drivers/nfc/nfcmrvl/uart.c

   1 /**
   2  * Marvell NFC-over-UART driver
   3  *
   4  * Copyright (C) 2015, Marvell International Ltd.
   5  *
   6  * This software file (the "File") is distributed by Marvell International
   7  * Ltd. under the terms of the GNU General Public License Version 2, June 1991
   8  * (the "License").  You may use, redistribute and/or modify this File in
   9  * accordance with the terms and conditions of the License, a copy of which
  10  * is available on the worldwide web at
  11  * http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
  12  *
  13  * THE FILE IS DISTRIBUTED AS-IS, WITHOUT WARRANTY OF ANY KIND, AND THE
  14  * IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
  15  * ARE EXPRESSLY DISCLAIMED.  The License provides additional details about
  16  * this warranty disclaimer.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/delay.h>
  21 #include <linux/of_gpio.h>
  22 #include <net/nfc/nci.h>
  23 #include <net/nfc/nci_core.h>
  24 #include "nfcmrvl.h"
  25
  26 static unsigned int hci_muxed;
  27 static unsigned int flow_control;
  28 static unsigned int break_control;
  29 static unsigned int reset_n_io;
  30
  31 /*
  32 ** NFCMRVL NCI OPS
  33 */
  34
  35 static int nfcmrvl_uart_nci_open(struct nfcmrvl_private *priv)
  36 {
  37         return 0;
  38 }
  39
  40 static int nfcmrvl_uart_nci_close(struct nfcmrvl_private *priv)
  41 {
  42         return 0;
  43 }
  44
  45 static int nfcmrvl_uart_nci_send(struct nfcmrvl_private *priv,
  46                                  struct sk_buff *skb)
  47 {
  48         struct nci_uart *nu = priv->drv_data;
  49
  50         return nu->ops.send(nu, skb);
  51 }
  52
  53 static struct nfcmrvl_if_ops uart_ops = {
  54         .nci_open = nfcmrvl_uart_nci_open,
  55         .nci_close = nfcmrvl_uart_nci_close,
  56         .nci_send = nfcmrvl_uart_nci_send,
  57 };
  58
  59 #ifdef CONFIG_OF
  60
  61 static int nfcmrvl_uart_parse_dt(struct device_node *node,
  62                                  struct nfcmrvl_platform_data *pdata)
  63 {
  64         struct device_node *matched_node;
  65         int ret;
  66
  67         matched_node = of_find_compatible_node(node, NULL, "mrvl,nfc-uart");
  68         if (!matched_node)
  69                 return -ENODEV;
  70
  71         ret = nfcmrvl_parse_dt(matched_node, pdata);
  72         if (ret < 0) {
  73                 pr_err("Failed to get generic entries\n");
  74                 return ret;
  75         }
  76
  77         if (of_find_property(matched_node, "flow-control", NULL))
  78                 pdata->flow_control = 1;
  79         else
  80                 pdata->flow_control = 0;
  81
  82         if (of_find_property(matched_node, "break-control", NULL))
  83                 pdata->break_control = 1;
  84         else
  85                 pdata->break_control = 0;
  86
  87         return 0;
  88 }
  89
  90 #else
  91
  92 static int nfcmrvl_uart_parse_dt(struct device_node *node,
  93                                  struct nfcmrvl_platform_data *pdata)
  94 {
  95         return -ENODEV;
  96 }
  97
  98 #endif
  99
 100 /*
 101 ** NCI UART OPS
 102 */
 103
 104 static int nfcmrvl_nci_uart_open(struct nci_uart *nu)
 105 {
 106         struct nfcmrvl_private *priv;
 107         struct nfcmrvl_platform_data *pdata = NULL;
 108         struct nfcmrvl_platform_data config;
 109
 110         /*
 111          * Platform data cannot be used here since usually it is already used
 112          * by low level serial driver. We can try to retrieve serial device
 113          * and check if DT entries were added.
