[deliverable/linux.git] / drivers / gpu / drm / i915 / intel_dp_i2c.c

/*
 * Copyright © 2009 Keith Packard
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/i2c.h>
#include "intel_dp.h"

/* Run a single AUX_CH I2C transaction, writing/reading data as necessary */

#define MODE_I2C_START	1
#define MODE_I2C_WRITE	2
#define MODE_I2C_READ	4
#define MODE_I2C_STOP	8

static int
i2c_algo_dp_aux_transaction(struct i2c_adapter *adapter, int mode,
			    uint8_t write_byte, uint8_t *read_byte)
{
	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
	uint16_t address = algo_data->address;
	uint8_t msg[5];
	uint8_t reply[2];
	int msg_bytes;
	int reply_bytes;
	int ret;

	/* Set up the command byte */
	if (mode & MODE_I2C_READ)
		msg[0] = AUX_I2C_READ << 4;
	else
		msg[0] = AUX_I2C_WRITE << 4;

	if (!(mode & MODE_I2C_STOP))
		msg[0] |= AUX_I2C_MOT << 4;

	msg[1] = address >> 8;
	msg[2] = address;

	switch (mode) {
	case MODE_I2C_WRITE:
		msg[3] = 0;
		msg[4] = write_byte;
		msg_bytes = 5;
		reply_bytes = 1;
		break;
	case MODE_I2C_READ:
		msg[3] = 0;
		msg_bytes = 4;
		reply_bytes = 2;
		break;
	default:
		msg_bytes = 3;
		reply_bytes = 1;
		break;
	}

	for (;;) {
		ret = (*algo_data->aux_ch)(adapter,
					   msg, msg_bytes,
					   reply, reply_bytes);
		if (ret < 0) {
			printk(KERN_ERR "aux_ch failed %d\n", ret);
			return ret;
		}
		switch (reply[0] & AUX_I2C_REPLY_MASK) {
		case AUX_I2C_REPLY_ACK:
			if (mode == MODE_I2C_READ) {
				*read_byte = reply[1];
			}
			return reply_bytes - 1;
		case AUX_I2C_REPLY_NACK:
			printk(KERN_ERR "aux_ch nack\n");
			return -EREMOTEIO;
		case AUX_I2C_REPLY_DEFER:
			printk(KERN_ERR "aux_ch defer\n");
			udelay(100);
			break;
		default:
			printk(KERN_ERR "aux_ch invalid reply 0x%02x\n", reply[0]);
			return -EREMOTEIO;
		}
	}
}

/*
 * I2C over AUX CH
 */

/*
 * Send the address. If the I2C link is running, this 'restarts'
 * the connection with the new address, this is used for doing
 * a write followed by a read (as needed for DDC)
 */
static int
i2c_algo_dp_aux_address(struct i2c_adapter *adapter, u16 address, bool reading)
{
	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
	int mode = MODE_I2C_START;
	int ret;

	if (reading)
		mode |= MODE_I2C_READ;
	else
		mode |= MODE_I2C_WRITE;
	algo_data->address = address;
	algo_data->running = true;
	ret = i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL);
	return ret;
}

/*
 * Stop the I2C transaction. This closes out the link, sending
 * a bare address packet with the MOT bit turned off
 */
static void
i2c_algo_dp_aux_stop(struct i2c_adapter *adapter, bool reading)
{
	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
	int mode = MODE_I2C_STOP;

	if (reading)
		mode |= MODE_I2C_READ;
	else
		mode |= MODE_I2C_WRITE;
	if (algo_data->running) {
		(void) i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL);
		algo_data->running = false;
	}
}

/*
 * Write a single byte to the current I2C address, the
 * the I2C link must be running or this returns -EIO
 */
static int
i2c_algo_dp_aux_put_byte(struct i2c_adapter *adapter, u8 byte)
{
	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
	int ret;

	if (!algo_data->running)
		return -EIO;

	ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_WRITE, byte, NULL);
	return ret;
}

/*
 * Read a single byte from the current I2C address, the
 * I2C link must be running or this returns -EIO
 */
static int
i2c_algo_dp_aux_get_byte(struct i2c_adapter *adapter, u8 *byte_ret)
{
	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
	int ret;

	if (!algo_data->running)
		return -EIO;

	ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_READ, 0, byte_ret);
	return ret;
}

static int
i2c_algo_dp_aux_xfer(struct i2c_adapter *adapter,
		     struct i2c_msg *msgs,
		     int num)
{
	int ret = 0;
	bool reading = false;
	int m;
	int b;

	for (m = 0; m < num; m++) {
		u16 len = msgs[m].len;
		u8 *buf = msgs[m].buf;
		reading = (msgs[m].flags & I2C_M_RD) != 0;
		ret = i2c_algo_dp_aux_address(adapter, msgs[m].addr, reading);
		if (ret < 0)
			break;
		if (reading) {
			for (b = 0; b < len; b++) {
				ret = i2c_algo_dp_aux_get_byte(adapter, &buf[b]);
				if (ret < 0)
					break;
			}
		} else {
			for (b = 0; b < len; b++) {
				ret = i2c_algo_dp_aux_put_byte(adapter, buf[b]);
				if (ret < 0)
					break;
			}
		}
		if (ret < 0)
			break;
	}
	if (ret >= 0)
		ret = num;
	i2c_algo_dp_aux_stop(adapter, reading);
	printk(KERN_ERR "dp_aux_xfer return %d\n", ret);
	return ret;
}

