicc-present"); + + r = ndlc_probe(phy, &spi_phy_ops, &dev->dev, + ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM, + &phy->ndlc, &phy->se_status); + if (r < 0) { + nfc_err(&dev->dev, "Unable to register ndlc layer\n"); + return r; + } + + phy->irq_active = true; + r = devm_request_threaded_irq(&dev->dev, dev->irq, NULL, + st_nci_irq_thread_fn, + IRQF_ONESHOT, + ST_NCI_SPI_DRIVER_NAME, phy); + if (r < 0) + nfc_err(&dev->dev, "Unable to register IRQ handler\n"); + + return r; +} + +static void st_nci_spi_remove(struct spi_device *dev) +{ + struct st_nci_spi_phy *phy = spi_get_drvdata(dev); + + ndlc_remove(phy->ndlc); +} + +static struct spi_device_id st_nci_spi_id_table[] = { + {ST_NCI_SPI_DRIVER_NAME, 0}, + {"st21nfcb-spi", 0}, + {} +}; +MODULE_DEVICE_TABLE(spi, st_nci_spi_id_table); + +static const struct acpi_device_id st_nci_spi_acpi_match[] __maybe_unused = { + {"SMO2101", 0}, + {} +}; +MODULE_DEVICE_TABLE(acpi, st_nci_spi_acpi_match); + +static const struct of_device_id of_st_nci_spi_match[] __maybe_unused = { + { .compatible = "st,st21nfcb-spi", }, + {} +}; +MODULE_DEVICE_TABLE(of, of_st_nci_spi_match); + +static struct spi_driver st_nci_spi_driver = { + .driver = { + .name = ST_NCI_SPI_DRIVER_NAME, + .of_match_table = of_match_ptr(of_st_nci_spi_match), + .acpi_match_table = ACPI_PTR(st_nci_spi_acpi_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); |