1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
4  *
5  *  Copyright (C) 2011 Weinmann Medical GmbH
6  *  Author: Nikolaus Voss <n.voss@weinmann.de>
7  *
8  *  Evolved from original work by:
9  *  Copyright (C) 2004 Rick Bronson
10  *  Converted to 2.6 by Andrew Victor <andrew@sanpeople.com>
11  *
12  *  Borrowed heavily from original work by:
13  *  Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
14  */
15 
16 #include <linux/clk.h>
17 #include <linux/err.h>
18 #include <linux/i2c.h>
19 #include <linux/io.h>
20 #include <linux/module.h>
21 #include <linux/of.h>
22 #include <linux/of_device.h>
23 #include <linux/platform_device.h>
24 #include <linux/pm_runtime.h>
25 #include <linux/pinctrl/consumer.h>
26 
27 #include "i2c-at91.h"
28 
29 unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
30 {
31 	return readl_relaxed(dev->base + reg);
32 }
33 
34 void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
35 {
36 	writel_relaxed(val, dev->base + reg);
37 }
38 
39 void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
40 {
41 	at91_twi_write(dev, AT91_TWI_IDR, AT91_TWI_INT_MASK);
42 }
43 
44 void at91_twi_irq_save(struct at91_twi_dev *dev)
45 {
46 	dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & AT91_TWI_INT_MASK;
47 	at91_disable_twi_interrupts(dev);
48 }
49 
50 void at91_twi_irq_restore(struct at91_twi_dev *dev)
51 {
52 	at91_twi_write(dev, AT91_TWI_IER, dev->imr);
53 }
54 
55 void at91_init_twi_bus(struct at91_twi_dev *dev)
56 {
57 	at91_disable_twi_interrupts(dev);
58 	at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
59 	if (dev->slave_detected)
60 		at91_init_twi_bus_slave(dev);
61 	else
62 		at91_init_twi_bus_master(dev);
63 }
64 
65 static struct at91_twi_pdata at91rm9200_config = {
66 	.clk_max_div = 5,
67 	.clk_offset = 3,
68 	.has_unre_flag = true,
69 	.has_alt_cmd = false,
70 	.has_hold_field = false,
71 	.has_dig_filtr = false,
72 	.has_adv_dig_filtr = false,
73 	.has_ana_filtr = false,
74 };
75 
76 static struct at91_twi_pdata at91sam9261_config = {
77 	.clk_max_div = 5,
78 	.clk_offset = 4,
79 	.has_unre_flag = false,
80 	.has_alt_cmd = false,
81 	.has_hold_field = false,
82 	.has_dig_filtr = false,
83 	.has_adv_dig_filtr = false,
84 	.has_ana_filtr = false,
85 };
86 
87 static struct at91_twi_pdata at91sam9260_config = {
88 	.clk_max_div = 7,
89 	.clk_offset = 4,
90 	.has_unre_flag = false,
91 	.has_alt_cmd = false,
92 	.has_hold_field = false,
93 	.has_dig_filtr = false,
94 	.has_adv_dig_filtr = false,
95 	.has_ana_filtr = false,
96 };
97 
98 static struct at91_twi_pdata at91sam9g20_config = {
99 	.clk_max_div = 7,
100 	.clk_offset = 4,
101 	.has_unre_flag = false,
102 	.has_alt_cmd = false,
103 	.has_hold_field = false,
104 	.has_dig_filtr = false,
105 	.has_adv_dig_filtr = false,
106 	.has_ana_filtr = false,
107 };
108 
109 static struct at91_twi_pdata at91sam9g10_config = {
110 	.clk_max_div = 7,
111 	.clk_offset = 4,
112 	.has_unre_flag = false,
113 	.has_alt_cmd = false,
114 	.has_hold_field = false,
115 	.has_dig_filtr = false,
116 	.has_adv_dig_filtr = false,
117 	.has_ana_filtr = false,
118 };
119 
120 static const struct platform_device_id at91_twi_devtypes[] = {
121 	{
122 		.name = "i2c-at91rm9200",
123 		.driver_data = (unsigned long) &at91rm9200_config,
124 	}, {
125 		.name = "i2c-at91sam9261",
126 		.driver_data = (unsigned long) &at91sam9261_config,
127 	}, {
128 		.name = "i2c-at91sam9260",
129 		.driver_data = (unsigned long) &at91sam9260_config,
130 	}, {
131 		.name = "i2c-at91sam9g20",
132 		.driver_data = (unsigned long) &at91sam9g20_config,
133 	}, {
134 		.name = "i2c-at91sam9g10",
135 		.driver_data = (unsigned long) &at91sam9g10_config,
