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/platform_device.h>
23 #include <linux/pm_runtime.h>
24 #include <linux/pinctrl/consumer.h>
25 
26 #include "i2c-at91.h"
27 
28 unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
29 {
30 	return readl_relaxed(dev->base + reg);
31 }
32 
33 void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
34 {
35 	writel_relaxed(val, dev->base + reg);
36 }
37 
38 void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
39 {
40 	at91_twi_write(dev, AT91_TWI_IDR, AT91_TWI_INT_MASK);
41 }
42 
43 void at91_twi_irq_save(struct at91_twi_dev *dev)
44 {
45 	dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & AT91_TWI_INT_MASK;
46 	at91_disable_twi_interrupts(dev);
47 }
48 
49 void at91_twi_irq_restore(struct at91_twi_dev *dev)
50 {
51 	at91_twi_write(dev, AT91_TWI_IER, dev->imr);
52 }
53 
54 void at91_init_twi_bus(struct at91_twi_dev *dev)
55 {
56 	at91_disable_twi_interrupts(dev);
57 	at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
58 	if (dev->slave_detected)
59 		at91_init_twi_bus_slave(dev);
60 	else
61 		at91_init_twi_bus_master(dev);
62 }
63 
64 static struct at91_twi_pdata at91rm9200_config = {
65 	.clk_max_div = 5,
66 	.clk_offset = 3,
67 	.has_unre_flag = true,
68 };
69 
70 static struct at91_twi_pdata at91sam9261_config = {
71 	.clk_max_div = 5,
72 	.clk_offset = 4,
73 };
74 
75 static struct at91_twi_pdata at91sam9260_config = {
76 	.clk_max_div = 7,
77 	.clk_offset = 4,
78 };
79 
80 static struct at91_twi_pdata at91sam9g20_config = {
81 	.clk_max_div = 7,
82 	.clk_offset = 4,
83 };
84 
85 static struct at91_twi_pdata at91sam9g10_config = {
86 	.clk_max_div = 7,
87 	.clk_offset = 4,
88 };
89 
90 static const struct platform_device_id at91_twi_devtypes[] = {
91 	{
92 		.name = "i2c-at91rm9200",
93 		.driver_data = (unsigned long) &at91rm9200_config,
94 	}, {
95 		.name = "i2c-at91sam9261",
96 		.driver_data = (unsigned long) &at91sam9261_config,
97 	}, {
98 		.name = "i2c-at91sam9260",
99 		.driver_data = (unsigned long) &at91sam9260_config,
100 	}, {
101 		.name = "i2c-at91sam9g20",
102 		.driver_data = (unsigned long) &at91sam9g20_config,
103 	}, {
104 		.name = "i2c-at91sam9g10",
105 		.driver_data = (unsigned long) &at91sam9g10_config,
106 	}, {
107 		/* sentinel */
108 	}
109 };
110 
111 #if defined(CONFIG_OF)
112 static struct at91_twi_pdata at91sam9x5_config = {
113 	.clk_max_div = 7,
114 	.clk_offset = 4,
115 };
116 
117 static struct at91_twi_pdata sama5d4_config = {
118 	.clk_max_div = 7,
119 	.clk_offset = 4,
120 	.has_hold_field = true,
121 	.has_dig_filtr = true,
122 };
123 
124 static struct at91_twi_pdata sama5d2_config = {
125 	.clk_max_div = 7,
126 	.clk_offset = 3,
127 	.has_unre_flag = true,
128 	.has_alt_cmd = true,
129 	.has_hold_field = true,
130 	.has_dig_filtr = true,
131 	.has_adv_dig_filtr = true,
132 	.has_ana_filtr = true,
133 	.has_clear_cmd = false,	/* due to errata, CLEAR cmd is not working */
134 };
135 
136 static struct at91_twi_pdata sam9x60_config = {
137 	.clk_max_div = 7,
138 	.clk_offset = 3,
139 	.has_unre_flag = true,
140 	.has_alt_cmd = true,
141 	.has_hold_field = true,
142 	.has_dig_filtr = true,
143 	.has_adv_dig_filtr = true,
144 	.has_ana_filtr = true,
145 	.has_clear_cmd = true,
146 };
147 
148 static const struct of_device_id atmel_twi_dt_ids[] = {
149 	{
150 		.compatible = "atmel,at91rm9200-i2c",
151 		.data = &at91rm9200_config,
152 	}, {
153 		.compatible = "atmel,at91sam9260-i2c",
154 		.data = &at91sam9260_config,
155 	}, {
156 		.compatible = "atmel,at91sam9261-i2c",
157 		.data = &at91sam9261_config,
158 	}, {
159 		.compatible = "atmel,at91sam9g20-i2c",
160 		.data = &at91sam9g20_config,
161 	}, {
162 		.compatible = "atmel,at91sam9g10-i2c",
163 		.data = &at91sam9g10_config,
164 	}, {
165 		.compatible = "atmel,at91sam9x5-i2c",
166 		.data = &at91sam9x5_config,
167 	}, {
168 		.compatible = "atmel,sama5d4-i2c",
169 		.data = &sama5d4_config,
170 	}, {
171 		.compatible = "atmel,sama5d2-i2c",
172 		.data = &sama5d2_config,
173 	}, {
174 		.compatible = "microchip,sam9x60-i2c",
175 		.data = &sam9x60_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 	dev->base = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