static u32
i2c_algo_dp_aux_functionality(struct i2c_adapter *adapter)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
	       I2C_FUNC_10BIT_ADDR;
}

static const struct i2c_algorithm i2c_dp_aux_algo = {
	.master_xfer	= i2c_algo_dp_aux_xfer,
	.functionality	= i2c_algo_dp_aux_functionality,
};

static void
i2c_dp_aux_reset_bus(struct i2c_adapter *adapter)
{
	(void) i2c_algo_dp_aux_address(adapter, 0, false);
	(void) i2c_algo_dp_aux_stop(adapter, false);
					   
}

static int
i2c_dp_aux_prepare_bus(struct i2c_adapter *adapter)
{
	adapter->algo = &i2c_dp_aux_algo;
	adapter->retries = 3;
	i2c_dp_aux_reset_bus(adapter);
	return 0;
}

int
i2c_dp_aux_add_bus(struct i2c_adapter *adapter)
{
	int error;
	
	error = i2c_dp_aux_prepare_bus(adapter);
	if (error)
		return error;
	error = i2c_add_adapter(adapter);
	return error;
}
EXPORT_SYMBOL(i2c_dp_aux_add_bus);
Commit	Line	Data
a4fc5ed6 KP	1	/*
	2	* Copyright © 2009 Keith Packard
	3	*
	4	* Permission to use, copy, modify, distribute, and sell this software and its
	5	* documentation for any purpose is hereby granted without fee, provided that
	6	* the above copyright notice appear in all copies and that both that copyright
	7	* notice and this permission notice appear in supporting documentation, and
	8	* that the name of the copyright holders not be used in advertising or
	9	* publicity pertaining to distribution of the software without specific,
	10	* written prior permission. The copyright holders make no representations
	11	* about the suitability of this software for any purpose. It is provided "as
	12	* is" without express or implied warranty.
	13	*
	14	* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
	15	* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
	16	* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
	17	* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
	18	* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
	19	* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
	20	* OF THIS SOFTWARE.
	21	*/
	22
	23	#include <linux/kernel.h>
	24	#include <linux/module.h>
	25	#include <linux/delay.h>
	26	#include <linux/slab.h>
	27	#include <linux/init.h>
	28	#include <linux/errno.h>
	29	#include <linux/sched.h>
	30	#include <linux/i2c.h>
	31	#include "intel_dp.h"
	32
	33	/* Run a single AUX_CH I2C transaction, writing/reading data as necessary */
	34
	35	#define MODE_I2C_START 1
	36	#define MODE_I2C_WRITE 2
	37	#define MODE_I2C_READ 4
	38	#define MODE_I2C_STOP 8
	39
	40	static int
	41	i2c_algo_dp_aux_transaction(struct i2c_adapter *adapter, int mode,
	42	uint8_t write_byte, uint8_t *read_byte)
	43	{
	44	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
	45	uint16_t address = algo_data->address;
	46	uint8_t msg[5];
	47	uint8_t reply[2];
	48	int msg_bytes;
	49	int reply_bytes;
	50	int ret;
	51
	52	/* Set up the command byte */
	53	if (mode & MODE_I2C_READ)
	54	msg[0] = AUX_I2C_READ << 4;
	55	else
	56	msg[0] = AUX_I2C_WRITE << 4;
	57
	58	if (!(mode & MODE_I2C_STOP))
	59	msg[0] \|= AUX_I2C_MOT << 4;
	60
	61	msg[1] = address >> 8;
	62	msg[2] = address;
	63
	64	switch (mode) {
65	case MODE_I2C_WRITE:
66	msg[3] = 0;
67	msg[4] = write_byte;
68	msg_bytes = 5;
69	reply_bytes = 1;
70	break;
71	case MODE_I2C_READ:
72	msg[3] = 0;
73	msg_bytes = 4;
74	reply_bytes = 2;
75	break;
76	default:
77	msg_bytes = 3;
78	reply_bytes = 1;
79	break;
80	}
81
82	for (;;) {
83	ret = (*algo_data->aux_ch)(adapter,
84	msg, msg_bytes,
85	reply, reply_bytes);
86	if (ret < 0) {
87	printk(KERN_ERR "aux_ch failed %d\n", ret);
88	return ret;
89	}
90	switch (reply[0] & AUX_I2C_REPLY_MASK) {
91	case AUX_I2C_REPLY_ACK:
92	if (mode == MODE_I2C_READ) {
93	*read_byte = reply[1];
94	}
95	return reply_bytes - 1;
96	case AUX_I2C_REPLY_NACK:
97	printk(KERN_ERR "aux_ch nack\n");
98	return -EREMOTEIO;
99	case AUX_I2C_REPLY_DEFER:
100	printk(KERN_ERR "aux_ch defer\n");
101	udelay(100);
102	break;
103	default:
104	printk(KERN_ERR "aux_ch invalid reply 0x%02x\n", reply[0]);
105	return -EREMOTEIO;
106	}
107	}
108	}
109
110	/*
111	* I2C over AUX CH
112	*/
