summaryrefslogtreecommitdiff
path: root/drivers/misc/atmel-ssc.c
blob: e11a0bd6c66e3f6068fbe032e1c67412ab09b6d3 (plain)
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
/*
 * Atmel SSC driver
 *
 * Copyright (C) 2007 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/platform_device.h>
#include <linux/list.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/atmel-ssc.h>
#include <linux/slab.h>
#include <linux/module.h>

#include <linux/of.h>

/* Serialize access to ssc_list and user count */
static DEFINE_SPINLOCK(user_lock);
static LIST_HEAD(ssc_list);

struct ssc_device *ssc_request(unsigned int ssc_num)
{
	int ssc_valid = 0;
	struct ssc_device *ssc;

	spin_lock(&user_lock);
	list_for_each_entry(ssc, &ssc_list, list) {
		if (ssc->pdev->dev.of_node) {
			if (of_alias_get_id(ssc->pdev->dev.of_node, "ssc")
				== ssc_num) {
				ssc_valid = 1;
				break;
			}
		} else if (ssc->pdev->id == ssc_num) {
			ssc_valid = 1;
			break;
		}
	}

	if (!ssc_valid) {
		spin_unlock(&user_lock);
		pr_err("ssc: ssc%d platform device is missing\n", ssc_num);
		return ERR_PTR(-ENODEV);
	}

	if (ssc->user) {
		spin_unlock(&user_lock);
		dev_dbg(&ssc->pdev->dev, "module busy\n");
		return ERR_PTR(-EBUSY);
	}
	ssc->user++;
	spin_unlock(&user_lock);

	clk_prepare(ssc->clk);

	return ssc;
}
EXPORT_SYMBOL(ssc_request);

void ssc_free(struct ssc_device *ssc)
{
	bool disable_clk = true;

	spin_lock(&user_lock);
	if (ssc->user)
		ssc->user--;
	else {
		disable_clk = false;
		dev_dbg(&ssc->pdev->dev, "device already free\n");
	}
	spin_unlock(&user_lock);

	if (disable_clk)
		clk_unprepare(ssc->clk);
}
EXPORT_SYMBOL(ssc_free);

static struct atmel_ssc_platform_data at91rm9200_config = {
	.use_dma = 0,
	.has_fslen_ext = 0,
};

static struct atmel_ssc_platform_data at91sam9rl_config = {
	.use_dma = 0,
	.has_fslen_ext = 1,
};

static struct atmel_ssc_platform_data at91sam9g45_config = {
	.use_dma = 1,
	.has_fslen_ext = 1,
};

static const struct platform_device_id atmel_ssc_devtypes[] = {
	{
		.name = "at91rm9200_ssc",
		.driver_data = (unsigned long) &at91rm9200_config,
	}, {
		.name = "at91sam9rl_ssc",
		.driver_data = (unsigned long) &at91sam9rl_config,
	}, {
		.name = "at91sam9g45_ssc",
		.driver_data = (unsigned long) &at91sam9g45_config,
	}, {
		/* sentinel */
	}
};

#ifdef CONFIG_OF
static const struct of_device_id atmel_ssc_dt_ids[] = {
	{
		.compatible = "atmel,at91rm9200-ssc",
		.data = &at91rm9200_config,
	}, {
		.compatible = "atmel,at91sam9rl-ssc",
		.data = &at91sam9rl_config,
	}, {
		.compatible = "atmel,at91sam9g45-ssc",
		.data = &at91sam9g45_config,
	}, {
		/* sentinel */
	}
};
MODULE_DEVICE_TABLE(of, atmel_ssc_dt_ids);
#endif

static inline const struct atmel_ssc_platform_data * __init
	atmel_ssc_get_driver_data(struct platform_device *pdev)
{
	if (pdev->dev.of_node) {
		const struct of_device_id *match;
		match = of_match_node(atmel_ssc_dt_ids, pdev->dev.of_node);
		if (match == NULL)
			return NULL;
		return match->data;
	}

	return (struct atmel_ssc_platform_data *)
		platform_get_device_id(pdev)->driver_data;
}

static int ssc_probe(struct platform_device *pdev)
{
	struct resource *regs;
	struct ssc_device *ssc;
	const struct atmel_ssc_platform_data *plat_dat;

	ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL);
	if (!ssc) {
		dev_dbg(&pdev->dev, "out of memory\n");
		return -ENOMEM;
	}

	ssc->pdev = pdev;

	plat_dat = atmel_ssc_get_driver_data(pdev);
	if (!plat_dat)
		return -ENODEV;
	ssc->pdata = (struct atmel_ssc_platform_data *)plat_dat;

	if (pdev->dev.of_node) {
		struct device_node *np = pdev->dev.of_node;
		ssc->clk_from_rk_pin =
			of_property_read_bool(np, "atmel,clk-from-rk-pin");
	}

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

	ssc->phybase = regs->start;

	ssc->clk = devm_clk_get(&pdev->dev, "pclk");
	if (IS_ERR(ssc->clk)) {
		dev_dbg(&pdev->dev, "no pclk clock defined\n");
		return -ENXIO;
	}

	/* disable all interrupts */
	clk_prepare_enable(ssc->clk);
	ssc_writel(ssc->regs, IDR, -1);
	ssc_readl(ssc->regs, SR);
	clk_disable_unprepare(ssc->clk);

	ssc->irq = platform_get_irq(pdev, 0);
	if (!ssc->irq) {
		dev_dbg(&pdev->dev, "could not get irq\n");
		return -ENXIO;
	}

	spin_lock(&user_lock);
	list_add_tail(&ssc->list, &ssc_list);
	spin_unlock(&user_lock);

	platform_set_drvdata(pdev, ssc);

	dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
			ssc->regs, ssc->irq);

	return 0;
}

static int ssc_remove(struct platform_device *pdev)
{
	struct ssc_device *ssc = platform_get_drvdata(pdev);

	spin_lock(&user_lock);
	list_del(&ssc->list);
	spin_unlock(&user_lock);

	return 0;
}

static struct platform_driver ssc_driver = {
	.driver		= {
		.name		= "ssc",
		.of_match_table	= of_match_ptr(atmel_ssc_dt_ids),
	},
	.id_table	= atmel_ssc_devtypes,
	.probe		= ssc_probe,
	.remove		= ssc_remove,
};
module_platform_driver(ssc_driver);

MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ssc");