1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Driver for Atmel Flexcom
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2015 Atmel Corporation
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>
8*4882a593Smuzhiyun */
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #include <linux/module.h>
11*4882a593Smuzhiyun #include <linux/types.h>
12*4882a593Smuzhiyun #include <linux/kernel.h>
13*4882a593Smuzhiyun #include <linux/platform_device.h>
14*4882a593Smuzhiyun #include <linux/of.h>
15*4882a593Smuzhiyun #include <linux/of_platform.h>
16*4882a593Smuzhiyun #include <linux/err.h>
17*4882a593Smuzhiyun #include <linux/io.h>
18*4882a593Smuzhiyun #include <linux/clk.h>
19*4882a593Smuzhiyun #include <dt-bindings/mfd/atmel-flexcom.h>
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun /* I/O register offsets */
22*4882a593Smuzhiyun #define FLEX_MR 0x0 /* Mode Register */
23*4882a593Smuzhiyun #define FLEX_VERSION 0xfc /* Version Register */
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun /* Mode Register bit fields */
26*4882a593Smuzhiyun #define FLEX_MR_OPMODE_OFFSET (0) /* Operating Mode */
27*4882a593Smuzhiyun #define FLEX_MR_OPMODE_MASK (0x3 << FLEX_MR_OPMODE_OFFSET)
28*4882a593Smuzhiyun #define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) & \
29*4882a593Smuzhiyun FLEX_MR_OPMODE_MASK)
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun struct atmel_flexcom {
32*4882a593Smuzhiyun void __iomem *base;
33*4882a593Smuzhiyun u32 opmode;
34*4882a593Smuzhiyun struct clk *clk;
35*4882a593Smuzhiyun };
36*4882a593Smuzhiyun
atmel_flexcom_probe(struct platform_device * pdev)37*4882a593Smuzhiyun static int atmel_flexcom_probe(struct platform_device *pdev)
38*4882a593Smuzhiyun {
39*4882a593Smuzhiyun struct device_node *np = pdev->dev.of_node;
40*4882a593Smuzhiyun struct resource *res;
41*4882a593Smuzhiyun struct atmel_flexcom *ddata;
42*4882a593Smuzhiyun int err;
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
45*4882a593Smuzhiyun if (!ddata)
46*4882a593Smuzhiyun return -ENOMEM;
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun platform_set_drvdata(pdev, ddata);
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode);
51*4882a593Smuzhiyun if (err)
52*4882a593Smuzhiyun return err;
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART ||
55*4882a593Smuzhiyun ddata->opmode > ATMEL_FLEXCOM_MODE_TWI)
56*4882a593Smuzhiyun return -EINVAL;
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
59*4882a593Smuzhiyun ddata->base = devm_ioremap_resource(&pdev->dev, res);
60*4882a593Smuzhiyun if (IS_ERR(ddata->base))
61*4882a593Smuzhiyun return PTR_ERR(ddata->base);
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun ddata->clk = devm_clk_get(&pdev->dev, NULL);
64*4882a593Smuzhiyun if (IS_ERR(ddata->clk))
65*4882a593Smuzhiyun return PTR_ERR(ddata->clk);
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun err = clk_prepare_enable(ddata->clk);
68*4882a593Smuzhiyun if (err)
69*4882a593Smuzhiyun return err;
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun /*
72*4882a593Smuzhiyun * Set the Operating Mode in the Mode Register: only the selected device
73*4882a593Smuzhiyun * is clocked. Hence, registers of the other serial devices remain
74*4882a593Smuzhiyun * inaccessible and are read as zero. Also the external I/O lines of the
75*4882a593Smuzhiyun * Flexcom are muxed to reach the selected device.
76*4882a593Smuzhiyun */
77*4882a593Smuzhiyun writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR);
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun clk_disable_unprepare(ddata->clk);
80*4882a593Smuzhiyun
81*4882a593Smuzhiyun return devm_of_platform_populate(&pdev->dev);
82*4882a593Smuzhiyun }
83*4882a593Smuzhiyun
84*4882a593Smuzhiyun static const struct of_device_id atmel_flexcom_of_match[] = {
85*4882a593Smuzhiyun { .compatible = "atmel,sama5d2-flexcom" },
86*4882a593Smuzhiyun { /* sentinel */ }
87*4882a593Smuzhiyun };
88*4882a593Smuzhiyun MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
89*4882a593Smuzhiyun
atmel_flexcom_resume_noirq(struct device * dev)90*4882a593Smuzhiyun static int __maybe_unused atmel_flexcom_resume_noirq(struct device *dev)
91*4882a593Smuzhiyun {
92*4882a593Smuzhiyun struct atmel_flexcom *ddata = dev_get_drvdata(dev);
93*4882a593Smuzhiyun int err;
94*4882a593Smuzhiyun u32 val;
95*4882a593Smuzhiyun
96*4882a593Smuzhiyun err = clk_prepare_enable(ddata->clk);
97*4882a593Smuzhiyun if (err)
98*4882a593Smuzhiyun return err;
99*4882a593Smuzhiyun
100*4882a593Smuzhiyun val = FLEX_MR_OPMODE(ddata->opmode),
101*4882a593Smuzhiyun writel(val, ddata->base + FLEX_MR);
102*4882a593Smuzhiyun
103*4882a593Smuzhiyun clk_disable_unprepare(ddata->clk);
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun return 0;
106*4882a593Smuzhiyun }
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun static const struct dev_pm_ops atmel_flexcom_pm_ops = {
109*4882a593Smuzhiyun .resume_noirq = atmel_flexcom_resume_noirq,
110*4882a593Smuzhiyun };
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun static struct platform_driver atmel_flexcom_driver = {
113*4882a593Smuzhiyun .probe = atmel_flexcom_probe,
114*4882a593Smuzhiyun .driver = {
115*4882a593Smuzhiyun .name = "atmel_flexcom",
116*4882a593Smuzhiyun .pm = pm_ptr(&atmel_flexcom_pm_ops),
117*4882a593Smuzhiyun .of_match_table = atmel_flexcom_of_match,
118*4882a593Smuzhiyun },
119*4882a593Smuzhiyun };
120*4882a593Smuzhiyun
121*4882a593Smuzhiyun module_platform_driver(atmel_flexcom_driver);
122*4882a593Smuzhiyun
123*4882a593Smuzhiyun MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>");
124*4882a593Smuzhiyun MODULE_DESCRIPTION("Atmel Flexcom MFD driver");
125*4882a593Smuzhiyun MODULE_LICENSE("GPL v2");
126