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 };
70 
71 static struct at91_twi_pdata at91sam9261_config = {
72 	.clk_max_div = 5,
73 	.clk_offset = 4,
74 };
75 
76 static struct at91_twi_pdata at91sam9260_config = {
77 	.clk_max_div = 7,
78 	.clk_offset = 4,
79 };
80 
81 static struct at91_twi_pdata at91sam9g20_config = {
82 	.clk_max_div = 7,
83 	.clk_offset = 4,
84 };
85 
86 static struct at91_twi_pdata at91sam9g10_config = {
87 	.clk_max_div = 7,
88 	.clk_offset = 4,
89 };
90 
91 static const struct platform_device_id at91_twi_devtypes[] = {
92 	{
93 		.name = "i2c-at91rm9200",
94 		.driver_data = (unsigned long) &at91rm9200_config,
95 	}, {
96 		.name = "i2c-at91sam9261",
97 		.driver_data = (unsigned long) &at91sam9261_config,
98 	}, {
99 		.name = "i2c-at91sam9260",
100 		.driver_data = (unsigned long) &at91sam9260_config,
101 	}, {
102 		.name = "i2c-at91sam9g20",
103 		.driver_data = (unsigned long) &at91sam9g20_config,
104 	}, {
105 		.name = "i2c-at91sam9g10",
106 		.driver_data = (unsigned long) &at91sam9g10_config,
107 	}, {
108 		/* sentinel */
109 	}
110 };
111 
112 #if defined(CONFIG_OF)
113 static struct at91_twi_pdata at91sam9x5_config = {
114 	.clk_max_div = 7,
115 	.clk_offset = 4,
116 };
117 
118 static struct at91_twi_pdata sama5d4_config = {
119 	.clk_max_div = 7,
120 	.clk_offset = 4,
121 	.has_hold_field = true,
122 	.has_dig_filtr = true,
123 };
124 
125 static struct at91_twi_pdata sama5d2_config = {
126 	.clk_max_div = 7,
127 	.clk_offset = 3,
128 	.has_unre_flag = true,
129 	.has_alt_cmd = true,
130 	.has_hold_field = true,
131 	.has_dig_filtr = true,
132 	.has_adv_dig_filtr = true,
133 	.has_ana_filtr = true,
134 	.has_clear_cmd = false,	/* due to errata, CLEAR cmd is not working */
135 };
136 
137 static struct at91_twi_pdata sam9x60_config = {
138 	.clk_max_div = 7,
139 	.clk_offset = 3,
140 	.has_unre_flag = true,
141 	.has_alt_cmd = true,
142 	.has_hold_field = true,
143 	.has_dig_filtr = true,
144 	.has_adv_dig_filtr = true,
145 	.has_ana_filtr = true,
146 	.has_clear_cmd = true,
147 };
148 
149 static const struct of_device_id atmel_twi_dt_ids[] = {
150 	{
151 		.compatible = "atmel,at91rm9200-i2c",
152 		.data = &at91rm9200_config,
153 	}, {
154 		.compatible = "atmel,at91sam9260-i2c",
155 		.data = &at91sam9260_config,
156 	}, {
157 		.compatible = "atmel,at91sam9261-i2c",
158 		.data = &at91sam9261_config,
159 	}, {
160 		.compatible = "atmel,at91sam9g20-i2c",
161 		.data = &at91sam9g20_config,
162 	}, {
163 		.compatible = "atmel,at91sam9g10-i2c",
164 		.data = &at91sam9g10_config,
165 	}, {
166 		.compatible = "atmel,at91sam9x5-i2c",
167 		.data = &at91sam9x5_config,
168 	}, {
169 		.compatible = "atmel,sama5d4-i2c",
170 		.data = &sama5d4_config,
171 	}, {
172 		.compatible = "atmel,sama5d2-i2c",
173 		.data = &sama5d2_config,
174 	}, {
175 		.compatible = "microchip,sam9x60-i2c",
176 		.data = &sam9x60_config,
177 	}, {
178 		/* sentinel */
179 	}
180 };
181 MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
182 #endif
183 
184 static struct at91_twi_pdata *at91_twi_get_driver_data(
185 					struct platform_device *pdev)
186 {
187 	if (pdev->dev.of_node) {
188 		const struct of_device_id *match;
189 		match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node);
190 		if (!match)
191 			return NULL;
192 		return (struct at91_twi_pdata *)match->data;
193 	}
194 	return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
195 }
196 
197 static int at91_twi_probe(struct platform_device *pdev)
198 {
199 	struct at91_twi_dev *dev;
200 	struct resource *mem;
201 	int rc;
202 	u32 phy_addr;
203 
204 	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
205 	if (!dev)
206 		return -ENOMEM;
207 
208 	dev->dev = &pdev->dev;
209 
210 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
211 	if (!mem)
212 		return -ENODEV;
213 	phy_addr = mem->start;
214 
215 	dev->pdata = at91_twi_get_driver_data(pdev);
216 	if (!dev->pdata)
217 		return -ENODEV;
218 
219 	dev->base = devm_ioremap_resource(&pdev->dev, mem);
220 	if (IS_ERR(dev->base))
