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230 lines
5.3 KiB
230 lines
5.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* lm70.c |
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* |
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* The LM70 is a temperature sensor chip from National Semiconductor (NS). |
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* Copyright (C) 2006 Kaiwan N Billimoria <[email protected]> |
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* |
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* The LM70 communicates with a host processor via an SPI/Microwire Bus |
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* interface. The complete datasheet is available at National's website |
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* here: |
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* http://www.national.com/pf/LM/LM70.html |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/device.h> |
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#include <linux/err.h> |
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#include <linux/sysfs.h> |
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#include <linux/hwmon.h> |
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#include <linux/mutex.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/property.h> |
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#include <linux/spi/spi.h> |
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#include <linux/slab.h> |
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#include <linux/acpi.h> |
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#define DRVNAME "lm70" |
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#define LM70_CHIP_LM70 0 /* original NS LM70 */ |
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#define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */ |
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#define LM70_CHIP_LM71 2 /* NS LM71 */ |
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#define LM70_CHIP_LM74 3 /* NS LM74 */ |
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#define LM70_CHIP_TMP122 4 /* TI TMP122/TMP124 */ |
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struct lm70 { |
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struct spi_device *spi; |
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struct mutex lock; |
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unsigned int chip; |
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}; |
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/* sysfs hook function */ |
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static ssize_t temp1_input_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct lm70 *p_lm70 = dev_get_drvdata(dev); |
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struct spi_device *spi = p_lm70->spi; |
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int status, val = 0; |
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u8 rxbuf[2]; |
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s16 raw = 0; |
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if (mutex_lock_interruptible(&p_lm70->lock)) |
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return -ERESTARTSYS; |
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/* |
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* spi_read() requires a DMA-safe buffer; so we use |
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* spi_write_then_read(), transmitting 0 bytes. |
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*/ |
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status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2); |
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if (status < 0) { |
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dev_warn(dev, "spi_write_then_read failed with status %d\n", |
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status); |
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goto out; |
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} |
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raw = (rxbuf[0] << 8) + rxbuf[1]; |
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dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n", |
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rxbuf[0], rxbuf[1], raw); |
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/* |
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* LM70: |
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* The "raw" temperature read into rxbuf[] is a 16-bit signed 2's |
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* complement value. Only the MSB 11 bits (1 sign + 10 temperature |
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* bits) are meaningful; the LSB 5 bits are to be discarded. |
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* See the datasheet. |
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* |
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* Further, each bit represents 0.25 degrees Celsius; so, multiply |
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* by 0.25. Also multiply by 1000 to represent in millidegrees |
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* Celsius. |
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* So it's equivalent to multiplying by 0.25 * 1000 = 250. |
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* |
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* LM74 and TMP121/TMP122/TMP123/TMP124: |
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* 13 bits of 2's complement data, discard LSB 3 bits, |
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* resolution 0.0625 degrees celsius. |
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* |
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* LM71: |
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* 14 bits of 2's complement data, discard LSB 2 bits, |
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* resolution 0.0312 degrees celsius. |
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*/ |
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switch (p_lm70->chip) { |
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case LM70_CHIP_LM70: |
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val = ((int)raw / 32) * 250; |
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break; |
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case LM70_CHIP_TMP121: |
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case LM70_CHIP_TMP122: |
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case LM70_CHIP_LM74: |
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val = ((int)raw / 8) * 625 / 10; |
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break; |
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case LM70_CHIP_LM71: |
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val = ((int)raw / 4) * 3125 / 100; |
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break; |
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} |
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status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */ |
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out: |
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mutex_unlock(&p_lm70->lock); |
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return status; |
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} |
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static DEVICE_ATTR_RO(temp1_input); |
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static struct attribute *lm70_attrs[] = { |
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&dev_attr_temp1_input.attr, |
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NULL |
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}; |
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ATTRIBUTE_GROUPS(lm70); |
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/*----------------------------------------------------------------------*/ |
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#ifdef CONFIG_OF |
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static const struct of_device_id lm70_of_ids[] = { |
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{ |
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.compatible = "ti,lm70", |
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.data = (void *) LM70_CHIP_LM70, |
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}, |
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{ |
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.compatible = "ti,tmp121", |
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.data = (void *) LM70_CHIP_TMP121, |
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}, |
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{ |
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.compatible = "ti,tmp122", |
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.data = (void *) LM70_CHIP_TMP122, |
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}, |
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{ |
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.compatible = "ti,lm71", |
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.data = (void *) LM70_CHIP_LM71, |
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}, |
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{ |
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.compatible = "ti,lm74", |
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.data = (void *) LM70_CHIP_LM74, |
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}, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, lm70_of_ids); |
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#endif |
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#ifdef CONFIG_ACPI |
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static const struct acpi_device_id lm70_acpi_ids[] = { |
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{ |
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.id = "LM000070", |
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.driver_data = LM70_CHIP_LM70, |
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}, |
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{ |
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.id = "TMP00121", |
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.driver_data = LM70_CHIP_TMP121, |
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}, |
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{ |
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.id = "LM000071", |
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.driver_data = LM70_CHIP_LM71, |
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}, |
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{ |
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.id = "LM000074", |
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.driver_data = LM70_CHIP_LM74, |
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}, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(acpi, lm70_acpi_ids); |
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#endif |
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static int lm70_probe(struct spi_device *spi) |
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{ |
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struct device *hwmon_dev; |
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struct lm70 *p_lm70; |
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int chip; |
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if (dev_fwnode(&spi->dev)) |
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chip = (int)(uintptr_t)device_get_match_data(&spi->dev); |
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else |
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chip = spi_get_device_id(spi)->driver_data; |
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/* signaling is SPI_MODE_0 */ |
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if (spi->mode & (SPI_CPOL | SPI_CPHA)) |
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return -EINVAL; |
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/* NOTE: we assume 8-bit words, and convert to 16 bits manually */ |
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p_lm70 = devm_kzalloc(&spi->dev, sizeof(*p_lm70), GFP_KERNEL); |
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if (!p_lm70) |
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return -ENOMEM; |
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mutex_init(&p_lm70->lock); |
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p_lm70->chip = chip; |
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p_lm70->spi = spi; |
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hwmon_dev = devm_hwmon_device_register_with_groups(&spi->dev, |
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spi->modalias, |
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p_lm70, lm70_groups); |
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return PTR_ERR_OR_ZERO(hwmon_dev); |
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} |
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static const struct spi_device_id lm70_ids[] = { |
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{ "lm70", LM70_CHIP_LM70 }, |
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{ "tmp121", LM70_CHIP_TMP121 }, |
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{ "tmp122", LM70_CHIP_TMP122 }, |
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{ "lm71", LM70_CHIP_LM71 }, |
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{ "lm74", LM70_CHIP_LM74 }, |
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{ }, |
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}; |
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MODULE_DEVICE_TABLE(spi, lm70_ids); |
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static struct spi_driver lm70_driver = { |
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.driver = { |
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.name = "lm70", |
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.of_match_table = of_match_ptr(lm70_of_ids), |
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.acpi_match_table = ACPI_PTR(lm70_acpi_ids), |
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}, |
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.id_table = lm70_ids, |
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.probe = lm70_probe, |
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}; |
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module_spi_driver(lm70_driver); |
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MODULE_AUTHOR("Kaiwan N Billimoria"); |
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MODULE_DESCRIPTION("NS LM70 and compatibles Linux driver"); |
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MODULE_LICENSE("GPL");
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