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8#include <linux/clk.h>
9#include <linux/interrupt.h>
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/of.h>
13#include <linux/of_device.h>
14#include <linux/platform_device.h>
15#include <linux/regmap.h>
16
17#include <media/cec.h>
18
19#define CEC_NAME "stm32-cec"
20
21
22#define CEC_CR 0x0000
23#define CEC_CFGR 0x0004
24#define CEC_TXDR 0x0008
25#define CEC_RXDR 0x000C
26#define CEC_ISR 0x0010
27#define CEC_IER 0x0014
28
29#define TXEOM BIT(2)
30#define TXSOM BIT(1)
31#define CECEN BIT(0)
32
33#define LSTN BIT(31)
34#define OAR GENMASK(30, 16)
35#define SFTOP BIT(8)
36#define BRDNOGEN BIT(7)
37#define LBPEGEN BIT(6)
38#define BREGEN BIT(5)
39#define BRESTP BIT(4)
40#define RXTOL BIT(3)
41#define SFT GENMASK(2, 0)
42#define FULL_CFG (LSTN | SFTOP | BRDNOGEN | LBPEGEN | BREGEN | BRESTP \
43 | RXTOL)
44
45#define TXACKE BIT(12)
46#define TXERR BIT(11)
47#define TXUDR BIT(10)
48#define TXEND BIT(9)
49#define TXBR BIT(8)
50#define ARBLST BIT(7)
51#define RXACKE BIT(6)
52#define RXOVR BIT(2)
53#define RXEND BIT(1)
54#define RXBR BIT(0)
55
56#define ALL_TX_IT (TXEND | TXBR | TXACKE | TXERR | TXUDR | ARBLST)
57#define ALL_RX_IT (RXEND | RXBR | RXACKE | RXOVR)
58
59
60
61
62
63
64#define CEC_XFER_TIMEOUT_MS (5 * 400 + 100)
65
66struct stm32_cec {
67 struct cec_adapter *adap;
68 struct device *dev;
69 struct clk *clk_cec;
70 struct clk *clk_hdmi_cec;
71 struct reset_control *rstc;
72 struct regmap *regmap;
73 int irq;
74 u32 irq_status;
75 struct cec_msg rx_msg;
76 struct cec_msg tx_msg;
77 int tx_cnt;
78};
79
80static void cec_hw_init(struct stm32_cec *cec)
81{
82 regmap_update_bits(cec->regmap, CEC_CR, TXEOM | TXSOM | CECEN, 0);
83
84 regmap_update_bits(cec->regmap, CEC_IER, ALL_TX_IT | ALL_RX_IT,
85 ALL_TX_IT | ALL_RX_IT);
86
87 regmap_update_bits(cec->regmap, CEC_CFGR, FULL_CFG, FULL_CFG);
88}
89
90static void stm32_tx_done(struct stm32_cec *cec, u32 status)
91{
92 if (status & (TXERR | TXUDR)) {
93 cec_transmit_done(cec->adap, CEC_TX_STATUS_ERROR,
94 0, 0, 0, 1);
95 return;
96 }
97
98 if (status & ARBLST) {
99 cec_transmit_done(cec->adap, CEC_TX_STATUS_ARB_LOST,
100 1, 0, 0, 0);
101 return;
102 }
103
104 if (status & TXACKE) {
105 cec_transmit_done(cec->adap, CEC_TX_STATUS_NACK,
106 0, 1, 0, 0);
107 return;
108 }
109
110 if (cec->irq_status & TXBR) {
111
112 if (cec->tx_cnt < cec->tx_msg.len)
113 regmap_write(cec->regmap, CEC_TXDR,
114 cec->tx_msg.msg[cec->tx_cnt++]);
115
116
117 if (cec->tx_cnt == cec->tx_msg.len)
118 regmap_update_bits(cec->regmap, CEC_CR, TXEOM, TXEOM);
119 }
120
121 if (cec->irq_status & TXEND)
122 cec_transmit_done(cec->adap, CEC_TX_STATUS_OK, 0, 0, 0, 0);
123}
124
125static void stm32_rx_done(struct stm32_cec *cec, u32 status)
126{
127 if (cec->irq_status & (RXACKE | RXOVR)) {
128 cec->rx_msg.len = 0;
129 return;
130 }
131
132 if (cec->irq_status & RXBR) {
133 u32 val;
