xref: /openbmc/linux/drivers/nfc/nfcmrvl/spi.c (revision 0d3b051a)
1 /**
2  * Marvell NFC-over-SPI driver: SPI interface related functions
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/interrupt.h>
21 #include <linux/pm_runtime.h>
22 #include <linux/nfc.h>
23 #include <linux/gpio.h>
24 #include <linux/of_irq.h>
25 #include <linux/of_gpio.h>
26 #include <net/nfc/nci.h>
27 #include <net/nfc/nci_core.h>
28 #include <linux/spi/spi.h>
29 #include "nfcmrvl.h"
30 
31 #define SPI_WAIT_HANDSHAKE	1
32 
33 struct nfcmrvl_spi_drv_data {
34 	unsigned long flags;
35 	struct spi_device *spi;
36 	struct nci_spi *nci_spi;
37 	struct completion handshake_completion;
38 	struct nfcmrvl_private *priv;
39 };
40 
41 static irqreturn_t nfcmrvl_spi_int_irq_thread_fn(int irq, void *drv_data_ptr)
42 {
43 	struct nfcmrvl_spi_drv_data *drv_data = drv_data_ptr;
44 	struct sk_buff *skb;
45 
46 	/*
47 	 * Special case where we are waiting for SPI_INT deassertion to start a
48 	 * transfer.
49 	 */
50 	if (test_and_clear_bit(SPI_WAIT_HANDSHAKE, &drv_data->flags)) {
51 		complete(&drv_data->handshake_completion);
52 		return IRQ_HANDLED;
53 	}
54 
55 	/* Normal case, SPI_INT deasserted by slave to trigger a master read */
56 
57 	skb = nci_spi_read(drv_data->nci_spi);
58 	if (!skb) {
59 		nfc_err(&drv_data->spi->dev, "failed to read spi packet");
60 		return IRQ_HANDLED;
61 	}
62 
63 	if (nfcmrvl_nci_recv_frame(drv_data->priv, skb) < 0)
64 		nfc_err(&drv_data->spi->dev, "corrupted RX packet");
65 
66 	return IRQ_HANDLED;
67 }
68 
69 static int nfcmrvl_spi_nci_open(struct nfcmrvl_private *priv)
70 {
71 	return 0;
72 }
73 
74 static int nfcmrvl_spi_nci_close(struct nfcmrvl_private *priv)
75 {
76 	return 0;
77 }
78 
79 static int nfcmrvl_spi_nci_send(struct nfcmrvl_private *priv,
80 				struct sk_buff *skb)
81 {
82 	struct nfcmrvl_spi_drv_data *drv_data = priv->drv_data;
83 	int err;
84 
85 	/* Reinit completion for slave handshake */
86 	reinit_completion(&drv_data->handshake_completion);
87 	set_bit(SPI_WAIT_HANDSHAKE, &drv_data->flags);
88 
89 	/*
90 	 * Append a dummy byte at the end of SPI frame. This is due to a
91 	 * specific DMA implementation in the controller
92 	 */
93 	skb_put(skb, 1);
94 
95 	/* Send the SPI packet */
96 	err = nci_spi_send(drv_data->nci_spi, &drv_data->handshake_completion,
97 			   skb);
98 	if (err)
99 		nfc_err(priv->dev, "spi_send failed %d", err);
100 
101 	return err;
102 }
103 
104 static void nfcmrvl_spi_nci_update_config(struct nfcmrvl_private *priv,
105 					  const void *param)
106 {
107 	struct nfcmrvl_spi_drv_data *drv_data = priv->drv_data;
108 	const struct nfcmrvl_fw_spi_config *config = param;
109 
110 	drv_data->nci_spi->xfer_speed_hz = config->clk;
111 }
112 
113 static struct nfcmrvl_if_ops spi_ops = {
114 	.nci_open = nfcmrvl_spi_nci_open,
115 	.nci_close = nfcmrvl_spi_nci_close,
116 	.nci_send = nfcmrvl_spi_nci_send,
117 	.nci_update_config = nfcmrvl_spi_nci_update_config,
118 };
119 