 114          */
 115
 116         if (nu->tty->dev->parent && nu->tty->dev->parent->of_node)
 117                 if (nfcmrvl_uart_parse_dt(nu->tty->dev->parent->of_node,
 118                                           &config) == 0)
 119                         pdata = &config;
 120
 121         if (!pdata) {
 122                 pr_info("No platform data / DT -> fallback to module params\n");
 123                 config.hci_muxed = hci_muxed;
 124                 config.reset_n_io = reset_n_io;
 125                 config.flow_control = flow_control;
 126                 config.break_control = break_control;
 127                 pdata = &config;
 128         }
 129
 130         priv = nfcmrvl_nci_register_dev(nu, &uart_ops, nu->tty->dev, pdata);
 131         if (IS_ERR(priv))
 132                 return PTR_ERR(priv);
 133
 134         priv->phy = NFCMRVL_PHY_UART;
 135
 136         nu->drv_data = priv;
 137         nu->ndev = priv->ndev;
 138
 139         /* Set BREAK */
 140         if (priv->config.break_control && nu->tty->ops->break_ctl)
 141                 nu->tty->ops->break_ctl(nu->tty, -1);
 142
 143         return 0;
 144 }
 145
 146 static void nfcmrvl_nci_uart_close(struct nci_uart *nu)
 147 {
 148         nfcmrvl_nci_unregister_dev((struct nfcmrvl_private *)nu->drv_data);
 149 }
 150
 151 static int nfcmrvl_nci_uart_recv(struct nci_uart *nu, struct sk_buff *skb)
 152 {
 153         return nfcmrvl_nci_recv_frame((struct nfcmrvl_private *)nu->drv_data,
 154                                       skb);
 155 }
 156
 157 static void nfcmrvl_nci_uart_tx_start(struct nci_uart *nu)
 158 {
 159         struct nfcmrvl_private *priv = (struct nfcmrvl_private *)nu->drv_data;
 160
 161         /* Remove BREAK to wake up the NFCC */
 162         if (priv->config.break_control && nu->tty->ops->break_ctl) {
 163                 nu->tty->ops->break_ctl(nu->tty, 0);
 164                 usleep_range(3000, 5000);
 165         }
 166 }
 167
 168 static void nfcmrvl_nci_uart_tx_done(struct nci_uart *nu)
 169 {
 170         struct nfcmrvl_private *priv = (struct nfcmrvl_private *)nu->drv_data;
 171
 172         /*
 173         ** To ensure that if the NFCC goes in DEEP SLEEP sate we can wake him
 174         ** up. we set BREAK. Once we will be ready to send again we will remove
 175         ** it.
 176         */
 177         if (priv->config.break_control && nu->tty->ops->break_ctl)
 178                 nu->tty->ops->break_ctl(nu->tty, -1);
 179 }
 180
 181 static struct nci_uart nfcmrvl_nci_uart = {
 182         .owner  = THIS_MODULE,
 183         .name   = "nfcmrvl_uart",
 184         .driver = NCI_UART_DRIVER_MARVELL,
 185         .ops    = {
 186                 .open           = nfcmrvl_nci_uart_open,
 187                 .close          = nfcmrvl_nci_uart_close,
 188                 .recv           = nfcmrvl_nci_uart_recv,
 189                 .tx_start       = nfcmrvl_nci_uart_tx_start,
 190                 .tx_done        = nfcmrvl_nci_uart_tx_done,
 191         }
 192 };
 193
 194 /*
 195 ** Module init
 196 */
 197
 198 static int nfcmrvl_uart_init_module(void)
 199 {
 200         return nci_uart_register(&nfcmrvl_nci_uart);
 201 }
 202
 203 static void nfcmrvl_uart_exit_module(void)
 204 {
 205         nci_uart_unregister(&nfcmrvl_nci_uart);
 206 }
 207
 208 module_init(nfcmrvl_uart_init_module);
 209 module_exit(nfcmrvl_uart_exit_module);
 210
 211 MODULE_AUTHOR("Marvell International Ltd.");
 212 MODULE_DESCRIPTION("Marvell NFC-over-UART");
 213 MODULE_LICENSE("GPL v2");
 214
 215 module_param(flow_control, uint, 0);
 216 MODULE_PARM_DESC(flow_control, "Tell if UART needs flow control at init.");
 217
 218 module_param(break_control, uint, 0);
 219 MODULE_PARM_DESC(break_control, "Tell if UART driver must drive break signal.");
 220
 221 module_param(hci_muxed, uint, 0);
 222 MODULE_PARM_DESC(hci_muxed, "Tell if transport is muxed in HCI one.");
 223
 224 module_param(reset_n_io, uint, 0);
 225 MODULE_PARM_DESC(reset_n_io, "GPIO that is wired to RESET_N signal.");