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726b6324 MS |
1 | /* |
2 | * Copyright (C) 2015, Samsung Electronics Co., Ltd. | |
3 | * | |
4 | * Author: Marek Szyprowski <m.szyprowski@samsung.com> | |
5 | * | |
6 | * License terms: GNU General Public License (GPL) version 2 | |
7 | * | |
8 | * Simple eMMC hardware reset provider | |
9 | */ | |
10 | #include <linux/delay.h> | |
11 | #include <linux/kernel.h> | |
d97a1e5d SK |
12 | #include <linux/init.h> |
13 | #include <linux/platform_device.h> | |
14 | #include <linux/module.h> | |
726b6324 MS |
15 | #include <linux/slab.h> |
16 | #include <linux/device.h> | |
17 | #include <linux/err.h> | |
18 | #include <linux/gpio/consumer.h> | |
19 | #include <linux/reboot.h> | |
20 | ||
21 | #include <linux/mmc/host.h> | |
22 | ||
23 | #include "pwrseq.h" | |
24 | ||
25 | struct mmc_pwrseq_emmc { | |
26 | struct mmc_pwrseq pwrseq; | |
27 | struct notifier_block reset_nb; | |
28 | struct gpio_desc *reset_gpio; | |
29 | }; | |
30 | ||
f01b72d0 SK |
31 | #define to_pwrseq_emmc(p) container_of(p, struct mmc_pwrseq_emmc, pwrseq) |
32 | ||
726b6324 MS |
33 | static void __mmc_pwrseq_emmc_reset(struct mmc_pwrseq_emmc *pwrseq) |
34 | { | |
35 | gpiod_set_value(pwrseq->reset_gpio, 1); | |
36 | udelay(1); | |
37 | gpiod_set_value(pwrseq->reset_gpio, 0); | |
38 | udelay(200); | |
39 | } | |
40 | ||
41 | static void mmc_pwrseq_emmc_reset(struct mmc_host *host) | |
42 | { | |
f01b72d0 | 43 | struct mmc_pwrseq_emmc *pwrseq = to_pwrseq_emmc(host->pwrseq); |
726b6324 MS |
44 | |
45 | __mmc_pwrseq_emmc_reset(pwrseq); | |
46 | } | |
47 | ||
726b6324 MS |
48 | static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this, |
49 | unsigned long mode, void *cmd) | |
50 | { | |
51 | struct mmc_pwrseq_emmc *pwrseq = container_of(this, | |
52 | struct mmc_pwrseq_emmc, reset_nb); | |
53 | ||
54 | __mmc_pwrseq_emmc_reset(pwrseq); | |
55 | return NOTIFY_DONE; | |
56 | } | |
57 | ||
d97a1e5d SK |
58 | static const struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = { |
59 | .post_power_on = mmc_pwrseq_emmc_reset, | |
60 | }; | |
61 | ||
62 | static int mmc_pwrseq_emmc_probe(struct platform_device *pdev) | |
726b6324 MS |
63 | { |
64 | struct mmc_pwrseq_emmc *pwrseq; | |
d97a1e5d | 65 | struct device *dev = &pdev->dev; |
726b6324 | 66 | |
d97a1e5d | 67 | pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL); |
726b6324 | 68 | if (!pwrseq) |
d97a1e5d | 69 | return -ENOMEM; |
726b6324 | 70 | |
d97a1e5d SK |
71 | pwrseq->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW); |
72 | if (IS_ERR(pwrseq->reset_gpio)) | |
73 | return PTR_ERR(pwrseq->reset_gpio); | |
726b6324 MS |
74 | |
75 | /* | |
76 | * register reset handler to ensure emmc reset also from | |
1c6e58d8 JMC |
77 | * emergency_reboot(), priority 255 is the highest priority |
78 | * so it will be executed before any system reboot handler. | |
726b6324 MS |
79 | */ |
80 | pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb; | |
1c6e58d8 | 81 | pwrseq->reset_nb.priority = 255; |
726b6324 MS |
82 | register_restart_handler(&pwrseq->reset_nb); |
83 | ||
84 | pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops; | |
d97a1e5d SK |
85 | pwrseq->pwrseq.dev = dev; |
86 | pwrseq->pwrseq.owner = THIS_MODULE; | |
87 | platform_set_drvdata(pdev, pwrseq); | |
88 | ||
89 | return mmc_pwrseq_register(&pwrseq->pwrseq); | |
90 | } | |
91 | ||
92 | static int mmc_pwrseq_emmc_remove(struct platform_device *pdev) | |
93 | { | |
94 | struct mmc_pwrseq_emmc *pwrseq = platform_get_drvdata(pdev); | |
95 | ||
96 | unregister_restart_handler(&pwrseq->reset_nb); | |
97 | mmc_pwrseq_unregister(&pwrseq->pwrseq); | |
726b6324 | 98 | |
d97a1e5d | 99 | return 0; |
726b6324 | 100 | } |
d97a1e5d SK |
101 | |
102 | static const struct of_device_id mmc_pwrseq_emmc_of_match[] = { | |
103 | { .compatible = "mmc-pwrseq-emmc",}, | |
104 | {/* sentinel */}, | |
105 | }; | |
106 | ||
107 | MODULE_DEVICE_TABLE(of, mmc_pwrseq_emmc_of_match); | |
108 | ||
109 | static struct platform_driver mmc_pwrseq_emmc_driver = { | |
110 | .probe = mmc_pwrseq_emmc_probe, | |
111 | .remove = mmc_pwrseq_emmc_remove, | |
112 | .driver = { | |
113 | .name = "pwrseq_emmc", | |
114 | .of_match_table = mmc_pwrseq_emmc_of_match, | |
115 | }, | |
116 | }; | |
117 | ||
118 | module_platform_driver(mmc_pwrseq_emmc_driver); | |
119 | MODULE_LICENSE("GPL v2"); |