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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 | /* * lm70.c * * The LM70 is a temperature sensor chip from National Semiconductor (NS). * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com> * * The LM70 communicates with a host processor via an SPI/Microwire Bus * interface. The complete datasheet is available at National's website * here: * http://www.national.com/pf/LM/LM70.html * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/init.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/device.h> #include <linux/err.h> #include <linux/sysfs.h> #include <linux/hwmon.h> #include <linux/mutex.h> #include <linux/mod_devicetable.h> #include <linux/spi/spi.h> #include <linux/slab.h> #define DRVNAME "lm70" #define LM70_CHIP_LM70 0 /* original NS LM70 */ #define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */ struct lm70 { struct device *hwmon_dev; struct mutex lock; unsigned int chip; }; /* sysfs hook function */ static ssize_t lm70_sense_temp(struct device *dev, struct device_attribute *attr, char *buf) { struct spi_device *spi = to_spi_device(dev); int status, val = 0; u8 rxbuf[2]; s16 raw=0; struct lm70 *p_lm70 = spi_get_drvdata(spi); if (mutex_lock_interruptible(&p_lm70->lock)) return -ERESTARTSYS; /* * spi_read() requires a DMA-safe buffer; so we use * spi_write_then_read(), transmitting 0 bytes. */ status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2); if (status < 0) { pr_warn("spi_write_then_read failed with status %d\n", status); goto out; } raw = (rxbuf[0] << 8) + rxbuf[1]; dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n", rxbuf[0], rxbuf[1], raw); /* * LM70: * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's * complement value. Only the MSB 11 bits (1 sign + 10 temperature * bits) are meaningful; the LSB 5 bits are to be discarded. * See the datasheet. * * Further, each bit represents 0.25 degrees Celsius; so, multiply * by 0.25. Also multiply by 1000 to represent in millidegrees * Celsius. * So it's equivalent to multiplying by 0.25 * 1000 = 250. * * TMP121/TMP123: * 13 bits of 2's complement data, discard LSB 3 bits, * resolution 0.0625 degrees celsius. */ switch (p_lm70->chip) { case LM70_CHIP_LM70: val = ((int)raw / 32) * 250; break; case LM70_CHIP_TMP121: val = ((int)raw / 8) * 625 / 10; break; } status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */ out: mutex_unlock(&p_lm70->lock); return status; } static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL); static ssize_t lm70_show_name(struct device *dev, struct device_attribute *devattr, char *buf) { struct lm70 *p_lm70 = dev_get_drvdata(dev); int ret; switch (p_lm70->chip) { case LM70_CHIP_LM70: ret = sprintf(buf, "lm70\n"); break; case LM70_CHIP_TMP121: ret = sprintf(buf, "tmp121\n"); break; default: ret = -EINVAL; } return ret; } static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL); /*----------------------------------------------------------------------*/ static int __devinit lm70_probe(struct spi_device *spi) { int chip = spi_get_device_id(spi)->driver_data; struct lm70 *p_lm70; int status; /* signaling is SPI_MODE_0 for both LM70 and TMP121 */ if (spi->mode & (SPI_CPOL | SPI_CPHA)) return -EINVAL; /* 3-wire link (shared SI/SO) for LM70 */ if (chip == LM70_CHIP_LM70 && !(spi->mode & SPI_3WIRE)) return -EINVAL; /* NOTE: we assume 8-bit words, and convert to 16 bits manually */ p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL); if (!p_lm70) return -ENOMEM; mutex_init(&p_lm70->lock); p_lm70->chip = chip; /* sysfs hook */ p_lm70->hwmon_dev = hwmon_device_register(&spi->dev); if (IS_ERR(p_lm70->hwmon_dev)) { dev_dbg(&spi->dev, "hwmon_device_register failed.\n"); status = PTR_ERR(p_lm70->hwmon_dev); goto out_dev_reg_failed; } spi_set_drvdata(spi, p_lm70); if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input)) || (status = device_create_file(&spi->dev, &dev_attr_name))) { dev_dbg(&spi->dev, "device_create_file failure.\n"); goto out_dev_create_file_failed; } return 0; out_dev_create_file_failed: device_remove_file(&spi->dev, &dev_attr_temp1_input); hwmon_device_unregister(p_lm70->hwmon_dev); out_dev_reg_failed: spi_set_drvdata(spi, NULL); kfree(p_lm70); return status; } static int __devexit lm70_remove(struct spi_device *spi) { struct lm70 *p_lm70 = spi_get_drvdata(spi); device_remove_file(&spi->dev, &dev_attr_temp1_input); device_remove_file(&spi->dev, &dev_attr_name); hwmon_device_unregister(p_lm70->hwmon_dev); spi_set_drvdata(spi, NULL); kfree(p_lm70); return 0; } static const struct spi_device_id lm70_ids[] = { { "lm70", LM70_CHIP_LM70 }, { "tmp121", LM70_CHIP_TMP121 }, { }, }; MODULE_DEVICE_TABLE(spi, lm70_ids); static struct spi_driver lm70_driver = { .driver = { .name = "lm70", .owner = THIS_MODULE, }, .id_table = lm70_ids, .probe = lm70_probe, .remove = __devexit_p(lm70_remove), }; static int __init init_lm70(void) { return spi_register_driver(&lm70_driver); } static void __exit cleanup_lm70(void) { spi_unregister_driver(&lm70_driver); } module_init(init_lm70); module_exit(cleanup_lm70); MODULE_AUTHOR("Kaiwan N Billimoria"); MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver"); MODULE_LICENSE("GPL"); |