i2c/busses/i2c-digicolor.c

13 #include <linux/i2c.h>
71 static void dc_i2c_cmd(struct dc_i2c *i2c, u8 cmd)
73 	writeb_relaxed(cmd | II_COMMAND_GO, i2c->regs + II_COMMAND);
86 static void dc_i2c_data(struct dc_i2c *i2c, u8 data)
88 	writeb_relaxed(data, i2c->regs + II_DATA);
91 static void dc_i2c_write_byte(struct dc_i2c *i2c, u8 byte)
93 	dc_i2c_data(i2c, byte);
94 	dc_i2c_cmd(i2c, II_CMD_SEND_ACK);
97 static void dc_i2c_write_buf(struct dc_i2c *i2c)
99 	dc_i2c_write_byte(i2c, i2c->msg->buf[i2c->msgbuf_ptr++]);
102 static void dc_i2c_next_read(struct dc_i2c *i2c)
104 	bool last = (i2c->msgbuf_ptr + 1 == i2c->msg->len);
106 	dc_i2c_cmd(i2c, last ? II_CMD_GET_NOACK : II_CMD_GET_ACK);
109 static void dc_i2c_stop(struct dc_i2c *i2c)
111 	i2c->state = STATE_STOP;
112 	if (i2c->last)
113 		dc_i2c_cmd(i2c, II_CMD_STOP);
115 		complete(&i2c->done);
118 static u8 dc_i2c_read_byte(struct dc_i2c *i2c)
120 	return readb_relaxed(i2c->regs + II_DATA);
123 static void dc_i2c_read_buf(struct dc_i2c *i2c)
125 	i2c->msg->buf[i2c->msgbuf_ptr++] = dc_i2c_read_byte(i2c);
126 	dc_i2c_next_read(i2c);
129 static void dc_i2c_set_irq(struct dc_i2c *i2c, int enable)
132 		writeb_relaxed(1, i2c->regs + II_INTFLAG_CLEAR);
133 	writeb_relaxed(!!enable, i2c->regs + II_INTENABLE);
136 static int dc_i2c_cmd_status(struct dc_i2c *i2c)
138 	u8 cmd = readb_relaxed(i2c->regs + II_COMMAND);
143 static void dc_i2c_start_msg(struct dc_i2c *i2c, int first)
145 	struct i2c_msg *msg = i2c->msg;
148 		i2c->state = STATE_START;
149 		dc_i2c_cmd(i2c, first ? II_CMD_START : II_CMD_RESTART);
151 		i2c->state = STATE_READ;
152 		dc_i2c_next_read(i2c);
154 		i2c->state = STATE_WRITE;
155 		dc_i2c_write_buf(i2c);
161 	struct dc_i2c *i2c = dev_id;
162 	int cmd_status = dc_i2c_cmd_status(i2c);
165 	writeb_relaxed(1, i2c->regs + II_INTFLAG_CLEAR);
167 	spin_lock(&i2c->lock);
171 		i2c->error = -EIO;
172 		complete(&i2c->done);
176 	switch (i2c->state) {
178 		addr_cmd = dc_i2c_addr_cmd(i2c->msg);
179 		dc_i2c_write_byte(i2c, addr_cmd);
180 		i2c->state = STATE_ADDR;
183 		if (i2c->msg->flags & I2C_M_RD) {
184 			dc_i2c_next_read(i2c);
185 			i2c->state = STATE_READ;
188 		i2c->state = STATE_WRITE;
191 		if (i2c->msgbuf_ptr < i2c->msg->len)
192 			dc_i2c_write_buf(i2c);
194 			dc_i2c_stop(i2c);
197 		if (i2c->msgbuf_ptr < i2c->msg->len)
198 			dc_i2c_read_buf(i2c);
200 			dc_i2c_stop(i2c);
203 		i2c->state = STATE_IDLE;
204 		complete(&i2c->done);
209 	spin_unlock(&i2c->lock);
213 static int dc_i2c_xfer_msg(struct dc_i2c *i2c, struct i2c_msg *msg, int first,
219 	spin_lock_irqsave(&i2c->lock, flags);
220 	i2c->msg = msg;
221 	i2c->msgbuf_ptr = 0;
222 	i2c->last = last;
223 	i2c->error = 0;
225 	reinit_completion(&i2c->done);
226 	dc_i2c_set_irq(i2c, 1);
227 	dc_i2c_start_msg(i2c, first);
228 	spin_unlock_irqrestore(&i2c->lock, flags);
230 	timeout = wait_for_completion_timeout(&i2c->done, timeout);
231 	dc_i2c_set_irq(i2c, 0);
233 		i2c->state = STATE_IDLE;
237 	if (i2c->error)
238 		return i2c->error;
245 	struct dc_i2c *i2c = adap->algo_data;
249 		ret = dc_i2c_xfer_msg(i2c, &msgs[i], i == 0, i == num - 1);
257 static int dc_i2c_init_hw(struct dc_i2c *i2c)
259 	unsigned long clk_rate = clk_get_rate(i2c->clk);
262 	writeb_relaxed(II_CONTROL_LOCAL_RESET, i2c->regs + II_CONTROL);
264 	writeb_relaxed(0, i2c->regs + II_CONTROL);
267 	clocktime = DIV_ROUND_UP(clk_rate, 64 * i2c->frequency);
269 		dev_err(i2c->dev, "can't set bus speed of %u Hz\n",
270 			i2c->frequency);
273 	writeb_relaxed(clocktime - 1, i2c->regs + II_CLOCKTIME);
291 	struct dc_i2c *i2c;
294 	i2c = devm_kzalloc(&pdev->dev, sizeof(struct dc_i2c), GFP_KERNEL);
295 	if (!i2c)
299 				 &i2c->frequency))
300 		i2c->frequency = I2C_MAX_STANDARD_MODE_FREQ;
302 	i2c->dev = &pdev->dev;
303 	platform_set_drvdata(pdev, i2c);
305 	spin_lock_init(&i2c->lock);
306 	init_completion(&i2c->done);
308 	i2c->clk = devm_clk_get(&pdev->dev, NULL);
309 	if (IS_ERR(i2c->clk))
310 		return PTR_ERR(i2c->clk);
312 	i2c->regs = devm_platform_ioremap_resource(pdev, 0);
313 	if (IS_ERR(i2c->regs))
314 		return PTR_ERR(i2c->regs);
321 			       dev_name(&pdev->dev), i2c);
325 	strscpy(i2c->adap.name, "Conexant Digicolor I2C adapter",
326 		sizeof(i2c->adap.name));
327 	i2c->adap.owner = THIS_MODULE;
328 	i2c->adap.algo = &dc_i2c_algorithm;
329 	i2c->adap.dev.parent = &pdev->dev;
330 	i2c->adap.dev.of_node = np;
331 	i2c->adap.algo_data = i2c;
333 	ret = dc_i2c_init_hw(i2c);
337 	ret = clk_prepare_enable(i2c->clk);
341 	ret = i2c_add_adapter(&i2c->adap);
343 		clk_disable_unprepare(i2c->clk);
352 	struct dc_i2c *i2c = platform_get_drvdata(pdev);
354 	i2c_del_adapter(&i2c->adap);
355 	clk_disable_unprepare(i2c->clk);
359 	{ .compatible = "cnxt,cx92755-i2c" },
368 		.name  = "digicolor-i2c",