bus.c

  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 ******************************************************************************/
 32static int
 33nvkm_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
 39static void
 40nvkm_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
 46static void
 47nvkm_i2c_bus_setscl(void *data, int state)
 48{
 49	struct nvkm_i2c_bus *bus = data;
 50	bus->func->drive_scl(bus, state);
 51}
 52
 53static void
 54nvkm_i2c_bus_setsda(void *data, int state)
 55{
 56	struct nvkm_i2c_bus *bus = data;
 57	bus->func->drive_sda(bus, state);
 58}
 59
 60static int
 61nvkm_i2c_bus_getscl(void *data)
 62{
 63	struct nvkm_i2c_bus *bus = data;
 64	return bus->func->sense_scl(bus);
 65}
 66
 67static int
 68nvkm_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 ******************************************************************************/
 77static int
 78nvkm_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
 92static u32
 93nvkm_i2c_bus_func(struct i2c_adapter *adap)
 94{
 95	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 96}
 97
 98static const struct i2c_algorithm
 99nvkm_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 ******************************************************************************/
107void
108nvkm_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
119void
120nvkm_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
128void
129nvkm_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
137int
138nvkm_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
156int
157nvkm_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
193void
194nvkm_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
207int
208nvkm_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
256int
257nvkm_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}