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,
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
136static 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
199static const struct mcp23s08_info mcp23s08_spi = {
200	.regmap = &mcp23x08_regmap,
201	.type = MCP_TYPE_S08,
202	.ngpio = 8,
203	.reg_shift = 0,
204};
205
206static const struct mcp23s08_info mcp23s17_spi = {
207	.regmap = &mcp23x17_regmap,
208	.type = MCP_TYPE_S17,
209	.ngpio = 16,
210	.reg_shift = 1,
211};
212
213static 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
221static 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};
227MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
228
229static 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};
238MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
239
240static 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
249static 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 */
258subsys_initcall(mcp23s08_spi_init);
259
260static void mcp23s08_spi_exit(void)
261{
262	spi_unregister_driver(&mcp23s08_driver);
263}
264module_exit(mcp23s08_spi_exit);
265
266MODULE_LICENSE("GPL");
267