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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Driver for Atmel Flexcom4 *5 * Copyright (C) 2015 Atmel Corporation6 *7 * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>8 */9 10#include <linux/module.h>11#include <linux/types.h>12#include <linux/kernel.h>13#include <linux/platform_device.h>14#include <linux/of.h>15#include <linux/of_platform.h>16#include <linux/err.h>17#include <linux/io.h>18#include <linux/clk.h>19#include <dt-bindings/mfd/atmel-flexcom.h>20 21/* I/O register offsets */22#define FLEX_MR 0x0 /* Mode Register */23#define FLEX_VERSION 0xfc /* Version Register */24 25/* Mode Register bit fields */26#define FLEX_MR_OPMODE_OFFSET (0) /* Operating Mode */27#define FLEX_MR_OPMODE_MASK (0x3 << FLEX_MR_OPMODE_OFFSET)28#define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) & \29 FLEX_MR_OPMODE_MASK)30 31struct atmel_flexcom {32 void __iomem *base;33 u32 opmode;34 struct clk *clk;35};36 37static int atmel_flexcom_probe(struct platform_device *pdev)38{39 struct device_node *np = pdev->dev.of_node;40 struct atmel_flexcom *ddata;41 int err;42 43 ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);44 if (!ddata)45 return -ENOMEM;46 47 platform_set_drvdata(pdev, ddata);48 49 err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode);50 if (err)51 return err;52 53 if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART ||54 ddata->opmode > ATMEL_FLEXCOM_MODE_TWI)55 return -EINVAL;56 57 ddata->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);58 if (IS_ERR(ddata->base))59 return PTR_ERR(ddata->base);60 61 ddata->clk = devm_clk_get(&pdev->dev, NULL);62 if (IS_ERR(ddata->clk))63 return PTR_ERR(ddata->clk);64 65 err = clk_prepare_enable(ddata->clk);66 if (err)67 return err;68 69 /*70 * Set the Operating Mode in the Mode Register: only the selected device71 * is clocked. Hence, registers of the other serial devices remain72 * inaccessible and are read as zero. Also the external I/O lines of the73 * Flexcom are muxed to reach the selected device.74 */75 writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR);76 77 clk_disable_unprepare(ddata->clk);78 79 return devm_of_platform_populate(&pdev->dev);80}81 82static const struct of_device_id atmel_flexcom_of_match[] = {83 { .compatible = "atmel,sama5d2-flexcom" },84 { /* sentinel */ }85};86MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);87 88static int __maybe_unused atmel_flexcom_resume_noirq(struct device *dev)89{90 struct atmel_flexcom *ddata = dev_get_drvdata(dev);91 int err;92 u32 val;93 94 err = clk_prepare_enable(ddata->clk);95 if (err)96 return err;97 98 val = FLEX_MR_OPMODE(ddata->opmode),99 writel(val, ddata->base + FLEX_MR);100 101 clk_disable_unprepare(ddata->clk);102 103 return 0;104}105 106static const struct dev_pm_ops __maybe_unused atmel_flexcom_pm_ops = {107 .resume_noirq = atmel_flexcom_resume_noirq,108};109 110static struct platform_driver atmel_flexcom_driver = {111 .probe = atmel_flexcom_probe,112 .driver = {113 .name = "atmel_flexcom",114 .pm = pm_ptr(&atmel_flexcom_pm_ops),115 .of_match_table = atmel_flexcom_of_match,116 },117};118 119module_platform_driver(atmel_flexcom_driver);120 121MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>");122MODULE_DESCRIPTION("Atmel Flexcom MFD driver");123MODULE_LICENSE("GPL v2");124