| Cyrille Pitchen | 5c41f11 | 2015-09-28 11:13:26 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Driver for Atmel Flexcom |
| 3 | * |
| 4 | * Copyright (C) 2015 Atmel Corporation |
| 5 | * |
| 6 | * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, but WITHOUT |
| 13 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 14 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| 15 | * more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License along with |
| 18 | * this program. If not, see <http://www.gnu.org/licenses/>. |
| 19 | */ |
| 20 | |
| 21 | #include <linux/module.h> |
| 22 | #include <linux/types.h> |
| 23 | #include <linux/kernel.h> |
| 24 | #include <linux/platform_device.h> |
| 25 | #include <linux/of.h> |
| 26 | #include <linux/of_platform.h> |
| 27 | #include <linux/err.h> |
| 28 | #include <linux/io.h> |
| 29 | #include <linux/clk.h> |
| 30 | #include <dt-bindings/mfd/atmel-flexcom.h> |
| 31 | |
| 32 | /* I/O register offsets */ |
| 33 | #define FLEX_MR 0x0 /* Mode Register */ |
| 34 | #define FLEX_VERSION 0xfc /* Version Register */ |
| 35 | |
| 36 | /* Mode Register bit fields */ |
| 37 | #define FLEX_MR_OPMODE_OFFSET (0) /* Operating Mode */ |
| 38 | #define FLEX_MR_OPMODE_MASK (0x3 << FLEX_MR_OPMODE_OFFSET) |
| 39 | #define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) & \ |
| 40 | FLEX_MR_OPMODE_MASK) |
| 41 | |
| 42 | |
| 43 | static int atmel_flexcom_probe(struct platform_device *pdev) |
| 44 | { |
| 45 | struct device_node *np = pdev->dev.of_node; |
| 46 | struct clk *clk; |
| 47 | struct resource *res; |
| 48 | void __iomem *base; |
| 49 | u32 opmode; |
| 50 | int err; |
| 51 | |
| 52 | err = of_property_read_u32(np, "atmel,flexcom-mode", &opmode); |
| 53 | if (err) |
| 54 | return err; |
| 55 | |
| 56 | if (opmode < ATMEL_FLEXCOM_MODE_USART || |
| 57 | opmode > ATMEL_FLEXCOM_MODE_TWI) |
| 58 | return -EINVAL; |
| 59 | |
| 60 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 61 | base = devm_ioremap_resource(&pdev->dev, res); |
| 62 | if (IS_ERR(base)) |
| 63 | return PTR_ERR(base); |
| 64 | |
| 65 | clk = devm_clk_get(&pdev->dev, NULL); |
| 66 | if (IS_ERR(clk)) |
| 67 | return PTR_ERR(clk); |
| 68 | |
| 69 | err = clk_prepare_enable(clk); |
| 70 | if (err) |
| 71 | return err; |
| 72 | |
| 73 | /* |
| 74 | * Set the Operating Mode in the Mode Register: only the selected device |
| 75 | * is clocked. Hence, registers of the other serial devices remain |
| 76 | * inaccessible and are read as zero. Also the external I/O lines of the |
| 77 | * Flexcom are muxed to reach the selected device. |
| 78 | */ |
| 79 | writel(FLEX_MR_OPMODE(opmode), base + FLEX_MR); |
| 80 | |
| 81 | clk_disable_unprepare(clk); |
| 82 | |
| 83 | return of_platform_populate(np, NULL, NULL, &pdev->dev); |
| 84 | } |
| 85 | |
| 86 | static const struct of_device_id atmel_flexcom_of_match[] = { |
| 87 | { .compatible = "atmel,sama5d2-flexcom" }, |
| 88 | { /* sentinel */ } |
| 89 | }; |
| 90 | MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match); |
| 91 | |
| 92 | static struct platform_driver atmel_flexcom_driver = { |
| 93 | .probe = atmel_flexcom_probe, |
| 94 | .driver = { |
| 95 | .name = "atmel_flexcom", |
| 96 | .of_match_table = atmel_flexcom_of_match, |
| 97 | }, |
| 98 | }; |
| 99 | |
| 100 | module_platform_driver(atmel_flexcom_driver); |
| 101 | |
| 102 | MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>"); |
| 103 | MODULE_DESCRIPTION("Atmel Flexcom MFD driver"); |
| 104 | MODULE_LICENSE("GPL v2"); |