1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C) 2010-2013 Bluecherry, LLC <https://www.bluecherrydvr.com>
6 * Ben Collins <bcollins@ubuntu.com>
9 * John Brooks <john.brooks@bluecherry.net>
12 /* XXX: The SOLO6x10 i2c does not have separate interrupts for each i2c
13 * channel. The bus can only handle one i2c event at a time. The below handles
14 * this all wrong. We should be using the status registers to see if the bus
15 * is in use, and have a global lock to check the status register. Also,
16 * the bulk of the work should be handled out-of-interrupt. The ugly loops
17 * that occur during interrupt scare me. The ISR should merely signal
18 * thread context, ACK the interrupt, and move on. -- BenC */
20 #include <linux/kernel.h>
21 #include <linux/sched/signal.h>
25 u8 solo_i2c_readbyte(struct solo_dev *solo_dev, int id, u8 addr, u8 off)
27 struct i2c_msg msgs[2];
35 msgs[1].flags = I2C_M_RD;
40 i2c_transfer(&solo_dev->i2c_adap[id], msgs, 2);
45 void solo_i2c_writebyte(struct solo_dev *solo_dev, int id, u8 addr,
58 i2c_transfer(&solo_dev->i2c_adap[id], &msgs, 1);
61 static void solo_i2c_flush(struct solo_dev *solo_dev, int wr)
65 ctrl = SOLO_IIC_CH_SET(solo_dev->i2c_id);
67 if (solo_dev->i2c_state == IIC_STATE_START)
68 ctrl |= SOLO_IIC_START;
71 ctrl |= SOLO_IIC_WRITE;
73 ctrl |= SOLO_IIC_READ;
74 if (!(solo_dev->i2c_msg->flags & I2C_M_NO_RD_ACK))
75 ctrl |= SOLO_IIC_ACK_EN;
78 if (solo_dev->i2c_msg_ptr == solo_dev->i2c_msg->len)
79 ctrl |= SOLO_IIC_STOP;
81 solo_reg_write(solo_dev, SOLO_IIC_CTRL, ctrl);
84 static void solo_i2c_start(struct solo_dev *solo_dev)
86 u32 addr = solo_dev->i2c_msg->addr << 1;
88 if (solo_dev->i2c_msg->flags & I2C_M_RD)
91 solo_dev->i2c_state = IIC_STATE_START;
92 solo_reg_write(solo_dev, SOLO_IIC_TXD, addr);
93 solo_i2c_flush(solo_dev, 1);
96 static void solo_i2c_stop(struct solo_dev *solo_dev)
98 solo_irq_off(solo_dev, SOLO_IRQ_IIC);
99 solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
100 solo_dev->i2c_state = IIC_STATE_STOP;
101 wake_up(&solo_dev->i2c_wait);
104 static int solo_i2c_handle_read(struct solo_dev *solo_dev)
107 if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
108 solo_i2c_flush(solo_dev, 0);
112 solo_dev->i2c_msg_ptr = 0;
114 solo_dev->i2c_msg_num--;
116 if (solo_dev->i2c_msg_num == 0) {
117 solo_i2c_stop(solo_dev);
121 if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
122 solo_i2c_start(solo_dev);
124 if (solo_dev->i2c_msg->flags & I2C_M_RD)
127 solo_i2c_stop(solo_dev);
133 static int solo_i2c_handle_write(struct solo_dev *solo_dev)
136 if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
137 solo_reg_write(solo_dev, SOLO_IIC_TXD,
138 solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr]);
139 solo_dev->i2c_msg_ptr++;
140 solo_i2c_flush(solo_dev, 1);
144 solo_dev->i2c_msg_ptr = 0;
146 solo_dev->i2c_msg_num--;
148 if (solo_dev->i2c_msg_num == 0) {
149 solo_i2c_stop(solo_dev);
153 if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
154 solo_i2c_start(solo_dev);
156 if (solo_dev->i2c_msg->flags & I2C_M_RD)