120 static int nfcmrvl_spi_parse_dt(struct device_node *node,
121 				struct nfcmrvl_platform_data *pdata)
122 {
123 	int ret;
124 
125 	ret = nfcmrvl_parse_dt(node, pdata);
126 	if (ret < 0) {
127 		pr_err("Failed to get generic entries\n");
128 		return ret;
129 	}
130 
131 	ret = irq_of_parse_and_map(node, 0);
132 	if (ret < 0) {
133 		pr_err("Unable to get irq, error: %d\n", ret);
134 		return ret;
135 	}
136 	pdata->irq = ret;
137 
138 	return 0;
139 }
140 
141 static int nfcmrvl_spi_probe(struct spi_device *spi)
142 {
143 	struct nfcmrvl_platform_data *pdata;
144 	struct nfcmrvl_platform_data config;
145 	struct nfcmrvl_spi_drv_data *drv_data;
146 	int ret = 0;
147 
148 	drv_data = devm_kzalloc(&spi->dev, sizeof(*drv_data), GFP_KERNEL);
149 	if (!drv_data)
150 		return -ENOMEM;
151 
152 	drv_data->spi = spi;
153 	drv_data->priv = NULL;
154 	spi_set_drvdata(spi, drv_data);
155 
156 	pdata = spi->dev.platform_data;
157 
158 	if (!pdata && spi->dev.of_node)
159 		if (nfcmrvl_spi_parse_dt(spi->dev.of_node, &config) == 0)
160 			pdata = &config;
161 
162 	if (!pdata)
163 		return -EINVAL;
164 
165 	ret = devm_request_threaded_irq(&drv_data->spi->dev, pdata->irq,
166 					NULL, nfcmrvl_spi_int_irq_thread_fn,
167 					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
168 					"nfcmrvl_spi_int", drv_data);
169 	if (ret < 0) {
170 		nfc_err(&drv_data->spi->dev, "Unable to register IRQ handler");
171 		return -ENODEV;
172 	}
173 
174 	drv_data->priv = nfcmrvl_nci_register_dev(NFCMRVL_PHY_SPI,
175 						  drv_data, &spi_ops,
176 						  &drv_data->spi->dev,
177 						  pdata);
178 	if (IS_ERR(drv_data->priv))
179 		return PTR_ERR(drv_data->priv);
180 
181 	drv_data->priv->support_fw_dnld = true;
182 
183 	drv_data->nci_spi = nci_spi_allocate_spi(drv_data->spi, 0, 10,
184 						 drv_data->priv->ndev);
185 
186 	/* Init completion for slave handshake */
187 	init_completion(&drv_data->handshake_completion);
188 	return 0;
189 }
190 
191 static int nfcmrvl_spi_remove(struct spi_device *spi)
192 {
193 	struct nfcmrvl_spi_drv_data *drv_data = spi_get_drvdata(spi);
194 
195 	nfcmrvl_nci_unregister_dev(drv_data->priv);
196 	return 0;
197 }
198 
199 static const struct of_device_id of_nfcmrvl_spi_match[] = {
200 	{ .compatible = "marvell,nfc-spi", },
201 	{},
202 };
203 MODULE_DEVICE_TABLE(of, of_nfcmrvl_spi_match);
204 
205 static const struct spi_device_id nfcmrvl_spi_id_table[] = {
206 	{ "nfcmrvl_spi", 0 },
207 	{ }
208 };
209 MODULE_DEVICE_TABLE(spi, nfcmrvl_spi_id_table);
210 
211 static struct spi_driver nfcmrvl_spi_driver = {
212 	.probe		= nfcmrvl_spi_probe,
213 	.remove		= nfcmrvl_spi_remove,
214 	.id_table	= nfcmrvl_spi_id_table,
215 	.driver		= {
216 		.name		= "nfcmrvl_spi",
217 		.owner		= THIS_MODULE,
218 		.of_match_table	= of_match_ptr(of_nfcmrvl_spi_match),
219 	},
220 };
221 
222 module_spi_driver(nfcmrvl_spi_driver);
223 
224 MODULE_AUTHOR("Marvell International Ltd.");
225 MODULE_DESCRIPTION("Marvell NFC-over-SPI driver");
226 MODULE_LICENSE("GPL v2");
227