136 	}, {
137 		/* sentinel */
138 	}
139 };
140 
141 #if defined(CONFIG_OF)
142 static struct at91_twi_pdata at91sam9x5_config = {
143 	.clk_max_div = 7,
144 	.clk_offset = 4,
145 	.has_unre_flag = false,
146 	.has_alt_cmd = false,
147 	.has_hold_field = false,
148 	.has_dig_filtr = false,
149 	.has_adv_dig_filtr = false,
150 	.has_ana_filtr = false,
151 };
152 
153 static struct at91_twi_pdata sama5d4_config = {
154 	.clk_max_div = 7,
155 	.clk_offset = 4,
156 	.has_unre_flag = false,
157 	.has_alt_cmd = false,
158 	.has_hold_field = true,
159 	.has_dig_filtr = true,
160 	.has_adv_dig_filtr = false,
161 	.has_ana_filtr = false,
162 };
163 
164 static struct at91_twi_pdata sama5d2_config = {
165 	.clk_max_div = 7,
166 	.clk_offset = 3,
167 	.has_unre_flag = true,
168 	.has_alt_cmd = true,
169 	.has_hold_field = true,
170 	.has_dig_filtr = true,
171 	.has_adv_dig_filtr = true,
172 	.has_ana_filtr = true,
173 };
174 
175 static struct at91_twi_pdata sam9x60_config = {
176 	.clk_max_div = 7,
177 	.clk_offset = 3,
178 	.has_unre_flag = true,
179 	.has_alt_cmd = true,
180 	.has_hold_field = true,
181 	.has_dig_filtr = true,
182 	.has_adv_dig_filtr = true,
183 	.has_ana_filtr = true,
184 };
185 
186 static const struct of_device_id atmel_twi_dt_ids[] = {
187 	{
188 		.compatible = "atmel,at91rm9200-i2c",
189 		.data = &at91rm9200_config,
190 	}, {
191 		.compatible = "atmel,at91sam9260-i2c",
192 		.data = &at91sam9260_config,
193 	}, {
194 		.compatible = "atmel,at91sam9261-i2c",
195 		.data = &at91sam9261_config,
196 	}, {
197 		.compatible = "atmel,at91sam9g20-i2c",
198 		.data = &at91sam9g20_config,
199 	}, {
200 		.compatible = "atmel,at91sam9g10-i2c",
201 		.data = &at91sam9g10_config,
202 	}, {
203 		.compatible = "atmel,at91sam9x5-i2c",
204 		.data = &at91sam9x5_config,
205 	}, {
206 		.compatible = "atmel,sama5d4-i2c",
207 		.data = &sama5d4_config,
208 	}, {
209 		.compatible = "atmel,sama5d2-i2c",
210 		.data = &sama5d2_config,
211 	}, {
212 		.compatible = "microchip,sam9x60-i2c",
213 		.data = &sam9x60_config,
214 	}, {
215 		/* sentinel */
216 	}
217 };
218 MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
219 #endif
220 
221 static struct at91_twi_pdata *at91_twi_get_driver_data(
222 					struct platform_device *pdev)
223 {
224 	if (pdev->dev.of_node) {
225 		const struct of_device_id *match;
226 		match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node);
227 		if (!match)
228 			return NULL;
229 		return (struct at91_twi_pdata *)match->data;
230 	}
231 	return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
232 }
233 
234 static int at91_twi_probe(struct platform_device *pdev)
235 {
236 	struct at91_twi_dev *dev;
237 	struct resource *mem;
238 	int rc;
239 	u32 phy_addr;
240 
241 	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
242 	if (!dev)
243 		return -ENOMEM;
244 
245 	dev->dev = &pdev->dev;
246 
247 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
248 	if (!mem)
249 		return -ENODEV;
250 	phy_addr = mem->start;
251 
252 	dev->pdata = at91_twi_get_driver_data(pdev);
253 	if (!dev->pdata)
254 		return -ENODEV;
255 
256 	dev->base = devm_ioremap_resource(&pdev->dev, mem);
257 	if (IS_ERR(dev->base))
258 		return PTR_ERR(dev->base);
259 
260 	dev->irq = platform_get_irq(pdev, 0);
261 	if (dev->irq < 0)
262 		return dev->irq;
263 
264 	platform_set_drvdata(pdev, dev);
265 
266 	dev->clk = devm_clk_get(dev->dev, NULL);
267 	if (IS_ERR(dev->clk)) {
268 		dev_err(dev->dev, "no clock defined\n");
269 		return -ENODEV;
270 	}
271 	clk_prepare_enable(dev->clk);
272 
273 	snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
274 	i2c_set_adapdata(&dev->adapter, dev);