157 solo_i2c_stop(solo_dev);
165 int solo_i2c_isr(struct solo_dev *solo_dev)
167 u32 status = solo_reg_read(solo_dev, SOLO_IIC_CTRL);
171 if (CHK_FLAGS(status, SOLO_IIC_STATE_TRNS | SOLO_IIC_STATE_SIG_ERR)
172 || solo_dev->i2c_id < 0) {
173 solo_i2c_stop(solo_dev);
177 switch (solo_dev->i2c_state) {
178 case IIC_STATE_START:
179 if (solo_dev->i2c_msg->flags & I2C_M_RD) {
180 solo_dev->i2c_state = IIC_STATE_READ;
181 ret = solo_i2c_handle_read(solo_dev);
185 solo_dev->i2c_state = IIC_STATE_WRITE;
187 case IIC_STATE_WRITE:
188 ret = solo_i2c_handle_write(solo_dev);
192 solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr] =
193 solo_reg_read(solo_dev, SOLO_IIC_RXD);
194 solo_dev->i2c_msg_ptr++;
196 ret = solo_i2c_handle_read(solo_dev);
200 solo_i2c_stop(solo_dev);
206 static int solo_i2c_master_xfer(struct i2c_adapter *adap,
207 struct i2c_msg msgs[], int num)
209 struct solo_dev *solo_dev = adap->algo_data;
210 unsigned long timeout;
215 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
216 if (&solo_dev->i2c_adap[i] == adap)
220 if (i == SOLO_I2C_ADAPTERS)
221 return num; /* XXX Right return value for failure? */
223 mutex_lock(&solo_dev->i2c_mutex);
224 solo_dev->i2c_id = i;
225 solo_dev->i2c_msg = msgs;
226 solo_dev->i2c_msg_num = num;
227 solo_dev->i2c_msg_ptr = 0;
229 solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
230 solo_irq_on(solo_dev, SOLO_IRQ_IIC);
231 solo_i2c_start(solo_dev);
236 prepare_to_wait(&solo_dev->i2c_wait, &wait,
239 if (solo_dev->i2c_state == IIC_STATE_STOP)
242 timeout = schedule_timeout(timeout);
246 if (signal_pending(current))
250 finish_wait(&solo_dev->i2c_wait, &wait);
251 ret = num - solo_dev->i2c_msg_num;
252 solo_dev->i2c_state = IIC_STATE_IDLE;
253 solo_dev->i2c_id = -1;
255 mutex_unlock(&solo_dev->i2c_mutex);
260 static u32 solo_i2c_functionality(struct i2c_adapter *adap)
265 static const struct i2c_algorithm solo_i2c_algo = {
266 .master_xfer = solo_i2c_master_xfer,
267 .functionality = solo_i2c_functionality,
270 int solo_i2c_init(struct solo_dev *solo_dev)
275 solo_reg_write(solo_dev, SOLO_IIC_CFG,
276 SOLO_IIC_PRESCALE(8) | SOLO_IIC_ENABLE);
278 solo_dev->i2c_id = -1;
279 solo_dev->i2c_state = IIC_STATE_IDLE;
280 init_waitqueue_head(&solo_dev->i2c_wait);
281 mutex_init(&solo_dev->i2c_mutex);
283 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
284 struct i2c_adapter *adap = &solo_dev->i2c_adap[i];
286 snprintf(adap->name, I2C_NAME_SIZE, "%s I2C %d",
288 adap->algo = &solo_i2c_algo;
289 adap->algo_data = solo_dev;
291 adap->dev.parent = &solo_dev->pdev->dev;
293 ret = i2c_add_adapter(adap);
295 adap->algo_data = NULL;
301 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
302 if (!solo_dev->i2c_adap[i].algo_data)
304 i2c_del_adapter(&solo_dev->i2c_adap[i]);
305 solo_dev->i2c_adap[i].algo_data = NULL;
313 void solo_i2c_exit(struct solo_dev *solo_dev)
317 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
318 if (!solo_dev->i2c_adap[i].algo_data)
320 i2c_del_adapter(&solo_dev->i2c_adap[i]);
321 solo_dev->i2c_adap[i].algo_data = NULL;