1/*
  2 * drivers/usb/otg/nop-usb-xceiv.c
  3 *
  4 * NOP USB transceiver for all USB transceiver which are either built-in
  5 * into USB IP or which are mostly autonomous.
  6 *
  7 * Copyright (C) 2009 Texas Instruments Inc
  8 * Author: Ajay Kumar Gupta <ajay.gupta@ti.com>
  9 *
 10 * This program is free software; you can redistribute it and/or modify
 11 * it under the terms of the GNU General Public License as published by
 12 * the Free Software Foundation; either version 2 of the License, or
 13 * (at your option) any later version.
 14 *
 15 * This program is distributed in the hope that it will be useful,
 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 18 * GNU General Public License for more details.
 19 *
 20 * You should have received a copy of the GNU General Public License
 21 * along with this program; if not, write to the Free Software
 22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 23 *
 24 * Current status:
 25 *	This provides a "nop" transceiver for PHYs which are
 26 *	autonomous such as isp1504, isp1707, etc.
 27 */
 28
 29#include <linux/module.h>
 30#include <linux/platform_device.h>
 31#include <linux/dma-mapping.h>
 32#include <linux/usb/otg.h>
 33#include <linux/usb/usb_phy_gen_xceiv.h>
 34#include <linux/slab.h>
 35#include <linux/clk.h>
 36#include <linux/regulator/consumer.h>
 37#include <linux/of.h>
 38#include <linux/of_gpio.h>
 39#include <linux/gpio.h>
 40#include <linux/delay.h>
 41
 42#include "phy-generic.h"
 43
 44static struct platform_device *pd;
 45
 46void usb_nop_xceiv_register(void)
 47{
 48	if (pd)
 49		return;
 50	pd = platform_device_register_simple("usb_phy_gen_xceiv", -1, NULL, 0);
 51	if (IS_ERR(pd)) {
 52		pr_err("Unable to register generic usb transceiver\n");
 53		pd = NULL;
 54		return;
 55	}
 56}
 57EXPORT_SYMBOL(usb_nop_xceiv_register);
 58
 59void usb_nop_xceiv_unregister(void)
 60{
 61	platform_device_unregister(pd);
 62	pd = NULL;
 63}
 64EXPORT_SYMBOL(usb_nop_xceiv_unregister);
 65
 66static int nop_set_suspend(struct usb_phy *x, int suspend)
 67{
 68	return 0;
 69}
 70
 71static void nop_reset_set(struct usb_phy_gen_xceiv *nop, int asserted)
 72{
 73	int value;
 74
 75	if (!gpio_is_valid(nop->gpio_reset))
 76		return;
 77
 78	value = asserted;
 79	if (nop->reset_active_low)
 80		value = !value;
 81
 82	gpio_set_value_cansleep(nop->gpio_reset, value);
 83
 84	if (!asserted)
 85		usleep_range(10000, 20000);
 86}
 87
 88int usb_gen_phy_init(struct usb_phy *phy)
 89{
 90	struct usb_phy_gen_xceiv *nop = dev_get_drvdata(phy->dev);
 91
 92	if (!IS_ERR(nop->vcc)) {
 93		if (regulator_enable(nop->vcc))
 94			dev_err(phy->dev, "Failed to enable power\n");
 95	}
 96
 97	if (!IS_ERR(nop->clk))
 98		clk_prepare_enable(nop->clk);
 99
100	/* De-assert RESET */
101	nop_reset_set(nop, 0);
102
103	return 0;
104}
105EXPORT_SYMBOL_GPL(usb_gen_phy_init);
106
107void usb_gen_phy_shutdown(struct usb_phy *phy)
108{
109	struct usb_phy_gen_xceiv *nop = dev_get_drvdata(phy->dev);
110
111	/* Assert RESET */
112	nop_reset_set(nop, 1);
113
114	if (!IS_ERR(nop->clk))
115		clk_disable_unprepare(nop->clk);
116
117	if (!IS_ERR(nop->vcc)) {
118		if (regulator_disable(nop->vcc))
119			dev_err(phy->dev, "Failed to disable power\n");
120	}
121}
122EXPORT_SYMBOL_GPL(usb_gen_phy_shutdown);
123
124static int nop_set_peripheral(struct usb_otg *otg, struct usb_gadget *gadget)
125{
126	if (!otg)
127		return -ENODEV;
128
129	if (!gadget) {
130		otg->gadget = NULL;
131		return -ENODEV;
132	}
133
134	otg->gadget = gadget;
135	otg->phy->state = OTG_STATE_B_IDLE;
136	return 0;
137}
138
139static int nop_set_host(struct usb_otg *otg, struct usb_bus *host)
140{
141	if (!otg)
142		return -ENODEV;
143
144	if (!host) {
145		otg->host = NULL;
146		return -ENODEV;
147	}
148
149	otg->host = host;
150	return 0;
151}
152
153int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_gen_xceiv *nop,
154		struct usb_phy_gen_xceiv_platform_data *pdata)
155{
156	enum usb_phy_type type = USB_PHY_TYPE_USB2;
157	int err;
158
159	u32 clk_rate = 0;
160	bool needs_vcc = false;
161
162	nop->reset_active_low = true;	/* default behaviour */
