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104 lines
2.9 KiB
104 lines
2.9 KiB
/* |
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* Driver for Atmel Flexcom |
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* |
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* Copyright (C) 2015 Atmel Corporation |
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* |
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* Author: Cyrille Pitchen <cyrille.pitchen@atmel.com> |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License version 2 as |
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* published by the Free Software Foundation. |
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* |
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* This program is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
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* more details. |
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* |
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* You should have received a copy of the GNU General Public License along with |
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* this program. If not, see <http://www.gnu.org/licenses/>. |
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*/ |
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#include <linux/module.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/platform_device.h> |
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#include <linux/of.h> |
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#include <linux/of_platform.h> |
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#include <linux/err.h> |
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#include <linux/io.h> |
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#include <linux/clk.h> |
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#include <dt-bindings/mfd/atmel-flexcom.h> |
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/* I/O register offsets */ |
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#define FLEX_MR 0x0 /* Mode Register */ |
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#define FLEX_VERSION 0xfc /* Version Register */ |
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/* Mode Register bit fields */ |
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#define FLEX_MR_OPMODE_OFFSET (0) /* Operating Mode */ |
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#define FLEX_MR_OPMODE_MASK (0x3 << FLEX_MR_OPMODE_OFFSET) |
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#define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) & \ |
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FLEX_MR_OPMODE_MASK) |
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static int atmel_flexcom_probe(struct platform_device *pdev) |
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{ |
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struct device_node *np = pdev->dev.of_node; |
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struct clk *clk; |
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struct resource *res; |
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void __iomem *base; |
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u32 opmode; |
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int err; |
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err = of_property_read_u32(np, "atmel,flexcom-mode", &opmode); |
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if (err) |
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return err; |
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if (opmode < ATMEL_FLEXCOM_MODE_USART || |
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opmode > ATMEL_FLEXCOM_MODE_TWI) |
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return -EINVAL; |
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
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base = devm_ioremap_resource(&pdev->dev, res); |
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if (IS_ERR(base)) |
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return PTR_ERR(base); |
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clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(clk)) |
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return PTR_ERR(clk); |
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err = clk_prepare_enable(clk); |
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if (err) |
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return err; |
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/* |
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* Set the Operating Mode in the Mode Register: only the selected device |
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* is clocked. Hence, registers of the other serial devices remain |
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* inaccessible and are read as zero. Also the external I/O lines of the |
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* Flexcom are muxed to reach the selected device. |
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*/ |
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writel(FLEX_MR_OPMODE(opmode), base + FLEX_MR); |
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clk_disable_unprepare(clk); |
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return devm_of_platform_populate(&pdev->dev); |
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} |
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static const struct of_device_id atmel_flexcom_of_match[] = { |
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{ .compatible = "atmel,sama5d2-flexcom" }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match); |
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static struct platform_driver atmel_flexcom_driver = { |
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.probe = atmel_flexcom_probe, |
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.driver = { |
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.name = "atmel_flexcom", |
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.of_match_table = atmel_flexcom_of_match, |
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}, |
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}; |
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module_platform_driver(atmel_flexcom_driver); |
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MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>"); |
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MODULE_DESCRIPTION("Atmel Flexcom MFD driver"); |
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MODULE_LICENSE("GPL v2");
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