1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
|
// SPDX-License-Identifier: GPL-2.0-only
// SPDX-FileCopyrightText: (C) 2015 Atmel Corporation
/*
* Driver for Atmel Flexcom
* Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>
*/
#include <common.h>
#include <of.h>
#include <linux/clk.h>
#include <dt-bindings/mfd/atmel-flexcom.h>
/* I/O register offsets */
#define FLEX_MR 0x0 /* Mode Register */
#define FLEX_VERSION 0xfc /* Version Register */
/* Mode Register bit fields */
#define FLEX_MR_OPMODE_OFFSET (0) /* Operating Mode */
#define FLEX_MR_OPMODE_MASK (0x3 << FLEX_MR_OPMODE_OFFSET)
#define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) & \
FLEX_MR_OPMODE_MASK)
static int atmel_flexcom_probe(struct device_d *dev)
{
struct resource *res;
struct clk *clk;
u32 opmode;
int err;
err = of_property_read_u32(dev->device_node,
"atmel,flexcom-mode", &opmode);
if (err)
return err;
if (opmode < ATMEL_FLEXCOM_MODE_USART || opmode > ATMEL_FLEXCOM_MODE_TWI)
return -EINVAL;
res = dev_request_mem_resource(dev, 0);
if (IS_ERR(res))
return PTR_ERR(res);
clk = clk_get(dev, NULL);
if (IS_ERR(clk))
return PTR_ERR(clk);
err = clk_enable(clk);
if (err)
return err;
/*
* Set the Operating Mode in the Mode Register: only the selected device
* is clocked. Hence, registers of the other serial devices remain
* inaccessible and are read as zero. Also the external I/O lines of the
* Flexcom are muxed to reach the selected device.
*/
writel(FLEX_MR_OPMODE(opmode), IOMEM(res->start) + FLEX_MR);
clk_disable(clk);
return of_platform_populate(dev->device_node, NULL, dev);
}
static const struct of_device_id atmel_flexcom_of_match[] = {
{ .compatible = "atmel,sama5d2-flexcom" },
{ /* sentinel */ }
};
static struct driver_d atmel_flexcom_driver = {
.probe = atmel_flexcom_probe,
.name = "atmel_flexcom",
.of_compatible = atmel_flexcom_of_match,
};
coredevice_platform_driver(atmel_flexcom_driver);
|
