1 /*
2  * Synopsys DesignWare I2C adapter driver.
3  *
4  * Based on the TI DAVINCI I2C adapter driver.
5  *
6  * Copyright (C) 2006 Texas Instruments.
7  * Copyright (C) 2007 MontaVista Software Inc.
8  * Copyright (C) 2009 Provigent Ltd.
9  *
10  * ----------------------------------------------------------------------------
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License as published by
14  * the Free Software Foundation; either version 2 of the License, or
15  * (at your option) any later version.
16  *
17  * This program is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20  * GNU General Public License for more details.
21  * ----------------------------------------------------------------------------
22  *
23  */
24 #include <linux/acpi.h>
25 #include <linux/clk-provider.h>
26 #include <linux/clk.h>
27 #include <linux/delay.h>
28 #include <linux/dmi.h>
29 #include <linux/err.h>
30 #include <linux/errno.h>
31 #include <linux/i2c.h>
32 #include <linux/interrupt.h>
33 #include <linux/io.h>
34 #include <linux/kernel.h>
35 #include <linux/module.h>
36 #include <linux/of.h>
37 #include <linux/platform_data/i2c-designware.h>
38 #include <linux/platform_device.h>
39 #include <linux/pm.h>
40 #include <linux/pm_runtime.h>
41 #include <linux/property.h>
42 #include <linux/reset.h>
43 #include <linux/sched.h>
44 #include <linux/slab.h>
45 
46 #include "i2c-designware-core.h"
47 
48 static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
49 {
50 	return clk_get_rate(dev->clk)/1000;
51 }
52 
53 #ifdef CONFIG_ACPI
54 /*
55  * The HCNT/LCNT information coming from ACPI should be the most accurate
56  * for given platform. However, some systems get it wrong. On such systems
57  * we get better results by calculating those based on the input clock.
58  */
59 static const struct dmi_system_id dw_i2c_no_acpi_params[] = {
60 	{
61 		.ident = "Dell Inspiron 7348",
62 		.matches = {
63 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
64 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7348"),
65 		},
66 	},
67 	{ }
68 };
69 
70 static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
71 			       u16 *hcnt, u16 *lcnt, u32 *sda_hold)
72 {
73 	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
74 	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
75 	union acpi_object *obj;
76 
77 	if (dmi_check_system(dw_i2c_no_acpi_params))
78 		return;
79 
80 	if (ACPI_FAILURE(acpi_evaluate_object(handle, method, NULL, &buf)))
81 		return;
82 
83 	obj = (union acpi_object *)buf.pointer;
84 	if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 3) {
85 		const union acpi_object *objs = obj->package.elements;
86 
87 		*hcnt = (u16)objs[0].integer.value;
88 		*lcnt = (u16)objs[1].integer.value;
89 		*sda_hold = (u32)objs[2].integer.value;
90 	}
91 
92 	kfree(buf.pointer);
93 }
94 
95 static int dw_i2c_acpi_configure(struct platform_device *pdev)
96 {
97 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
98 	u32 ss_ht = 0, fp_ht = 0, hs_ht = 0, fs_ht = 0;
99 	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
100 	const struct acpi_device_id *id;
101 	struct acpi_device *adev;
102 	const char *uid;
103 
104 	dev->adapter.nr = -1;
105 	dev->tx_fifo_depth = 32;
106 	dev->rx_fifo_depth = 32;
107 
108 	/*
109 	 * Try to get SDA hold time and *CNT values from an ACPI method for
110 	 * selected speed modes.
111 	 */
112 	dw_i2c_acpi_params(pdev, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, &ss_ht);
113 	dw_i2c_acpi_params(pdev, "FPCN", &dev->fp_hcnt, &dev->fp_lcnt, &fp_ht);
114 	dw_i2c_acpi_params(pdev, "HSCN", &dev->hs_hcnt, &dev->hs_lcnt, &hs_ht);
115 	dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt, &fs_ht);
116 
117 	switch (dev->clk_freq) {
118 	case 100000:
119 		dev->sda_hold_time = ss_ht;
120 		break;
121 	case 1000000:
122 		dev->sda_hold_time = fp_ht;
123 		break;
124 	case 3400000:
125 		dev->sda_hold_time = hs_ht;
126 		break;
127 	case 400000:
128 	default:
129 		dev->sda_hold_time = fs_ht;
130 		break;
131 	}
132 
133 	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
134 	if (id && id->driver_data)
135 		dev->flags |= (u32)id->driver_data;
136 
137 	if (acpi_bus_get_device(handle, &adev))
138 		return -ENODEV;
139 
140 	/*
141 	 * Cherrytrail I2C7 gets used for the PMIC which gets accessed
142 	 * through ACPI opregions during late suspend / early resume
143 	 * disable pm for it.
