nfc/nfcmrvl/spi.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Marvell NFC-over-SPI driver: SPI interface related functions
0004  *
0005  * Copyright (C) 2015, Marvell International Ltd.
0006  */
0007
0008 #include <linux/module.h>
0009 #include <linux/interrupt.h>
0010 #include <linux/nfc.h>
0011 #include <linux/of_irq.h>
0012 #include <net/nfc/nci.h>
0013 #include <net/nfc/nci_core.h>
0014 #include <linux/spi/spi.h>
0015 #include "nfcmrvl.h"
0016
0017 #define SPI_WAIT_HANDSHAKE  1
0018
0019 struct nfcmrvl_spi_drv_data {
0020     unsigned long flags;
0021     struct spi_device *spi;
0022     struct nci_spi *nci_spi;
0023     struct completion handshake_completion;
0024     struct nfcmrvl_private *priv;
0025 };
0026
0027 static irqreturn_t nfcmrvl_spi_int_irq_thread_fn(int irq, void *drv_data_ptr)
0028 {
0029     struct nfcmrvl_spi_drv_data *drv_data = drv_data_ptr;
0030     struct sk_buff *skb;
0031
0032     /*
0033      * Special case where we are waiting for SPI_INT deassertion to start a
0034      * transfer.
0035      */
0036     if (test_and_clear_bit(SPI_WAIT_HANDSHAKE, &drv_data->flags)) {
0037         complete(&drv_data->handshake_completion);
0038         return IRQ_HANDLED;
0039     }
0040
0041     /* Normal case, SPI_INT deasserted by slave to trigger a master read */
0042
0043     skb = nci_spi_read(drv_data->nci_spi);
0044     if (!skb) {
0045         nfc_err(&drv_data->spi->dev, "failed to read spi packet");
0046         return IRQ_HANDLED;
0047     }
0048
0049     if (nfcmrvl_nci_recv_frame(drv_data->priv, skb) < 0)
0050         nfc_err(&drv_data->spi->dev, "corrupted RX packet");
0051
0052     return IRQ_HANDLED;
0053 }
0054
0055 static int nfcmrvl_spi_nci_open(struct nfcmrvl_private *priv)
0056 {
0057     return 0;
0058 }
0059
0060 static int nfcmrvl_spi_nci_close(struct nfcmrvl_private *priv)
0061 {
0062     return 0;
0063 }
0064
0065 static int nfcmrvl_spi_nci_send(struct nfcmrvl_private *priv,
0066                 struct sk_buff *skb)
0067 {
0068     struct nfcmrvl_spi_drv_data *drv_data = priv->drv_data;
0069     int err;
0070
0071     /* Reinit completion for slave handshake */
0072     reinit_completion(&drv_data->handshake_completion);
0073     set_bit(SPI_WAIT_HANDSHAKE, &drv_data->flags);
0074
0075     /*
0076      * Append a dummy byte at the end of SPI frame. This is due to a
0077      * specific DMA implementation in the controller
0078      */
0079     skb_put(skb, 1);
0080
0081     /* Send the SPI packet */
0082     err = nci_spi_send(drv_data->nci_spi, &drv_data->handshake_completion,
0083                skb);
0084     if (err)
0085         nfc_err(priv->dev, "spi_send failed %d", err);
0086
0087     return err;
0088 }
0089
0090 static void nfcmrvl_spi_nci_update_config(struct nfcmrvl_private *priv,
0091                       const void *param)
0092 {
0093     struct nfcmrvl_spi_drv_data *drv_data = priv->drv_data;
0094     const struct nfcmrvl_fw_spi_config *config = param;
0095
0096     drv_data->nci_spi->xfer_speed_hz = config->clk;
0097 }
0098
0099 static const struct nfcmrvl_if_ops spi_ops = {
0100     .nci_open = nfcmrvl_spi_nci_open,
0101     .nci_close = nfcmrvl_spi_nci_close,
0102     .nci_send = nfcmrvl_spi_nci_send,
0103     .nci_update_config = nfcmrvl_spi_nci_update_config,
0104 };
0105
0106 static int nfcmrvl_spi_parse_dt(struct device_node *node,