210 	if (IS_ERR(dev->base))
211 		return PTR_ERR(dev->base);
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->irq = platform_get_irq(pdev, 0);
219 	if (dev->irq < 0)
220 		return dev->irq;
221 
222 	platform_set_drvdata(pdev, dev);
223 
224 	dev->clk = devm_clk_get(dev->dev, NULL);
225 	if (IS_ERR(dev->clk))
226 		return dev_err_probe(dev->dev, PTR_ERR(dev->clk), "no clock defined\n");
227 
228 	clk_prepare_enable(dev->clk);
229 
230 	snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
231 	i2c_set_adapdata(&dev->adapter, dev);
232 	dev->adapter.owner = THIS_MODULE;
233 	dev->adapter.class = I2C_CLASS_DEPRECATED;
234 	dev->adapter.dev.parent = dev->dev;
235 	dev->adapter.nr = pdev->id;
236 	dev->adapter.timeout = AT91_I2C_TIMEOUT;
237 	dev->adapter.dev.of_node = pdev->dev.of_node;
238 
239 	dev->slave_detected = i2c_detect_slave_mode(&pdev->dev);
240 
241 	if (dev->slave_detected)
242 		rc = at91_twi_probe_slave(pdev, phy_addr, dev);
243 	else
244 		rc = at91_twi_probe_master(pdev, phy_addr, dev);
245 	if (rc)
246 		return rc;
247 
248 	at91_init_twi_bus(dev);
249 
250 	pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
251 	pm_runtime_use_autosuspend(dev->dev);
252 	pm_runtime_set_active(dev->dev);
253 	pm_runtime_enable(dev->dev);
254 
255 	rc = i2c_add_numbered_adapter(&dev->adapter);
256 	if (rc) {
257 		clk_disable_unprepare(dev->clk);
258 
259 		pm_runtime_disable(dev->dev);
260 		pm_runtime_set_suspended(dev->dev);
261 
262 		return rc;
263 	}
264 
265 	dev_info(dev->dev, "AT91 i2c bus driver (hw version: %#x).\n",
266 		 at91_twi_read(dev, AT91_TWI_VER));
267 	return 0;
268 }
269 
270 static void at91_twi_remove(struct platform_device *pdev)
271 {
272 	struct at91_twi_dev *dev = platform_get_drvdata(pdev);
273 
274 	i2c_del_adapter(&dev->adapter);
275 	clk_disable_unprepare(dev->clk);
276 
277 	pm_runtime_disable(dev->dev);
278 	pm_runtime_set_suspended(dev->dev);
279 }
280 
281 static int __maybe_unused at91_twi_runtime_suspend(struct device *dev)
282 {
283 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
284 
285 	clk_disable_unprepare(twi_dev->clk);
286 
287 	pinctrl_pm_select_sleep_state(dev);
288 
289 	return 0;
290 }
291 
292 static int __maybe_unused at91_twi_runtime_resume(struct device *dev)
293 {
294 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
295 
296 	pinctrl_pm_select_default_state(dev);
297 
298 	return clk_prepare_enable(twi_dev->clk);
299 }
300 
301 static int __maybe_unused at91_twi_suspend_noirq(struct device *dev)
302 {
303 	if (!pm_runtime_status_suspended(dev))
304 		at91_twi_runtime_suspend(dev);
305 
306 	return 0;
307 }
308 
309 static int __maybe_unused at91_twi_resume_noirq(struct device *dev)
310 {
311 	struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
312 	int ret;
313 
314 	if (!pm_runtime_status_suspended(dev)) {
315 		ret = at91_twi_runtime_resume(dev);
316 		if (ret)
317 			return ret;
318 	}
319 
320 	pm_runtime_mark_last_busy(dev);
321 	pm_request_autosuspend(dev);
322 
323 	at91_init_twi_bus(twi_dev);
324 
325 	return 0;
326 }
327 
328 static const struct dev_pm_ops __maybe_unused at91_twi_pm = {
329 	.suspend_noirq	= at91_twi_suspend_noirq,
330 	.resume_noirq	= at91_twi_resume_noirq,
331 	.runtime_suspend	= at91_twi_runtime_suspend,
332 	.runtime_resume		= at91_twi_runtime_resume,
333 };
334 
335 static struct platform_driver at91_twi_driver = {
336 	.probe		= at91_twi_probe,
337 	.remove_new	= at91_twi_remove,
338 	.id_table	= at91_twi_devtypes,
339 	.driver		= {
340 		.name	= "at91_i2c",
341 		.of_match_table = of_match_ptr(atmel_twi_dt_ids),
342 		.pm	= pm_ptr(&at91_twi_pm),
343 	},
344 };
345 
346 static int __init at91_twi_init(void)
347 {
348 	return platform_driver_register(&at91_twi_driver);
349 }
350 
351 static void __exit at91_twi_exit(void)
352 {
353 	platform_driver_unregister(&at91_twi_driver);
354 }
355 
356 subsys_initcall(at91_twi_init);
357 module_exit(at91_twi_exit);
358 
359 MODULE_AUTHOR("Nikolaus Voss <n.voss@weinmann.de>");
360 MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
361 MODULE_LICENSE("GPL");
362 MODULE_ALIAS("platform:at91_i2c");
363