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caab277b | 1 | // SPDX-License-Identifier: GPL-2.0-only |
5c41f11c CP |
2 | /* |
3 | * Driver for Atmel Flexcom | |
4 | * | |
5 | * Copyright (C) 2015 Atmel Corporation | |
6 | * | |
7 | * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com> | |
5c41f11c CP |
8 | */ |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/types.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/platform_device.h> | |
14 | #include <linux/of.h> | |
15 | #include <linux/of_platform.h> | |
16 | #include <linux/err.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/clk.h> | |
19 | #include <dt-bindings/mfd/atmel-flexcom.h> | |
20 | ||
21 | /* I/O register offsets */ | |
22 | #define FLEX_MR 0x0 /* Mode Register */ | |
23 | #define FLEX_VERSION 0xfc /* Version Register */ | |
24 | ||
25 | /* Mode Register bit fields */ | |
26 | #define FLEX_MR_OPMODE_OFFSET (0) /* Operating Mode */ | |
27 | #define FLEX_MR_OPMODE_MASK (0x3 << FLEX_MR_OPMODE_OFFSET) | |
28 | #define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) & \ | |
29 | FLEX_MR_OPMODE_MASK) | |
30 | ||
7fdec110 RI |
31 | struct atmel_flexcom { |
32 | void __iomem *base; | |
33 | u32 opmode; | |
34 | struct clk *clk; | |
35 | }; | |
5c41f11c CP |
36 | |
37 | static int atmel_flexcom_probe(struct platform_device *pdev) | |
38 | { | |
39 | struct device_node *np = pdev->dev.of_node; | |
5c41f11c | 40 | struct resource *res; |
7fdec110 | 41 | struct atmel_flexcom *ddata; |
5c41f11c CP |
42 | int err; |
43 | ||
7fdec110 RI |
44 | ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL); |
45 | if (!ddata) | |
46 | return -ENOMEM; | |
47 | ||
48 | platform_set_drvdata(pdev, ddata); | |
49 | ||
50 | err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode); | |
5c41f11c CP |
51 | if (err) |
52 | return err; | |
53 | ||
7fdec110 RI |
54 | if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART || |
55 | ddata->opmode > ATMEL_FLEXCOM_MODE_TWI) | |
5c41f11c CP |
56 | return -EINVAL; |
57 | ||
58 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
7fdec110 RI |
59 | ddata->base = devm_ioremap_resource(&pdev->dev, res); |
60 | if (IS_ERR(ddata->base)) | |
61 | return PTR_ERR(ddata->base); | |
5c41f11c | 62 | |
7fdec110 RI |
63 | ddata->clk = devm_clk_get(&pdev->dev, NULL); |
64 | if (IS_ERR(ddata->clk)) | |
65 | return PTR_ERR(ddata->clk); | |
5c41f11c | 66 | |
7fdec110 | 67 | err = clk_prepare_enable(ddata->clk); |
5c41f11c CP |
68 | if (err) |
69 | return err; | |
70 | ||
71 | /* | |
72 | * Set the Operating Mode in the Mode Register: only the selected device | |
73 | * is clocked. Hence, registers of the other serial devices remain | |
74 | * inaccessible and are read as zero. Also the external I/O lines of the | |
75 | * Flexcom are muxed to reach the selected device. | |
76 | */ | |
7fdec110 | 77 | writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR); |
5c41f11c | 78 | |
7fdec110 | 79 | clk_disable_unprepare(ddata->clk); |
5c41f11c | 80 | |
ad56b2a4 | 81 | return devm_of_platform_populate(&pdev->dev); |
5c41f11c CP |
82 | } |
83 | ||
84 | static const struct of_device_id atmel_flexcom_of_match[] = { | |
85 | { .compatible = "atmel,sama5d2-flexcom" }, | |
86 | { /* sentinel */ } | |
87 | }; | |
88 | MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match); | |
89 | ||
7fdec110 RI |
90 | #ifdef CONFIG_PM_SLEEP |
91 | static int atmel_flexcom_resume(struct device *dev) | |
92 | { | |
93 | struct atmel_flexcom *ddata = dev_get_drvdata(dev); | |
94 | int err; | |
95 | u32 val; | |
96 | ||
97 | err = clk_prepare_enable(ddata->clk); | |
98 | if (err) | |
99 | return err; | |
100 | ||
101 | val = FLEX_MR_OPMODE(ddata->opmode), | |
102 | writel(val, ddata->base + FLEX_MR); | |
103 | ||
104 | clk_disable_unprepare(ddata->clk); | |
105 | ||
106 | return 0; | |
107 | } | |
108 | #endif | |
109 | ||
110 | static SIMPLE_DEV_PM_OPS(atmel_flexcom_pm_ops, NULL, | |
111 | atmel_flexcom_resume); | |
112 | ||
5c41f11c CP |
113 | static struct platform_driver atmel_flexcom_driver = { |
114 | .probe = atmel_flexcom_probe, | |
115 | .driver = { | |
116 | .name = "atmel_flexcom", | |
7fdec110 | 117 | .pm = &atmel_flexcom_pm_ops, |
5c41f11c CP |
118 | .of_match_table = atmel_flexcom_of_match, |
119 | }, | |
120 | }; | |
121 | ||
122 | module_platform_driver(atmel_flexcom_driver); | |
123 | ||
124 | MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>"); | |
125 | MODULE_DESCRIPTION("Atmel Flexcom MFD driver"); | |
126 | MODULE_LICENSE("GPL v2"); |