1e1a8e913SKaiwan N Billimoria /* 2e1a8e913SKaiwan N Billimoria * lm70.c 3e1a8e913SKaiwan N Billimoria * 4e1a8e913SKaiwan N Billimoria * The LM70 is a temperature sensor chip from National Semiconductor (NS). 5e1a8e913SKaiwan N Billimoria * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com> 6e1a8e913SKaiwan N Billimoria * 7e1a8e913SKaiwan N Billimoria * The LM70 communicates with a host processor via an SPI/Microwire Bus 8e1a8e913SKaiwan N Billimoria * interface. The complete datasheet is available at National's website 9e1a8e913SKaiwan N Billimoria * here: 10e1a8e913SKaiwan N Billimoria * http://www.national.com/pf/LM/LM70.html 11e1a8e913SKaiwan N Billimoria * 12e1a8e913SKaiwan N Billimoria * This program is free software; you can redistribute it and/or modify 13e1a8e913SKaiwan N Billimoria * it under the terms of the GNU General Public License as published by 14e1a8e913SKaiwan N Billimoria * the Free Software Foundation; either version 2 of the License, or 15e1a8e913SKaiwan N Billimoria * (at your option) any later version. 16e1a8e913SKaiwan N Billimoria * 17e1a8e913SKaiwan N Billimoria * This program is distributed in the hope that it will be useful, 18e1a8e913SKaiwan N Billimoria * but WITHOUT ANY WARRANTY; without even the implied warranty of 19e1a8e913SKaiwan N Billimoria * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20e1a8e913SKaiwan N Billimoria * GNU General Public License for more details. 21e1a8e913SKaiwan N Billimoria * 22e1a8e913SKaiwan N Billimoria * You should have received a copy of the GNU General Public License 23e1a8e913SKaiwan N Billimoria * along with this program; if not, write to the Free Software 24e1a8e913SKaiwan N Billimoria * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 25e1a8e913SKaiwan N Billimoria */ 26e1a8e913SKaiwan N Billimoria 275713017eSJoe Perches #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 285713017eSJoe Perches 29e1a8e913SKaiwan N Billimoria #include <linux/init.h> 30e1a8e913SKaiwan N Billimoria #include <linux/module.h> 31e1a8e913SKaiwan N Billimoria #include <linux/kernel.h> 32e1a8e913SKaiwan N Billimoria #include <linux/device.h> 33e1a8e913SKaiwan N Billimoria #include <linux/err.h> 34e1a8e913SKaiwan N Billimoria #include <linux/sysfs.h> 35e1a8e913SKaiwan N Billimoria #include <linux/hwmon.h> 364bfe6604SMatthias Kaehlcke #include <linux/mutex.h> 378cec03eeSAnton Vorontsov #include <linux/mod_devicetable.h> 38e1a8e913SKaiwan N Billimoria #include <linux/spi/spi.h> 395a0e3ad6STejun Heo #include <linux/slab.h> 40a1dc86ebSRabin Vincent #include <linux/of_device.h> 414bfe6604SMatthias Kaehlcke 42e1a8e913SKaiwan N Billimoria 43e1a8e913SKaiwan N Billimoria #define DRVNAME "lm70" 44e1a8e913SKaiwan N Billimoria 45c8ac32e4SManuel Lauss #define LM70_CHIP_LM70 0 /* original NS LM70 */ 46c8ac32e4SManuel