2 * drivers/staging/media/st-cec/stih-cec.c
5 * Copyright (C) STMicroelectronic SA 2016
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 #include <linux/clk.h>
13 #include <linux/interrupt.h>
14 #include <linux/kernel.h>
15 #include <linux/mfd/syscon.h>
16 #include <linux/module.h>
18 #include <linux/platform_device.h>
20 #include <media/cec.h>
22 #define CEC_NAME "stih-cec"
25 #define CEC_CLK_DIV 0x0
27 #define CEC_IRQ_CTRL 0x8
28 #define CEC_STATUS 0xC
29 #define CEC_EXT_STATUS 0x10
30 #define CEC_TX_CTRL 0x14
31 #define CEC_FREE_TIME_THRESH 0x18
32 #define CEC_BIT_TOUT_THRESH 0x1C
33 #define CEC_BIT_PULSE_THRESH 0x20
35 #define CEC_TX_ARRAY_CTRL 0x28
36 #define CEC_CTRL2 0x2C
37 #define CEC_TX_ERROR_STS 0x30
38 #define CEC_ADDR_TABLE 0x34
39 #define CEC_DATA_ARRAY_CTRL 0x38
40 #define CEC_DATA_ARRAY_STATUS 0x3C
41 #define CEC_TX_DATA_BASE 0x40
42 #define CEC_TX_DATA_TOP 0x50
43 #define CEC_TX_DATA_SIZE 0x1
44 #define CEC_RX_DATA_BASE 0x54
45 #define CEC_RX_DATA_TOP 0x64
46 #define CEC_RX_DATA_SIZE 0x1
49 #define CEC_LINE_INACTIVE_EN BIT(0)
50 #define CEC_AUTO_BUS_ERR_EN BIT(1)
51 #define CEC_STOP_ON_ARB_ERR_EN BIT(2)
52 #define CEC_TX_REQ_WAIT_EN BIT(3)
54 /* CEC_DATA_ARRAY_CTRL */
55 #define CEC_TX_ARRAY_EN BIT(0)
56 #define CEC_RX_ARRAY_EN BIT(1)
57 #define CEC_TX_ARRAY_RESET BIT(2)
58 #define CEC_RX_ARRAY_RESET BIT(3)
59 #define CEC_TX_N_OF_BYTES_IRQ_EN BIT(4)
60 #define CEC_TX_STOP_ON_NACK BIT(7)
62 /* CEC_TX_ARRAY_CTRL */
63 #define CEC_TX_N_OF_BYTES 0x1F
64 #define CEC_TX_START BIT(5)
65 #define CEC_TX_AUTO_SOM_EN BIT(6)
66 #define CEC_TX_AUTO_EOM_EN BIT(7)
69 #define CEC_TX_DONE_IRQ_EN BIT(0)
70 #define CEC_ERROR_IRQ_EN BIT(2)
71 #define CEC_RX_DONE_IRQ_EN BIT(3)
72 #define CEC_RX_SOM_IRQ_EN BIT(4)
73 #define CEC_RX_EOM_IRQ_EN BIT(5)
74 #define CEC_FREE_TIME_IRQ_EN BIT(6)
75 #define CEC_PIN_STS_IRQ_EN BIT(7)
78 #define CEC_IN_FILTER_EN BIT(0)
79 #define CEC_PWR_SAVE_EN BIT(1)
81 #define CEC_ACK_CTRL BIT(5)
82 #define CEC_RX_RESET_EN BIT(6)
83 #define CEC_IGNORE_RX_ERROR BIT(7)
86 #define CEC_TX_DONE_STS BIT(0)
87 #define CEC_TX_ACK_GET_STS BIT(1)
88 #define CEC_ERROR_STS BIT(2)
89 #define CEC_RX_DONE_STS BIT(3)
90 #define CEC_RX_SOM_STS BIT(4)
91 #define CEC_RX_EOM_STS BIT(5)
92 #define CEC_FREE_TIME_IRQ_STS BIT(6)
93 #define CEC_PIN_STS BIT(7)
94 #define CEC_SBIT_TOUT_STS BIT(8)
95 #define CEC_DBIT_TOUT_STS BIT(9)
96 #define CEC_LPULSE_ERROR_STS BIT(10)
97 #define CEC_HPULSE_ERROR_STS BIT(11)
98 #define CEC_TX_ERROR BIT(12)
99 #define CEC_TX_ARB_ERROR BIT(13)
100 #define CEC_RX_ERROR_MIN BIT(14)
101 #define CEC_RX_ERROR_MAX BIT(15)
103 /* Signal free time in bit periods (2.4ms) */
104 #define CEC_PRESENT_INIT_SFT 7
105 #define CEC_NEW_INIT_SFT 5
106 #define CEC_RETRANSMIT_SFT 3
108 /* Constants for CEC_BIT_TOUT_THRESH register */
109 #define CEC_SBIT_TOUT_47MS BIT(1)
110 #define CEC_SBIT_TOUT_48MS (BIT(0) | BIT(1))
111 #define CEC_SBIT_TOUT_50MS BIT(2)
112 #define CEC_DBIT_TOUT_27MS BIT(0)
