1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Driver for Atmel Flexcom |
4 | * |
5 | * Copyright (C) 2015 Atmel Corporation |
6 | * |
7 | * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com> |
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 | |
31 | struct atmel_flexcom { |
32 | void __iomem *base; |
33 | u32 opmode; |
34 | struct clk *clk; |
35 | }; |
36 | |
37 | static int atmel_flexcom_probe(struct platform_device *pdev) |
38 | { |
39 | struct device_node *np = pdev->dev.of_node; |
40 | struct atmel_flexcom *ddata; |
41 | int err; |
42 | |
43 | ddata = devm_kzalloc(dev: &pdev->dev, size: sizeof(*ddata), GFP_KERNEL); |
44 | if (!ddata) |
45 | return -ENOMEM; |
46 | |
47 | platform_set_drvdata(pdev, data: ddata); |
48 | |
49 | err = of_property_read_u32(np, propname: "atmel,flexcom-mode" , out_value: &ddata->opmode); |
50 | if (err) |
51 | return err; |
52 | |
53 | if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART || |
54 | ddata->opmode > ATMEL_FLEXCOM_MODE_TWI) |
55 | return -EINVAL; |
56 | |
57 | ddata->base = devm_platform_get_and_ioremap_resource(pdev, index: 0, NULL); |
58 | if (IS_ERR(ptr: ddata->base)) |
59 | return PTR_ERR(ptr: ddata->base); |
60 | |
61 | ddata->clk = devm_clk_get(dev: &pdev->dev, NULL); |
62 | if (IS_ERR(ptr: ddata->clk)) |
63 | return PTR_ERR(ptr: ddata->clk); |
64 | |
65 | err = clk_prepare_enable(clk: ddata->clk); |
66 | if (err) |
67 | return err; |
68 | |
69 | /* |
70 | * Set the Operating Mode in the Mode Register: only the selected device |
71 | * is clocked. Hence, registers of the other serial devices remain |
72 | * inaccessible and are read as zero. Also the external I/O lines of the |
73 | * Flexcom are muxed to reach the selected device. |
74 | */ |
75 | writel(FLEX_MR_OPMODE(ddata->opmode), addr: ddata->base + FLEX_MR); |
76 | |
77 | clk_disable_unprepare(clk: ddata->clk); |
78 | |
79 | return devm_of_platform_populate(dev: &pdev->dev); |
80 | } |
81 | |
82 | static const struct of_device_id atmel_flexcom_of_match[] = { |
83 | { .compatible = "atmel,sama5d2-flexcom" }, |
84 | { /* sentinel */ } |
85 | }; |
86 | MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match); |
87 | |
88 | static int __maybe_unused atmel_flexcom_resume_noirq(struct device *dev) |
89 | { |
90 | struct atmel_flexcom *ddata = dev_get_drvdata(dev); |
91 | int err; |
92 | u32 val; |
93 | |
94 | err = clk_prepare_enable(clk: ddata->clk); |
95 | if (err) |
96 | return err; |
97 | |
98 | val = FLEX_MR_OPMODE(ddata->opmode), |
99 | writel(val, addr: ddata->base + FLEX_MR); |
100 | |
101 | clk_disable_unprepare(clk: ddata->clk); |
102 | |
103 | return 0; |
104 | } |
105 | |
106 | static const struct dev_pm_ops __maybe_unused atmel_flexcom_pm_ops = { |
107 | .resume_noirq = atmel_flexcom_resume_noirq, |
108 | }; |
109 | |
110 | static struct platform_driver atmel_flexcom_driver = { |
111 | .probe = atmel_flexcom_probe, |
112 | .driver = { |
113 | .name = "atmel_flexcom" , |
114 | .pm = pm_ptr(&atmel_flexcom_pm_ops), |
115 | .of_match_table = atmel_flexcom_of_match, |
116 | }, |
117 | }; |
118 | |
119 | module_platform_driver(atmel_flexcom_driver); |
120 | |
121 | MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>" ); |
122 | MODULE_DESCRIPTION("Atmel Flexcom MFD driver" ); |
123 | MODULE_LICENSE("GPL v2" ); |
124 | |