1 /*
2  * Synopsys DesignWare I2C adapter driver (master only).
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/kernel.h>
25 #include <linux/module.h>
26 #include <linux/delay.h>
27 #include <linux/i2c.h>
28 #include <linux/clk.h>
29 #include <linux/clk-provider.h>
30 #include <linux/errno.h>
31 #include <linux/sched.h>
32 #include <linux/err.h>
33 #include <linux/interrupt.h>
34 #include <linux/of.h>
35 #include <linux/platform_device.h>
36 #include <linux/pm.h>
37 #include <linux/pm_runtime.h>
38 #include <linux/io.h>
39 #include <linux/slab.h>
40 #include <linux/acpi.h>
41 #include <linux/platform_data/i2c-designware.h>
42 #include "i2c-designware-core.h"
43 
44 static struct i2c_algorithm i2c_dw_algo = {
45 	.master_xfer	= i2c_dw_xfer,
46 	.functionality	= i2c_dw_func,
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 static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
55 			       u16 *hcnt, u16 *lcnt, u32 *sda_hold)
56 {
57 	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
58 	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
59 	union acpi_object *obj;
60 
61 	if (ACPI_FAILURE(acpi_evaluate_object(handle, method, NULL, &buf)))
62 		return;
63 
64 	obj = (union acpi_object *)buf.pointer;
65 	if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 3) {
66 		const union acpi_object *objs = obj->package.elements;
67 
68 		*hcnt = (u16)objs[0].integer.value;
69 		*lcnt = (u16)objs[1].integer.value;
70 		if (sda_hold)
71 			*sda_hold = (u32)objs[2].integer.value;
72 	}
73 
74 	kfree(buf.pointer);
75 }
76 
77 static int dw_i2c_acpi_configure(struct platform_device *pdev)
78 {
79 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
80 	const struct acpi_device_id *id;
81 
82 	dev->adapter.nr = -1;
83 	dev->tx_fifo_depth = 32;
84 	dev->rx_fifo_depth = 32;
85 
86 	/*
87 	 * Try to get SDA hold time and *CNT values from an ACPI method if
88 	 * it exists for both supported speed modes.
89 	 */
90 	dw_i2c_acpi_params(pdev, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, NULL);
91 	dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt,
92 			   &dev->sda_hold_time);
93 
94 	/*
95 	 * Provide a way for Designware I2C host controllers that are not
96 	 * based on Intel LPSS to specify their input clock frequency via
97 	 * id->driver_data.
98 	 */
99 	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
100 	if (id && id->driver_data)
101 		clk_register_fixed_rate(&pdev->dev, dev_name(&pdev->dev), NULL,
102 					CLK_IS_ROOT, id->driver_data);
103 
104 	return 0;
105 }
106 
107 static void dw_i2c_acpi_unconfigure(struct platform_device *pdev)
108 {
109 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
110 	const struct acpi_device_id *id;
111 
112 	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
113 	if (id && id->driver_data)
114 		clk_unregister(dev->clk);
115 }
116 
117 static const struct acpi_device_id dw_i2c_acpi_match[] = {
118 	{ "INT33C2", 0 },
119 	{ "INT33C3", 0 },
120 	{ "INT3432", 0 },
121 	{ "INT3433", 0 },
122 	{ "80860F41", 0 },
123 	{ "808622C1", 0 },
124 	{ "AMD0010", 133 * 1000 * 1000 },
125 	{ }
126 };
127 MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
128 #else
129 static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
130 {
131 	return -ENODEV;
132 }
133 static inline void dw_i2c_acpi_unconfigure(struct platform_device *pdev) { }
134 #endif
135 
136 static int dw_i2c_probe(struct platform_device *pdev)
137 {
138 	struct dw_i2c_dev *dev;
139 	struct i2c_adapter *adap;
140 	struct resource *mem;
141 	struct dw_i2c_platform_data *pdata;
142 	int irq, r;
143 	u32 clk_freq, ht = 0;
144 
145 	irq = platform_get_irq(pdev, 0);
146 	if (irq < 0) {
147 		dev_err(&pdev->dev, "no irq resource?\n");
148 		return irq; /* -ENXIO */
149 	}
150 
151 	dev = devm_kzalloc(&pdev->dev, sizeof(struct dw_i2c_dev), GFP_KERNEL);
152 	if (!dev)
153 		return -ENOMEM;
154 
155 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
156 	dev->base = devm_ioremap_resource(&pdev->dev, mem);
157 	if (IS_ERR(dev->base))
158 		return PTR_ERR(dev->base);
159 
160 	init_completion(&dev->cmd_complete);
161 	mutex_init(&dev->lock);
162 	dev->dev = &pdev->dev;
163 	dev->irq = irq;
164 	platform_set_drvdata(pdev, dev);
165 
166 	/* fast mode by default because of legacy reasons */
167 	clk_freq = 400000;
168 
169 	if (ACPI_COMPANION(&pdev->dev)) {
170 		dw_i2c_acpi_configure(pdev);
171 	} else if (pdev->dev.of_node) {
172 		of_property_read_u32(pdev->dev.of_node,
173 					"i2c-sda-hold-time-ns", &ht);
174 
175 		of_property_read_u32(pdev->dev.of_node,
176 				     "i2c-sda-falling-time-ns",
177 				     &dev->sda_falling_time);
178 		of_property_read_u32(pdev->dev.of_node,
179 				     "i2c-scl-falling-time-ns",
180 				     &dev->scl_falling_time);
181 
182 		of_property_read_u32(pdev->dev.of_node, "clock-frequency",
183 				     &clk_freq);
184 
185 		/* Only standard mode at 100kHz and fast mode at 400kHz
186 		 * are supported.
