free electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
/*
 * Synopsys DesignWare I2C adapter driver (master only).
 *
 * Based on the TI DAVINCI I2C adapter driver.
 *
 * Copyright (C) 2006 Texas Instruments.
 * Copyright (C) 2007 MontaVista Software Inc.
 * Copyright (C) 2009 Provigent Ltd.
 *
 * ----------------------------------------------------------------------------
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * ----------------------------------------------------------------------------
 *
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <linux/io.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/platform_data/i2c-designware.h>
#include "i2c-designware-core.h"

static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
{
	return clk_get_rate(dev->clk)/1000;
}

#ifdef CONFIG_ACPI
/*
 * The HCNT/LCNT information coming from ACPI should be the most accurate
 * for given platform. However, some systems get it wrong. On such systems
 * we get better results by calculating those based on the input clock.
 */
static const struct dmi_system_id dw_i2c_no_acpi_params[] = {
	{
		.ident = "Dell Inspiron 7348",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7348"),
		},
	},
	{ }
};

static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
			       u16 *hcnt, u16 *lcnt, u32 *sda_hold)
{
	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
	union acpi_object *obj;

	if (dmi_check_system(dw_i2c_no_acpi_params))
		return;

	if (ACPI_FAILURE(acpi_evaluate_object(handle, method, NULL, &buf)))
		return;

	obj = (union acpi_object *)buf.pointer;
	if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 3) {
		const union acpi_object *objs = obj->package.elements;

		*hcnt = (u16)objs[0].integer.value;
		*lcnt = (u16)objs[1].integer.value;
		if (sda_hold)
			*sda_hold = (u32)objs[2].integer.value;
	}

	kfree(buf.pointer);
}

static int dw_i2c_acpi_configure(struct platform_device *pdev)
{
	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
	const struct acpi_device_id *id;

	dev->adapter.nr = -1;
	dev->tx_fifo_depth = 32;
	dev->rx_fifo_depth = 32;

	/*
	 * Try to get SDA hold time and *CNT values from an ACPI method if
	 * it exists for both supported speed modes.
	 */
	dw_i2c_acpi_params(pdev, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, NULL);
	dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt,
			   &dev->sda_hold_time);
	dw_i2c_acpi_params(pdev, "FPCN", &dev->fp_hcnt, &dev->fp_lcnt, NULL);
	dw_i2c_acpi_params(pdev, "HSCN", &dev->hs_hcnt, &dev->hs_lcnt, NULL);

	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
	if (id && id->driver_data)
		dev->accessor_flags |= (u32)id->driver_data;

	return 0;
}

static const struct acpi_device_id dw_i2c_acpi_match[] = {
	{ "INT33C2", 0 },
	{ "INT33C3", 0 },
	{ "INT3432", 0 },
	{ "INT3433", 0 },
	{ "80860F41", 0 },
	{ "808622C1", 0 },
	{ "AMD0010", ACCESS_INTR_MASK },
	{ "AMDI0010", ACCESS_INTR_MASK },
	{ "AMDI0510", 0 },
	{ "APMC0D0F", 0 },
	{ }
};
MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
#else
static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
{
	return -ENODEV;
}
#endif

static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
{
	if (IS_ERR(i_dev->clk))
		return PTR_ERR(i_dev->clk);

	if (prepare)
		return clk_prepare_enable(i_dev->clk);

	clk_disable_unprepare(i_dev->clk);
	return 0;
}

static void dw_i2c_set_fifo_size(struct dw_i2c_dev *dev, int id)
{
	u32 param, tx_fifo_depth, rx_fifo_depth;

	/*
	 * Try to detect the FIFO depth if not set by interface driver,
	 * the depth could be from 2 to 256 from HW spec.
	 */
	param = i2c_dw_read_comp_param(dev);
	tx_fifo_depth = ((param >> 16) & 0xff) + 1;
	rx_fifo_depth = ((param >> 8)  & 0xff) + 1;
	if (!dev->tx_fifo_depth) {
		dev->tx_fifo_depth = tx_fifo_depth;
		dev->rx_fifo_depth = rx_fifo_depth;
		dev->adapter.nr = id;
	} else if (tx_fifo_depth >= 2) {
		dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth,
				tx_fifo_depth);
		dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth,
				rx_fifo_depth);
	}
}

static int dw_i2c_plat_probe(struct platform_device *pdev)
{
	struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
	struct dw_i2c_dev *dev;
	struct i2c_adapter *adap;
	struct resource *mem;
	int irq, r;
	u32 acpi_speed, ht = 0;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	dev = devm_kzalloc(&pdev->dev, sizeof(struct dw_i2c_dev), GFP_KERNEL);
	if (!dev)
		return -ENOMEM;

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	dev->base = devm_ioremap_resource(&pdev->dev, mem);
	if (IS_ERR(dev->base))
		return PTR_ERR(dev->base);

	dev->dev = &pdev->dev;
	dev->irq = irq;
	platform_set_drvdata(pdev, dev);

	dev->rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
	if (IS_ERR(dev->rst)) {
		if (PTR_ERR(dev->rst) == -EPROBE_DEFER)
			return -EPROBE_DEFER;
	} else {
		reset_control_deassert(dev->rst);
	}

	if (pdata) {
		dev->clk_freq = pdata->i2c_scl_freq;
	} else {
		device_property_read_u32(&pdev->dev, "i2c-sda-hold-time-ns",
					 &ht);
		device_property_read_u32(&pdev->dev, "i2c-sda-falling-time-ns",
					 &dev->sda_falling_time);
		device_property_read_u32(&pdev->dev, "i2c-scl-falling-time-ns",
					 &dev->scl_falling_time);
		device_property_read_u32(&pdev->dev, "clock-frequency",
					 &dev->clk_freq);
	}

	acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
	/*
	 * Find bus speed from the "clock-frequency" device property, ACPI
	 * or by using fast mode if neither is set.
	 */
	if (acpi_speed && dev->clk_freq)
		dev->clk_freq = min(dev->clk_freq, acpi_speed);
	else if (acpi_speed || dev->clk_freq)
		dev->clk_freq = max(dev->clk_freq, acpi_speed);
	else
		dev->clk_freq = 400000;

	if (has_acpi_companion(&pdev->dev))
		dw_i2c_acpi_configure(pdev);