221 		return PTR_ERR(dev->base);
222 
223 	dev->irq = platform_get_irq(pdev, 0);
224 	if (dev->irq < 0)
225 		return dev->irq;
226 
227 	platform_set_drvdata(pdev, dev);
228 
229 	dev->clk = devm_clk_get(dev->dev, NULL);
230 	if (IS_ERR(dev->clk)) {
231 		dev_err(dev->dev, "no clock defined\n");
232 		return -ENODEV;
233 	}
234 	clk_prepare_enable(dev->clk);
235 
236 	snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
237 	i2c_set_adapdata(&dev->adapter, dev);
238 	dev->adapter.owner = THIS_MODULE;
239 	dev->adapter.class = I2C_CLASS_DEPRECATED;
240 	dev->adapter.dev.parent = dev->dev;
241 	dev->adapter.nr = pdev->id;
242 	dev->adapter.timeout = AT91_I2C_TIMEOUT;
243 	dev->adapter.dev.of_node = pdev->dev.of_node;
244 
245 	dev->slave_detected = i2c_detect_slave_mode(&pdev->dev);
246 
247 	if (dev->slave_detected)
248 		rc = at91_twi_probe_slave(pdev, phy_addr, dev);
249 	else
250 		rc = at91_twi_probe_master(pdev, phy_addr, dev);
251 	if (rc)
252 		return rc;
253 
254 	at91_init_twi_bus(dev);
255 
256 	pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
257 	pm_runtime_use_autosuspend(dev->dev);
258 	pm_runtime_set_active(dev->dev);
259 	pm_runtime_enable(dev->dev);
260 
261 	rc = i2c_add_numbered_adapter(&dev->adapter);
262 	if (rc) {
263 		clk_disable_unprepare(dev->clk);
264 
265 		pm_runtime_disable(dev->dev);
266 		pm_runtime_set_suspended(dev->dev);
267 
268 		return rc;
269 	}
270 
271 	dev_info(dev->dev, "AT91 i2c bus driver (hw version: %#x).\n",
272 		 at91_twi_read(dev, AT91_TWI_VER));
273 	return 0;
274 }
275 
276 static int at91_twi_remove(struct platform_device *pdev)
277 {
278 	struct at91_twi_dev *dev = platform_get_drvdata(pdev);
279 
280 	i2c_del_adapter(&dev->adapter);
281 	clk_disable_unprepare(dev->clk);
282 
283 	pm_runtime_disable(dev->dev);
284 	pm_runtime_set_suspended(dev->dev);
285 
286 	return 0;
287 }
288 
289 static int __maybe_unused at91_twi_runtime_suspend(struct device *dev)
290 {
291 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
292 
293 	clk_disable_unprepare(twi_dev->clk);
294 
295 	pinctrl_pm_select_sleep_state(dev);
296 
297 	return 0;
298 }
299 
300 static int __maybe_unused at91_twi_runtime_resume(struct device *dev)
301 {
302 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
303 
304 	pinctrl_pm_select_default_state(dev);
305 
306 	return clk_prepare_enable(twi_dev->clk);
307 }
308 
309 static int __maybe_unused at91_twi_suspend_noirq(struct device *dev)
310 {
311 	if (!pm_runtime_status_suspended(dev))
312 		at91_twi_runtime_suspend(dev);
313 
314 	return 0;
315 }
316 
317 static int __maybe_unused at91_twi_resume_noirq(struct device *dev)
318 {
319 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
320 	int ret;
321 
322 	if (!pm_runtime_status_suspended(dev)) {
323 		ret = at91_twi_runtime_resume(dev);
324 		if (ret)
325 			return ret;
326 	}
327 
328 	pm_runtime_mark_last_busy(dev);
329 	pm_request_autosuspend(dev);
330 
331 	at91_init_twi_bus(twi_dev);
332 
333 	return 0;
334 }
335 
336 static const struct dev_pm_ops __maybe_unused at91_twi_pm = {
337 	.suspend_noirq	= at91_twi_suspend_noirq,
338 	.resume_noirq	= at91_twi_resume_noirq,
339 	.runtime_suspend	= at91_twi_runtime_suspend,
340 	.runtime_resume		= at91_twi_runtime_resume,
341 };
342 
343 static struct platform_driver at91_twi_driver = {
344 	.probe		= at91_twi_probe,
345 	.remove		= at91_twi_remove,
346 	.id_table	= at91_twi_devtypes,
347 	.driver		= {
348 		.name	= "at91_i2c",
349 		.of_match_table = of_match_ptr(atmel_twi_dt_ids),
350 		.pm	= pm_ptr(&at91_twi_pm),
351 	},
352 };
353 
354 static int __init at91_twi_init(void)
355 {
356 	return platform_driver_register(&at91_twi_driver);
357 }
358 
359 static void __exit at91_twi_exit(void)
360 {
361 	platform_driver_unregister(&at91_twi_driver);
362 }
363 
364 subsys_initcall(at91_twi_init);
365 module_exit(at91_twi_exit);
366 
367 MODULE_AUTHOR("Nikolaus Voss <n.voss@weinmann.de>");
368 MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
369 MODULE_LICENSE("GPL");
370 MODULE_ALIAS("platform:at91_i2c");
371