1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * I2C multi-instantiate driver, pseudo driver to instantiate multiple
4 * i2c-clients from a single fwnode.
5 *
6 * Copyright 2018 Hans de Goede <hdegoede@redhat.com>
7 */
8
9#include <linux/acpi.h>
10#include <linux/bits.h>
11#include <linux/i2c.h>
12#include <linux/interrupt.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/platform_device.h>
16#include <linux/types.h>
17
18#define IRQ_RESOURCE_TYPE	GENMASK(1, 0)
19#define IRQ_RESOURCE_NONE	0
20#define IRQ_RESOURCE_GPIO	1
21#define IRQ_RESOURCE_APIC	2
22
23struct i2c_inst_data {
24	const char *type;
25	unsigned int flags;
26	int irq_idx;
27};
28
29struct i2c_multi_inst_data {
30	int num_clients;
31	struct i2c_client *clients[];
32};
33
34static int i2c_multi_inst_count(struct acpi_resource *ares, void *data)
35{
36	struct acpi_resource_i2c_serialbus *sb;
37	int *count = data;
38
39	if (i2c_acpi_get_i2c_resource(ares, &sb))
40		*count = *count + 1;
41
42	return 1;
43}
44
45static int i2c_multi_inst_count_resources(struct acpi_device *adev)
46{
47	LIST_HEAD(r);
48	int count = 0;
49	int ret;
50
51	ret = acpi_dev_get_resources(adev, &r, i2c_multi_inst_count, &count);
52	if (ret < 0)
53		return ret;
54
55	acpi_dev_free_resource_list(&r);
56	return count;
57}
58
59static int i2c_multi_inst_probe(struct platform_device *pdev)
60{
61	struct i2c_multi_inst_data *multi;
62	const struct acpi_device_id *match;
63	const struct i2c_inst_data *inst_data;
64	struct i2c_board_info board_info = {};
65	struct device *dev = &pdev->dev;
66	struct acpi_device *adev;
67	char name[32];
68	int i, ret;
69
70	match = acpi_match_device(dev->driver->acpi_match_table, dev);
71	if (!match) {
72		dev_err(dev, "Error ACPI match data is missing\n");
73		return -ENODEV;
74	}
75	inst_data = (const struct i2c_inst_data *)match->driver_data;
76
77	adev = ACPI_COMPANION(dev);
78
79	/* Count number of clients to instantiate */
80	ret = i2c_multi_inst_count_resources(adev);
81	if (ret < 0)
82		return ret;
83
84	multi = devm_kmalloc(dev, struct_size(multi, clients, ret), GFP_KERNEL);
85	if (!multi)
86		return -ENOMEM;
87
88	multi->num_clients = ret;
89
90	for (i = 0; i < multi->num_clients && inst_data[i].type; i++) {
91		memset(&board_info, 0, sizeof(board_info));
92		strlcpy(board_info.type, inst_data[i].type, I2C_NAME_SIZE);
93		snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev),
94			 inst_data[i].type, i);
95		board_info.dev_name = name;
96		switch (inst_data[i].flags & IRQ_RESOURCE_TYPE) {
97		case IRQ_RESOURCE_GPIO:
98			ret = acpi_dev_gpio_irq_get(adev, inst_data[i].irq_idx);
99			if (ret < 0) {
100				dev_err(dev, "Error requesting irq at index %d: %d\n",
101					inst_data[i].irq_idx, ret);
102				goto error;
103			}
104			board_info.irq = ret;
105			break;
106		case IRQ_RESOURCE_APIC:
107			ret = platform_get_irq(pdev, inst_data[i].irq_idx);
108			if (ret < 0) {
109				dev_dbg(dev, "Error requesting irq at index %d: %d\n",
110					inst_data[i].irq_idx, ret);
111				goto error;
112			}
113			board_info.irq = ret;
114			break;
115		default:
116			board_info.irq = 0;
117			break;
118		}
119		multi->clients[i] = i2c_acpi_new_device(dev, i, &board_info);
