1 /*
2  * Mac80211 SPI driver for ST-Ericsson CW1200 device
3  *
4  * Copyright (c) 2011, Sagrad Inc.
5  * Author:  Solomon Peachy <speachy@sagrad.com>
6  *
7  * Based on cw1200_sdio.c
8  * Copyright (c) 2010, ST-Ericsson
9  * Author: Dmitry Tarnyagin <dmitry.tarnyagin@lockless.no>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  */
15 
16 #include <linux/module.h>
17 #include <linux/gpio.h>
18 #include <linux/delay.h>
19 #include <linux/spinlock.h>
20 #include <linux/interrupt.h>
21 #include <net/mac80211.h>
22 
23 #include <linux/spi/spi.h>
24 #include <linux/device.h>
25 
26 #include "cw1200.h"
27 #include "hwbus.h"
28 #include <linux/platform_data/net-cw1200.h>
29 #include "hwio.h"
30 
31 MODULE_AUTHOR("Solomon Peachy <speachy@sagrad.com>");
32 MODULE_DESCRIPTION("mac80211 ST-Ericsson CW1200 SPI driver");
33 MODULE_LICENSE("GPL");
34 MODULE_ALIAS("spi:cw1200_wlan_spi");
35 
36 /* #define SPI_DEBUG */
37 
38 struct hwbus_priv {
39 	struct spi_device	*func;
40 	struct cw1200_common	*core;
41 	const struct cw1200_platform_data_spi *pdata;
42 	spinlock_t		lock; /* Serialize all bus operations */
43 	wait_queue_head_t       wq;
44 	int claimed;
45 };
46 
47 #define SDIO_TO_SPI_ADDR(addr) ((addr & 0x1f)>>2)
48 #define SET_WRITE 0x7FFF /* usage: and operation */
49 #define SET_READ 0x8000  /* usage: or operation */
50 
51 /* Notes on byte ordering:
52    LE:  B0 B1 B2 B3
53    BE:  B3 B2 B1 B0
54 
55    Hardware expects 32-bit data to be written as 16-bit BE words:
56 
57    B1 B0 B3 B2
58 */
59 
60 static int cw1200_spi_memcpy_fromio(struct hwbus_priv *self,
61 				     unsigned int addr,
62 				     void *dst, int count)
63 {
64 	int ret, i;
65 	u16 regaddr;
66 	struct spi_message      m;
67 
68 	struct spi_transfer     t_addr = {
69 		.tx_buf         = &regaddr,
70 		.len            = sizeof(regaddr),
71 	};
72 	struct spi_transfer     t_msg = {
73 		.rx_buf         = dst,
74 		.len            = count,
75 	};
76 
77 	regaddr = (SDIO_TO_SPI_ADDR(addr))<<12;
78 	regaddr |= SET_READ;
79 	regaddr |= (count>>1);
80 
81 #ifdef SPI_DEBUG
82 	pr_info("READ : %04d from 0x%02x (%04x)\n", count, addr, regaddr);
83 #endif
84 
85 	/* Header is LE16 */
86 	regaddr = cpu_to_le16(regaddr);
87 
88 	/* We have to byteswap if the SPI bus is limited to 8b operation
89 	   or we are running on a Big Endian system
90 	*/
91 #if defined(__LITTLE_ENDIAN)
92 	if (self->func->bits_per_word == 8)
93 #endif
94 		regaddr = swab16(regaddr);
95 
96 	spi_message_init(&m);
97 	spi_message_add_tail(&t_addr, &m);
98 	spi_message_add_tail(&t_msg, &m);
99 	ret = spi_sync(self->func, &m);
100 
101 #ifdef SPI_DEBUG
102 	pr_info("READ : ");
103 	for (i = 0; i < t_addr.len; i++)
104 		printk("%02x ", ((u8 *)t_addr.tx_buf)[i]);
105 	printk(" : ");
106 	for (i = 0; i < t_msg.len; i++)
107 		printk("%02x ", ((u8 *)t_msg.rx_buf)[i]);
108 	printk("\n");
109 #endif
110 
111 	/* We have to byteswap if the SPI bus is limited to 8b operation
112 	   or we are running on a Big Endian system
113 	*/
114 #if defined(__LITTLE_ENDIAN)
115 	if (self->func->bits_per_word == 8)
116 #endif
117 	{
