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  */
32 struct vsc73xx_spi {
33 	struct spi_device	*spi;
34 	struct mutex		lock; /* Protects SPI traffic */
35 	struct vsc73xx		vsc;
36 };
37 
38 static const struct vsc73xx_ops vsc73xx_spi_ops;
39 
40 static 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 
52 static 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 
94 static 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 
134 static 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 
162 static int vsc73xx_spi_remove(struct spi_device *spi)
163 {
164 	struct vsc73xx_spi *vsc_spi = spi_get_drvdata(spi);
165 
166 	if (!vsc_spi)
167 		return 0;
168 
169 	vsc73xx_remove(&vsc_spi->vsc);
170 
171 	spi_set_drvdata(spi, NULL);
172 
173 	return 0;
174 }
175 
176 static void vsc73xx_spi_shutdown(struct spi_device *spi)
177 {
178 	struct vsc73xx_spi *vsc_spi = spi_get_drvdata(spi);
179 
180 	if (!vsc_spi)
181 		return;
182 
183 	vsc73xx_shutdown(&vsc_spi->vsc);
184 
185 	spi_set_drvdata(spi, NULL);
186 }
187 
188 static const struct vsc73xx_ops vsc73xx_spi_ops = {
189 	.read = vsc73xx_spi_read,
190 	.write = vsc73xx_spi_write,
191 };
192 
193 static const struct of_device_id vsc73xx_of_match[] = {
194 	{
195 		.compatible = "vitesse,vsc7385",
196 	},
197 	{
198 		.compatible = "vitesse,vsc7388",
199 	},
200 	{
201 		.compatible = "vitesse,vsc7395",
202 	},
203 	{
204 		.compatible = "vitesse,vsc7398",
205 	},
206 	{ },
207 };
208 MODULE_DEVICE_TABLE(of, vsc73xx_of_match);
209 
210 static struct spi_driver vsc73xx_spi_driver = {
211 	.probe = vsc73xx_spi_probe,
212 	.remove = vsc73xx_spi_remove,
213 	.shutdown = vsc73xx_spi_shutdown,
214 	.driver = {
215 		.name = "vsc73xx-spi",
216 		.of_match_table = vsc73xx_of_match,
217 	},
218 };
219 module_spi_driver(vsc73xx_spi_driver);
220 
221 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
222 MODULE_DESCRIPTION("Vitesse VSC7385/7388/7395/7398 SPI driver");
223 MODULE_LICENSE("GPL v2");
224