Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
[linux-2.6.git] / drivers / mmc / host / sdhci-cns3xxx.c
1 /*
2  * SDHCI support for CNS3xxx SoC
3  *
4  * Copyright 2008 Cavium Networks
5  * Copyright 2010 MontaVista Software, LLC.
6  *
7  * Authors: Scott Shu
8  *          Anton Vorontsov <avorontsov@mvista.com>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2 as
12  * published by the Free Software Foundation.
13  */
14
15 #include <linux/delay.h>
16 #include <linux/device.h>
17 #include <linux/mmc/host.h>
18 #include <linux/module.h>
19 #include <mach/cns3xxx.h>
20 #include "sdhci-pltfm.h"
21
22 static unsigned int sdhci_cns3xxx_get_max_clk(struct sdhci_host *host)
23 {
24         return 150000000;
25 }
26
27 static void sdhci_cns3xxx_set_clock(struct sdhci_host *host, unsigned int clock)
28 {
29         struct device *dev = mmc_dev(host->mmc);
30         int div = 1;
31         u16 clk;
32         unsigned long timeout;
33
34         if (clock == host->clock)
35                 return;
36
37         sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
38
39         if (clock == 0)
40                 goto out;
41
42         while (host->max_clk / div > clock) {
43                 /*
44                  * On CNS3xxx divider grows linearly up to 4, and then
45                  * exponentially up to 256.
46                  */
47                 if (div < 4)
48                         div += 1;
49                 else if (div < 256)
50                         div *= 2;
51                 else
52                         break;
53         }
54
55         dev_dbg(dev, "desired SD clock: %d, actual: %d\n",
56                 clock, host->max_clk / div);
57
58         /* Divide by 3 is special. */
59         if (div != 3)
60                 div >>= 1;
61
62         clk = div << SDHCI_DIVIDER_SHIFT;
63         clk |= SDHCI_CLOCK_INT_EN;
64         sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
65
66         timeout = 20;
67         while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
68                         & SDHCI_CLOCK_INT_STABLE)) {
69                 if (timeout == 0) {
70                         dev_warn(dev, "clock is unstable");
71                         break;
72                 }
73                 timeout--;
74                 mdelay(1);
75         }
76
77         clk |= SDHCI_CLOCK_CARD_EN;
78         sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
79 out:
80         host->clock = clock;
81 }
82
83 static struct sdhci_ops sdhci_cns3xxx_ops = {
84         .get_max_clock  = sdhci_cns3xxx_get_max_clk,
85         .set_clock      = sdhci_cns3xxx_set_clock,
86 };
87
88 static struct sdhci_pltfm_data sdhci_cns3xxx_pdata = {
89         .ops = &sdhci_cns3xxx_ops,
90         .quirks = SDHCI_QUIRK_BROKEN_DMA |
91                   SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
92                   SDHCI_QUIRK_INVERTED_WRITE_PROTECT |
93                   SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN |
94                   SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
95                   SDHCI_QUIRK_NONSTANDARD_CLOCK,
96 };
97
98 static int __devinit sdhci_cns3xxx_probe(struct platform_device *pdev)
99 {
100         return sdhci_pltfm_register(pdev, &sdhci_cns3xxx_pdata);
101 }
102
103 static int __devexit sdhci_cns3xxx_remove(struct platform_device *pdev)
104 {
105         return sdhci_pltfm_unregister(pdev);
106 }
107
108 static struct platform_driver sdhci_cns3xxx_driver = {
109         .driver         = {
110                 .name   = "sdhci-cns3xxx",
111                 .owner  = THIS_MODULE,
112                 .pm     = SDHCI_PLTFM_PMOPS,
113         },
114         .probe          = sdhci_cns3xxx_probe,
115         .remove         = __devexit_p(sdhci_cns3xxx_remove),
116 };
117
118 static int __init sdhci_cns3xxx_init(void)
119 {
120         return platform_driver_register(&sdhci_cns3xxx_driver);
121 }
122 module_init(sdhci_cns3xxx_init);
123
124 static void __exit sdhci_cns3xxx_exit(void)
125 {
126         platform_driver_unregister(&sdhci_cns3xxx_driver);
127 }
128 module_exit(sdhci_cns3xxx_exit);
129
130 MODULE_DESCRIPTION("SDHCI driver for CNS3xxx");
131 MODULE_AUTHOR("Scott Shu, "
132               "Anton Vorontsov <avorontsov@mvista.com>");
133 MODULE_LICENSE("GPL v2");