1 /*
2  * Copyright 2015 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 <bskeggs@redhat.com>
23  */
24 #include "bus.h"
25 #include "pad.h"
26 
27 #include <core/option.h>
28 
29 /*******************************************************************************
30  * i2c-algo-bit
31  ******************************************************************************/
32 static int
33 nvkm_i2c_bus_pre_xfer(struct i2c_adapter *adap)
34 {
35 	struct nvkm_i2c_bus *bus = container_of(adap, typeof(*bus), i2c);
36 	return nvkm_i2c_bus_acquire(bus);
37 }
38 
39 static void
40 nvkm_i2c_bus_post_xfer(struct i2c_adapter *adap)
41 {
42 	struct nvkm_i2c_bus *bus = container_of(adap, typeof(*bus), i2c);
43 	return nvkm_i2c_bus_release(bus);
44 }
45 
46 static void
47 nvkm_i2c_bus_setscl(void *data, int state)
48 {
49 	struct nvkm_i2c_bus *bus = data;
50 	bus->func->drive_scl(bus, state);
51 }
52 
53 static void
54 nvkm_i2c_bus_setsda(void *data, int state)
55 {
56 	struct nvkm_i2c_bus *bus = data;
57 	bus->func->drive_sda(bus, state);
58 }
59 
60 static int
61 nvkm_i2c_bus_getscl(void *data)
62 {
63 	struct nvkm_i2c_bus *bus = data;
64 	return bus->func->sense_scl(bus);
65 }
66 
67 static int
68 nvkm_i2c_bus_getsda(void *data)
69 {
70 	struct nvkm_i2c_bus *bus = data;
71 	return bus->func->sense_sda(bus);
72 }
73 
74 /*******************************************************************************
75  * !i2c-algo-bit (off-chip i2c bus / hw i2c / internal bit-banging algo)
76  ******************************************************************************/
77 static int
78 nvkm_i2c_bus_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
79 {
80 	struct nvkm_i2c_bus *bus = container_of(adap, typeof(*bus), i2c);
81 	int ret;
82 
83 	ret = nvkm_i2c_bus_acquire(bus);
84 	if (ret)
85 		return ret;
86 
87 	ret = bus->func->xfer(bus, msgs, num);
88 	nvkm_i2c_bus_release(bus);
89 	return ret;
90 }
91 
92 static u32
93 nvkm_i2c_bus_func(struct i2c_adapter *adap)
94 {
95 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
96 }
97 
98 static const struct i2c_algorithm
99 nvkm_i2c_bus_algo = {
100 	.master_xfer = nvkm_i2c_bus_xfer,
101 	.functionality = nvkm_i2c_bus_func,
102 };
103 
104 /*******************************************************************************
105  * nvkm_i2c_bus base
106  ******************************************************************************/
107 void
108 nvkm_i2c_bus_init(struct nvkm_i2c_bus *bus)
109 {
110 	BUS_TRACE(bus, "init");
111 	if (bus->func->init)
112 		bus->func->init(bus);
113 
114 	mutex_lock(&bus->mutex);
115 	bus->enabled = true;
116 	mutex_unlock(&bus->mutex);
117 }
118 
119 void
120 nvkm_i2c_bus_fini(struct nvkm_i2c_bus *bus)
121 {
122 	BUS_TRACE(bus, "fini");
123 	mutex_lock(&bus->mutex);
124 	bus->enabled = false;
125 	mutex_unlock(&bus->mutex);
126 }
127 
128 void
129 nvkm_i2c_bus_release(struct nvkm_i2c_bus *bus)
130 {
131 	struct nvkm_i2c_pad *pad = bus->pad;
132 	BUS_TRACE(bus, "release");
133 	nvkm_i2c_pad_release(pad);
134 	mutex_unlock(&bus->mutex);
135 }
136 
137 int
138 nvkm_i2c_bus_acquire(struct nvkm_i2c_bus *bus)
139 {
140 	struct nvkm_i2c_pad *pad = bus->pad;
141 	int ret;
142 
143 	BUS_TRACE(bus, "acquire");
144 	mutex_lock(&bus->mutex);
145 
146 	if (bus->enabled)
147 		ret = nvkm_i2c_pad_acquire(pad, NVKM_I2C_PAD_I2C);
