| /* |
| * Driver for Atmel Flexcom |
| * |
| * Copyright (C) 2015 Atmel Corporation |
| * |
| * Author: Cyrille Pitchen <[email protected]> |
| * |
| * 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 <[email protected]>"); |
| MODULE_DESCRIPTION("Atmel Flexcom MFD driver"); |
| MODULE_LICENSE("GPL v2"); |
