c461e98496c308924f96a3daa65c37d60d0f3f8e
[linux-3.10.git] / arch / arm / mach-imx / mmdc.c
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
24 static 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
54 static struct of_device_id imx_mmdc_dt_ids[] = {
55         { .compatible = "fsl,imx6q-mmdc", },
56         { /* sentinel */ }
57 };
58
59 static 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
68 static int __init imx_mmdc_init(void)
69 {
70         return platform_driver_register(&imx_mmdc_driver);
71 }
72 postcore_initcall(imx_mmdc_init);