tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 <mach/cns3xxx.h>
19#include "sdhci-pltfm.h"
20
21static unsigned int sdhci_cns3xxx_get_max_clk(struct sdhci_host *host)
22{
23 return 150000000;
24}
25
26static void sdhci_cns3xxx_set_clock(struct sdhci_host *host, unsigned int clock)
27{
28 struct device *dev = mmc_dev(host->mmc);
29 int div = 1;
30 u16 clk;
31 unsigned long timeout;
32
33 if (clock == host->clock)
34 return;
35
36 sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
37
38 if (clock == 0)
39 goto out;
40
41 while (host->max_clk / div > clock) {
42 /*
43 * On CNS3xxx divider grows linearly up to 4, and then
44 * exponentially up to 256.
45 */
46 if (div < 4)
47 div += 1;
48 else if (div < 256)
49 div *= 2;
50 else
51 break;
52 }
53
54 dev_dbg(dev, "desired SD clock: %d, actual: %d\n",
55 clock, host->max_clk / div);
56
57 /* Divide by 3 is special. */
58 if (div != 3)
59 div >>= 1;
60
61 clk = div << SDHCI_DIVIDER_SHIFT;
62 clk |= SDHCI_CLOCK_INT_EN;
63 sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
64
65 timeout = 20;
66 while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
67 & SDHCI_CLOCK_INT_STABLE)) {
68 if (timeout == 0) {
69 dev_warn(dev, "clock is unstable");
70 break;
71 }
72 timeout--;
73 mdelay(1);
74 }
75
76 clk |= SDHCI_CLOCK_CARD_EN;
77 sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
78out:
79 host->clock = clock;
80}
81
82static struct sdhci_ops sdhci_cns3xxx_ops = {
83 .get_max_clock = sdhci_cns3xxx_get_max_clk,
84 .set_clock = sdhci_cns3xxx_set_clock,
85};
86
87static struct sdhci_pltfm_data sdhci_cns3xxx_pdata = {
88 .ops = &sdhci_cns3xxx_ops,
89 .quirks = SDHCI_QUIRK_BROKEN_DMA |
90 SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
91 SDHCI_QUIRK_INVERTED_WRITE_PROTECT |
92 SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN |
93 SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
94 SDHCI_QUIRK_NONSTANDARD_CLOCK,
95};
96
97static int __devinit sdhci_cns3xxx_probe(struct platform_device *pdev)
98{
99 return sdhci_pltfm_register(pdev, &sdhci_cns3xxx_pdata);
100}
101
102static int __devexit sdhci_cns3xxx_remove(struct platform_device *pdev)
103{
104 return sdhci_pltfm_unregister(pdev);
105}
106
107static struct platform_driver sdhci_cns3xxx_driver = {
108 .driver = {
109 .name = "sdhci-cns3xxx",
110 .owner = THIS_MODULE,
111 },
112 .probe = sdhci_cns3xxx_probe,
113 .remove = __devexit_p(sdhci_cns3xxx_remove),
114#ifdef CONFIG_PM
115 .suspend = sdhci_pltfm_suspend,
116 .resume = sdhci_pltfm_resume,
117#endif
118};
119
120static int __init sdhci_cns3xxx_init(void)
121{
122 return platform_driver_register(&sdhci_cns3xxx_driver);
123}
124module_init(sdhci_cns3xxx_init);
125
126static void __exit sdhci_cns3xxx_exit(void)
127{
128 platform_driver_unregister(&sdhci_cns3xxx_driver);
129}
130module_exit(sdhci_cns3xxx_exit);
131
132MODULE_DESCRIPTION("SDHCI driver for CNS3xxx");
133MODULE_AUTHOR("Scott Shu, "
134 "Anton Vorontsov <avorontsov@mvista.com>");
135MODULE_LICENSE("GPL v2");