1 /*
2  * Copyright 2009 Red Hat Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  *
22  * Authors: Ben Skeggs
23  */
24 
25 #include <linux/string_helpers.h>
26 
27 #include "aux.h"
28 #include "pad.h"
29 
30 static int
31 nvkm_i2c_aux_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
32 {
33 	struct nvkm_i2c_aux *aux = container_of(adap, typeof(*aux), i2c);
34 	struct i2c_msg *msg = msgs;
35 	int ret, mcnt = num;
36 
37 	ret = nvkm_i2c_aux_acquire(aux);
38 	if (ret)
39 		return ret;
40 
41 	while (mcnt--) {
42 		u8 remaining = msg->len;
43 		u8 *ptr = msg->buf;
44 
45 		while (remaining) {
46 			u8 cnt, retries, cmd;
47 
48 			if (msg->flags & I2C_M_RD)
49 				cmd = 1;
50 			else
51 				cmd = 0;
52 
53 			if (mcnt || remaining > 16)
54 				cmd |= 4; /* MOT */
55 
56 			for (retries = 0, cnt = 0;
57 			     retries < 32 && !cnt;
58 			     retries++) {
59 				cnt = min_t(u8, remaining, 16);
60 				ret = aux->func->xfer(aux, true, cmd,
61 						      msg->addr, ptr, &cnt);
62 				if (ret < 0)
63 					goto out;
64 			}
65 			if (!cnt) {
66 				AUX_TRACE(aux, "no data after 32 retries");
67 				ret = -EIO;
68 				goto out;
69 			}
70 
71 			ptr += cnt;
72 			remaining -= cnt;
73 		}
74 
75 		msg++;
76 	}
77 
78 	ret = num;
79 out:
80 	nvkm_i2c_aux_release(aux);
81 	return ret;
82 }
83 
84 static u32
85 nvkm_i2c_aux_i2c_func(struct i2c_adapter *adap)
86 {
87 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
88 }
89 
90 static const struct i2c_algorithm
91 nvkm_i2c_aux_i2c_algo = {
92 	.master_xfer = nvkm_i2c_aux_i2c_xfer,
93 	.functionality = nvkm_i2c_aux_i2c_func
94 };
95 
96 void
97 nvkm_i2c_aux_monitor(struct nvkm_i2c_aux *aux, bool monitor)
98 {
99 	struct nvkm_i2c_pad *pad = aux->pad;
100 	AUX_TRACE(aux, "monitor: %s", str_yes_no(monitor));
101 	if (monitor)
102 		nvkm_i2c_pad_mode(pad, NVKM_I2C_PAD_AUX);
103 	else
104 		nvkm_i2c_pad_mode(pad, NVKM_I2C_PAD_OFF);
105 }
106 
107 void
108 nvkm_i2c_aux_release(struct nvkm_i2c_aux *aux)
109 {
110 	struct nvkm_i2c_pad *pad = aux->pad;
111 	AUX_TRACE(aux, "release");
112 	nvkm_i2c_pad_release(pad);
113 	mutex_unlock(&aux->mutex);
114 }
115 
116 int
117 nvkm_i2c_aux_acquire(struct nvkm_i2c_aux *aux)
118 {
119 	struct nvkm_i2c_pad *pad = aux->pad;
120 	int ret;
121 
122 	AUX_TRACE(aux, "acquire");
123 	mutex_lock(&aux->mutex);
124 
125 	if (aux->enabled)
126 		ret = nvkm_i2c_pad_acquire(pad, NVKM_I2C_PAD_AUX);
127 	else
128 		ret = -EIO;
129 
130 	if (ret)
131 		mutex_unlock(&aux->mutex);
132 	return ret;
133 }
134 
135 int
136 nvkm_i2c_aux_xfer(struct nvkm_i2c_aux *aux, bool retry, u8 type,
137 		  u32 addr, u8 *data, u8 *size)
138 {
139 	if (!*size && !aux->func->address_only) {
140 		AUX_ERR(aux, "address-only transaction dropped");
141 		return -ENOSYS;
142 	}
143 	return aux->func->xfer(aux, retry, type, addr, data, size);
144 }
145 
146 int
147 nvkm_i2c_aux_lnk_ctl(struct nvkm_i2c_aux *aux, int nr, int bw, bool ef)
148 {
149 	if (aux->func->lnk_ctl)
150 		return aux->func->lnk_ctl(aux, nr, bw, ef);
151 	return -ENODEV;
152 }
153 
154 void
155 nvkm_i2c_aux_del(struct nvkm_i2c_aux **paux)
156 {
157 	struct nvkm_i2c_aux *aux = *paux;
158 	if (aux && !WARN_ON(!aux->func)) {
159 		AUX_TRACE(aux, "dtor");
160 		list_del(&aux->head);
161 		i2c_del_adapter(&aux->i2c);
162 		kfree(*paux);
163 		*paux = NULL;
164 	}
165 }
166 
167 void
168 nvkm_i2c_aux_init(struct nvkm_i2c_aux *aux)
169 {
170 	AUX_TRACE(aux, "init");
171 	mutex_lock(&aux->mutex);
172 	aux->enabled = true;
173 	mutex_unlock(&aux->mutex);
174 }
175 
176 void
177 nvkm_i2c_aux_fini(struct nvkm_i2c_aux *aux)
178 {
179 	AUX_TRACE(aux, "fini");
180 	mutex_lock(&aux->mutex);
181 	aux->enabled = false;
182 	mutex_unlock(&aux->mutex);
183 }
184 
185 int
186 nvkm_i2c_aux_ctor(const struct nvkm_i2c_aux_func *func,
187 		  struct nvkm_i2c_pad *pad, int id,
188 		  struct nvkm_i2c_aux *aux)
189 {
190 	struct nvkm_device *device = pad->i2c->subdev.device;
191 
192 	aux->func = func;
193 	aux->pad = pad;
194 	aux->id = id;
195 	mutex_init(&aux->mutex);
196 	list_add_tail(&aux->head, &pad->i2c->aux);
197 	AUX_TRACE(aux, "ctor");
198 
199 	snprintf(aux->i2c.name, sizeof(aux->i2c.name), "nvkm-%s-aux-%04x",
200 		 dev_name(device->dev), id);
201 	aux->i2c.owner = THIS_MODULE;
202 	aux->i2c.dev.parent = device->dev;
203 	aux->i2c.algo = &nvkm_i2c_aux_i2c_algo;
204 	return i2c_add_adapter(&aux->i2c);
205 }
206 
207 int
208 nvkm_i2c_aux_new_(const struct nvkm_i2c_aux_func *func,
209 		  struct nvkm_i2c_pad *pad, int id,
210 		  struct nvkm_i2c_aux **paux)
211 {
212 	if (!(*paux = kzalloc(sizeof(**paux), GFP_KERNEL)))
213 		return -ENOMEM;
214 	return nvkm_i2c_aux_ctor(func, pad, id, *paux);
215 }
216