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 irq, ret;
260 
261 	irq = platform_get_irq(pdev, 0);
262 	if (irq < 0)
263 		return irq;
264 
265 	dev = devm_kzalloc(&pdev->dev, sizeof(struct dw_i2c_dev), GFP_KERNEL);
266 	if (!dev)
267 		return -ENOMEM;
268 
269 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
270 	dev->base = devm_ioremap_resource(&pdev->dev, mem);
271 	if (IS_ERR(dev->base))
272 		return PTR_ERR(dev->base);
273 
274 	dev->dev = &pdev->dev;
275 	dev->irq = irq;
276 	platform_set_drvdata(pdev, dev);
277 
278 	dev->rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
279 	if (IS_ERR(dev->rst)) {
280 		if (PTR_ERR(dev->rst) == -EPROBE_DEFER)
281 			return -EPROBE_DEFER;
282 	} else {
283 		reset_control_deassert(dev->rst);
284 	}
285 
286 	if (pdata) {
287 		dev->clk_freq = pdata->i2c_scl_freq;
288 	} else {
289 		device_property_read_u32(&pdev->dev, "i2c-sda-hold-time-ns",
290 					 &ht);
291 		device_property_read_u32(&pdev->dev, "i2c-sda-falling-time-ns",
292 					 &dev->sda_falling_time);
293 		device_property_read_u32(&pdev->dev, "i2c-scl-falling-time-ns",
294 					 &dev->scl_falling_time);
295 		device_property_read_u32(&pdev->dev, "clock-frequency",
296 					 &dev->clk_freq);
297 	}
298 
299 	acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
300 	/* Some broken DSTDs use 1MiHz instead of 1MHz */
301 	if (acpi_speed == 1048576)
302 		acpi_speed = 1000000;
303 	/*
304 	 * Find bus speed from the "clock-frequency" device property, ACPI
305 	 * or by using fast mode if neither is set.
306 	 */
307 	if (acpi_speed && dev->clk_freq)
308 		dev->clk_freq = min(dev->clk_freq, acpi_speed);
309 	else if (acpi_speed || dev->clk_freq)
310 		dev->clk_freq = max(dev->clk_freq, acpi_speed);
311 	else
312 		dev->clk_freq = 400000;
313 
314 	if (has_acpi_companion(&pdev->dev))
315 		dw_i2c_acpi_configure(pdev);
316 
317 	/*
318 	 * Only standard mode at 100kHz, fast mode at 400kHz,
319 	 * fast mode plus at 1MHz and high speed mode at 3.4MHz are supported.
320 	 */
321 	if (dev->clk_freq != 100000 && dev->clk_freq != 400000
322 	    && dev->clk_freq != 1000000 && dev->clk_freq != 3400000) {
323 		dev_err(&pdev->dev,
324 			"%d Hz is unsupported, only 100kHz, 400kHz, 1MHz and 3.4MHz are supported\n",
325 			dev->clk_freq);
326 		ret = -EINVAL;
327 		goto exit_reset;
328 	}
329 
330 	ret = i2c_dw_probe_lock_support(dev);
331 	if (ret)
332 		goto exit_reset;
333 
334 	if (i2c_detect_slave_mode(&pdev->dev))
335 		i2c_dw_configure_slave(dev);
336 	else
337 		i2c_dw_configure_master(dev);
338 
339 	dev->clk = devm_clk_get(&pdev->dev, NULL);
340 	if (!i2c_dw_plat_prepare_clk(dev, true)) {
341 		dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
342 
343 		if (!dev->sda_hold_time && ht)
344 			dev->sda_hold_time = div_u64(
345 				(u64)dev->get_clk_rate_khz(dev) * ht + 500000,
346 				1000000);
347 	}
348 
349 	dw_i2c_set_fifo_size(dev, pdev->id);
350 
351 	adap = &dev->adapter;
352 	adap->owner = THIS_MODULE;
353 	adap->class = I2C_CLASS_DEPRECATED;
354 	ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
355 	adap->dev.of_node = pdev->dev.of_node;
356 
357 	if (dev->pm_disabled) {
358 		pm_runtime_forbid(&pdev->dev);
359 	} else {
360 		pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
361 		pm_runtime_use_autosuspend(&pdev->dev);
362 		pm_runtime_set_active(&pdev->dev);
363 		pm_runtime_enable(&pdev->dev);
364 	}
365 
366 	if (dev->mode == DW_IC_SLAVE)
367 		ret = i2c_dw_probe_slave(dev);
368 	else
369 		ret = i2c_dw_probe(dev);
