1/*
 2 * Copyright 2011 Freescale Semiconductor, Inc.
 3 * Copyright 2011 Linaro Ltd.
 4 *
 5 * The code contained herein is licensed under the GNU General Public
 6 * License. You may obtain a copy of the GNU General Public License
 7 * Version 2 or later at the following locations:
 8 *
 9 * http://www.opensource.org/licenses/gpl-license.html
10 * http://www.gnu.org/copyleft/gpl.html
11 */
12
13#include <linux/init.h>
14#include <linux/io.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/of_address.h>
18#include <linux/of_device.h>
19
20#define MMDC_MAPSR		0x404
21#define BP_MMDC_MAPSR_PSD	0
22#define BP_MMDC_MAPSR_PSS	4
23
24static int __devinit imx_mmdc_probe(struct platform_device *pdev)
25{
26	struct device_node *np = pdev->dev.of_node;
27	void __iomem *mmdc_base, *reg;
28	u32 val;
29	int timeout = 0x400;
30
31	mmdc_base = of_iomap(np, 0);
32	WARN_ON(!mmdc_base);
33
34	reg = mmdc_base + MMDC_MAPSR;
35
36	/* Enable automatic power saving */
37	val = readl_relaxed(reg);
38	val &= ~(1 << BP_MMDC_MAPSR_PSD);
39	writel_relaxed(val, reg);
40
41	/* Ensure it's successfully enabled */
42	while (!(readl_relaxed(reg) & 1 << BP_MMDC_MAPSR_PSS) && --timeout)
43		cpu_relax();
44
45	if (unlikely(!timeout)) {
46		pr_warn("%s: failed to enable automatic power saving\n",
47			__func__);
48		return -EBUSY;
49	}
50
51	return 0;
52}
53
54static struct of_device_id imx_mmdc_dt_ids[] = {
55	{ .compatible = "fsl,imx6q-mmdc", },
56	{ /* sentinel */ }
57};
58
59static struct platform_driver imx_mmdc_driver = {
60	.driver		= {
61		.name	= "imx-mmdc",
62		.owner	= THIS_MODULE,
63		.of_match_table = imx_mmdc_dt_ids,
64	},
65	.probe		= imx_mmdc_probe,
66};
67
68static int __init imx_mmdc_init(void)
69{
70	return platform_driver_register(&imx_mmdc_driver);
71}
72postcore_initcall(imx_mmdc_init);