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,const struct mcp23s08_info * info)82 static int mcp23s08_spi_regmap_init(struct mcp23s08 *mcp, struct device *dev,
83 unsigned int addr,
84 const struct mcp23s08_info *info)
85 {
86 struct regmap_config *copy;
87 const char *name;
88
89 switch (info->type) {
90 case MCP_TYPE_S08:
91 mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s08.%d", addr);
92 if (!mcp->chip.label)
93 return -ENOMEM;
94
95 name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
96 if (!name)
97 return -ENOMEM;
98
99 break;
100
101 case MCP_TYPE_S17:
102 mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s17.%d", addr);
103 if (!mcp->chip.label)
104 return -ENOMEM;
105
106 name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
107 if (!name)
108 return -ENOMEM;
109
110 break;
111
112 case MCP_TYPE_S18:
113 mcp->chip.label = info->label;
114 name = info->regmap->name;
115 break;
116
117 default:
118 dev_err(dev, "invalid device type (%d)\n", info->type);
119 return -EINVAL;
120 }
121
122 mcp->reg_shift = info->reg_shift;
123 mcp->chip.ngpio = info->ngpio;
124 copy = devm_kmemdup(dev, info->regmap, sizeof(*info->regmap), GFP_KERNEL);
125 if (!copy)
126 return -ENOMEM;
127
128 copy->name = name;
129
130 mcp->regmap = devm_regmap_init(dev, &mcp23sxx_spi_regmap, mcp, copy);
131 if (IS_ERR(mcp->regmap))
132 dev_err(dev, "regmap init failed for %s\n", mcp->chip.label);
133 return PTR_ERR_OR_ZERO(mcp->regmap);
134 }
135
mcp23s08_probe(struct spi_device * spi)136 static int mcp23s08_probe(struct spi_device *spi)
137 {
138 struct mcp23s08_driver_data *data;
139 const struct mcp23s08_info *info;
140 struct device *dev = &spi->dev;
141 unsigned long spi_present_mask;
142 unsigned int ngpio = 0;
143 unsigned int addr;
144 int chips;
145 int ret;
146 u32 v;
147
148 info = spi_get_device_match_data(spi);
149
150 ret = device_property_read_u32(dev, "microchip,spi-present-mask", &v);
151 if (ret) {
152 ret = device_property_read_u32(dev, "mcp,spi-present-mask", &v);
153 if (ret) {
154 dev_err(dev, "missing spi-present-mask");
155 return ret;
156 }
157 }
158 spi_present_mask = v;
159
160 if (!spi_present_mask || spi_present_mask >= BIT(MCP_MAX_DEV_PER_CS)) {
161 dev_err(dev, "invalid spi-present-mask");
162 return -ENODEV;
163 }
164
165 chips = hweight_long(spi_present_mask);
166
167 data = devm_kzalloc(dev, struct_size(data, chip, chips), GFP_KERNEL);
168 if (!data)
169 return -ENOMEM;
170
171 spi_set_drvdata(spi, data);
172
173 for_each_set_bit(addr, &spi_present_mask, MCP_MAX_DEV_PER_CS) {
174 data->mcp[addr] = &data->chip[--chips];
175 data->mcp[addr]->irq = spi->irq;
176
177 ret = mcp23s08_spi_regmap_init(data->mcp[addr], dev, addr, info);
178 if (ret)
179 return ret;
180
181 data->mcp[addr]->pinctrl_desc.name = devm_kasprintf(dev, GFP_KERNEL,
182 "mcp23xxx-pinctrl.%d",
183 addr);
184 if (!data->mcp[addr]->pinctrl_desc.name)
185 return -ENOMEM;
186
187 ret = mcp23s08_probe_one(data->mcp[addr], dev, 0x40 | (addr << 1),
188 info->type, -1);
189 if (ret < 0)
190 return ret;
191
192 ngpio += data->mcp[addr]->chip.ngpio;
193 }
194 data->ngpio = ngpio;
195
196 return 0;
197 }
198
199 static const struct mcp23s08_info mcp23s08_spi = {
200 .regmap = &mcp23x08_regmap,
201 .type = MCP_TYPE_S08,
202 .ngpio = 8,
203 .reg_shift = 0,
204 };
205
206 static const struct mcp23s08_info mcp23s17_spi = {
207 .regmap = &mcp23x17_regmap,
208 .type = MCP_TYPE_S17,
209 .ngpio = 16,
210 .reg_shift = 1,
211 };
212
213 static const struct mcp23s08_info mcp23s18_spi = {
214 .regmap = &mcp23x17_regmap,
215 .label = "mcp23s18",
216 .type = MCP_TYPE_S18,
217 .ngpio = 16,
218 .reg_shift = 1,
219 };
220
221 static const struct spi_device_id mcp23s08_ids[] = {
222 { "mcp23s08", (kernel_ulong_t)&mcp23s08_spi },
223 { "mcp23s17", (kernel_ulong_t)&mcp23s17_spi },
224 { "mcp23s18", (kernel_ulong_t)&mcp23s18_spi },
225 { }
226 };
227 MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
228
229 static const struct of_device_id mcp23s08_spi_of_match[] = {
230 { .compatible = "microchip,mcp23s08", .data = &mcp23s08_spi },
231 { .compatible = "microchip,mcp23s17", .data = &mcp23s17_spi },
232 { .compatible = "microchip,mcp23s18", .data = &mcp23s18_spi },
233 /* NOTE: The use of the mcp prefix is deprecated and will be removed. */
234 { .compatible = "mcp,mcp23s08", .data = &mcp23s08_spi },
235 { .compatible = "mcp,mcp23s17", .data = &mcp23s17_spi },
236 { }
237 };
238 MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
239
240 static struct spi_driver mcp23s08_driver = {
241 .probe = mcp23s08_probe,
242 .id_table = mcp23s08_ids,
243 .driver = {
244 .name = "mcp23s08",
245 .of_match_table = mcp23s08_spi_of_match,
246 },
247 };
248
mcp23s08_spi_init(void)249 static int __init mcp23s08_spi_init(void)
250 {
251 return spi_register_driver(&mcp23s08_driver);
252 }
253
254 /*
255 * Register after SPI postcore initcall and before
256 * subsys initcalls that may rely on these GPIOs.
257 */
258 subsys_initcall(mcp23s08_spi_init);
259
mcp23s08_spi_exit(void)260 static void mcp23s08_spi_exit(void)
261 {
262 spi_unregister_driver(&mcp23s08_driver);
263 }
264 module_exit(mcp23s08_spi_exit);
265
266 MODULE_DESCRIPTION("MCP23S08 SPI GPIO driver");
267 MODULE_LICENSE("GPL");
268