144 	 */
145 	uid = adev->pnp.unique_id;
146 	if ((dev->flags & MODEL_CHERRYTRAIL) && !strcmp(uid, "7"))
147 		dev->pm_disabled = true;
148 
149 	return 0;
150 }
151 
152 static const struct acpi_device_id dw_i2c_acpi_match[] = {
153 	{ "INT33C2", 0 },
154 	{ "INT33C3", 0 },
155 	{ "INT3432", 0 },
156 	{ "INT3433", 0 },
157 	{ "80860F41", 0 },
158 	{ "808622C1", MODEL_CHERRYTRAIL },
159 	{ "AMD0010", ACCESS_INTR_MASK },
160 	{ "AMDI0010", ACCESS_INTR_MASK },
161 	{ "AMDI0510", 0 },
162 	{ "APMC0D0F", 0 },
163 	{ "HISI02A1", 0 },
164 	{ "HISI02A2", 0 },
165 	{ }
166 };
167 MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
168 #else
169 static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
170 {
171 	return -ENODEV;
172 }
173 #endif
174 
175 static void i2c_dw_configure_master(struct dw_i2c_dev *dev)
176 {
177 	dev->functionality = I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY;
178 
179 	dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
180 			  DW_IC_CON_RESTART_EN;
181 
182 	dev->mode = DW_IC_MASTER;
183 
184 	switch (dev->clk_freq) {
185 	case 100000:
186 		dev->master_cfg |= DW_IC_CON_SPEED_STD;
187 		break;
188 	case 3400000:
189 		dev->master_cfg |= DW_IC_CON_SPEED_HIGH;
190 		break;
191 	default:
192 		dev->master_cfg |= DW_IC_CON_SPEED_FAST;
193 	}
194 }
195 
196 static void i2c_dw_configure_slave(struct dw_i2c_dev *dev)
197 {
198 	dev->functionality = I2C_FUNC_SLAVE | DW_IC_DEFAULT_FUNCTIONALITY;
199 
200 	dev->slave_cfg = DW_IC_CON_RX_FIFO_FULL_HLD_CTRL |
201 			 DW_IC_CON_RESTART_EN | DW_IC_CON_STOP_DET_IFADDRESSED;
202 
203 	dev->mode = DW_IC_SLAVE;
204 
205 	switch (dev->clk_freq) {
206 	case 100000:
207 		dev->slave_cfg |= DW_IC_CON_SPEED_STD;
208 		break;
209 	case 3400000:
210 		dev->slave_cfg |= DW_IC_CON_SPEED_HIGH;
211 		break;
212 	default:
213 		dev->slave_cfg |= DW_IC_CON_SPEED_FAST;
214 	}
215 }
216 
217 static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
218 {
219 	if (IS_ERR(i_dev->clk))
220 		return PTR_ERR(i_dev->clk);
221 
222 	if (prepare)
223 		return clk_prepare_enable(i_dev->clk);
224 
225 	clk_disable_unprepare(i_dev->clk);
226 	return 0;
227 }
228 
229 static void dw_i2c_set_fifo_size(struct dw_i2c_dev *dev, int id)
230 {
231 	u32 param, tx_fifo_depth, rx_fifo_depth;
232 
233 	/*
234 	 * Try to detect the FIFO depth if not set by interface driver,
235 	 * the depth could be from 2 to 256 from HW spec.
