go7007-i2c.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2005-2006 Micronas USA Inc.
  4 */
  5
  6#include <linux/module.h>
  7#include <linux/delay.h>
  8#include <linux/sched.h>
  9#include <linux/list.h>
 10#include <linux/unistd.h>
 11#include <linux/time.h>
 12#include <linux/device.h>
 13#include <linux/i2c.h>
 14#include <linux/mutex.h>
 15#include <linux/uaccess.h>
 16
 17#include "go7007-priv.h"
 18
 19/********************* Driver for on-board I2C adapter *********************/
 20
 21/* #define GO7007_I2C_DEBUG */
 22
 23#define SPI_I2C_ADDR_BASE		0x1400
 24#define STATUS_REG_ADDR			(SPI_I2C_ADDR_BASE + 0x2)
 25#define I2C_CTRL_REG_ADDR		(SPI_I2C_ADDR_BASE + 0x6)
 26#define I2C_DEV_UP_ADDR_REG_ADDR	(SPI_I2C_ADDR_BASE + 0x7)
 27#define I2C_LO_ADDR_REG_ADDR		(SPI_I2C_ADDR_BASE + 0x8)
 28#define I2C_DATA_REG_ADDR		(SPI_I2C_ADDR_BASE + 0x9)
 29#define I2C_CLKFREQ_REG_ADDR		(SPI_I2C_ADDR_BASE + 0xa)
 30
 31#define I2C_STATE_MASK			0x0007
 32#define I2C_READ_READY_MASK		0x0008
 33
 34/* There is only one I2C port on the TW2804 that feeds all four GO7007 VIPs
 35 * on the Adlink PCI-MPG24, so access is shared between all of them. */
 36static DEFINE_MUTEX(adlink_mpg24_i2c_mutex);
 37
 38static inline void adlink_mpg24_i2c_lock(struct go7007 *go)
 39{
 40	/* Bridge the I2C port on this GO7007 to the shared bus */
 41	mutex_lock(&adlink_mpg24_i2c_mutex);
 42	go7007_write_addr(go, 0x3c82, 0x0020);
 43}
 44
 45static inline void adlink_mpg24_i2c_unlock(struct go7007 *go)
 46{
 47	/* Isolate the I2C port on this GO7007 from the shared bus */
 48	go7007_write_addr(go, 0x3c82, 0x0000);
 49	mutex_unlock(&adlink_mpg24_i2c_mutex);
 50}
 51
 52static int go7007_i2c_xfer(struct go7007 *go, u16 addr, int read,
 53		u16 command, int flags, u8 *data)
 54{
 55	int i, ret = -EIO;
 56	u16 val;
 57
 58	if (go->status == STATUS_SHUTDOWN)
 59		return -ENODEV;
 60
 61#ifdef GO7007_I2C_DEBUG
 62	if (read)
 63		dev_dbg(go->dev, "go7007-i2c: reading 0x%02x on 0x%02x\n",
 64			command, addr);
 65	else
 66		dev_dbg(go->dev,
 67			"go7007-i2c: writing 0x%02x to 0x%02x on 0x%02x\n",
 68			*data, command, addr);
 69#endif
 70
 71	mutex_lock(&go->hw_lock);
 72
 73	if (go->board_id == GO7007_BOARDID_ADLINK_MPG24)
 74		adlink_mpg24_i2c_lock(go);
 75
 76	/* Wait for I2C adapter to be ready */
 77	for (i = 0; i < 10; ++i) {
 78		if (go7007_read_addr(go, STATUS_REG_ADDR, &val) < 0)
 79			goto i2c_done;
 80		if (!(val & I2C_STATE_MASK))
 81			break;
 82		msleep(100);
 83	}
 84	if (i == 10) {
 85		dev_err(go->dev, "go7007-i2c: I2C adapter is hung\n");
 86		goto i2c_done;
 87	}
 88
 89	/* Set target register (command) */
 90	go7007_write_addr(go, I2C_CTRL_REG_ADDR, flags);
 91	go7007_write_addr(go, I2C_LO_ADDR_REG_ADDR, command);
 92
 93	/* If we're writing, send the data and target address and we're done */
 94	if (!read) {
 95		go7007_write_addr(go, I2C_DATA_REG_ADDR, *data);
 96		go7007_write_addr(go, I2C_DEV_UP_ADDR_REG_ADDR,
 97					(addr << 9) | (command >> 8));
 98		ret = 0;
 99		goto i2c_done;
100	}
101
102	/* Otherwise, we're reading.  First clear i2c_rx_data_rdy. */
103	if (go7007_read_addr(go, I2C_DATA_REG_ADDR, &val) < 0)
104		goto i2c_done;
105
106	/* Send the target address plus read flag */