134
135 regmap_read(cec->regmap, CEC_RXDR, &val);
136 cec->rx_msg.msg[cec->rx_msg.len++] = val & 0xFF;
137 }
138
139 if (cec->irq_status & RXEND) {
140 cec_received_msg(cec->adap, &cec->rx_msg);
141 cec->rx_msg.len = 0;
142 }
143}
144
145static irqreturn_t stm32_cec_irq_thread(int irq, void *arg)
146{
147 struct stm32_cec *cec = arg;
148
149 if (cec->irq_status & ALL_TX_IT)
150 stm32_tx_done(cec, cec->irq_status);
151
152 if (cec->irq_status & ALL_RX_IT)
153 stm32_rx_done(cec, cec->irq_status);
154
155 cec->irq_status = 0;
156
157 return IRQ_HANDLED;
158}
159
160static irqreturn_t stm32_cec_irq_handler(int irq, void *arg)
161{
162 struct stm32_cec *cec = arg;
163
164 regmap_read(cec->regmap, CEC_ISR, &cec->irq_status);
165
166 regmap_update_bits(cec->regmap, CEC_ISR,
167 ALL_TX_IT | ALL_RX_IT,
168 ALL_TX_IT | ALL_RX_IT);
169
170 return IRQ_WAKE_THREAD;
171}
172
173static int stm32_cec_adap_enable(struct cec_adapter *adap, bool enable)
174{
175 struct stm32_cec *cec = adap->priv;
176 int ret = 0;
177
178 if (enable) {
179 ret = clk_enable(cec->clk_cec);
180 if (ret)
181 dev_err(cec->dev, "fail to enable cec clock\n");
182
183 clk_enable(cec->clk_hdmi_cec);
184 regmap_update_bits(cec->regmap, CEC_CR, CECEN, CECEN);
185 } else {
186 clk_disable(cec->clk_cec);
187 clk_disable(cec->clk_hdmi_cec);
188 regmap_update_bits(cec->regmap, CEC_CR, CECEN, 0);
189 }
190
191 return ret;
192}
193
194static int stm32_cec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
195{
196 struct stm32_cec *cec = adap->priv;
197 u32 oar = (1 << logical_addr) << 16;
198 u32 val;
199
200
201 regmap_read_poll_timeout(cec->regmap, CEC_CR, val, !(val & TXSOM),
202 100, CEC_XFER_TIMEOUT_MS * 1000);
203 regmap_update_bits(cec->regmap, CEC_CR, CECEN, 0);
204
205 if (logical_addr == CEC_LOG_ADDR_INVALID)
206 regmap_update_bits(cec->regmap, CEC_CFGR, OAR, 0);
207 else
208 regmap_update_bits(cec->regmap, CEC_CFGR, oar, oar);
209
210 regmap_update_bits(cec->regmap, CEC_CR, CECEN, CECEN);
211
212 return 0;
213}
214
215static int stm32_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
216 u32 signal_free_time, struct cec_msg *msg)
217{
218 struct stm32_cec *cec = adap->priv;
219
220
221 cec->tx_msg = *msg;
222 cec->tx_cnt = 0;
223
224
225
226
227
228 if (cec->tx_msg.len == 1)
229 regmap_update_bits(cec->regmap, CEC_CR, TXEOM, TXEOM);
230
231
232 regmap_update_bits(cec->regmap, CEC_CR, TXSOM, TXSOM);
233
234
235 regmap_write(cec->regmap, CEC_TXDR, cec->tx_msg.msg[0]);
236 cec->tx_cnt++;
237
238 return 0;
239}
240
241static const struct cec_adap_ops stm32_cec_adap_ops = {
242 .adap_enable = stm32_cec_adap_enable,
243 .adap_log_addr = stm32_cec_adap_log_addr,
244 .adap_transmit = stm32_cec_adap_transmit,
245};
246
247static const struct regmap_config stm32_cec_regmap_cfg = {
248 .reg_bits = 32,
249 .val_bits = 32,
250 .reg_stride = sizeof(u32),
251 .max_register = 0x14,
