1// SPDX-License-Identifier: GPL-2.0
2/* DSA driver for:
3 * Vitesse VSC7385 SparX-G5 5+1-port Integrated Gigabit Ethernet Switch
4 * Vitesse VSC7388 SparX-G8 8-port Integrated Gigabit Ethernet Switch
5 * Vitesse VSC7395 SparX-G5e 5+1-port Integrated Gigabit Ethernet Switch
6 * Vitesse VSC7398 SparX-G8e 8-port Integrated Gigabit Ethernet Switch
7 *
8 * This driver takes control of the switch chip over SPI and
9 * configures it to route packages around when connected to a CPU port.
10 *
11 * Copyright (C) 2018 Linus Wallej <linus.walleij@linaro.org>
12 * Includes portions of code from the firmware uploader by:
13 * Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
14 */
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/of.h>
18#include <linux/spi/spi.h>
19
20#include "vitesse-vsc73xx.h"
21
22#define VSC73XX_CMD_SPI_MODE_READ		0
23#define VSC73XX_CMD_SPI_MODE_WRITE		1
24#define VSC73XX_CMD_SPI_MODE_SHIFT		4
25#define VSC73XX_CMD_SPI_BLOCK_SHIFT		5
26#define VSC73XX_CMD_SPI_BLOCK_MASK		0x7
27#define VSC73XX_CMD_SPI_SUBBLOCK_MASK		0xf
28
29/*
30 * struct vsc73xx_spi - VSC73xx SPI state container
31 */
32struct vsc73xx_spi {
33	struct spi_device	*spi;
34	struct mutex		lock; /* Protects SPI traffic */
35	struct vsc73xx		vsc;
36};
37
38static const struct vsc73xx_ops vsc73xx_spi_ops;
39
40static u8 vsc73xx_make_addr(u8 mode, u8 block, u8 subblock)
41{
42	u8 ret;
43
44	ret =
45	    (block & VSC73XX_CMD_SPI_BLOCK_MASK) << VSC73XX_CMD_SPI_BLOCK_SHIFT;
46	ret |= (mode & 1) << VSC73XX_CMD_SPI_MODE_SHIFT;
47	ret |= subblock & VSC73XX_CMD_SPI_SUBBLOCK_MASK;
48
49	return ret;
50}
51
52static int vsc73xx_spi_read(struct vsc73xx *vsc, u8 block, u8 subblock, u8 reg,
53			    u32 *val)
54{
55	struct vsc73xx_spi *vsc_spi = vsc->priv;
56	struct spi_transfer t[2];
57	struct spi_message m;
58	u8 cmd[4];
59	u8 buf[4];
60	int ret;
61
62	if (!vsc73xx_is_addr_valid(block, subblock))
63		return -EINVAL;
64
65	spi_message_init(&m);
66
67	memset(&t, 0, sizeof(t));
68
69	t[0].tx_buf = cmd;
70	t[0].len = sizeof(cmd);
71	spi_message_add_tail(&t[0], &m);
72
73	t[1].rx_buf = buf;
74	t[1].len = sizeof(buf);
75	spi_message_add_tail(&t[1], &m);
76
77	cmd[0] = vsc73xx_make_addr(VSC73XX_CMD_SPI_MODE_READ, block, subblock);
78	cmd[1] = reg;
79	cmd[2] = 0;
80	cmd[3] = 0;
81
82	mutex_lock(&vsc_spi->lock);
83	ret = spi_sync(vsc_spi->spi, &m);
84	mutex_unlock(&vsc_spi->lock);
85
86	if (ret)
87		return ret;
88
89	*val = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
90
91	return 0;
92}
93
94static int vsc73xx_spi_write(struct vsc73xx *vsc, u8 block, u8 subblock, u8 reg,
95			     u32 val)
96{
97	struct vsc73xx_spi *vsc_spi = vsc->priv;
98	struct spi_transfer t[2];
99	struct spi_message m;
100	u8 cmd[2];
101	u8 buf[4];
102	int ret;
103
104	if (!vsc73xx_is_addr_valid(block, subblock))
105		return -EINVAL;
106
107	spi_message_init(&m);
108
109	memset(&t, 0, sizeof(t));
110
111	t[0].tx_buf = cmd;
112	t[0].len = sizeof(cmd);
113	spi_message_add_tail(&t[0], &m);
114
115	t[1].tx_buf = buf;
116	t[1].len = sizeof(buf);
117	spi_message_add_tail(&t[1], &m);
118
119	cmd[0] = vsc73xx_make_addr(VSC73XX_CMD_SPI_MODE_WRITE, block, subblock);
120	cmd[1] = reg;
121
122	buf[0] = (val >> 24) & 0xff;
123	buf[1] = (val >> 16) & 0xff;
124	buf[2] = (val >> 8) & 0xff;
125	buf[3] = val & 0xff;
126
127	mutex_lock(&vsc_spi->lock);
128	ret = spi_sync(vsc_spi->spi, &m);
129	mutex_unlock(&vsc_spi->lock);
130
131	return ret;
132}
133
134static int vsc73xx_spi_probe(struct spi_device *spi)
135{
136	struct device *dev = &spi->dev;
137	struct vsc73xx_spi *vsc_spi;
138	int ret;
139
140	vsc_spi = devm_kzalloc(dev, sizeof(*vsc_spi), GFP_KERNEL);
141	if (!vsc_spi)
142		return -ENOMEM;
143
144	spi_set_drvdata(spi, vsc_spi);
145	vsc_spi->spi = spi_dev_get(spi);
146	vsc_spi->vsc.dev = dev;
147	vsc_spi->vsc.priv = vsc_spi;
148	vsc_spi->vsc.ops = &vsc73xx_spi_ops;
149	mutex_init(&vsc_spi->lock);
150
151	spi->mode = SPI_MODE_0;
152	spi->bits_per_word = 8;
153	ret = spi_setup(spi);
154	if (ret < 0) {
155		dev_err(dev, "spi setup failed.\n");
156		return ret;
157	}
158
159	return vsc73xx_probe(&vsc_spi->vsc);
160}
161
162static int vsc73xx_spi_remove(struct spi_device *spi)
163{
164	struct vsc73xx_spi *vsc_spi = spi_get_drvdata(spi);
165
166	return vsc73xx_remove(&vsc_spi->vsc);
167}
168
169static const struct vsc73xx_ops vsc73xx_spi_ops = {
170	.read = vsc73xx_spi_read,
171	.write = vsc73xx_spi_write,
172};
173
174static const struct of_device_id vsc73xx_of_match[] = {
175	{
176		.compatible = "vitesse,vsc7385",
177	},
178	{
179		.compatible = "vitesse,vsc7388",
180	},
181	{
182		.compatible = "vitesse,vsc7395",
183	},
184	{
185		.compatible = "vitesse,vsc7398",
186	},
187	{ },
188};
189MODULE_DEVICE_TABLE(of, vsc73xx_of_match);
190
191static struct spi_driver vsc73xx_spi_driver = {
192	.probe = vsc73xx_spi_probe,
193	.remove = vsc73xx_spi_remove,
194	.driver = {
195		.name = "vsc73xx-spi",
196		.of_match_table = vsc73xx_of_match,
197	},
198};
199module_spi_driver(vsc73xx_spi_driver);
200
201MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
202MODULE_DESCRIPTION("Vitesse VSC7385/7388/7395/7398 SPI driver");
203MODULE_LICENSE("GPL v2");
204