1/*
2 * Atmel SSC driver
3 *
4 * Copyright (C) 2007 Atmel Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/platform_device.h>
12#include <linux/list.h>
13#include <linux/clk.h>
14#include <linux/err.h>
15#include <linux/io.h>
16#include <linux/spinlock.h>
17#include <linux/atmel-ssc.h>
18#include <linux/slab.h>
19#include <linux/module.h>
20
21#include <linux/of.h>
22
23/* Serialize access to ssc_list and user count */
24static DEFINE_SPINLOCK(user_lock);
25static LIST_HEAD(ssc_list);
26
27struct ssc_device *ssc_request(unsigned int ssc_num)
28{
29	int ssc_valid = 0;
30	struct ssc_device *ssc;
31
32	spin_lock(&user_lock);
33	list_for_each_entry(ssc, &ssc_list, list) {
34		if (ssc->pdev->dev.of_node) {
35			if (of_alias_get_id(ssc->pdev->dev.of_node, "ssc")
36				== ssc_num) {
37				ssc_valid = 1;
38				break;
39			}
40		} else if (ssc->pdev->id == ssc_num) {
41			ssc_valid = 1;
42			break;
43		}
44	}
45
46	if (!ssc_valid) {
47		spin_unlock(&user_lock);
48		pr_err("ssc: ssc%d platform device is missing\n", ssc_num);
49		return ERR_PTR(-ENODEV);
50	}
51
52	if (ssc->user) {
53		spin_unlock(&user_lock);
54		dev_dbg(&ssc->pdev->dev, "module busy\n");
55		return ERR_PTR(-EBUSY);
56	}
57	ssc->user++;
58	spin_unlock(&user_lock);
59
60	clk_prepare(ssc->clk);
61
62	return ssc;
63}
64EXPORT_SYMBOL(ssc_request);
65
66void ssc_free(struct ssc_device *ssc)
67{
68	bool disable_clk = true;
69
70	spin_lock(&user_lock);
71	if (ssc->user)
72		ssc->user--;
73	else {
74		disable_clk = false;
75		dev_dbg(&ssc->pdev->dev, "device already free\n");
76	}
77	spin_unlock(&user_lock);
78
79	if (disable_clk)
80		clk_unprepare(ssc->clk);
81}
82EXPORT_SYMBOL(ssc_free);
83
84static struct atmel_ssc_platform_data at91rm9200_config = {
85	.use_dma = 0,
86	.has_fslen_ext = 0,
87};
88
89static struct atmel_ssc_platform_data at91sam9rl_config = {
90	.use_dma = 0,
91	.has_fslen_ext = 1,
92};
93
94static struct atmel_ssc_platform_data at91sam9g45_config = {
95	.use_dma = 1,
96	.has_fslen_ext = 1,
97};
98
99static const struct platform_device_id atmel_ssc_devtypes[] = {
100	{
101		.name = "at91rm9200_ssc",
102		.driver_data = (unsigned long) &at91rm9200_config,
103	}, {
104		.name = "at91sam9rl_ssc",
105		.driver_data = (unsigned long) &at91sam9rl_config,
106	}, {
107		.name = "at91sam9g45_ssc",
108		.driver_data = (unsigned long) &at91sam9g45_config,
109	}, {
110		/* sentinel */
111	}
112};
113
114#ifdef CONFIG_OF
115static const struct of_device_id atmel_ssc_dt_ids[] = {
116	{
117		.compatible = "atmel,at91rm9200-ssc",
118		.data = &at91rm9200_config,
119	}, {
120		.compatible = "atmel,at91sam9rl-ssc",
121		.data = &at91sam9rl_config,
122	}, {
123		.compatible = "atmel,at91sam9g45-ssc",
124		.data = &at91sam9g45_config,
125	}, {
126		/* sentinel */
127	}
128};
129MODULE_DEVICE_TABLE(of, atmel_ssc_dt_ids);
130#endif
131
132static inline const struct atmel_ssc_platform_data * __init
133	atmel_ssc_get_driver_data(struct platform_device *pdev)
134{
135	if (pdev->dev.of_node) {
136		const struct of_device_id *match;
137		match = of_match_node(atmel_ssc_dt_ids, pdev->dev.of_node);
138		if (match == NULL)
139			return NULL;
140		return match->data;
141	}
142
143	return (struct atmel_ssc_platform_data *)
144		platform_get_device_id(pdev)->driver_data;
145}
146
147static int ssc_probe(struct platform_device *pdev)
148{
149	struct resource *regs;
150	struct ssc_device *ssc;
151	const struct atmel_ssc_platform_data *plat_dat;
152
153	ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL);
154	if (!ssc) {
155		dev_dbg(&pdev->dev, "out of memory\n");
156		return -ENOMEM;
157	}
158
159	ssc->pdev = pdev;
160
161	plat_dat = atmel_ssc_get_driver_data(pdev);
162	if (!plat_dat)
163		return -ENODEV;
164	ssc->pdata = (struct atmel_ssc_platform_data *)plat_dat;
165
166	if (pdev->dev.of_node) {
167		struct device_node *np = pdev->dev.of_node;
168		ssc->clk_from_rk_pin =
169			of_property_read_bool(np, "atmel,clk-from-rk-pin");
170	}
171
172	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
173	ssc->regs = devm_ioremap_resource(&pdev->dev, regs);
174	if (IS_ERR(ssc->regs))
175		return PTR_ERR(ssc->regs);
176
177	ssc->phybase = regs->start;
178
179	ssc->clk = devm_clk_get(&pdev->dev, "pclk");
180	if (IS_ERR(ssc->clk)) {
181		dev_dbg(&pdev->dev, "no pclk clock defined\n");
182		return -ENXIO;
183	}
184
185	/* disable all interrupts */
186	clk_prepare_enable(ssc->clk);
187	ssc_writel(ssc->regs, IDR, -1);
188	ssc_readl(ssc->regs, SR);
189	clk_disable_unprepare(ssc->clk);
190
191	ssc->irq = platform_get_irq(pdev, 0);
192	if (!ssc->irq) {
193		dev_dbg(&pdev->dev, "could not get irq\n");
194		return -ENXIO;
195	}
196
197	spin_lock(&user_lock);
198	list_add_tail(&ssc->list, &ssc_list);
199	spin_unlock(&user_lock);
200
201	platform_set_drvdata(pdev, ssc);
202
203	dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
204			ssc->regs, ssc->irq);
205
206	return 0;
207}
208
209static int ssc_remove(struct platform_device *pdev)
210{
211	struct ssc_device *ssc = platform_get_drvdata(pdev);
212
213	spin_lock(&user_lock);
214	list_del(&ssc->list);
215	spin_unlock(&user_lock);
216
217	return 0;
218}
219
220static struct platform_driver ssc_driver = {
221	.driver		= {
222		.name		= "ssc",
223		.of_match_table	= of_match_ptr(atmel_ssc_dt_ids),
224	},
225	.id_table	= atmel_ssc_devtypes,
226	.probe		= ssc_probe,
227	.remove		= ssc_remove,
228};
229module_platform_driver(ssc_driver);
230
231MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
232MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");
233MODULE_LICENSE("GPL");
234MODULE_ALIAS("platform:ssc");
235