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 };
72 
73 static struct at91_twi_pdata at91sam9261_config = {
74 	.clk_max_div = 5,
75 	.clk_offset = 4,
76 	.has_unre_flag = false,
77 	.has_alt_cmd = false,
78 	.has_hold_field = false,
79 };
80 
81 static struct at91_twi_pdata at91sam9260_config = {
82 	.clk_max_div = 7,
83 	.clk_offset = 4,
84 	.has_unre_flag = false,
85 	.has_alt_cmd = false,
86 	.has_hold_field = false,
87 };
88 
89 static struct at91_twi_pdata at91sam9g20_config = {
90 	.clk_max_div = 7,
91 	.clk_offset = 4,
92 	.has_unre_flag = false,
93 	.has_alt_cmd = false,
94 	.has_hold_field = false,
95 };
96 
97 static struct at91_twi_pdata at91sam9g10_config = {
98 	.clk_max_div = 7,
99 	.clk_offset = 4,
100 	.has_unre_flag = false,
101 	.has_alt_cmd = false,
102 	.has_hold_field = false,
103 };
104 
105 static const struct platform_device_id at91_twi_devtypes[] = {
106 	{
107 		.name = "i2c-at91rm9200",
108 		.driver_data = (unsigned long) &at91rm9200_config,
109 	}, {
110 		.name = "i2c-at91sam9261",
111 		.driver_data = (unsigned long) &at91sam9261_config,
112 	}, {
113 		.name = "i2c-at91sam9260",
114 		.driver_data = (unsigned long) &at91sam9260_config,
115 	}, {
116 		.name = "i2c-at91sam9g20",
117 		.driver_data = (unsigned long) &at91sam9g20_config,
118 	}, {
119 		.name = "i2c-at91sam9g10",
120 		.driver_data = (unsigned long) &at91sam9g10_config,
121 	}, {
122 		/* sentinel */
123 	}
124 };
125 
126 #if defined(CONFIG_OF)
127 static struct at91_twi_pdata at91sam9x5_config = {
128 	.clk_max_div = 7,
129 	.clk_offset = 4,
130 	.has_unre_flag = false,
131 	.has_alt_cmd = false,
132 	.has_hold_field = false,
133 };
134 
135 static struct at91_twi_pdata sama5d4_config = {
136 	.clk_max_div = 7,
137 	.clk_offset = 4,
138 	.has_unre_flag = false,
139 	.has_alt_cmd = false,
140 	.has_hold_field = true,
141 };
142 
143 static struct at91_twi_pdata sama5d2_config = {
144 	.clk_max_div = 7,
145 	.clk_offset = 3,
146 	.has_unre_flag = true,
147 	.has_alt_cmd = true,
148 	.has_hold_field = true,
149 };
150 
151 static const struct of_device_id atmel_twi_dt_ids[] = {
152 	{
153 		.compatible = "atmel,at91rm9200-i2c",
154 		.data = &at91rm9200_config,
155 	}, {
156 		.compatible = "atmel,at91sam9260-i2c",
157 		.data = &at91sam9260_config,
158 	}, {
159 		.compatible = "atmel,at91sam9261-i2c",
160 		.data = &at91sam9261_config,
161 	}, {
162 		.compatible = "atmel,at91sam9g20-i2c",
163 		.data = &at91sam9g20_config,
164 	}, {
165 		.compatible = "atmel,at91sam9g10-i2c",
166 		.data = &at91sam9g10_config,
167 	}, {
168 		.compatible = "atmel,at91sam9x5-i2c",
169 		.data = &at91sam9x5_config,
170 	}, {
171 		.compatible = "atmel,sama5d4-i2c",
172 		.data = &sama5d4_config,
173 	}, {
174 		.compatible = "atmel,sama5d2-i2c",
175 		.data = &sama5d2_config,
176 	}, {
177 		/* sentinel */
178 	}
179 };
180 MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
181 #endif
182 
183 static struct at91_twi_pdata *at91_twi_get_driver_data(
184 					struct platform_device *pdev)
185 {
186 	if (pdev->dev.of_node) {
187 		const struct of_device_id *match;
188 		match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node);
189 		if (!match)
190 			return NULL;
191 		return (struct at91_twi_pdata *)match->data;
192 	}
193 	return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
194 }
195 
196 static int at91_twi_probe(struct platform_device *pdev)
197 {
198 	struct at91_twi_dev *dev;
199 	struct resource *mem;
200 	int rc;
201 	u32 phy_addr;
202 
203 	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
204 	if (!dev)
205 		return -ENOMEM;
206 
207 	dev->dev = &pdev->dev;
208 
209 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
210 	if (!mem)
211 		return -ENODEV;
212 	phy_addr = mem->start;
213 
214 	dev->pdata = at91_twi_get_driver_data(pdev);
215 	if (!dev->pdata)
216 		return -ENODEV;
217 
218 	dev->base = devm_ioremap_resource(&pdev->dev, mem);
219 	if (IS_ERR(dev->base))
220 		return PTR_ERR(dev->base);
221 
222 	dev->irq = platform_get_irq(pdev, 0);