Lauss #define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */ 47a86e94dcSChristophe Leroy #define LM70_CHIP_LM71 2 /* NS LM71 */ 48a86e94dcSChristophe Leroy #define LM70_CHIP_LM74 3 /* NS LM74 */ 49c8ac32e4SManuel Lauss 50e1a8e913SKaiwan N Billimoria struct lm70 { 51aa9bcddaSGuenter Roeck struct spi_device *spi; 524bfe6604SMatthias Kaehlcke struct mutex lock; 53c8ac32e4SManuel Lauss unsigned int chip; 54e1a8e913SKaiwan N Billimoria }; 55e1a8e913SKaiwan N Billimoria 56e1a8e913SKaiwan N Billimoria /* sysfs hook function */ 5789cb4af8SJulia Lawall static ssize_t temp1_input_show(struct device *dev, 58e1a8e913SKaiwan N Billimoria struct device_attribute *attr, char *buf) 59e1a8e913SKaiwan N Billimoria { 60aa9bcddaSGuenter Roeck struct lm70 *p_lm70 = dev_get_drvdata(dev); 61aa9bcddaSGuenter Roeck struct spi_device *spi = p_lm70->spi; 62c8ac32e4SManuel Lauss int status, val = 0; 63e1a8e913SKaiwan N Billimoria u8 rxbuf[2]; 64e1a8e913SKaiwan N Billimoria s16 raw = 0; 65e1a8e913SKaiwan N Billimoria 664bfe6604SMatthias Kaehlcke if (mutex_lock_interruptible(&p_lm70->lock)) 67e1a8e913SKaiwan N Billimoria return -ERESTARTSYS; 68e1a8e913SKaiwan N Billimoria 69e1a8e913SKaiwan N Billimoria /* 70e1a8e913SKaiwan N Billimoria * spi_read() requires a DMA-safe buffer; so we use 71e1a8e913SKaiwan N Billimoria * spi_write_then_read(), transmitting 0 bytes. 72e1a8e913SKaiwan N Billimoria */ 73e1a8e913SKaiwan N Billimoria status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2); 74e1a8e913SKaiwan N Billimoria if (status < 0) { 755713017eSJoe Perches pr_warn("spi_write_then_read failed with status %d\n", status); 76e1a8e913SKaiwan N Billimoria goto out; 77e1a8e913SKaiwan N Billimoria } 782b730051SKaiwan N Billimoria raw = (rxbuf[0] << 8) + rxbuf[1]; 792b730051SKaiwan N Billimoria dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n", 802b730051SKaiwan N Billimoria rxbuf[0], rxbuf[1], raw); 81e1a8e913SKaiwan N Billimoria 82e1a8e913SKaiwan N Billimoria /* 83c8ac32e4SManuel Lauss * LM70: 84e1a8e913SKaiwan N Billimoria * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's 85e1a8e913SKaiwan N Billimoria * complement value. Only the MSB 11 bits (1 sign + 10 temperature 86e1a8e913SKaiwan N Billimoria * bits) are meaningful; the LSB 5 bits are to be discarded. 87e1a8e913SKaiwan N Billimoria * See the datasheet. 88e1a8e913SKaiwan N Billimoria * 89e1a8e913SKaiwan N Billimoria * Further, each bit represents 0.25 degrees Celsius; so, multiply 90e1a8e913SKaiwan N Billimoria * by 0.25. Also multiply by 1000 to represent in millidegrees 91e1a8e913SKaiwan N Billimoria * Celsius. 92e1a8e913SKaiwan N Billimoria * So it's equivalent to multiplying by 0.25 * 1000 = 250. 93c8ac32e4SManuel Lauss * 94a86e94dcSChristophe Leroy * LM74 and TMP121/TMP123: 95c8ac32e4SManuel Lauss * 13 bits of 2's complement data, discard LSB 3 bits, 96c8ac32e4SManuel Lauss * resolution 0.0625 degrees celsius. 