120		if (IS_ERR(multi->clients[i])) {
121			ret = PTR_ERR(multi->clients[i]);
122			if (ret != -EPROBE_DEFER)
123				dev_err(dev, "Error creating i2c-client, idx %d\n", i);
124			goto error;
125		}
126	}
127	if (i < multi->num_clients) {
128		dev_err(dev, "Error finding driver, idx %d\n", i);
129		ret = -ENODEV;
130		goto error;
131	}
132
133	platform_set_drvdata(pdev, multi);
134	return 0;
135
136error:
137	while (--i >= 0)
138		i2c_unregister_device(multi->clients[i]);
139
140	return ret;
141}
142
143static int i2c_multi_inst_remove(struct platform_device *pdev)
144{
145	struct i2c_multi_inst_data *multi = platform_get_drvdata(pdev);
146	int i;
147
148	for (i = 0; i < multi->num_clients; i++)
149		i2c_unregister_device(multi->clients[i]);
150
151	return 0;
152}
153
154static const struct i2c_inst_data bsg1160_data[]  = {
155	{ "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
156	{ "bmc150_magn" },
157	{ "bmg160" },
158	{}
159};
160
161static const struct i2c_inst_data bsg2150_data[]  = {
162	{ "bmc150_accel", IRQ_RESOURCE_GPIO, 0 },
163	{ "bmc150_magn" },
164	/* The resources describe a 3th client, but it is not really there. */
165	{ "bsg2150_dummy_dev" },
166	{}
167};
168
169/*
170 * Device with _HID INT3515 (TI PD controllers) has some unresolved interrupt
171 * issues. The most common problem seen is interrupt flood.
172 *
173 * There are at least two known causes. Firstly, on some boards, the
174 * I2CSerialBus resource index does not match the Interrupt resource, i.e. they
175 * are not one-to-one mapped like in the array below. Secondly, on some boards
176 * the IRQ line from the PD controller is not actually connected at all. But the
177 * interrupt flood is also seen on some boards where those are not a problem, so
178 * there are some other problems as well.
179 *
180 * Because of the issues with the interrupt, the device is disabled for now. If
181 * you wish to debug the issues, uncomment the below, and add an entry for the
182 * INT3515 device to the i2c_multi_instance_ids table.
183 *
184 * static const struct i2c_inst_data int3515_data[]  = {
185 *	{ "tps6598x", IRQ_RESOURCE_APIC, 0 },
186 *	{ "tps6598x", IRQ_RESOURCE_APIC, 1 },
187 *	{ "tps6598x", IRQ_RESOURCE_APIC, 2 },
188 *	{ "tps6598x", IRQ_RESOURCE_APIC, 3 },
189 *	{ }
190 * };
191 */
192
193/*
194 * Note new device-ids must also be added to i2c_multi_instantiate_ids in
195 * drivers/acpi/scan.c: acpi_device_enumeration_by_parent().
196 */
197static const struct acpi_device_id i2c_multi_inst_acpi_ids[] = {
198	{ "BSG1160", (unsigned long)bsg1160_data },
199	{ "BSG2150", (unsigned long)bsg2150_data },
200	{ }
201};
202MODULE_DEVICE_TABLE(acpi, i2c_multi_inst_acpi_ids);
203
204static struct platform_driver i2c_multi_inst_driver = {
205	.driver	= {
206		.name = "I2C multi instantiate pseudo device driver",
207		.acpi_match_table = ACPI_PTR(i2c_multi_inst_acpi_ids),
208	},
209	.probe = i2c_multi_inst_probe,
210	.remove = i2c_multi_inst_remove,
211};
212module_platform_driver(i2c_multi_inst_driver);
213
214MODULE_DESCRIPTION("I2C multi instantiate pseudo device driver");
215MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
216MODULE_LICENSE("GPL");
217