223 	if (dev->irq < 0)
224 		return dev->irq;
225 
226 	platform_set_drvdata(pdev, dev);
227 
228 	dev->clk = devm_clk_get(dev->dev, NULL);
229 	if (IS_ERR(dev->clk)) {
230 		dev_err(dev->dev, "no clock defined\n");
231 		return -ENODEV;
232 	}
233 	clk_prepare_enable(dev->clk);
234 
235 	snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
236 	i2c_set_adapdata(&dev->adapter, dev);
237 	dev->adapter.owner = THIS_MODULE;
238 	dev->adapter.class = I2C_CLASS_DEPRECATED;
239 	dev->adapter.dev.parent = dev->dev;
240 	dev->adapter.nr = pdev->id;
241 	dev->adapter.timeout = AT91_I2C_TIMEOUT;
242 	dev->adapter.dev.of_node = pdev->dev.of_node;
243 
244 	dev->slave_detected = i2c_detect_slave_mode(&pdev->dev);
245 
246 	if (dev->slave_detected)
247 		rc = at91_twi_probe_slave(pdev, phy_addr, dev);
248 	else
249 		rc = at91_twi_probe_master(pdev, phy_addr, dev);
250 	if (rc)
251 		return rc;
252 
253 	at91_init_twi_bus(dev);
254 
255 	pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
256 	pm_runtime_use_autosuspend(dev->dev);
257 	pm_runtime_set_active(dev->dev);
258 	pm_runtime_enable(dev->dev);
259 
260 	rc = i2c_add_numbered_adapter(&dev->adapter);
261 	if (rc) {
262 		clk_disable_unprepare(dev->clk);
263 
264 		pm_runtime_disable(dev->dev);
265 		pm_runtime_set_suspended(dev->dev);
266 
267 		return rc;
268 	}
269 
270 	dev_info(dev->dev, "AT91 i2c bus driver (hw version: %#x).\n",
271 		 at91_twi_read(dev, AT91_TWI_VER));
272 	return 0;
273 }
274 
275 static int at91_twi_remove(struct platform_device *pdev)
276 {
277 	struct at91_twi_dev *dev = platform_get_drvdata(pdev);
278 
279 	i2c_del_adapter(&dev->adapter);
280 	clk_disable_unprepare(dev->clk);
281 
282 	pm_runtime_disable(dev->dev);
283 	pm_runtime_set_suspended(dev->dev);
284 
285 	return 0;
286 }
287 
288 #ifdef CONFIG_PM
289 
290 static int at91_twi_runtime_suspend(struct device *dev)
291 {
292 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
293 
294 	clk_disable_unprepare(twi_dev->clk);
295 
296 	pinctrl_pm_select_sleep_state(dev);
297 
298 	return 0;
299 }
300 
301 static int at91_twi_runtime_resume(struct device *dev)
302 {
303 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
304 
305 	pinctrl_pm_select_default_state(dev);
306 
307 	return clk_prepare_enable(twi_dev->clk);
308 }
309 
310 static int at91_twi_suspend_noirq(struct device *dev)
311 {
312 	if (!pm_runtime_status_suspended(dev))
313 		at91_twi_runtime_suspend(dev);
314 
315 	return 0;
316 }
317 
318 static int at91_twi_resume_noirq(struct device *dev)
319 {
320 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
321 	int ret;
322 
323 	if (!pm_runtime_status_suspended(dev)) {
324 		ret = at91_twi_runtime_resume(dev);
325 		if (ret)
326 			return ret;
327 	}
328 
329 	pm_runtime_mark_last_busy(dev);
330 	pm_request_autosuspend(dev);
331 
332 	at91_init_twi_bus(twi_dev);
333 
334 	return 0;
335 }
336 
337 static const struct dev_pm_ops at91_twi_pm = {
338 	.suspend_noirq	= at91_twi_suspend_noirq,
339 	.resume_noirq	= at91_twi_resume_noirq,
340 	.runtime_suspend	= at91_twi_runtime_suspend,
341 	.runtime_resume		= at91_twi_runtime_resume,
342 };
343 
344 #define at91_twi_pm_ops (&at91_twi_pm)
345 #else
346 #define at91_twi_pm_ops NULL
347 #endif
348 
349 static struct platform_driver at91_twi_driver = {
350 	.probe		= at91_twi_probe,
351 	.remove		= at91_twi_remove,
352 	.id_table	= at91_twi_devtypes,
353 	.driver		= {
354 		.name	= "at91_i2c",
355 		.of_match_table = of_match_ptr(atmel_twi_dt_ids),
356 		.pm	= at91_twi_pm_ops,
357 	},
358 };
359 
360 static int __init at91_twi_init(void)
361 {
362 	return platform_driver_register(&at91_twi_driver);
363 }
364 
365 static void __exit at91_twi_exit(void)
366 {
367 	platform_driver_unregister(&at91_twi_driver);
368 }
369 
370 subsys_initcall(at91_twi_init);
371 module_exit(at91_twi_exit);
372 
373 MODULE_AUTHOR("Nikolaus Voss <n.voss@weinmann.de>");
374 MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
375 MODULE_LICENSE("GPL");
376 MODULE_ALIAS("platform:at91_i2c");
377