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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 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 | // SPDX-License-Identifier: GPL-2.0-only /* * Driver for Atmel Flexcom * * Copyright (C) 2015 Atmel Corporation * * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com> */ #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) struct atmel_flexcom { void __iomem *base; u32 opmode; struct clk *clk; }; static int atmel_flexcom_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; struct atmel_flexcom *ddata; int err; ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL); if (!ddata) return -ENOMEM; platform_set_drvdata(pdev, ddata); err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode); if (err) return err; if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART || ddata->opmode > ATMEL_FLEXCOM_MODE_TWI) return -EINVAL; ddata->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); if (IS_ERR(ddata->base)) return PTR_ERR(ddata->base); ddata->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(ddata->clk)) return PTR_ERR(ddata->clk); err = clk_prepare_enable(ddata->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(ddata->opmode), ddata->base + FLEX_MR); clk_disable_unprepare(ddata->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 int __maybe_unused atmel_flexcom_resume_noirq(struct device *dev) { struct atmel_flexcom *ddata = dev_get_drvdata(dev); int err; u32 val; err = clk_prepare_enable(ddata->clk); if (err) return err; val = FLEX_MR_OPMODE(ddata->opmode), writel(val, ddata->base + FLEX_MR); clk_disable_unprepare(ddata->clk); return 0; } static const struct dev_pm_ops __maybe_unused atmel_flexcom_pm_ops = { .resume_noirq = atmel_flexcom_resume_noirq, }; static struct platform_driver atmel_flexcom_driver = { .probe = atmel_flexcom_probe, .driver = { .name = "atmel_flexcom", .pm = pm_ptr(&atmel_flexcom_pm_ops), .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"); |