97a86e94dcSChristophe Leroy * 98a86e94dcSChristophe Leroy * LM71: 99a86e94dcSChristophe Leroy * 14 bits of 2's complement data, discard LSB 2 bits, 100a86e94dcSChristophe Leroy * resolution 0.0312 degrees celsius. 101e1a8e913SKaiwan N Billimoria */ 102c8ac32e4SManuel Lauss switch (p_lm70->chip) { 103c8ac32e4SManuel Lauss case LM70_CHIP_LM70: 104e1a8e913SKaiwan N Billimoria val = ((int)raw / 32) * 250; 105c8ac32e4SManuel Lauss break; 106c8ac32e4SManuel Lauss 107c8ac32e4SManuel Lauss case LM70_CHIP_TMP121: 108a86e94dcSChristophe Leroy case LM70_CHIP_LM74: 109c8ac32e4SManuel Lauss val = ((int)raw / 8) * 625 / 10; 110c8ac32e4SManuel Lauss break; 111a86e94dcSChristophe Leroy 112a86e94dcSChristophe Leroy case LM70_CHIP_LM71: 113a86e94dcSChristophe Leroy val = ((int)raw / 4) * 3125 / 100; 114a86e94dcSChristophe Leroy break; 115c8ac32e4SManuel Lauss } 116c8ac32e4SManuel Lauss 11767f921d1SJean Delvare status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */ 118e1a8e913SKaiwan N Billimoria out: 1194bfe6604SMatthias Kaehlcke mutex_unlock(&p_lm70->lock); 120e1a8e913SKaiwan N Billimoria return status; 121e1a8e913SKaiwan N Billimoria } 122e1a8e913SKaiwan N Billimoria 12389cb4af8SJulia Lawall static DEVICE_ATTR_RO(temp1_input); 124e1a8e913SKaiwan N Billimoria 125aa9bcddaSGuenter Roeck static struct attribute *lm70_attrs[] = { 126aa9bcddaSGuenter Roeck &dev_attr_temp1_input.attr, 127aa9bcddaSGuenter Roeck NULL 128aa9bcddaSGuenter Roeck }; 12967f921d1SJean Delvare 130aa9bcddaSGuenter Roeck ATTRIBUTE_GROUPS(lm70); 13167f921d1SJean Delvare 132e1a8e913SKaiwan N Billimoria /*----------------------------------------------------------------------*/ 133e1a8e913SKaiwan N Billimoria 134a1dc86ebSRabin Vincent #ifdef CONFIG_OF 135a1dc86ebSRabin Vincent static const struct of_device_id lm70_of_ids[] = { 136a1dc86ebSRabin Vincent { 137a1dc86ebSRabin Vincent .compatible = "ti,lm70", 138a1dc86ebSRabin Vincent .data = (void *) LM70_CHIP_LM70, 139a1dc86ebSRabin Vincent }, 140a1dc86ebSRabin Vincent { 141a1dc86ebSRabin Vincent .compatible = "ti,tmp121", 142a1dc86ebSRabin Vincent .data = (void *) LM70_CHIP_TMP121, 143a1dc86ebSRabin Vincent }, 144a1dc86ebSRabin Vincent { 145a1dc86ebSRabin Vincent .compatible = "ti,lm71", 146a1dc86ebSRabin Vincent .data = (void *) LM70_CHIP_LM71, 147a1dc86ebSRabin Vincent }, 148a1dc86ebSRabin Vincent { 149a1dc86ebSRabin Vincent .compatible = "ti,lm74", 150a1dc86ebSRabin Vincent .data = (void *) LM70_CHIP_LM74, 151a1dc86ebSRabin Vincent }, 152a1dc86ebSRabin Vincent {}, 153a1dc86ebSRabin Vincent }; 154a1dc86ebSRabin Vincent MODULE_DEVICE_TABLE(of, lm70_of_ids); 155a1dc86ebSRabin Vincent #endif 156a1dc86ebSRabin Vincent 1576c931ae1SBill Pemberton static int