113
114	/*
115	* Send the address. If the I2C link is running, this 'restarts'
116	* the connection with the new address, this is used for doing
117	* a write followed by a read (as needed for DDC)
118	*/
119	static int
120	i2c_algo_dp_aux_address(struct i2c_adapter *adapter, u16 address, bool reading)
121	{
122	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
123	int mode = MODE_I2C_START;
124	int ret;
125
126	if (reading)
127	mode \|= MODE_I2C_READ;
128	else
129	mode \|= MODE_I2C_WRITE;
130	algo_data->address = address;
131	algo_data->running = true;
132	ret = i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL);
133	return ret;
134	}
135
136	/*
137	* Stop the I2C transaction. This closes out the link, sending
138	* a bare address packet with the MOT bit turned off
139	*/
140	static void
141	i2c_algo_dp_aux_stop(struct i2c_adapter *adapter, bool reading)
142	{
143	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
144	int mode = MODE_I2C_STOP;
145
146	if (reading)
147	mode \|= MODE_I2C_READ;
148	else
149	mode \|= MODE_I2C_WRITE;
150	if (algo_data->running) {
151	(void) i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL);
152	algo_data->running = false;
153	}
154	}
155
156	/*
157	* Write a single byte to the current I2C address, the
158	* the I2C link must be running or this returns -EIO
159	*/
160	static int
161	i2c_algo_dp_aux_put_byte(struct i2c_adapter *adapter, u8 byte)
162	{
163	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
164	int ret;
165
166	if (!algo_data->running)
167	return -EIO;
168
169	ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_WRITE, byte, NULL);
170	return ret;
171	}
172
173	/*
174	* Read a single byte from the current I2C address, the
175	* I2C link must be running or this returns -EIO
176	*/
177	static int
178	i2c_algo_dp_aux_get_byte(struct i2c_adapter adapter, u8 byte_ret)
179	{
180	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
181	int ret;
182
183	if (!algo_data->running)
184	return -EIO;
185
186	ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_READ, 0, byte_ret);
187	return ret;
188	}
189
190	static int
191	i2c_algo_dp_aux_xfer(struct i2c_adapter *adapter,
192	struct i2c_msg *msgs,
193	int num)
194	{
195	int ret = 0;
196	bool reading = false;
197	int m;
198	int b;
199
200	for (m = 0; m < num; m++) {
201	u16 len = msgs[m].len;
202	u8 *buf = msgs[m].buf;
203	reading = (msgs[m].flags & I2C_M_RD) != 0;
204	ret = i2c_algo_dp_aux_address(adapter, msgs[m].addr, reading);
205	if (ret < 0)
206	break;
207	if (reading) {
208	for (b = 0; b < len; b++) {
209	ret = i2c_algo_dp_aux_get_byte(adapter, &buf[b]);
210	if (ret < 0)
211	break;
212	}
213	} else {
214	for (b = 0; b < len; b++) {
215	ret = i2c_algo_dp_aux_put_byte(adapter, buf[b]);
216	if (ret < 0)
217	break;
218	}
219	}
220	if (ret < 0)
221	break;
222	}
223	if (ret >= 0)
224	ret = num;
225	i2c_algo_dp_aux_stop(adapter, reading);
226	printk(KERN_ERR "dp_aux_xfer return %d\n", ret);
227	return ret;
228	}
229
230	static u32
231	i2c_algo_dp_aux_functionality(struct i2c_adapter *adapter)
232	{
233	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL \|
234	I2C_FUNC_SMBUS_READ_BLOCK_DATA \|
235	I2C_FUNC_SMBUS_BLOCK_PROC_CALL \|
236	I2C_FUNC_10BIT_ADDR;
237	}
238
239	static const struct i2c_algorithm i2c_dp_aux_algo = {
240	.master_xfer = i2c_algo_dp_aux_xfer,
241	.functionality = i2c_algo_dp_aux_functionality,
242	};
243
244	static void
245	i2c_dp_aux_reset_bus(struct i2c_adapter *adapter)
246	{
247	(void) i2c_algo_dp_aux_address(adapter, 0, false);
248	(void) i2c_algo_dp_aux_stop(adapter, false);
249
250	}
251
252	static int
253	i2c_dp_aux_prepare_bus(struct i2c_adapter *adapter)
254	{
255	adapter->algo = &i2c_dp_aux_algo;
256	adapter->retries = 3;
257	i2c_dp_aux_reset_bus(adapter);
258	return 0;
259	}
260
261	int
262	i2c_dp_aux_add_bus(struct i2c_adapter *adapter)
263	{
264	int error;
265
266	error = i2c_dp_aux_prepare_bus(adapter);
267	if (error)
268	return error;
269	error = i2c_add_adapter(adapter);
270	return error;
271	}
272	EXPORT_SYMBOL(i2c_dp_aux_add_bus);