236 	 */
237 	param = i2c_dw_read_comp_param(dev);
238 	tx_fifo_depth = ((param >> 16) & 0xff) + 1;
239 	rx_fifo_depth = ((param >> 8)  & 0xff) + 1;
240 	if (!dev->tx_fifo_depth) {
241 		dev->tx_fifo_depth = tx_fifo_depth;
242 		dev->rx_fifo_depth = rx_fifo_depth;
243 		dev->adapter.nr = id;
244 	} else if (tx_fifo_depth >= 2) {
245 		dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth,
246 				tx_fifo_depth);
247 		dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth,
248 				rx_fifo_depth);
249 	}
250 }
251 
252 static int dw_i2c_plat_probe(struct platform_device *pdev)
253 {
254 	struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
255 	struct i2c_adapter *adap;
256 	struct dw_i2c_dev *dev;
257 	u32 acpi_speed, ht = 0;
258 	struct resource *mem;
259 	int i, irq, ret;
260 	const int supported_speeds[] = { 0, 100000, 400000, 1000000, 3400000 };
261 
262 	irq = platform_get_irq(pdev, 0);
263 	if (irq < 0)
264 		return irq;
265 
266 	dev = devm_kzalloc(&pdev->dev, sizeof(struct dw_i2c_dev), GFP_KERNEL);
267 	if (!dev)
268 		return -ENOMEM;
269 
270 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
271 	dev->base = devm_ioremap_resource(&pdev->dev, mem);
272 	if (IS_ERR(dev->base))
273 		return PTR_ERR(dev->base);
274 
275 	dev->dev = &pdev->dev;
276 	dev->irq = irq;
277 	platform_set_drvdata(pdev, dev);
278 
279 	dev->rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
280 	if (IS_ERR(dev->rst)) {
281 		if (PTR_ERR(dev->rst) == -EPROBE_DEFER)
282 			return -EPROBE_DEFER;
283 	} else {
284 		reset_control_deassert(dev->rst);
285 	}
286 
287 	if (pdata) {
288 		dev->clk_freq = pdata->i2c_scl_freq;
289 	} else {
290 		device_property_read_u32(&pdev->dev, "i2c-sda-hold-time-ns",
291 					 &ht);
292 		device_property_read_u32(&pdev->dev, "i2c-sda-falling-time-ns",
293 					 &dev->sda_falling_time);
294 		device_property_read_u32(&pdev->dev, "i2c-scl-falling-time-ns",
295 					 &dev->scl_falling_time);
296 		device_property_read_u32(&pdev->dev, "clock-frequency",
297 					 &dev->clk_freq);
298 	}
299 
300 	acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
301 	/*
302 	 * Some DSTDs use a non standard speed, round down to the lowest
303 	 * standard speed.
304 	 */
305 	for (i = 1; i < ARRAY_SIZE(supported_speeds); i++) {
306 		if (acpi_speed < supported_speeds[i])
307 			break;
308 	}
309 	acpi_speed = supported_speeds[i - 1];
310 
311 	/*
312 	 * Find bus speed from the "clock-frequency" device property, ACPI
313 	 * or by using fast mode if neither is set.
314 	 */
315 	if (acpi_speed && dev->clk_freq)
316 		dev->clk_freq = min(dev->clk_freq, acpi_speed);
317 	else if (acpi_speed || dev->clk_freq)
318 		dev->clk_freq = max(dev->clk_freq, acpi_speed);
319 	else
320 		dev->clk_freq = 400000;
321 
322 	if (has_acpi_companion(&pdev->dev))
323 		dw_i2c_acpi_configure(pdev);
324 
325 	/*
326 	 * Only standard mode at 100kHz, fast mode at 400kHz,
327 	 * fast mode plus at 1MHz and high speed mode at 3.4MHz are supported.
328 	 */
329 	if (dev->clk_freq != 100000 && dev->clk_freq != 400000
330 	    && dev->clk_freq != 1000000 && dev->clk_freq != 3400000) {
331 		dev_err(&pdev->dev,
332 			"%d Hz is unsupported, only 100kHz, 400kHz, 1MHz and 3.4MHz are supported\n",
333 			dev->clk_freq);
334 		ret = -EINVAL;
335 		goto exit_reset;
336 	}
337 
338 	ret = i2c_dw_probe_lock_support(dev);
339 	if (ret)
340 		goto exit_reset;
341 
342 	if (i2c_detect_slave_mode(&pdev->dev))
343 		i2c_dw_configure_slave(dev);
344 	else
345 		i2c_dw_configure_master(dev);
346 
347 	dev->clk = devm_clk_get(&pdev->dev, NULL);
348 	if (!i2c_dw_plat_prepare_clk(dev, true)) {
349 		dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
350 
351 		if (!dev->sda_hold_time && ht)
352 			dev->sda_hold_time = div_u64(
353 				(u64)dev->get_clk_rate_khz(dev) * ht + 500000,
354 				1000000);
355 	}
356 
357 	dw_i2c_set_fifo_size(dev, pdev->id);
358 
359 	adap = &dev->adapter;
360 	adap->owner = THIS_MODULE;
