uart.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Marvell NFC-over-UART driver
  4 *
  5 * Copyright (C) 2015, Marvell International Ltd.
  6 */
  7
  8#include <linux/delay.h>
  9#include <linux/device.h>
 10#include <linux/err.h>
 11#include <linux/module.h>
 12#include <linux/of.h>
 13#include <linux/printk.h>
 14
 15#include <net/nfc/nci.h>
 16#include <net/nfc/nci_core.h>
 17
 18#include "nfcmrvl.h"
 19
 20static unsigned int hci_muxed;
 21static unsigned int flow_control;
 22static unsigned int break_control;
 23static int reset_n_io = -EINVAL;
 24
 25/*
 26 * NFCMRVL NCI OPS
 27 */
 28
 29static int nfcmrvl_uart_nci_open(struct nfcmrvl_private *priv)
 30{
 31	return 0;
 32}
 33
 34static int nfcmrvl_uart_nci_close(struct nfcmrvl_private *priv)
 35{
 36	return 0;
 37}
 38
 39static int nfcmrvl_uart_nci_send(struct nfcmrvl_private *priv,
 40				 struct sk_buff *skb)
 41{
 42	struct nci_uart *nu = priv->drv_data;
 43
 44	return nu->ops.send(nu, skb);
 45}
 46
 47static void nfcmrvl_uart_nci_update_config(struct nfcmrvl_private *priv,
 48					   const void *param)
 49{
 50	struct nci_uart *nu = priv->drv_data;
 51	const struct nfcmrvl_fw_uart_config *config = param;
 52
 53	nci_uart_set_config(nu, le32_to_cpu(config->baudrate),
 54			    config->flow_control);
 55}
 56
 57static const struct nfcmrvl_if_ops uart_ops = {
 58	.nci_open = nfcmrvl_uart_nci_open,
 59	.nci_close = nfcmrvl_uart_nci_close,
 60	.nci_send = nfcmrvl_uart_nci_send,
 61	.nci_update_config = nfcmrvl_uart_nci_update_config
 62};
 63
 64static int nfcmrvl_uart_parse_dt(struct device_node *node,
 65				 struct nfcmrvl_platform_data *pdata)
 66{
 67	struct device_node *matched_node;
 68	int ret;
 69
 70	matched_node = of_get_compatible_child(node, "marvell,nfc-uart");
 71	if (!matched_node) {
 72		matched_node = of_get_compatible_child(node, "mrvl,nfc-uart");
 73		if (!matched_node)
 74			return -ENODEV;
 75	}
 76
 77	ret = nfcmrvl_parse_dt(matched_node, pdata);
 78	if (ret < 0) {
 79		pr_err("Failed to get generic entries\n");
 80		of_node_put(matched_node);
 81		return ret;
 82	}
 83
 84	pdata->flow_control = of_property_read_bool(matched_node, "flow-control");
 85	pdata->break_control = of_property_read_bool(matched_node, "break-control");
 86
 87	of_node_put(matched_node);
 88
 89	return 0;
 90}
 91
 92/*
 93 * NCI UART OPS
 94 */
 95
 96static int nfcmrvl_nci_uart_open(struct nci_uart *nu)
 97{
 98	struct nfcmrvl_private *priv;
 99	struct nfcmrvl_platform_data config;
100	const struct nfcmrvl_platform_data *pdata = NULL;
101	struct device *dev = nu->tty->dev;
102
103	/*
104	 * Platform data cannot be used here since usually it is already used
105	 * by low level serial driver. We can try to retrieve serial device
106	 * and check if DT entries were added.
107	 */
108
109	if (dev && dev->parent && dev->parent->of_node)
110		if (nfcmrvl_uart_parse_dt(dev->parent->of_node, &config) == 0)
111			pdata = &config;
112
113	if (!pdata) {
114		pr_info("No platform data / DT -> fallback to module params\n");
115		config.hci_muxed = hci_muxed;
116		config.reset_n_io = reset_n_io;
117		config.flow_control = flow_control;
118		config.break_control = break_control;
119		pdata = &config;
120	}
121
122	priv = nfcmrvl_nci_register_dev(NFCMRVL_PHY_UART, nu, &uart_ops,
123					dev, pdata);
124	if (IS_ERR(priv))
125		return PTR_ERR(priv);
126
127	priv->support_fw_dnld = true;
128
129	nu->drv_data = priv;
130	nu->ndev = priv->ndev;
131
132	return 0;
133}
134
135static void nfcmrvl_nci_uart_close(struct nci_uart *nu)
136{
137	nfcmrvl_nci_unregister_dev((struct nfcmrvl_private *)nu->drv_data);
138}
139
140static int nfcmrvl_nci_uart_recv(struct nci_uart *nu, struct sk_buff *skb)
141{
142	return nfcmrvl_nci_recv_frame((struct nfcmrvl_private *)nu->drv_data,
143				      skb);
144}
145
146static void nfcmrvl_nci_uart_tx_start(struct nci_uart *nu)
147{
148	struct nfcmrvl_private *priv = (struct nfcmrvl_private *)nu->drv_data;
149
150	if (priv->ndev->nfc_dev->fw_download_in_progress)
151		return;
152
153	/* Remove BREAK to wake up the NFCC */
154	if (priv->config.break_control && nu->tty->ops->break_ctl) {
155		nu->tty->ops->break_ctl(nu->tty, 0);
156		usleep_range(3000, 5000);
157	}
158}
159
160static void nfcmrvl_nci_uart_tx_done(struct nci_uart *nu)
161{
162	struct nfcmrvl_private *priv = (struct nfcmrvl_private *)nu->drv_data;
163
164	if (priv->ndev->nfc_dev->fw_download_in_progress)
165		return;
166
167	/*
168	 * To ensure that if the NFCC goes in DEEP SLEEP sate we can wake him
169	 * up. we set BREAK. Once we will be ready to send again we will remove
170	 * it.
171	 */
172	if (priv->config.break_control && nu->tty->ops->break_ctl) {
173		nu->tty->ops->break_ctl(nu->tty, -1);
174		usleep_range(1000, 3000);
175	}
176}
177
178static struct nci_uart nfcmrvl_nci_uart = {
179	.owner  = THIS_MODULE,
180	.name   = "nfcmrvl_uart",
181	.driver = NCI_UART_DRIVER_MARVELL,
182	.ops	= {
183		.open		= nfcmrvl_nci_uart_open,
184		.close		= nfcmrvl_nci_uart_close,
185		.recv		= nfcmrvl_nci_uart_recv,
186		.tx_start	= nfcmrvl_nci_uart_tx_start,
187		.tx_done	= nfcmrvl_nci_uart_tx_done,
188	}
189};
190module_driver(nfcmrvl_nci_uart, nci_uart_register, nci_uart_unregister);
191
192MODULE_AUTHOR("Marvell International Ltd.");
193MODULE_DESCRIPTION("Marvell NFC-over-UART");
194MODULE_LICENSE("GPL v2");
195
196module_param(flow_control, uint, 0);
197MODULE_PARM_DESC(flow_control, "Tell if UART needs flow control at init.");
198
199module_param(break_control, uint, 0);
200MODULE_PARM_DESC(break_control, "Tell if UART driver must drive break signal.");
201
202module_param(hci_muxed, uint, 0);
203MODULE_PARM_DESC(hci_muxed, "Tell if transport is muxed in HCI one.");
204
205module_param(reset_n_io, int, 0);
206MODULE_PARM_DESC(reset_n_io, "GPIO that is wired to RESET_N signal.");