tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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_enable(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_disable_unprepare(ssc->clk);
81}
82EXPORT_SYMBOL(ssc_free);
83
84static struct atmel_ssc_platform_data at91rm9200_config = {
85 .use_dma = 0,
86};
87
88static struct atmel_ssc_platform_data at91sam9g45_config = {
89 .use_dma = 1,
90};
91
92static const struct platform_device_id atmel_ssc_devtypes[] = {
93 {
94 .name = "at91rm9200_ssc",
95 .driver_data = (unsigned long) &at91rm9200_config,
96 }, {
97 .name = "at91sam9g45_ssc",
98 .driver_data = (unsigned long) &at91sam9g45_config,
99 }, {
100 /* sentinel */
101 }
102};
103
104#ifdef CONFIG_OF
105static const struct of_device_id atmel_ssc_dt_ids[] = {
106 {
107 .compatible = "atmel,at91rm9200-ssc",
108 .data = &at91rm9200_config,
109 }, {
110 .compatible = "atmel,at91sam9g45-ssc",
111 .data = &at91sam9g45_config,
112 }, {
113 /* sentinel */
114 }
115};
116MODULE_DEVICE_TABLE(of, atmel_ssc_dt_ids);
117#endif
118
119static inline const struct atmel_ssc_platform_data * __init
120 atmel_ssc_get_driver_data(struct platform_device *pdev)
121{
122 if (pdev->dev.of_node) {
123 const struct of_device_id *match;
124 match = of_match_node(atmel_ssc_dt_ids, pdev->dev.of_node);
125 if (match == NULL)
126 return NULL;
127 return match->data;
128 }
129
130 return (struct atmel_ssc_platform_data *)
131 platform_get_device_id(pdev)->driver_data;
132}
133
134static int ssc_probe(struct platform_device *pdev)
135{
136 struct resource *regs;
137 struct ssc_device *ssc;
138 const struct atmel_ssc_platform_data *plat_dat;
139
140 ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL);
141 if (!ssc) {
142 dev_dbg(&pdev->dev, "out of memory\n");
143 return -ENOMEM;
144 }
145
146 ssc->pdev = pdev;
147
148 plat_dat = atmel_ssc_get_driver_data(pdev);
149 if (!plat_dat)
150 return -ENODEV;
151 ssc->pdata = (struct atmel_ssc_platform_data *)plat_dat;
152
153 if (pdev->dev.of_node) {
154 struct device_node *np = pdev->dev.of_node;
155 ssc->clk_from_rk_pin =
156 of_property_read_bool(np, "atmel,clk-from-rk-pin");
157 }
158
159 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
160 ssc->regs = devm_ioremap_resource(&pdev->dev, regs);
161 if (IS_ERR(ssc->regs))
162 return PTR_ERR(ssc->regs);
163
164 ssc->phybase = regs->start;
165
166 ssc->clk = devm_clk_get(&pdev->dev, "pclk");
167 if (IS_ERR(ssc->clk)) {
168 dev_dbg(&pdev->dev, "no pclk clock defined\n");
169 return -ENXIO;
170 }
171
172 /* disable all interrupts */
173 clk_prepare_enable(ssc->clk);
174 ssc_writel(ssc->regs, IDR, -1);
175 ssc_readl(ssc->regs, SR);
176 clk_disable_unprepare(ssc->clk);
177
178 ssc->irq = platform_get_irq(pdev, 0);
179 if (!ssc->irq) {
180 dev_dbg(&pdev->dev, "could not get irq\n");
181 return -ENXIO;
182 }
183
184 spin_lock(&user_lock);
185 list_add_tail(&ssc->list, &ssc_list);
186 spin_unlock(&user_lock);
187
188 platform_set_drvdata(pdev, ssc);
189
190 dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
191 ssc->regs, ssc->irq);
192
193 return 0;
194}
195
196static int ssc_remove(struct platform_device *pdev)
197{
198 struct ssc_device *ssc = platform_get_drvdata(pdev);
199
200 spin_lock(&user_lock);
201 list_del(&ssc->list);
202 spin_unlock(&user_lock);
203
204 return 0;
205}
206
207static struct platform_driver ssc_driver = {
208 .driver = {
209 .name = "ssc",
210 .owner = THIS_MODULE,
211 .of_match_table = of_match_ptr(atmel_ssc_dt_ids),
212 },
213 .id_table = atmel_ssc_devtypes,
214 .probe = ssc_probe,
215 .remove = ssc_remove,
216};
217module_platform_driver(ssc_driver);
218
219MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
220MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");
221MODULE_LICENSE("GPL");
222MODULE_ALIAS("platform:ssc");