1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * common keywest i2c layer
4  *
5  * Copyright (c) by Takashi Iwai <tiwai@suse.de>
6  */
7 
8 
9 #include <linux/init.h>
10 #include <linux/i2c.h>
11 #include <linux/delay.h>
12 #include <linux/module.h>
13 #include <sound/core.h>
14 #include "pmac.h"
15 
16 static struct pmac_keywest *keywest_ctx;
17 static bool keywest_probed;
18 
keywest_probe(struct i2c_client * client,const struct i2c_device_id * id)19 static int keywest_probe(struct i2c_client *client,
20 			 const struct i2c_device_id *id)
21 {
22 	keywest_probed = true;
23 	/* If instantiated via i2c-powermac, we still need to set the client */
24 	if (!keywest_ctx->client)
25 		keywest_ctx->client = client;
26 	i2c_set_clientdata(client, keywest_ctx);
27 	return 0;
28 }
29 
30 /*
31  * This is kind of a hack, best would be to turn powermac to fixed i2c
32  * bus numbers and declare the sound device as part of platform
33  * initialization
34  */
keywest_attach_adapter(struct i2c_adapter * adapter)35 static int keywest_attach_adapter(struct i2c_adapter *adapter)
36 {
37 	struct i2c_board_info info;
38 	struct i2c_client *client;
39 
40 	if (! keywest_ctx)
41 		return -EINVAL;
42 
43 	if (strncmp(adapter->name, "mac-io", 6))
44 		return -EINVAL; /* ignored */
45 
46 	memset(&info, 0, sizeof(struct i2c_board_info));
47 	strscpy(info.type, "keywest", I2C_NAME_SIZE);
48 	info.addr = keywest_ctx->addr;
49 	client = i2c_new_client_device(adapter, &info);
50 	if (IS_ERR(client))
51 		return PTR_ERR(client);
52 	keywest_ctx->client = client;
53 
54 	/*
55 	 * We know the driver is already loaded, so the device should be
56 	 * already bound. If not it means binding failed, and then there
57 	 * is no point in keeping the device instantiated.
58 	 */
59 	if (!keywest_ctx->client->dev.driver) {
60 		i2c_unregister_device(keywest_ctx->client);
61 		keywest_ctx->client = NULL;
62 		return -ENODEV;
63 	}
64 
65 	/*
66 	 * Let i2c-core delete that device on driver removal.
67 	 * This is safe because i2c-core holds the core_lock mutex for us.
68 	 */
69 	list_add_tail(&keywest_ctx->client->detected,
70 		      &to_i2c_driver(keywest_ctx->client->dev.driver)->clients);
71 	return 0;
72 }
73 
keywest_remove(struct i2c_client * client)74 static int keywest_remove(struct i2c_client *client)
75 {
76 	if (! keywest_ctx)
77 		return 0;
78 	if (client == keywest_ctx->client)
79 		keywest_ctx->client = NULL;
80 
81 	return 0;
82 }
83 
84 
85 static const struct i2c_device_id keywest_i2c_id[] = {
86 	{ "MAC,tas3004", 0 },		/* instantiated by i2c-powermac */
87 	{ "keywest", 0 },		/* instantiated by us if needed */
88 	{ }
89 };
90 MODULE_DEVICE_TABLE(i2c, keywest_i2c_id);
91 
92 static struct i2c_driver keywest_driver = {
93 	.driver = {
94 		.name = "PMac Keywest Audio",
95 	},
96 	.probe = keywest_probe,
97 	.remove = keywest_remove,
98 	.id_table = keywest_i2c_id,
99 };
100 
101 /* exported */
snd_pmac_keywest_cleanup(struct pmac_keywest * i2c)102 void snd_pmac_keywest_cleanup(struct pmac_keywest *i2c)
103 {
104 	if (keywest_ctx && keywest_ctx == i2c) {
105 		i2c_del_driver(&keywest_driver);
106 		keywest_ctx = NULL;
107 	}
108 }
109 
snd_pmac_tumbler_post_init(void)110 int snd_pmac_tumbler_post_init(void)
111 {
112 	int err;
113 
114 	if (!keywest_ctx || !keywest_ctx->client)
115 		return -ENXIO;
116 
117 	err = keywest_ctx->init_client(keywest_ctx);
118 	if (err < 0) {
119 		snd_printk(KERN_ERR "tumbler: %i :cannot initialize the MCS\n", err);
120 		return err;
121 	}
122 	return 0;
123 }
124 
125 /* exported */
snd_pmac_keywest_init(struct pmac_keywest * i2c)126 int snd_pmac_keywest_init(struct pmac_keywest *i2c)
127 {
128 	struct i2c_adapter *adap;
129 	int err, i = 0;
130 
131 	if (keywest_ctx)
132 		return -EBUSY;
133 
134 	adap = i2c_get_adapter(0);
135 	if (!adap)
136 		return -EPROBE_DEFER;
137 
138 	keywest_ctx = i2c;
139 
140 	err = i2c_add_driver(&keywest_driver);
141 	if (err) {
142 		snd_printk(KERN_ERR "cannot register keywest i2c driver\n");
143 		i2c_put_adapter(adap);
144 		return err;
145 	}
146 
147 	/* There was already a device from i2c-powermac. Great, let's return */
148 	if (keywest_probed)
149 		return 0;
150 
151 	/* We assume Macs have consecutive I2C bus numbers starting at 0 */
152 	while (adap) {
153 		/* Scan for devices to be bound to */
154 		err = keywest_attach_adapter(adap);
155 		if (!err)
156 			return 0;
157 		i2c_put_adapter(adap);
158 		adap = i2c_get_adapter(++i);
159 	}
160 
161 	return -ENODEV;
162 }
163