	/*
	 * Only standard mode at 100kHz, fast mode at 400kHz,
	 * fast mode plus at 1MHz and high speed mode at 3.4MHz are supported.
	 */
	if (dev->clk_freq != 100000 && dev->clk_freq != 400000
	    && dev->clk_freq != 1000000 && dev->clk_freq != 3400000) {
		dev_err(&pdev->dev,
			"Only 100kHz, 400kHz, 1MHz and 3.4MHz supported");
		r = -EINVAL;
		goto exit_reset;
	}

	r = i2c_dw_eval_lock_support(dev);
	if (r)
		goto exit_reset;

	dev->functionality = I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY;

	dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
			  DW_IC_CON_RESTART_EN;

	switch (dev->clk_freq) {
	case 100000:
		dev->master_cfg |= DW_IC_CON_SPEED_STD;
		break;
	case 3400000:
		dev->master_cfg |= DW_IC_CON_SPEED_HIGH;
		break;
	default:
		dev->master_cfg |= DW_IC_CON_SPEED_FAST;
	}

	dev->clk = devm_clk_get(&pdev->dev, NULL);
	if (!i2c_dw_plat_prepare_clk(dev, true)) {
		dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;

		if (!dev->sda_hold_time && ht)
			dev->sda_hold_time = div_u64(
				(u64)dev->get_clk_rate_khz(dev) * ht + 500000,
				1000000);
	}

	dw_i2c_set_fifo_size(dev, pdev->id);

	adap = &dev->adapter;
	adap->owner = THIS_MODULE;
	adap->class = I2C_CLASS_DEPRECATED;
	ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
	adap->dev.of_node = pdev->dev.of_node;

	if (dev->pm_runtime_disabled) {
		pm_runtime_forbid(&pdev->dev);
	} else {
		pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
		pm_runtime_use_autosuspend(&pdev->dev);
		pm_runtime_set_active(&pdev->dev);
		pm_runtime_enable(&pdev->dev);
	}

	r = i2c_dw_probe(dev);
	if (r)
		goto exit_probe;

	return r;

exit_probe:
	if (!dev->pm_runtime_disabled)
		pm_runtime_disable(&pdev->dev);
exit_reset:
	if (!IS_ERR_OR_NULL(dev->rst))
		reset_control_assert(dev->rst);
	return r;
}

static int dw_i2c_plat_remove(struct platform_device *pdev)
{
	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);

	pm_runtime_get_sync(&pdev->dev);

	i2c_del_adapter(&dev->adapter);

	i2c_dw_disable(dev);

	pm_runtime_dont_use_autosuspend(&pdev->dev);
	pm_runtime_put_sync(&pdev->dev);
	if (!dev->pm_runtime_disabled)
		pm_runtime_disable(&pdev->dev);
	if (!IS_ERR_OR_NULL(dev->rst))
		reset_control_assert(dev->rst);

	return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id dw_i2c_of_match[] = {
	{ .compatible = "snps,designware-i2c", },
	{},
};
MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
#endif

#ifdef CONFIG_PM_SLEEP
static int dw_i2c_plat_prepare(struct device *dev)
{
	return pm_runtime_suspended(dev);
}

static void dw_i2c_plat_complete(struct device *dev)
{
	if (dev->power.direct_complete)
		pm_request_resume(dev);
}
#else
#define dw_i2c_plat_prepare	NULL
#define dw_i2c_plat_complete	NULL
#endif

#ifdef CONFIG_PM
static int dw_i2c_plat_suspend(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);

	i2c_dw_disable(i_dev);
	i2c_dw_plat_prepare_clk(i_dev, false);

	return 0;
}

static int dw_i2c_plat_resume(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);

	i2c_dw_plat_prepare_clk(i_dev, true);

	if (!i_dev->pm_runtime_disabled)
		i2c_dw_init(i_dev);

	return 0;
}

static const struct dev_pm_ops dw_i2c_dev_pm_ops = {
	.prepare = dw_i2c_plat_prepare,
	.complete = dw_i2c_plat_complete,
	SET_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume)
	SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL)
};

#define DW_I2C_DEV_PMOPS (&dw_i2c_dev_pm_ops)
#else
#define DW_I2C_DEV_PMOPS NULL
#endif

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:i2c_designware");

static struct platform_driver dw_i2c_driver = {
	.probe = dw_i2c_plat_probe,
	.remove = dw_i2c_plat_remove,
	.driver		= {
		.name	= "i2c_designware",
		.of_match_table = of_match_ptr(dw_i2c_of_match),
		.acpi_match_table = ACPI_PTR(dw_i2c_acpi_match),
		.pm	= DW_I2C_DEV_PMOPS,
	},
};

static int __init dw_i2c_init_driver(void)
{
	return platform_driver_register(&dw_i2c_driver);
}
subsys_initcall(dw_i2c_init_driver);

static void __exit dw_i2c_exit_driver(void)
{
	platform_driver_unregister(&dw_i2c_driver);
}
module_exit(dw_i2c_exit_driver);

MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter");
MODULE_LICENSE("GPL");