1 // SPDX-License-Identifier: GPL-2.0-or-later
5 * Copyright (C) 2012 Ezequiel Garcia
6 * <elezegarcia--a.t--gmail.com>
8 * Based on Easycap driver by R.M. Thomas
9 * Copyright (C) 2010 R.M. Thomas
10 * <rmthomas--a.t--sciolus.org>
13 #include <linux/module.h>
14 #include <linux/usb.h>
15 #include <linux/i2c.h>
18 #include "stk1160-reg.h"
20 static unsigned int i2c_debug;
21 module_param(i2c_debug, int, 0644);
22 MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
24 #define dprintk_i2c(fmt, args...) \
27 printk(KERN_DEBUG fmt, ##args); \
30 static int stk1160_i2c_busy_wait(struct stk1160 *dev, u8 wait_bit_mask)
35 /* Wait until read/write finish bit is set */
36 end = jiffies + msecs_to_jiffies(STK1160_I2C_TIMEOUT);
37 while (time_is_after_jiffies(end)) {
39 stk1160_read_reg(dev, STK1160_SICTL+1, &flag);
40 /* read/write done? */
41 if (flag & wait_bit_mask)
44 usleep_range(10 * USEC_PER_MSEC, 20 * USEC_PER_MSEC);
53 static int stk1160_i2c_write_reg(struct stk1160 *dev, u8 addr,
58 /* Set serial device address */
59 rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
63 /* Set i2c device register sub-address */
64 rc = stk1160_write_reg(dev, STK1160_SBUSW_WA, reg);
68 /* Set i2c device register value */
69 rc = stk1160_write_reg(dev, STK1160_SBUSW_WD, value);
74 rc = stk1160_write_reg(dev, STK1160_SICTL, 0x01);
78 rc = stk1160_i2c_busy_wait(dev, 0x04);
85 static int stk1160_i2c_read_reg(struct stk1160 *dev, u8 addr,
90 /* Set serial device address */
91 rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
95 /* Set i2c device register sub-address */
96 rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, reg);
101 rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
105 rc = stk1160_i2c_busy_wait(dev, 0x01);
109 rc = stk1160_read_reg(dev, STK1160_SBUSR_RD, value);
117 * stk1160_i2c_check_for_device()
118 * check if there is a i2c_device at the supplied address
120 static int stk1160_i2c_check_for_device(struct stk1160 *dev,
125 /* Set serial device address */
126 rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
130 /* Set device sub-address, we'll chip version reg */
131 rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, 0x00);
136 rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
140 rc = stk1160_i2c_busy_wait(dev, 0x01);
149 * the main i2c transfer function
151 static int stk1160_i2c_xfer(struct i2c_adapter *i2c_adap,
152 struct i2c_msg msgs[], int num)
154 struct stk1160 *dev = i2c_adap->algo_data;
157 for (i = 0; i < num; i++) {
158 addr = msgs[i].addr << 1;
159 dprintk_i2c("%s: addr=%x", __func__, addr);
162 /* no len: check only for device presence */
163 rc = stk1160_i2c_check_for_device(dev, addr);
165 dprintk_i2c(" no device\n");
169 } else if (msgs[i].flags & I2C_M_RD) {
170 /* read request without preceding register selection */
171 dprintk_i2c(" subaddr not selected");
175 } else if (i + 1 < num && msgs[i].len <= 2 &&
176 (msgs[i + 1].flags & I2C_M_RD) &&
177 msgs[i].addr == msgs[i + 1].addr) {
179 if (msgs[i].len != 1 || msgs[i + 1].len != 1) {
180 dprintk_i2c(" len not supported");
185 dprintk_i2c(" subaddr=%x", msgs[i].buf[0]);
187 rc = stk1160_i2c_read_reg(dev, addr, msgs[i].buf[0],
190 dprintk_i2c(" read=%x", *msgs[i + 1].buf);
192 /* consumed two msgs, so we skip one of them */
196 if (msgs[i].len != 2) {
197 dprintk_i2c(" len not supported");
202 dprintk_i2c(" subaddr=%x write=%x",
203 msgs[i].buf[0], msgs[i].buf[1]);
205 rc = stk1160_i2c_write_reg(dev, addr, msgs[i].buf[0],
211 dprintk_i2c(" OK\n");
216 dprintk_i2c(" ERROR: %d\n", rc);
221 * functionality(), what da heck is this?
223 static u32 functionality(struct i2c_adapter *adap)
225 return I2C_FUNC_SMBUS_EMUL;
228 static const struct i2c_algorithm algo = {
229 .master_xfer = stk1160_i2c_xfer,
230 .functionality = functionality,
233 static const struct i2c_adapter adap_template = {
234 .owner = THIS_MODULE,
239 static const struct i2c_client client_template = {
240 .name = "stk1160 internal",
244 * stk1160_i2c_register()
247 int stk1160_i2c_register(struct stk1160 *dev)
251 dev->i2c_adap = adap_template;
252 dev->i2c_adap.dev.parent = dev->dev;
253 strscpy(dev->i2c_adap.name, "stk1160", sizeof(dev->i2c_adap.name));
254 dev->i2c_adap.algo_data = dev;
256 i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
258 rc = i2c_add_adapter(&dev->i2c_adap);
260 stk1160_err("cannot add i2c adapter (%d)\n", rc);
264 dev->i2c_client = client_template;
265 dev->i2c_client.adapter = &dev->i2c_adap;
267 /* Set i2c clock divider device address */
268 stk1160_write_reg(dev, STK1160_SICTL_CD, 0x0f);
271 stk1160_write_reg(dev, STK1160_ASIC + 3, 0x00);
277 * stk1160_i2c_unregister()
280 int stk1160_i2c_unregister(struct stk1160 *dev)
282 i2c_del_adapter(&dev->i2c_adap);