118 		uint16_t *buf = (uint16_t *)dst;
119 		for (i = 0; i < ((count + 1) >> 1); i++)
120 			buf[i] = swab16(buf[i]);
121 	}
122 
123 	return ret;
124 }
125 
126 static int cw1200_spi_memcpy_toio(struct hwbus_priv *self,
127 				   unsigned int addr,
128 				   const void *src, int count)
129 {
130 	int rval, i;
131 	u16 regaddr;
132 	struct spi_transfer     t_addr = {
133 		.tx_buf         = &regaddr,
134 		.len            = sizeof(regaddr),
135 	};
136 	struct spi_transfer     t_msg = {
137 		.tx_buf         = src,
138 		.len            = count,
139 	};
140 	struct spi_message      m;
141 
142 	regaddr = (SDIO_TO_SPI_ADDR(addr))<<12;
143 	regaddr &= SET_WRITE;
144 	regaddr |= (count>>1);
145 
146 #ifdef SPI_DEBUG
147 	pr_info("WRITE: %04d  to  0x%02x (%04x)\n", count, addr, regaddr);
148 #endif
149 
150 	/* Header is LE16 */
151 	regaddr = cpu_to_le16(regaddr);
152 
153 	/* We have to byteswap if the SPI bus is limited to 8b operation
154 	   or we are running on a Big Endian system
155 	*/
156 #if defined(__LITTLE_ENDIAN)
157 	if (self->func->bits_per_word == 8)
158 #endif
159 	{
160 		uint16_t *buf = (uint16_t *)src;
161 	        regaddr = swab16(regaddr);
162 		for (i = 0; i < ((count + 1) >> 1); i++)
163 			buf[i] = swab16(buf[i]);
164 	}
165 
166 #ifdef SPI_DEBUG
167 	pr_info("WRITE: ");
168 	for (i = 0; i < t_addr.len; i++)
169 		printk("%02x ", ((u8 *)t_addr.tx_buf)[i]);
170 	printk(" : ");
171 	for (i = 0; i < t_msg.len; i++)
172 		printk("%02x ", ((u8 *)t_msg.tx_buf)[i]);
173 	printk("\n");
174 #endif
175 
176 	spi_message_init(&m);
177 	spi_message_add_tail(&t_addr, &m);
178 	spi_message_add_tail(&t_msg, &m);
179 	rval = spi_sync(self->func, &m);
180 
181 #ifdef SPI_DEBUG
182 	pr_info("WROTE: %d\n", m.actual_length);
183 #endif
184 
185 #if defined(__LITTLE_ENDIAN)
186 	/* We have to byteswap if the SPI bus is limited to 8b operation */
187 	if (self->func->bits_per_word == 8)
188 #endif
189 	{
190 		uint16_t *buf = (uint16_t *)src;
191 		for (i = 0; i < ((count + 1) >> 1); i++)
192 			buf[i] = swab16(buf[i]);
193 	}
194 	return rval;
195 }
196 
197 static void cw1200_spi_lock(struct hwbus_priv *self)
198 {
199 	unsigned long flags;
200 
201 	DECLARE_WAITQUEUE(wait, current);
202 
203 	might_sleep();
204 
205 	add_wait_queue(&self->wq, &wait);
206 	spin_lock_irqsave(&self->lock, flags);
207 	while (1) {
208 		set_current_state(TASK_UNINTERRUPTIBLE);
209 		if (!self->claimed)
210 			break;
211 		spin_unlock_irqrestore(&self->lock, flags);
212 		schedule();
213 		spin_lock_irqsave(&self->lock, flags);
214 	}
215 	set_current_state(TASK_RUNNING);
216 	self->claimed = 1;
217 	spin_unlock_irqrestore(&self->lock, flags);
218 	remove_wait_queue(&self->wq, &wait);
219 
220 	return;
221 }
222 
223 static void cw1200_spi_unlock(struct hwbus_priv *self)
224 {
225 	unsigned long flags;
226 
227 	spin_lock_irqsave(&self->lock, flags);
228 	self->claimed = 0;
229 	spin_unlock_irqrestore(&self->lock, flags);
230 	wake_up(&self->wq);
231 
232 	return;
233 }
234 
235 static irqreturn_t cw1200_spi_irq_handler(int irq, void *dev_id)
236 {
237 	struct hwbus_priv *self = dev_id;
