1/* 2 * dac7512.c - Linux kernel module for 3 * Texas Instruments DAC7512 4 * 5 * Copyright (c) 2009 Daniel Mack <daniel@caiaq.de> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 20 */ 21 22#include <linux/module.h> 23#include <linux/init.h> 24#include <linux/spi/spi.h> 25 26#define DAC7512_DRV_NAME "dac7512" 27#define DRIVER_VERSION "1.0" 28 29static ssize_t dac7512_store_val(struct device *dev, 30 struct device_attribute *attr, 31 const char *buf, size_t count) 32{ 33 struct spi_device *spi = to_spi_device(dev); 34 unsigned char tmp[2]; 35 unsigned long val; 36 37 if (strict_strtoul(buf, 10, &val) < 0) 38 return -EINVAL; 39 40 tmp[0] = val >> 8; 41 tmp[1] = val & 0xff; 42 spi_write(spi, tmp, sizeof(tmp)); 43 return count; 44} 45 46static DEVICE_ATTR(value, S_IWUSR, NULL, dac7512_store_val); 47 48static struct attribute *dac7512_attributes[] = { 49 &dev_attr_value.attr, 50 NULL 51}; 52 53static const struct attribute_group dac7512_attr_group = { 54 .attrs = dac7512_attributes, 55}; 56 57static int __devinit dac7512_probe(struct spi_device *spi) 58{ 59 int ret; 60 61 spi->bits_per_word = 8; 62 spi->mode = SPI_MODE_0; 63 ret = spi_setup(spi); 64 if (ret < 0) 65 return ret; 66 67 return sysfs_create_group(&spi->dev.kobj, &dac7512_attr_group); 68} 69 70static int __devexit dac7512_remove(struct spi_device *spi) 71{ 72 sysfs_remove_group(&spi->dev.kobj, &dac7512_attr_group); 73 return 0; 74} 75 76static struct spi_driver dac7512_driver = { 77 .driver = { 78 .name = DAC7512_DRV_NAME, 79 .owner = THIS_MODULE, 80 }, 81 .probe = dac7512_probe, 82 .remove = __devexit_p(dac7512_remove), 83}; 84 85static int __init dac7512_init(void) 86{ 87 return spi_register_driver(&dac7512_driver); 88} 89 90static void __exit dac7512_exit(void) 91{ 92 spi_unregister_driver(&dac7512_driver); 93} 94 95MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>"); 96MODULE_DESCRIPTION("DAC7512 16-bit DAC"); 97MODULE_LICENSE("GPL v2"); 98MODULE_VERSION(DRIVER_VERSION); 99 100module_init(dac7512_init); 101module_exit(dac7512_exit); 102