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 */
20struct mcp23s08_driver_data {
21	unsigned		ngpio;
22	struct mcp23s08		*mcp[8];
23	struct mcp23s08		chip[];
24};
25
26static 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
41static 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
60static 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
76static 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
82static 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
144static 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
211static const struct spi_device_id mcp23s08_ids[] = {
212	{ "mcp23s08", MCP_TYPE_S08 },
213	{ "mcp23s17", MCP_TYPE_S17 },
214	{ "mcp23s18", MCP_TYPE_S18 },
215	{ }
216};
217MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
218
219static 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};
243MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
244
245static 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
254static 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 */
263subsys_initcall(mcp23s08_spi_init);
264
265static void mcp23s08_spi_exit(void)
266{
267	spi_unregister_driver(&mcp23s08_driver);
268}
269module_exit(mcp23s08_spi_exit);
270
271MODULE_LICENSE("GPL");
272