107	go7007_write_addr(go, I2C_DEV_UP_ADDR_REG_ADDR,
108			(addr << 9) | 0x0100 | (command >> 8));
109
110	/* Wait for i2c_rx_data_rdy */
111	for (i = 0; i < 10; ++i) {
112		if (go7007_read_addr(go, STATUS_REG_ADDR, &val) < 0)
113			goto i2c_done;
114		if (val & I2C_READ_READY_MASK)
115			break;
116		msleep(100);
117	}
118	if (i == 10) {
119		dev_err(go->dev, "go7007-i2c: I2C adapter is hung\n");
120		goto i2c_done;
121	}
122
123	/* Retrieve the read byte */
124	if (go7007_read_addr(go, I2C_DATA_REG_ADDR, &val) < 0)
125		goto i2c_done;
126	*data = val;
127	ret = 0;
128
129i2c_done:
130	if (go->board_id == GO7007_BOARDID_ADLINK_MPG24)
131		adlink_mpg24_i2c_unlock(go);
132	mutex_unlock(&go->hw_lock);
133	return ret;
134}
135
136static int go7007_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
137		unsigned short flags, char read_write,
138		u8 command, int size, union i2c_smbus_data *data)
139{
140	struct go7007 *go = i2c_get_adapdata(adapter);
141
142	if (size != I2C_SMBUS_BYTE_DATA)
143		return -EIO;
144	return go7007_i2c_xfer(go, addr, read_write == I2C_SMBUS_READ, command,
145			flags & I2C_CLIENT_SCCB ? 0x10 : 0x00, &data->byte);
146}
147
148/* VERY LIMITED I2C master xfer function -- only needed because the
149 * SMBus functions only support 8-bit commands and the SAA7135 uses
150 * 16-bit commands.  The I2C interface on the GO7007, as limited as
151 * it is, does support this mode. */
152
153static int go7007_i2c_master_xfer(struct i2c_adapter *adapter,
154					struct i2c_msg msgs[], int num)
155{
156	struct go7007 *go = i2c_get_adapdata(adapter);
157	int i;
158
159	for (i = 0; i < num; ++i) {
160		/* We can only do two things here -- write three bytes, or
161		 * write two bytes and read one byte. */
162		if (msgs[i].len == 2) {
163			if (i + 1 == num || msgs[i].addr != msgs[i + 1].addr ||
164					(msgs[i].flags & I2C_M_RD) ||
165					!(msgs[i + 1].flags & I2C_M_RD) ||
166					msgs[i + 1].len != 1)
167				return -EIO;
168			if (go7007_i2c_xfer(go, msgs[i].addr, 1,
169					(msgs[i].buf[0] << 8) | msgs[i].buf[1],
170					0x01, &msgs[i + 1].buf[0]) < 0)
171				return -EIO;
172			++i;
173		} else if (msgs[i].len == 3) {
174			if (msgs[i].flags & I2C_M_RD)
175				return -EIO;
176			if (go7007_i2c_xfer(go, msgs[i].addr, 0,
177					(msgs[i].buf[0] << 8) | msgs[i].buf[1],
178					0x01, &msgs[i].buf[2]) < 0)
179				return -EIO;
180		} else
181			return -EIO;
182	}
183
184	return num;
185}
186
187static u32 go7007_functionality(struct i2c_adapter *adapter)
188{
189	return I2C_FUNC_SMBUS_BYTE_DATA;
190}
191
192static const struct i2c_algorithm go7007_algo = {
193	.smbus_xfer	= go7007_smbus_xfer,
194	.master_xfer	= go7007_i2c_master_xfer,
195	.functionality	= go7007_functionality,
196};
197
198static struct i2c_adapter go7007_adap_templ = {
199	.owner			= THIS_MODULE,
200	.name			= "WIS GO7007SB",
201	.algo			= &go7007_algo,
202};
203
204int go7007_i2c_init(struct go7007 *go)
205{
206	memcpy(&go->i2c_adapter, &go7007_adap_templ,
207			sizeof(go7007_adap_templ));
208	go->i2c_adapter.dev.parent = go->dev;
209	i2c_set_adapdata(&go->i2c_adapter, go);
210	if (i2c_add_adapter(&go->i2c_adapter) < 0) {
211		dev_err(go->dev,
212			"go7007-i2c: error: i2c_add_adapter failed\n");
213		return -1;
214	}
215	return 0;
216}