0107                 struct nfcmrvl_platform_data *pdata)
0108 {
0109     int ret;
0110
0111     ret = nfcmrvl_parse_dt(node, pdata);
0112     if (ret < 0) {
0113         pr_err("Failed to get generic entries\n");
0114         return ret;
0115     }
0116
0117     ret = irq_of_parse_and_map(node, 0);
0118     if (!ret) {
0119         pr_err("Unable to get irq\n");
0120         return -EINVAL;
0121     }
0122     pdata->irq = ret;
0123
0124     return 0;
0125 }
0126
0127 static int nfcmrvl_spi_probe(struct spi_device *spi)
0128 {
0129     const struct nfcmrvl_platform_data *pdata;
0130     struct nfcmrvl_platform_data config;
0131     struct nfcmrvl_spi_drv_data *drv_data;
0132     int ret = 0;
0133
0134     drv_data = devm_kzalloc(&spi->dev, sizeof(*drv_data), GFP_KERNEL);
0135     if (!drv_data)
0136         return -ENOMEM;
0137
0138     drv_data->spi = spi;
0139     drv_data->priv = NULL;
0140     spi_set_drvdata(spi, drv_data);
0141
0142     pdata = spi->dev.platform_data;
0143
0144     if (!pdata && spi->dev.of_node)
0145         if (nfcmrvl_spi_parse_dt(spi->dev.of_node, &config) == 0)
0146             pdata = &config;
0147
0148     if (!pdata)
0149         return -EINVAL;
0150
0151     ret = devm_request_threaded_irq(&drv_data->spi->dev, pdata->irq,
0152                     NULL, nfcmrvl_spi_int_irq_thread_fn,
0153                     IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
0154                     "nfcmrvl_spi_int", drv_data);
0155     if (ret < 0) {
0156         nfc_err(&drv_data->spi->dev, "Unable to register IRQ handler");
0157         return -ENODEV;
0158     }
0159
0160     drv_data->priv = nfcmrvl_nci_register_dev(NFCMRVL_PHY_SPI,
0161                           drv_data, &spi_ops,
0162                           &drv_data->spi->dev,
0163                           pdata);
0164     if (IS_ERR(drv_data->priv))
0165         return PTR_ERR(drv_data->priv);
0166
0167     drv_data->priv->support_fw_dnld = true;
0168
0169     drv_data->nci_spi = nci_spi_allocate_spi(drv_data->spi, 0, 10,
0170                          drv_data->priv->ndev);
0171
0172     /* Init completion for slave handshake */
0173     init_completion(&drv_data->handshake_completion);
0174     return 0;
0175 }
0176
0177 static void nfcmrvl_spi_remove(struct spi_device *spi)
0178 {
0179     struct nfcmrvl_spi_drv_data *drv_data = spi_get_drvdata(spi);
0180
0181     nfcmrvl_nci_unregister_dev(drv_data->priv);
0182 }
0183
0184 static const struct of_device_id of_nfcmrvl_spi_match[] __maybe_unused = {
0185     { .compatible = "marvell,nfc-spi", },
0186     {},
0187 };
0188 MODULE_DEVICE_TABLE(of, of_nfcmrvl_spi_match);
0189
0190 static const struct spi_device_id nfcmrvl_spi_id_table[] = {
0191     { "nfcmrvl_spi", 0 },
0192     { }
0193 };
0194 MODULE_DEVICE_TABLE(spi, nfcmrvl_spi_id_table);
0195
0196 static struct spi_driver nfcmrvl_spi_driver = {
0197     .probe      = nfcmrvl_spi_probe,
0198     .remove     = nfcmrvl_spi_remove,
0199     .id_table   = nfcmrvl_spi_id_table,
0200     .driver     = {
0201         .name       = "nfcmrvl_spi",
0202         .owner      = THIS_MODULE,
0203         .of_match_table = of_match_ptr(of_nfcmrvl_spi_match),
0204     },
0205 };
0206
0207 module_spi_driver(nfcmrvl_spi_driver);
0208
0209 MODULE_AUTHOR("Marvell International Ltd.");
0210 MODULE_DESCRIPTION("Marvell NFC-over-SPI driver");
0211 MODULE_LICENSE("GPL v2");