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/*
* Driver for Atmel Flexcom
*
* Copyright (C) 2015 Atmel Corporation
*
* Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/err.h>
#include <linux/io.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 platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct clk *clk;
struct resource *res;
void __iomem *base;
u32 opmode;
int err;
err = of_property_read_u32(np, "atmel,flexcom-mode", &opmode);
if (err)
return err;
if (opmode < ATMEL_FLEXCOM_MODE_USART ||
opmode > ATMEL_FLEXCOM_MODE_TWI)
return -EINVAL;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(base))
return PTR_ERR(base);
clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(clk))
return PTR_ERR(clk);
err = clk_prepare_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), base + FLEX_MR);
clk_disable_unprepare(clk);
return devm_of_platform_populate(&pdev->dev);
}
static const struct of_device_id atmel_flexcom_of_match[] = {
{ .compatible = "atmel,sama5d2-flexcom" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
static struct platform_driver atmel_flexcom_driver = {
.probe = atmel_flexcom_probe,
.driver = {
.name = "atmel_flexcom",
.of_match_table = atmel_flexcom_of_match,
},
};
module_platform_driver(atmel_flexcom_driver);
MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>");
MODULE_DESCRIPTION("Atmel Flexcom MFD driver");
MODULE_LICENSE("GPL v2");
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