252 .fast_io = true,
253};
254
255static int stm32_cec_probe(struct platform_device *pdev)
256{
257 u32 caps = CEC_CAP_DEFAULTS | CEC_CAP_PHYS_ADDR | CEC_MODE_MONITOR_ALL;
258 struct resource *res;
259 struct stm32_cec *cec;
260 void __iomem *mmio;
261 int ret;
262
263 cec = devm_kzalloc(&pdev->dev, sizeof(*cec), GFP_KERNEL);
264 if (!cec)
265 return -ENOMEM;
266
267 cec->dev = &pdev->dev;
268
269 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
270 mmio = devm_ioremap_resource(&pdev->dev, res);
271 if (IS_ERR(mmio))
272 return PTR_ERR(mmio);
273
274 cec->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "cec", mmio,
275 &stm32_cec_regmap_cfg);
276
277 if (IS_ERR(cec->regmap))
278 return PTR_ERR(cec->regmap);
279
280 cec->irq = platform_get_irq(pdev, 0);
281 if (cec->irq < 0)
282 return cec->irq;
283
284 ret = devm_request_threaded_irq(&pdev->dev, cec->irq,
285 stm32_cec_irq_handler,
286 stm32_cec_irq_thread,
287 0,
288 pdev->name, cec);
289 if (ret)
290 return ret;
291
292 cec->clk_cec = devm_clk_get(&pdev->dev, "cec");
293 if (IS_ERR(cec->clk_cec)) {
294 dev_err(&pdev->dev, "Cannot get cec clock\n");
295 return PTR_ERR(cec->clk_cec);
296 }
297
298 ret = clk_prepare(cec->clk_cec);
299 if (ret) {
300 dev_err(&pdev->dev, "Unable to prepare cec clock\n");
301 return ret;
302 }
303
304 cec->clk_hdmi_cec = devm_clk_get(&pdev->dev, "hdmi-cec");
305 if (!IS_ERR(cec->clk_hdmi_cec)) {
306 ret = clk_prepare(cec->clk_hdmi_cec);
307 if (ret) {
308 dev_err(&pdev->dev, "Unable to prepare hdmi-cec clock\n");
309 return ret;
310 }
311 }
312
313
314
315
316
317 cec->adap = cec_allocate_adapter(&stm32_cec_adap_ops, cec,
318 CEC_NAME, caps, CEC_MAX_LOG_ADDRS);
319 ret = PTR_ERR_OR_ZERO(cec->adap);
320 if (ret)
321 return ret;
322
323 ret = cec_register_adapter(cec->adap, &pdev->dev);
324 if (ret) {
325 cec_delete_adapter(cec->adap);
326 return ret;
327 }
328
329 cec_hw_init(cec);
330
331 platform_set_drvdata(pdev, cec);
332
333 return 0;
334}
335
336static int stm32_cec_remove(struct platform_device *pdev)
337{
338 struct stm32_cec *cec = platform_get_drvdata(pdev);
339
340 clk_unprepare(cec->clk_cec);
341 clk_unprepare(cec->clk_hdmi_cec);
342
343 cec_unregister_adapter(cec->adap);
344
345 return 0;
346}
347
348static const struct of_device_id stm32_cec_of_match[] = {
349 { .compatible = "st,stm32-cec" },
350 { }
351};
352MODULE_DEVICE_TABLE(of, stm32_cec_of_match);
353
354static struct platform_driver stm32_cec_driver = {
355 .probe = stm32_cec_probe,
356 .remove = stm32_cec_remove,
357 .driver = {
358 .name = CEC_NAME,
359 .of_match_table = stm32_cec_of_match,
360 },
361};
362
363module_platform_driver(stm32_cec_driver);
364
365MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
366MODULE_AUTHOR("Yannick Fertre <yannick.fertre@st.com>");
367MODULE_DESCRIPTION("STMicroelectronics STM32 Consumer Electronics Control");
368MODULE_LICENSE("GPL v2");
369
