| /* |
| * 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); |