113 #define CEC_DBIT_TOUT_28MS BIT(1)
114 #define CEC_DBIT_TOUT_29MS (BIT(0) | BIT(1))
116 /* Constants for CEC_BIT_PULSE_THRESH register */
117 #define CEC_BIT_LPULSE_03MS BIT(1)
118 #define CEC_BIT_HPULSE_03MS BIT(3)
120 /* Constants for CEC_DATA_ARRAY_STATUS register */
121 #define CEC_RX_N_OF_BYTES 0x1F
122 #define CEC_TX_N_OF_BYTES_SENT BIT(5)
123 #define CEC_RX_OVERRUN BIT(6)
126 struct cec_adapter *adap;
134 static int stih_cec_adap_enable(struct cec_adapter *adap, bool enable)
136 struct stih_cec *cec = cec_get_drvdata(adap);
139 /* The doc says (input TCLK_PERIOD * CEC_CLK_DIV) = 0.1ms */
140 unsigned long clk_freq = clk_get_rate(cec->clk);
141 u32 cec_clk_div = clk_freq / 10000;
143 writel(cec_clk_div, cec->regs + CEC_CLK_DIV);
145 /* Configuration of the durations activating a timeout */
146 writel(CEC_SBIT_TOUT_47MS | (CEC_DBIT_TOUT_28MS << 4),
147 cec->regs + CEC_BIT_TOUT_THRESH);
149 /* Configuration of the smallest allowed duration for pulses */
150 writel(CEC_BIT_LPULSE_03MS | CEC_BIT_HPULSE_03MS,
151 cec->regs + CEC_BIT_PULSE_THRESH);
153 /* Minimum received bit period threshold */
154 writel(BIT(5) | BIT(7), cec->regs + CEC_TX_CTRL);
156 /* Configuration of transceiver data arrays */
157 writel(CEC_TX_ARRAY_EN | CEC_RX_ARRAY_EN | CEC_TX_STOP_ON_NACK,
158 cec->regs + CEC_DATA_ARRAY_CTRL);
160 /* Configuration of the control bits for CEC Transceiver */
161 writel(CEC_IN_FILTER_EN | CEC_EN | CEC_RX_RESET_EN,
162 cec->regs + CEC_CTRL);
164 /* Clear logical addresses */
165 writel(0, cec->regs + CEC_ADDR_TABLE);
167 /* Clear the status register */
168 writel(0x0, cec->regs + CEC_STATUS);
170 /* Enable the interrupts */
171 writel(CEC_TX_DONE_IRQ_EN | CEC_RX_DONE_IRQ_EN |
172 CEC_RX_SOM_IRQ_EN | CEC_RX_EOM_IRQ_EN |
174 cec->regs + CEC_IRQ_CTRL);
177 /* Clear logical addresses */
178 writel(0, cec->regs + CEC_ADDR_TABLE);
180 /* Clear the status register */
181 writel(0x0, cec->regs + CEC_STATUS);
183 /* Disable the interrupts */
184 writel(0, cec->regs + CEC_IRQ_CTRL);
190 static int stih_cec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
192 struct stih_cec *cec = cec_get_drvdata(adap);
193 u32 reg = readl(cec->regs + CEC_ADDR_TABLE);
195 reg |= 1 << logical_addr;
197 if (logical_addr == CEC_LOG_ADDR_INVALID)
200 writel(reg, cec->regs + CEC_ADDR_TABLE);
205 static int stih_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
206 u32 signal_free_time, struct cec_msg *msg)
208 struct stih_cec *cec = cec_get_drvdata(adap);
211 /* Copy message into registers */
212 for (i = 0; i < msg->len; i++)
213 writeb(msg->msg[i], cec->regs + CEC_TX_DATA_BASE + i);
215 /* Start transmission, configure hardware to add start and stop bits
216 * Signal free time is handled by the hardware
218 writel(CEC_TX_AUTO_SOM_EN | CEC_TX_AUTO_EOM_EN | CEC_TX_START |
219 msg->len, cec->regs + CEC_TX_ARRAY_CTRL);
224 static void stih_tx_done(struct stih_cec *cec, u32 status)