lm70_probe(struct spi_device *spi) 158e1a8e913SKaiwan N Billimoria { 159a1dc86ebSRabin Vincent const struct of_device_id *match; 160aa9bcddaSGuenter Roeck struct device *hwmon_dev; 161e1a8e913SKaiwan N Billimoria struct lm70 *p_lm70; 162a1dc86ebSRabin Vincent int chip; 163a1dc86ebSRabin Vincent 164a1dc86ebSRabin Vincent match = of_match_device(lm70_of_ids, &spi->dev); 165a1dc86ebSRabin Vincent if (match) 166a1dc86ebSRabin Vincent chip = (int)(uintptr_t)match->data; 167a1dc86ebSRabin Vincent else 168a1dc86ebSRabin Vincent chip = spi_get_device_id(spi)->driver_data; 169e1a8e913SKaiwan N Billimoria 170a86e94dcSChristophe Leroy /* signaling is SPI_MODE_0 */ 1718cec03eeSAnton Vorontsov if (spi->mode & (SPI_CPOL | SPI_CPHA)) 1728cec03eeSAnton Vorontsov return -EINVAL; 1738cec03eeSAnton Vorontsov 1742b730051SKaiwan N Billimoria /* NOTE: we assume 8-bit words, and convert to 16 bits manually */ 1752b730051SKaiwan N Billimoria 17633ed6d4aSGuenter Roeck p_lm70 = devm_kzalloc(&spi->dev, sizeof(*p_lm70), GFP_KERNEL); 177e1a8e913SKaiwan N Billimoria if (!p_lm70) 178e1a8e913SKaiwan N Billimoria return -ENOMEM; 179e1a8e913SKaiwan N Billimoria 1804bfe6604SMatthias Kaehlcke mutex_init(&p_lm70->lock); 181c8ac32e4SManuel Lauss p_lm70->chip = chip; 182aa9bcddaSGuenter Roeck p_lm70->spi = spi; 183e1a8e913SKaiwan N Billimoria 184aa9bcddaSGuenter Roeck hwmon_dev = devm_hwmon_device_register_with_groups(&spi->dev, 185aa9bcddaSGuenter Roeck spi->modalias, 186aa9bcddaSGuenter Roeck p_lm70, lm70_groups); 187aa9bcddaSGuenter Roeck return PTR_ERR_OR_ZERO(hwmon_dev); 188e200c14fSGuenter Roeck } 189e200c14fSGuenter Roeck 1908cec03eeSAnton Vorontsov static const struct spi_device_id lm70_ids[] = { 1918cec03eeSAnton Vorontsov { "lm70", LM70_CHIP_LM70 }, 1928cec03eeSAnton Vorontsov { "tmp121", LM70_CHIP_TMP121 }, 193a86e94dcSChristophe Leroy { "lm71", LM70_CHIP_LM71 }, 194a86e94dcSChristophe Leroy { "lm74", LM70_CHIP_LM74 }, 1958cec03eeSAnton Vorontsov { }, 196c8ac32e4SManuel Lauss }; 1978cec03eeSAnton Vorontsov MODULE_DEVICE_TABLE(spi, lm70_ids); 198c8ac32e4SManuel Lauss 199e1a8e913SKaiwan N Billimoria static struct spi_driver lm70_driver = { 200e1a8e913SKaiwan N Billimoria .driver = { 201e1a8e913SKaiwan N Billimoria .name = "lm70", 202a1dc86ebSRabin Vincent .of_match_table = of_match_ptr(lm70_of_ids), 203e1a8e913SKaiwan N Billimoria }, 2048cec03eeSAnton Vorontsov .id_table = lm70_ids, 205e1a8e913SKaiwan N Billimoria .probe = lm70_probe, 206e1a8e913SKaiwan N Billimoria }; 207e1a8e913SKaiwan N Billimoria 20891efffe2SAxel Lin module_spi_driver(lm70_driver); 209e1a8e913SKaiwan N Billimoria 210e1a8e913SKaiwan N Billimoria MODULE_AUTHOR("Kaiwan N Billimoria"); 211a86e94dcSChristophe Leroy MODULE_DESCRIPTION("NS LM70 and compatibles Linux driver"); 212e1a8e913SKaiwan N Billimoria MODULE_LICENSE("GPL"); 213