370 
371 	if (ret)
372 		goto exit_probe;
373 
374 	return ret;
375 
376 exit_probe:
377 	if (!dev->pm_disabled)
378 		pm_runtime_disable(&pdev->dev);
379 exit_reset:
380 	if (!IS_ERR_OR_NULL(dev->rst))
381 		reset_control_assert(dev->rst);
382 	return ret;
383 }
384 
385 static int dw_i2c_plat_remove(struct platform_device *pdev)
386 {
387 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
388 
389 	pm_runtime_get_sync(&pdev->dev);
390 
391 	i2c_del_adapter(&dev->adapter);
392 
393 	dev->disable(dev);
394 
395 	pm_runtime_dont_use_autosuspend(&pdev->dev);
396 	pm_runtime_put_sync(&pdev->dev);
397 	if (!dev->pm_disabled)
398 		pm_runtime_disable(&pdev->dev);
399 	if (!IS_ERR_OR_NULL(dev->rst))
400 		reset_control_assert(dev->rst);
401 
402 	i2c_dw_remove_lock_support(dev);
403 
404 	return 0;
405 }
406 
407 #ifdef CONFIG_OF
408 static const struct of_device_id dw_i2c_of_match[] = {
409 	{ .compatible = "snps,designware-i2c", },
410 	{},
411 };
412 MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
413 #endif
414 
415 #ifdef CONFIG_PM_SLEEP
416 static int dw_i2c_plat_prepare(struct device *dev)
417 {
418 	return pm_runtime_suspended(dev);
419 }
420 
421 static void dw_i2c_plat_complete(struct device *dev)
422 {
423 	if (dev->power.direct_complete)
424 		pm_request_resume(dev);
425 }
426 #else
427 #define dw_i2c_plat_prepare	NULL
428 #define dw_i2c_plat_complete	NULL
429 #endif
430 
431 #ifdef CONFIG_PM
432 static int dw_i2c_plat_runtime_suspend(struct device *dev)
433 {
434 	struct platform_device *pdev = to_platform_device(dev);
435 	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
436 
437 	i_dev->disable(i_dev);
438 	i2c_dw_plat_prepare_clk(i_dev, false);
439 
440 	return 0;
441 }
442 
443 static int dw_i2c_plat_resume(struct device *dev)
444 {
445 	struct platform_device *pdev = to_platform_device(dev);
446 	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
447 
448 	i2c_dw_plat_prepare_clk(i_dev, true);
449 	i_dev->init(i_dev);
450 
451 	return 0;
452 }
453 
454 #ifdef CONFIG_PM_SLEEP
455 static int dw_i2c_plat_suspend(struct device *dev)
456 {
457 	pm_runtime_resume(dev);
458 	return dw_i2c_plat_runtime_suspend(dev);
459 }
460 #endif
461 
462 static const struct dev_pm_ops dw_i2c_dev_pm_ops = {
463 	.prepare = dw_i2c_plat_prepare,
464 	.complete = dw_i2c_plat_complete,
465 	SET_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume)
466 	SET_RUNTIME_PM_OPS(dw_i2c_plat_runtime_suspend,
467 			   dw_i2c_plat_resume,
468 			   NULL)
469 };
470 
471 #define DW_I2C_DEV_PMOPS (&dw_i2c_dev_pm_ops)
472 #else
473 #define DW_I2C_DEV_PMOPS NULL
474 #endif
475 
476 /* Work with hotplug and coldplug */
477 MODULE_ALIAS("platform:i2c_designware");
478 
479 static struct platform_driver dw_i2c_driver = {
480 	.probe = dw_i2c_plat_probe,
481 	.remove = dw_i2c_plat_remove,
482 	.driver		= {
483 		.name	= "i2c_designware",
484 		.of_match_table = of_match_ptr(dw_i2c_of_match),
485 		.acpi_match_table = ACPI_PTR(dw_i2c_acpi_match),
486 		.pm	= DW_I2C_DEV_PMOPS,
487 	},
488 };
489 
490 static int __init dw_i2c_init_driver(void)
491 {
492 	return platform_driver_register(&dw_i2c_driver);
493 }
494 subsys_initcall(dw_i2c_init_driver);
495 
496 static void __exit dw_i2c_exit_driver(void)
497 {
498 	platform_driver_unregister(&dw_i2c_driver);
499 }
500 module_exit(dw_i2c_exit_driver);
501 
502 MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
503 MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter");
504 MODULE_LICENSE("GPL");
505