163
164	if (dev->of_node) {
165		struct device_node *node = dev->of_node;
166		enum of_gpio_flags flags = 0;
167
168		if (of_property_read_u32(node, "clock-frequency", &clk_rate))
169			clk_rate = 0;
170
171		needs_vcc = of_property_read_bool(node, "vcc-supply");
172		nop->gpio_reset = of_get_named_gpio_flags(node, "reset-gpios",
173								0, &flags);
174		if (nop->gpio_reset == -EPROBE_DEFER)
175			return -EPROBE_DEFER;
176
177		nop->reset_active_low = flags & OF_GPIO_ACTIVE_LOW;
178
179	} else if (pdata) {
180		type = pdata->type;
181		clk_rate = pdata->clk_rate;
182		needs_vcc = pdata->needs_vcc;
183		nop->gpio_reset = pdata->gpio_reset;
184	} else {
185		nop->gpio_reset = -1;
186	}
187
188	nop->phy.otg = devm_kzalloc(dev, sizeof(*nop->phy.otg),
189			GFP_KERNEL);
190	if (!nop->phy.otg)
191		return -ENOMEM;
192
193	nop->clk = devm_clk_get(dev, "main_clk");
194	if (IS_ERR(nop->clk)) {
195		dev_dbg(dev, "Can't get phy clock: %ld\n",
196					PTR_ERR(nop->clk));
197	}
198
199	if (!IS_ERR(nop->clk) && clk_rate) {
200		err = clk_set_rate(nop->clk, clk_rate);
201		if (err) {
202			dev_err(dev, "Error setting clock rate\n");
203			return err;
204		}
205	}
206
207	nop->vcc = devm_regulator_get(dev, "vcc");
208	if (IS_ERR(nop->vcc)) {
209		dev_dbg(dev, "Error getting vcc regulator: %ld\n",
210					PTR_ERR(nop->vcc));
211		if (needs_vcc)
212			return -EPROBE_DEFER;
213	}
214
215	if (gpio_is_valid(nop->gpio_reset)) {
216		unsigned long gpio_flags;
217
218		/* Assert RESET */
219		if (nop->reset_active_low)
220			gpio_flags = GPIOF_OUT_INIT_LOW;
221		else
222			gpio_flags = GPIOF_OUT_INIT_HIGH;
223
224		err = devm_gpio_request_one(dev, nop->gpio_reset,
225						gpio_flags, dev_name(dev));
226		if (err) {
227			dev_err(dev, "Error requesting RESET GPIO %d\n",
228					nop->gpio_reset);
229			return err;
230		}
231	}
232
233	nop->dev		= dev;
234	nop->phy.dev		= nop->dev;
235	nop->phy.label		= "nop-xceiv";
236	nop->phy.set_suspend	= nop_set_suspend;
237	nop->phy.state		= OTG_STATE_UNDEFINED;
238	nop->phy.type		= type;
239
240	nop->phy.otg->phy		= &nop->phy;
241	nop->phy.otg->set_host		= nop_set_host;
242	nop->phy.otg->set_peripheral	= nop_set_peripheral;
243
244	return 0;
245}
246EXPORT_SYMBOL_GPL(usb_phy_gen_create_phy);
247
248static int usb_phy_gen_xceiv_probe(struct platform_device *pdev)
249{
250	struct device *dev = &pdev->dev;
251	struct usb_phy_gen_xceiv	*nop;
252	int err;
253
254	nop = devm_kzalloc(dev, sizeof(*nop), GFP_KERNEL);
255	if (!nop)
256		return -ENOMEM;
257
258	err = usb_phy_gen_create_phy(dev, nop, dev_get_platdata(&pdev->dev));
259	if (err)
260		return err;
261
262	nop->phy.init		= usb_gen_phy_init;
263	nop->phy.shutdown	= usb_gen_phy_shutdown;
264
265	err = usb_add_phy_dev(&nop->phy);
266	if (err) {
267		dev_err(&pdev->dev, "can't register transceiver, err: %d\n",
268			err);
269		return err;
270	}
271
272	platform_set_drvdata(pdev, nop);
273
274	return 0;
275}
276
277static int usb_phy_gen_xceiv_remove(struct platform_device *pdev)
278{
279	struct usb_phy_gen_xceiv *nop = platform_get_drvdata(pdev);
280
281	usb_remove_phy(&nop->phy);
282
283	return 0;
284}
285
286static const struct of_device_id nop_xceiv_dt_ids[] = {
287	{ .compatible = "usb-nop-xceiv" },
288	{ }
289};
290
291MODULE_DEVICE_TABLE(of, nop_xceiv_dt_ids);
292
293static struct platform_driver usb_phy_gen_xceiv_driver = {
294	.probe		= usb_phy_gen_xceiv_probe,
295	.remove		= usb_phy_gen_xceiv_remove,
296	.driver		= {
297		.name	= "usb_phy_gen_xceiv",
298		.owner	= THIS_MODULE,
299		.of_match_table = nop_xceiv_dt_ids,
300	},
301};
302
303static int __init usb_phy_gen_xceiv_init(void)
304{
305	return platform_driver_register(&usb_phy_gen_xceiv_driver);
306}
307subsys_initcall(usb_phy_gen_xceiv_init);
308
309static void __exit usb_phy_gen_xceiv_exit(void)
310{
311	platform_driver_unregister(&usb_phy_gen_xceiv_driver);
312}
313module_exit(usb_phy_gen_xceiv_exit);
314
315MODULE_ALIAS("platform:usb_phy_gen_xceiv");
316MODULE_AUTHOR("Texas Instruments Inc");
317MODULE_DESCRIPTION("NOP USB Transceiver driver");
318MODULE_LICENSE("GPL");