238 
239 	if (self->core) {
240 		cw1200_spi_lock(self);
241 		cw1200_irq_handler(self->core);
242 		cw1200_spi_unlock(self);
243 		return IRQ_HANDLED;
244 	} else {
245 		return IRQ_NONE;
246 	}
247 }
248 
249 static int cw1200_spi_irq_subscribe(struct hwbus_priv *self)
250 {
251 	int ret;
252 
253 	pr_debug("SW IRQ subscribe\n");
254 
255 	ret = request_threaded_irq(self->func->irq, NULL,
256 				   cw1200_spi_irq_handler,
257 				   IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
258 				   "cw1200_wlan_irq", self);
259 	if (WARN_ON(ret < 0))
260 		goto exit;
261 
262 	ret = enable_irq_wake(self->func->irq);
263 	if (WARN_ON(ret))
264 		goto free_irq;
265 
266 	return 0;
267 
268 free_irq:
269 	free_irq(self->func->irq, self);
270 exit:
271 	return ret;
272 }
273 
274 static int cw1200_spi_irq_unsubscribe(struct hwbus_priv *self)
275 {
276 	int ret = 0;
277 
278 	pr_debug("SW IRQ unsubscribe\n");
279 	disable_irq_wake(self->func->irq);
280 	free_irq(self->func->irq, self);
281 
282 	return ret;
283 }
284 
285 static int cw1200_spi_off(const struct cw1200_platform_data_spi *pdata)
286 {
287 	if (pdata->reset) {
288 		gpio_set_value(pdata->reset, 0);
289 		msleep(30); /* Min is 2 * CLK32K cycles */
290 		gpio_free(pdata->reset);
291 	}
292 
293 	if (pdata->power_ctrl)
294 		pdata->power_ctrl(pdata, false);
295 	if (pdata->clk_ctrl)
296 		pdata->clk_ctrl(pdata, false);
297 
298 	return 0;
299 }
300 
301 static int cw1200_spi_on(const struct cw1200_platform_data_spi *pdata)
302 {
303 	/* Ensure I/Os are pulled low */
304 	if (pdata->reset) {
305 		gpio_request(pdata->reset, "cw1200_wlan_reset");
306 		gpio_direction_output(pdata->reset, 0);
307 	}
308 	if (pdata->powerup) {
309 		gpio_request(pdata->powerup, "cw1200_wlan_powerup");
310 		gpio_direction_output(pdata->powerup, 0);
311 	}
312 	if (pdata->reset || pdata->powerup)
313 		msleep(10); /* Settle time? */
314 
315 	/* Enable 3v3 and 1v8 to hardware */
316 	if (pdata->power_ctrl) {
317 		if (pdata->power_ctrl(pdata, true)) {
318 			pr_err("power_ctrl() failed!\n");
319 			return -1;
320 		}
321 	}
322 
323 	/* Enable CLK32K */
324 	if (pdata->clk_ctrl) {
325 		if (pdata->clk_ctrl(pdata, true)) {
326 			pr_err("clk_ctrl() failed!\n");
327 			return -1;
328 		}
329 		msleep(10); /* Delay until clock is stable for 2 cycles */
330 	}
331 
332 	/* Enable POWERUP signal */
333 	if (pdata->powerup) {
334 		gpio_set_value(pdata->powerup, 1);
335 		msleep(250); /* or more..? */
336 	}
337 	/* Enable RSTn signal */
338 	if (pdata->reset) {
339 		gpio_set_value(pdata->reset, 1);
340 		msleep(50); /* Or more..? */
341 	}
342 	return 0;
343 }
344 
345 static size_t cw1200_spi_align_size(struct hwbus_priv *self, size_t size)
346 {
347 	return size & 1 ? size + 1 : size;
348 }
349 
350 static int cw1200_spi_pm(struct hwbus_priv *self, bool suspend)
351 {
352 	return irq_set_irq_wake(self->func->irq, suspend);
353 }
354 
355 static struct hwbus_ops cw1200_spi_hwbus_ops = {
356 	.hwbus_memcpy_fromio	= cw1200_spi_memcpy_fromio,
357 	.hwbus_memcpy_toio	= cw1200_spi_memcpy_toio,
358 	.lock			= cw1200_spi_lock,
