1 // SPDX-License-Identifier: GPL-2.0-only
2 /* MCP23S08 SPI GPIO driver */
3
4 #include <linux/mod_devicetable.h>
5 #include <linux/module.h>
6 #include <linux/property.h>
7 #include <linux/regmap.h>
8 #include <linux/spi/spi.h>
9
10 #include "pinctrl-mcp23s08.h"
11
12 #define MCP_MAX_DEV_PER_CS 8
13
14 /*
15 * A given spi_device can represent up to eight mcp23sxx chips
16 * sharing the same chipselect but using different addresses
17 * (e.g. chips #0 and #3 might be populated, but not #1 or #2).
18 * Driver data holds all the per-chip data.
19 */
20 struct mcp23s08_driver_data {
21 unsigned ngpio;
22 struct mcp23s08 *mcp[8];
23 struct mcp23s08 chip[];
24 };
25
mcp23sxx_spi_write(void * context,const void * data,size_t count)26 static int mcp23sxx_spi_write(void *context, const void *data, size_t count)
27 {
28 struct mcp23s08 *mcp = context;
29 struct spi_device *spi = to_spi_device(mcp->dev);
30 struct spi_message m;
31 struct spi_transfer t[2] = { { .tx_buf = &mcp->addr, .len = 1, },
32 { .tx_buf = data, .len = count, }, };
33
34 spi_message_init(&m);
35 spi_message_add_tail(&t[0], &m);
36 spi_message_add_tail(&t[1], &m);
37
38 return spi_sync(spi, &m);
39 }
40
mcp23sxx_spi_gather_write(void * context,const void * reg,size_t reg_size,const void * val,size_t val_size)41 static int mcp23sxx_spi_gather_write(void *context,
42 const void *reg, size_t reg_size,
43 const void *val, size_t val_size)
44 {
45 struct mcp23s08 *mcp = context;
46 struct spi_device *spi = to_spi_device(mcp->dev);
47 struct spi_message m;
48 struct spi_transfer t[3] = { { .tx_buf = &mcp->addr, .len = 1, },
49 { .tx_buf = reg, .len = reg_size, },
50 { .tx_buf = val, .len = val_size, }, };
51
52 spi_message_init(&m);
53 spi_message_add_tail(&t[0], &m);
54 spi_message_add_tail(&t[1], &m);
55 spi_message_add_tail(&t[2], &m);
56
57 return spi_sync(spi, &m);
58 }
59
mcp23sxx_spi_read(void * context,const void * reg,size_t reg_size,void * val,size_t val_size)60 static int mcp23sxx_spi_read(void *context, const void *reg, size_t reg_size,
61 void *val, size_t val_size)
62 {
63 struct mcp23s08 *mcp = context;
64 struct spi_device *spi = to_spi_device(mcp->dev);
65 u8 tx[2];
66
67 if (reg_size != 1)
68 return -EINVAL;
69
70 tx[0] = mcp->addr | 0x01;
71 tx[1] = *((u8 *) reg);
72
73 return spi_write_then_read(spi, tx, sizeof(tx), val, val_size);
74 }
75
76 static const struct regmap_bus mcp23sxx_spi_regmap = {
77 .write = mcp23sxx_spi_write,
78 .gather_write = mcp23sxx_spi_gather_write,
79 .read = mcp23sxx_spi_read,
80 };
81
mcp23s08_spi_regmap_init(struct mcp23s08 * mcp,struct device * dev,unsigned int addr,unsigned int type)82 static int mcp23s08_spi_regmap_init(struct mcp23s08 *mcp, struct device *dev,
83 unsigned int addr, unsigned int type)
84 {
85 const struct regmap_config *config;
86 struct regmap_config *copy;
87 const char *name;
88
89 switch (type) {
90 case MCP_TYPE_S08:
91 mcp->reg_shift = 0;
92 mcp->chip.ngpio = 8;
93 mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s08.%d", addr);
94 if (!mcp->chip.label)
95 return -ENOMEM;
96
97 config = &mcp23x08_regmap;
98 name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
99 if (!name)
100 return -ENOMEM;
101
102 break;
103
104 case MCP_TYPE_S17:
105 mcp->reg_shift = 1;
106 mcp->chip.ngpio = 16;
107 mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s17.%d", addr);
108 if (!mcp->chip.label)
109 return -ENOMEM;
110
111 config = &mcp23x17_regmap;
112 name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
113 if (!name)
114 return -ENOMEM;
115
116 break;
117
118 case MCP_TYPE_S18:
119 mcp->reg_shift = 1;
120 mcp->chip.ngpio = 16;
121 mcp->chip.label = "mcp23s18";
122
123 config = &mcp23x17_regmap;
124 name = config->name;
125 break;
126
127 default:
128 dev_err(dev, "invalid device type (%d)\n", type);
129 return -EINVAL;
130 }
131
132 copy = devm_kmemdup(dev, config, sizeof(*config), GFP_KERNEL);
133 if (!copy)
134 return -ENOMEM;
135
136 copy->name = name;
137
138 mcp->regmap = devm_regmap_init(dev, &mcp23sxx_spi_regmap, mcp, copy);
139 if (IS_ERR(mcp->regmap))
140 dev_err(dev, "regmap init failed for %s\n", mcp->chip.label);
141 return PTR_ERR_OR_ZERO(mcp->regmap);
142 }
143
mcp23s08_probe(struct spi_device * spi)144 static int mcp23s08_probe(struct spi_device *spi)
145 {
146 struct device *dev = &spi->dev;
147 struct mcp23s08_driver_data *data;
148 unsigned long spi_present_mask;
149 const void *match;
150 unsigned int addr;
151 unsigned int ngpio = 0;
152 int chips;
153 int type;
154 int ret;
155 u32 v;
156
157 match = device_get_match_data(dev);
158 if (match)
159 type = (int)(uintptr_t)match;
160 else
161 type = spi_get_device_id(spi)->driver_data;
162
163 ret = device_property_read_u32(dev, "microchip,spi-present-mask", &v);
164 if (ret) {
165 ret = device_property_read_u32(dev, "mcp,spi-present-mask", &v);
166 if (ret) {
167 dev_err(dev, "missing spi-present-mask");
168 return ret;
169 }
170 }
171 spi_present_mask = v;
172
173 if (!spi_present_mask || spi_present_mask >= BIT(MCP_MAX_DEV_PER_CS)) {
174 dev_err(dev, "invalid spi-present-mask");
175 return -ENODEV;
176 }
177
178 chips = hweight_long(spi_present_mask);
179
180 data = devm_kzalloc(dev, struct_size(data, chip, chips), GFP_KERNEL);
181 if (!data)
182 return -ENOMEM;
183
184 spi_set_drvdata(spi, data);
185
186 for_each_set_bit(addr, &spi_present_mask, MCP_MAX_DEV_PER_CS) {
187 data->mcp[addr] = &data->chip[--chips];
188 data->mcp[addr]->irq = spi->irq;
189
190 ret = mcp23s08_spi_regmap_init(data->mcp[addr], dev, addr, type);
191 if (ret)
192 return ret;
193
194 data->mcp[addr]->pinctrl_desc.name = devm_kasprintf(dev, GFP_KERNEL,
195 "mcp23xxx-pinctrl.%d",
196 addr);
197 if (!data->mcp[addr]->pinctrl_desc.name)
198 return -ENOMEM;
199
200 ret = mcp23s08_probe_one(data->mcp[addr], dev, 0x40 | (addr << 1), type, -1);
201 if (ret < 0)
202 return ret;
203
204 ngpio += data->mcp[addr]->chip.ngpio;
205 }
206 data->ngpio = ngpio;
207
208 return 0;
209 }
210
211 static const struct spi_device_id mcp23s08_ids[] = {
212 { "mcp23s08", MCP_TYPE_S08 },
213 { "mcp23s17", MCP_TYPE_S17 },
214 { "mcp23s18", MCP_TYPE_S18 },
215 { }
216 };
217 MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
218
219 static const struct of_device_id mcp23s08_spi_of_match[] = {
220 {
221 .compatible = "microchip,mcp23s08",
222 .data = (void *) MCP_TYPE_S08,
223 },
224 {
225 .compatible = "microchip,mcp23s17",
226 .data = (void *) MCP_TYPE_S17,
227 },
228 {
229 .compatible = "microchip,mcp23s18",
230 .data = (void *) MCP_TYPE_S18,
231 },
232 /* NOTE: The use of the mcp prefix is deprecated and will be removed. */
233 {
234 .compatible = "mcp,mcp23s08",
235 .data = (void *) MCP_TYPE_S08,
236 },
237 {
238 .compatible = "mcp,mcp23s17",
239 .data = (void *) MCP_TYPE_S17,
240 },
241 { }
242 };
243 MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
244
245 static struct spi_driver mcp23s08_driver = {
246 .probe = mcp23s08_probe,
247 .id_table = mcp23s08_ids,
248 .driver = {
249 .name = "mcp23s08",
250 .of_match_table = mcp23s08_spi_of_match,
251 },
252 };
253
mcp23s08_spi_init(void)254 static int __init mcp23s08_spi_init(void)
255 {
256 return spi_register_driver(&mcp23s08_driver);
257 }
258
259 /*
260 * Register after SPI postcore initcall and before
261 * subsys initcalls that may rely on these GPIOs.
262 */
263 subsys_initcall(mcp23s08_spi_init);
264
mcp23s08_spi_exit(void)265 static void mcp23s08_spi_exit(void)
266 {
267 spi_unregister_driver(&mcp23s08_driver);
268 }
269 module_exit(mcp23s08_spi_exit);
270
271 MODULE_LICENSE("GPL");
272