148 	else
149 		ret = -EIO;
150 
151 	if (ret)
152 		mutex_unlock(&bus->mutex);
153 	return ret;
154 }
155 
156 int
157 nvkm_i2c_bus_probe(struct nvkm_i2c_bus *bus, const char *what,
158 		   struct nvkm_i2c_bus_probe *info,
159 		   bool (*match)(struct nvkm_i2c_bus *,
160 				 struct i2c_board_info *, void *), void *data)
161 {
162 	int i;
163 
164 	BUS_DBG(bus, "probing %ss", what);
165 	for (i = 0; info[i].dev.addr; i++) {
166 		u8 orig_udelay = 0;
167 
168 		if ((bus->i2c.algo == &i2c_bit_algo) && (info[i].udelay != 0)) {
169 			struct i2c_algo_bit_data *algo = bus->i2c.algo_data;
170 			BUS_DBG(bus, "%dms delay instead of %dms",
171 				     info[i].udelay, algo->udelay);
172 			orig_udelay = algo->udelay;
173 			algo->udelay = info[i].udelay;
174 		}
175 
176 		if (nvkm_probe_i2c(&bus->i2c, info[i].dev.addr) &&
177 		    (!match || match(bus, &info[i].dev, data))) {
178 			BUS_DBG(bus, "detected %s: %s",
179 				what, info[i].dev.type);
180 			return i;
181 		}
182 
183 		if (orig_udelay) {
184 			struct i2c_algo_bit_data *algo = bus->i2c.algo_data;
185 			algo->udelay = orig_udelay;
186 		}
187 	}
188 
189 	BUS_DBG(bus, "no devices found.");
190 	return -ENODEV;
191 }
192 
193 void
194 nvkm_i2c_bus_del(struct nvkm_i2c_bus **pbus)
195 {
196 	struct nvkm_i2c_bus *bus = *pbus;
197 	if (bus && !WARN_ON(!bus->func)) {
198 		BUS_TRACE(bus, "dtor");
199 		list_del(&bus->head);
200 		i2c_del_adapter(&bus->i2c);
201 		kfree(bus->i2c.algo_data);
202 		kfree(*pbus);
203 		*pbus = NULL;
204 	}
205 }
206 
207 int
208 nvkm_i2c_bus_ctor(const struct nvkm_i2c_bus_func *func,
209 		  struct nvkm_i2c_pad *pad, int id,
210 		  struct nvkm_i2c_bus *bus)
211 {
212 	struct nvkm_device *device = pad->i2c->subdev.device;
213 	struct i2c_algo_bit_data *bit;
214 #ifndef CONFIG_NOUVEAU_I2C_INTERNAL_DEFAULT
215 	const bool internal = false;
216 #else
217 	const bool internal = true;
218 #endif
219 	int ret;
220 
221 	bus->func = func;
222 	bus->pad = pad;
223 	bus->id = id;
224 	mutex_init(&bus->mutex);
225 	list_add_tail(&bus->head, &pad->i2c->bus);
226 	BUS_TRACE(bus, "ctor");
227 
228 	snprintf(bus->i2c.name, sizeof(bus->i2c.name), "nvkm-%s-bus-%04x",
229 		 dev_name(device->dev), id);
230 	bus->i2c.owner = THIS_MODULE;
231 	bus->i2c.dev.parent = device->dev;
232 
233 	if ( bus->func->drive_scl &&
234 	    !nvkm_boolopt(device->cfgopt, "NvI2C", internal)) {
235 		if (!(bit = kzalloc(sizeof(*bit), GFP_KERNEL)))
236 			return -ENOMEM;
237 		bit->udelay = 10;
238 		bit->timeout = usecs_to_jiffies(2200);
239 		bit->data = bus;
240 		bit->pre_xfer = nvkm_i2c_bus_pre_xfer;
241 		bit->post_xfer = nvkm_i2c_bus_post_xfer;
242 		bit->setscl = nvkm_i2c_bus_setscl;
243 		bit->setsda = nvkm_i2c_bus_setsda;
244 		bit->getscl = nvkm_i2c_bus_getscl;
245 		bit->getsda = nvkm_i2c_bus_getsda;
246 		bus->i2c.algo_data = bit;
247 		ret = i2c_bit_add_bus(&bus->i2c);
248 	} else {
249 		bus->i2c.algo = &nvkm_i2c_bus_algo;
250 		ret = i2c_add_adapter(&bus->i2c);
251 	}
252 
253 	return ret;
254 }
255 
256 int
257 nvkm_i2c_bus_new_(const struct nvkm_i2c_bus_func *func,
258 		  struct nvkm_i2c_pad *pad, int id,
259 		  struct nvkm_i2c_bus **pbus)
260 {
261 	if (!(*pbus = kzalloc(sizeof(**pbus), GFP_KERNEL)))
262 		return -ENOMEM;
263 	return nvkm_i2c_bus_ctor(func, pad, id, *pbus);
264 }
265