359 	.unlock			= cw1200_spi_unlock,
360 	.align_size		= cw1200_spi_align_size,
361 	.power_mgmt		= cw1200_spi_pm,
362 };
363 
364 /* Probe Function to be called by SPI stack when device is discovered */
365 static int cw1200_spi_probe(struct spi_device *func)
366 {
367 	const struct cw1200_platform_data_spi *plat_data =
368 		dev_get_platdata(&func->dev);
369 	struct hwbus_priv *self;
370 	int status;
371 
372 	/* Sanity check speed */
373 	if (func->max_speed_hz > 52000000)
374 		func->max_speed_hz = 52000000;
375 	if (func->max_speed_hz < 1000000)
376 		func->max_speed_hz = 1000000;
377 
378 	/* Fix up transfer size */
379 	if (plat_data->spi_bits_per_word)
380 		func->bits_per_word = plat_data->spi_bits_per_word;
381 	if (!func->bits_per_word)
382 		func->bits_per_word = 16;
383 
384 	/* And finally.. */
385 	func->mode = SPI_MODE_0;
386 
387 	pr_info("cw1200_wlan_spi: Probe called (CS %d M %d BPW %d CLK %d)\n",
388 		func->chip_select, func->mode, func->bits_per_word,
389 		func->max_speed_hz);
390 
391 	if (cw1200_spi_on(plat_data)) {
392 		pr_err("spi_on() failed!\n");
393 		return -1;
394 	}
395 
396 	if (spi_setup(func)) {
397 		pr_err("spi_setup() failed!\n");
398 		return -1;
399 	}
400 
401 	self = devm_kzalloc(&func->dev, sizeof(*self), GFP_KERNEL);
402 	if (!self) {
403 		pr_err("Can't allocate SPI hwbus_priv.");
404 		return -ENOMEM;
405 	}
406 
407 	self->pdata = plat_data;
408 	self->func = func;
409 	spin_lock_init(&self->lock);
410 
411 	spi_set_drvdata(func, self);
412 
413 	init_waitqueue_head(&self->wq);
414 
415 	status = cw1200_spi_irq_subscribe(self);
416 
417 	status = cw1200_core_probe(&cw1200_spi_hwbus_ops,
418 				   self, &func->dev, &self->core,
419 				   self->pdata->ref_clk,
420 				   self->pdata->macaddr,
421 				   self->pdata->sdd_file,
422 				   self->pdata->have_5ghz);
423 
424 	if (status) {
425 		cw1200_spi_irq_unsubscribe(self);
426 		cw1200_spi_off(plat_data);
427 	}
428 
429 	return status;
430 }
431 
432 /* Disconnect Function to be called by SPI stack when device is disconnected */
433 static int cw1200_spi_disconnect(struct spi_device *func)
434 {
435 	struct hwbus_priv *self = spi_get_drvdata(func);
436 
437 	if (self) {
438 		cw1200_spi_irq_unsubscribe(self);
439 		if (self->core) {
440 			cw1200_core_release(self->core);
441 			self->core = NULL;
442 		}
443 	}
444 	cw1200_spi_off(dev_get_platdata(&func->dev));
445 
446 	return 0;
447 }
448 
449 static int __maybe_unused cw1200_spi_suspend(struct device *dev)
450 {
451 	struct hwbus_priv *self = spi_get_drvdata(to_spi_device(dev));
452 
453 	if (!cw1200_can_suspend(self->core))
454 		return -EAGAIN;
455 
456 	/* XXX notify host that we have to keep CW1200 powered on? */
457 	return 0;
458 }
459 
460 static SIMPLE_DEV_PM_OPS(cw1200_pm_ops, cw1200_spi_suspend, NULL);
461 
462 static struct spi_driver spi_driver = {
463 	.probe		= cw1200_spi_probe,
464 	.remove		= cw1200_spi_disconnect,
465 	.driver = {
466 		.name		= "cw1200_wlan_spi",
467 		.pm		= IS_ENABLED(CONFIG_PM) ? &cw1200_pm_ops : NULL,
468 	},
469 };
470 
471 module_spi_driver(spi_driver);
472