361 	adap->class = I2C_CLASS_DEPRECATED;
362 	ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
363 	adap->dev.of_node = pdev->dev.of_node;
364 
365 	if (dev->pm_disabled) {
366 		pm_runtime_forbid(&pdev->dev);
367 	} else {
368 		pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
369 		pm_runtime_use_autosuspend(&pdev->dev);
370 		pm_runtime_set_active(&pdev->dev);
371 		pm_runtime_enable(&pdev->dev);
372 	}
373 
374 	if (dev->mode == DW_IC_SLAVE)
375 		ret = i2c_dw_probe_slave(dev);
376 	else
377 		ret = i2c_dw_probe(dev);
378 
379 	if (ret)
380 		goto exit_probe;
381 
382 	return ret;
383 
384 exit_probe:
385 	if (!dev->pm_disabled)
386 		pm_runtime_disable(&pdev->dev);
387 exit_reset:
388 	if (!IS_ERR_OR_NULL(dev->rst))
389 		reset_control_assert(dev->rst);
390 	return ret;
391 }
392 
393 static int dw_i2c_plat_remove(struct platform_device *pdev)
394 {
395 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
396 
397 	pm_runtime_get_sync(&pdev->dev);
398 
399 	i2c_del_adapter(&dev->adapter);
400 
401 	dev->disable(dev);
402 
403 	pm_runtime_dont_use_autosuspend(&pdev->dev);
404 	pm_runtime_put_sync(&pdev->dev);
405 	if (!dev->pm_disabled)
406 		pm_runtime_disable(&pdev->dev);
407 	if (!IS_ERR_OR_NULL(dev->rst))
408 		reset_control_assert(dev->rst);
409 
410 	i2c_dw_remove_lock_support(dev);
411 
412 	return 0;
413 }
414 
415 #ifdef CONFIG_OF
416 static const struct of_device_id dw_i2c_of_match[] = {
417 	{ .compatible = "snps,designware-i2c", },
418 	{},
419 };
420 MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
421 #endif
422 
423 #ifdef CONFIG_PM_SLEEP
424 static int dw_i2c_plat_prepare(struct device *dev)
425 {
426 	return pm_runtime_suspended(dev);
427 }
428 
429 static void dw_i2c_plat_complete(struct device *dev)
430 {
431 	if (dev->power.direct_complete)
432 		pm_request_resume(dev);
433 }
434 #else
435 #define dw_i2c_plat_prepare	NULL
436 #define dw_i2c_plat_complete	NULL
437 #endif
438 
439 #ifdef CONFIG_PM
440 static int dw_i2c_plat_runtime_suspend(struct device *dev)
441 {
442 	struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
443 
444 	i_dev->disable(i_dev);
445 	i2c_dw_plat_prepare_clk(i_dev, false);
446 
447 	return 0;
448 }
449 
450 static int dw_i2c_plat_resume(struct device *dev)
451 {
452 	struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
453 
454 	i2c_dw_plat_prepare_clk(i_dev, true);
455 	i_dev->init(i_dev);
456 
457 	return 0;
458 }
459 
460 #ifdef CONFIG_PM_SLEEP
461 static int dw_i2c_plat_suspend(struct device *dev)
462 {
463 	pm_runtime_resume(dev);
464 	return dw_i2c_plat_runtime_suspend(dev);
465 }
466 #endif
467 
468 static const struct dev_pm_ops dw_i2c_dev_pm_ops = {
469 	.prepare = dw_i2c_plat_prepare,
470 	.complete = dw_i2c_plat_complete,
471 	SET_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume)
472 	SET_RUNTIME_PM_OPS(dw_i2c_plat_runtime_suspend,
473 			   dw_i2c_plat_resume,
474 			   NULL)
475 };
476 
477 #define DW_I2C_DEV_PMOPS (&dw_i2c_dev_pm_ops)
478 #else
479 #define DW_I2C_DEV_PMOPS NULL
480 #endif
481 
482 /* Work with hotplug and coldplug */
483 MODULE_ALIAS("platform:i2c_designware");
484 
485 static struct platform_driver dw_i2c_driver = {
486 	.probe = dw_i2c_plat_probe,
487 	.remove = dw_i2c_plat_remove,
488 	.driver		= {
489 		.name	= "i2c_designware",
490 		.of_match_table = of_match_ptr(dw_i2c_of_match),
491 		.acpi_match_table = ACPI_PTR(dw_i2c_acpi_match),
492 		.pm	= DW_I2C_DEV_PMOPS,
493 	},
494 };
495 
496 static int __init dw_i2c_init_driver(void)
497 {
498 	return platform_driver_register(&dw_i2c_driver);
499 }
500 subsys_initcall(dw_i2c_init_driver);
501 
502 static void __exit dw_i2c_exit_driver(void)
503 {
504 	platform_driver_unregister(&dw_i2c_driver);
505 }
506 module_exit(dw_i2c_exit_driver);
507 
508 MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
509 MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter");
510 MODULE_LICENSE("GPL");
511