275 	dev->adapter.owner = THIS_MODULE;
276 	dev->adapter.class = I2C_CLASS_DEPRECATED;
277 	dev->adapter.dev.parent = dev->dev;
278 	dev->adapter.nr = pdev->id;
279 	dev->adapter.timeout = AT91_I2C_TIMEOUT;
280 	dev->adapter.dev.of_node = pdev->dev.of_node;
281 
282 	dev->slave_detected = i2c_detect_slave_mode(&pdev->dev);
283 
284 	if (dev->slave_detected)
285 		rc = at91_twi_probe_slave(pdev, phy_addr, dev);
286 	else
287 		rc = at91_twi_probe_master(pdev, phy_addr, dev);
288 	if (rc)
289 		return rc;
290 
291 	at91_init_twi_bus(dev);
292 
293 	pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
294 	pm_runtime_use_autosuspend(dev->dev);
295 	pm_runtime_set_active(dev->dev);
296 	pm_runtime_enable(dev->dev);
297 
298 	rc = i2c_add_numbered_adapter(&dev->adapter);
299 	if (rc) {
300 		clk_disable_unprepare(dev->clk);
301 
302 		pm_runtime_disable(dev->dev);
303 		pm_runtime_set_suspended(dev->dev);
304 
305 		return rc;
306 	}
307 
308 	dev_info(dev->dev, "AT91 i2c bus driver (hw version: %#x).\n",
309 		 at91_twi_read(dev, AT91_TWI_VER));
310 	return 0;
311 }
312 
313 static int at91_twi_remove(struct platform_device *pdev)
314 {
315 	struct at91_twi_dev *dev = platform_get_drvdata(pdev);
316 
317 	i2c_del_adapter(&dev->adapter);
318 	clk_disable_unprepare(dev->clk);
319 
320 	pm_runtime_disable(dev->dev);
321 	pm_runtime_set_suspended(dev->dev);
322 
323 	return 0;
324 }
325 
326 #ifdef CONFIG_PM
327 
328 static int at91_twi_runtime_suspend(struct device *dev)
329 {
330 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
331 
332 	clk_disable_unprepare(twi_dev->clk);
333 
334 	pinctrl_pm_select_sleep_state(dev);
335 
336 	return 0;
337 }
338 
339 static int at91_twi_runtime_resume(struct device *dev)
340 {
341 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
342 
343 	pinctrl_pm_select_default_state(dev);
344 
345 	return clk_prepare_enable(twi_dev->clk);
346 }
347 
348 static int at91_twi_suspend_noirq(struct device *dev)
349 {
350 	if (!pm_runtime_status_suspended(dev))
351 		at91_twi_runtime_suspend(dev);
352 
353 	return 0;
354 }
355 
356 static int at91_twi_resume_noirq(struct device *dev)
357 {
358 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
359 	int ret;
360 
361 	if (!pm_runtime_status_suspended(dev)) {
362 		ret = at91_twi_runtime_resume(dev);
363 		if (ret)
364 			return ret;
365 	}
366 
367 	pm_runtime_mark_last_busy(dev);
368 	pm_request_autosuspend(dev);
369 
370 	at91_init_twi_bus(twi_dev);
371 
372 	return 0;
373 }
374 
375 static const struct dev_pm_ops at91_twi_pm = {
376 	.suspend_noirq	= at91_twi_suspend_noirq,
377 	.resume_noirq	= at91_twi_resume_noirq,
378 	.runtime_suspend	= at91_twi_runtime_suspend,
379 	.runtime_resume		= at91_twi_runtime_resume,
380 };
381 
382 #define at91_twi_pm_ops (&at91_twi_pm)
383 #else
384 #define at91_twi_pm_ops NULL
385 #endif
386 
387 static struct platform_driver at91_twi_driver = {
388 	.probe		= at91_twi_probe,
389 	.remove		= at91_twi_remove,
390 	.id_table	= at91_twi_devtypes,
391 	.driver		= {
392 		.name	= "at91_i2c",
393 		.of_match_table = of_match_ptr(atmel_twi_dt_ids),
394 		.pm	= at91_twi_pm_ops,
395 	},
396 };
397 
398 static int __init at91_twi_init(void)
399 {
400 	return platform_driver_register(&at91_twi_driver);
401 }
402 
403 static void __exit at91_twi_exit(void)
404 {
405 	platform_driver_unregister(&at91_twi_driver);
406 }
407 
408 subsys_initcall(at91_twi_init);
409 module_exit(at91_twi_exit);
410 
411 MODULE_AUTHOR("Nikolaus Voss <n.voss@weinmann.de>");
412 MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
413 MODULE_LICENSE("GPL");
414 MODULE_ALIAS("platform:at91_i2c");
415