226 if (status & CEC_TX_ERROR) {
227 cec_transmit_done(cec->adap, CEC_TX_STATUS_ERROR, 0, 0, 0, 1);
231 if (status & CEC_TX_ARB_ERROR) {
232 cec_transmit_done(cec->adap,
233 CEC_TX_STATUS_ARB_LOST, 1, 0, 0, 0);
237 if (!(status & CEC_TX_ACK_GET_STS)) {
238 cec_transmit_done(cec->adap, CEC_TX_STATUS_NACK, 0, 1, 0, 0);
242 cec_transmit_done(cec->adap, CEC_TX_STATUS_OK, 0, 0, 0, 0);
245 static void stih_rx_done(struct stih_cec *cec, u32 status)
247 struct cec_msg msg = {};
250 if (status & CEC_RX_ERROR_MIN)
253 if (status & CEC_RX_ERROR_MAX)
256 msg.len = readl(cec->regs + CEC_DATA_ARRAY_STATUS) & 0x1f;
264 for (i = 0; i < msg.len; i++)
265 msg.msg[i] = readl(cec->regs + CEC_RX_DATA_BASE + i);
267 cec_received_msg(cec->adap, &msg);
270 static irqreturn_t stih_cec_irq_handler_thread(int irq, void *priv)
272 struct stih_cec *cec = priv;
274 if (cec->irq_status & CEC_TX_DONE_STS)
275 stih_tx_done(cec, cec->irq_status);
277 if (cec->irq_status & CEC_RX_DONE_STS)
278 stih_rx_done(cec, cec->irq_status);
285 static irqreturn_t stih_cec_irq_handler(int irq, void *priv)
287 struct stih_cec *cec = priv;
289 cec->irq_status = readl(cec->regs + CEC_STATUS);
290 writel(cec->irq_status, cec->regs + CEC_STATUS);
292 return IRQ_WAKE_THREAD;
295 static const struct cec_adap_ops sti_cec_adap_ops = {
296 .adap_enable = stih_cec_adap_enable,
297 .adap_log_addr = stih_cec_adap_log_addr,
298 .adap_transmit = stih_cec_adap_transmit,
301 static int stih_cec_probe(struct platform_device *pdev)
303 struct device *dev = &pdev->dev;
304 struct resource *res;
305 struct stih_cec *cec;
308 cec = devm_kzalloc(dev, sizeof(*cec), GFP_KERNEL);
314 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
315 cec->regs = devm_ioremap_resource(dev, res);
316 if (IS_ERR(cec->regs))
317 return PTR_ERR(cec->regs);
319 cec->irq = platform_get_irq(pdev, 0);
323 ret = devm_request_threaded_irq(dev, cec->irq, stih_cec_irq_handler,
324 stih_cec_irq_handler_thread, 0,
329 cec->clk = devm_clk_get(dev, "cec-clk");
330 if (IS_ERR(cec->clk)) {
331 dev_err(dev, "Cannot get cec clock\n");
332 return PTR_ERR(cec->clk);
335 cec->adap = cec_allocate_adapter(&sti_cec_adap_ops, cec,
337 CEC_CAP_LOG_ADDRS | CEC_CAP_PASSTHROUGH |
338 CEC_CAP_PHYS_ADDR | CEC_CAP_TRANSMIT, 1);
339 ret = PTR_ERR_OR_ZERO(cec->adap);
343 ret = cec_register_adapter(cec->adap, &pdev->dev);
345 cec_delete_adapter(cec->adap);
349 platform_set_drvdata(pdev, cec);
353 static int stih_cec_remove(struct platform_device *pdev)
358 static const struct of_device_id stih_cec_match[] = {
360 .compatible = "st,stih-cec",
364 MODULE_DEVICE_TABLE(of, stih_cec_match);
366 static struct platform_driver stih_cec_pdrv = {
367 .probe = stih_cec_probe,
368 .remove = stih_cec_remove,
371 .of_match_table = stih_cec_match,
375 module_platform_driver(stih_cec_pdrv);
377 MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@linaro.org>");
378 MODULE_LICENSE("GPL");
379 MODULE_DESCRIPTION("STIH4xx CEC driver");