187 		 */
188 		if (clk_freq != 100000 && clk_freq != 400000) {
189 			dev_err(&pdev->dev, "Only 100kHz and 400kHz supported");
190 			return -EINVAL;
191 		}
192 	} else {
193 		pdata = dev_get_platdata(&pdev->dev);
194 		if (pdata)
195 			clk_freq = pdata->i2c_scl_freq;
196 	}
197 
198 	dev->functionality =
199 		I2C_FUNC_I2C |
200 		I2C_FUNC_10BIT_ADDR |
201 		I2C_FUNC_SMBUS_BYTE |
202 		I2C_FUNC_SMBUS_BYTE_DATA |
203 		I2C_FUNC_SMBUS_WORD_DATA |
204 		I2C_FUNC_SMBUS_I2C_BLOCK;
205 	if (clk_freq == 100000)
206 		dev->master_cfg =  DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
207 			DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_STD;
208 	else
209 		dev->master_cfg =  DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
210 			DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
211 
212 	dev->clk = devm_clk_get(&pdev->dev, NULL);
213 	dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
214 	if (IS_ERR(dev->clk))
215 		return PTR_ERR(dev->clk);
216 	clk_prepare_enable(dev->clk);
217 
218 	if (!dev->sda_hold_time && ht) {
219 		u32 ic_clk = dev->get_clk_rate_khz(dev);
220 
221 		dev->sda_hold_time = div_u64((u64)ic_clk * ht + 500000,
222 					     1000000);
223 	}
224 
225 	if (!dev->tx_fifo_depth) {
226 		u32 param1 = i2c_dw_read_comp_param(dev);
227 
228 		dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1;
229 		dev->rx_fifo_depth = ((param1 >> 8)  & 0xff) + 1;
230 		dev->adapter.nr = pdev->id;
231 	}
232 	r = i2c_dw_init(dev);
233 	if (r)
234 		return r;
235 
236 	i2c_dw_disable_int(dev);
237 	r = devm_request_irq(&pdev->dev, dev->irq, i2c_dw_isr, IRQF_SHARED,
238 			pdev->name, dev);
239 	if (r) {
240 		dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
241 		return r;
242 	}
243 
244 	adap = &dev->adapter;
245 	i2c_set_adapdata(adap, dev);
246 	adap->owner = THIS_MODULE;
247 	adap->class = I2C_CLASS_DEPRECATED;
248 	strlcpy(adap->name, "Synopsys DesignWare I2C adapter",
249 			sizeof(adap->name));
250 	adap->algo = &i2c_dw_algo;
251 	adap->dev.parent = &pdev->dev;
252 	adap->dev.of_node = pdev->dev.of_node;
253 
254 	r = i2c_add_numbered_adapter(adap);
255 	if (r) {
256 		dev_err(&pdev->dev, "failure adding adapter\n");
257 		return r;
258 	}
259 
260 	pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
261 	pm_runtime_use_autosuspend(&pdev->dev);
262 	pm_runtime_set_active(&pdev->dev);
263 	pm_runtime_enable(&pdev->dev);
264 
265 	return 0;
266 }
267 
268 static int dw_i2c_remove(struct platform_device *pdev)
269 {
270 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
271 
272 	pm_runtime_get_sync(&pdev->dev);
273 
274 	i2c_del_adapter(&dev->adapter);
275 
276 	i2c_dw_disable(dev);
277 
278 	pm_runtime_put(&pdev->dev);
279 	pm_runtime_disable(&pdev->dev);
280 
281 	if (ACPI_COMPANION(&pdev->dev))
282 		dw_i2c_acpi_unconfigure(pdev);
283 
284 	return 0;
285 }
286 
287 #ifdef CONFIG_OF
288 static const struct of_device_id dw_i2c_of_match[] = {
289 	{ .compatible = "snps,designware-i2c", },
290 	{},
291 };
292 MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
293 #endif
294 
295 #ifdef CONFIG_PM
296 static int dw_i2c_suspend(struct device *dev)
297 {
298 	struct platform_device *pdev = to_platform_device(dev);
299 	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
300 
301 	i2c_dw_disable(i_dev);
302 	clk_disable_unprepare(i_dev->clk);
303 
304 	return 0;
305 }
306 
307 static int dw_i2c_resume(struct device *dev)
308 {
309 	struct platform_device *pdev = to_platform_device(dev);
310 	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
311 
312 	clk_prepare_enable(i_dev->clk);
313 	i2c_dw_init(i_dev);
314 
315 	return 0;
316 }
317 #endif
318 
319 static UNIVERSAL_DEV_PM_OPS(dw_i2c_dev_pm_ops, dw_i2c_suspend,
320 			    dw_i2c_resume, NULL);
321 
322 /* work with hotplug and coldplug */
323 MODULE_ALIAS("platform:i2c_designware");
324 
325 static struct platform_driver dw_i2c_driver = {
326 	.probe = dw_i2c_probe,
327 	.remove = dw_i2c_remove,
328 	.driver		= {
329 		.name	= "i2c_designware",
330 		.owner	= THIS_MODULE,
331 		.of_match_table = of_match_ptr(dw_i2c_of_match),
332 		.acpi_match_table = ACPI_PTR(dw_i2c_acpi_match),
333 		.pm	= &dw_i2c_dev_pm_ops,
334 	},
335 };
336 
337 static int __init dw_i2c_init_driver(void)
338 {
339 	return platform_driver_register(&dw_i2c_driver);
340 }
341 subsys_initcall(dw_i2c_init_driver);
342 
343 static void __exit dw_i2c_exit_driver(void)
344 {
345 	platform_driver_unregister(&dw_i2c_driver);
346 }
347 module_exit(dw_i2c_exit_driver);
348 
349 MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
350 MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter");
351 MODULE_LICENSE("GPL");
352