From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pf0-x22e.google.com ([2607:f8b0:400e:c00::22e]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1a5qca-0003wH-N5 for barebox@lists.infradead.org; Mon, 07 Dec 2015 07:54:15 +0000 Received: by pfu207 with SMTP id 207so60915978pfu.2 for ; Sun, 06 Dec 2015 23:53:47 -0800 (PST) From: Andrey Smirnov Date: Sun, 6 Dec 2015 23:52:42 -0800 Message-Id: <1449474763-14099-6-git-send-email-andrew.smirnov@gmail.com> In-Reply-To: <1449474763-14099-1-git-send-email-andrew.smirnov@gmail.com> References: <1449474763-14099-1-git-send-email-andrew.smirnov@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 6/7] hwmon: Port Linux driver for LM75 sensor To: barebox@lists.infradead.org Cc: Andrey Smirnov Signed-off-by: Andrey Smirnov --- drivers/hwmon/Kconfig | 9 +++ drivers/hwmon/Makefile | 2 + drivers/hwmon/lm75.c | 194 +++++++++++++++++++++++++++++++++++++++++++++++++ drivers/hwmon/lm75.h | 48 ++++++++++++ 4 files changed, 253 insertions(+) create mode 100644 drivers/hwmon/lm75.c create mode 100644 drivers/hwmon/lm75.h diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig index 6ce06a7..db51d26 100644 --- a/drivers/hwmon/Kconfig +++ b/drivers/hwmon/Kconfig @@ -13,4 +13,13 @@ menuconfig HWMON if HWMON +config SENSORS_LM75 + tristate "National Semiconductor LM75 and compatibles" + depends on I2C + help + If you say yes here you get support for one common type of + temperature sensor chip, with models including: + + - National Semiconductor LM75, LM75A + endif # HWMON diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile index 47a2e58..e73e681 100644 --- a/drivers/hwmon/Makefile +++ b/drivers/hwmon/Makefile @@ -3,3 +3,5 @@ # obj-$(CONFIG_HWMON) += class.o + +obj-$(CONFIG_SENSORS_LM75) += lm75.o diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c new file mode 100644 index 0000000..5df85bf --- /dev/null +++ b/drivers/hwmon/lm75.c @@ -0,0 +1,194 @@ +/* + * lm75.c - Part of lm_sensors, Linux kernel modules for hardware + * monitoring + * Copyright (c) 1998, 1999 Frodo Looijaard + * + * 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. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "lm75.h" + + +/* + * This driver handles the LM75 and compatible digital temperature sensors. + */ + +enum lm75_type { /* keep sorted in alphabetical order */ + lm75, +}; + + + +/* The LM75 registers */ +#define LM75_REG_CONF 0x01 +static const u8 LM75_REG_TEMP[3] = { + 0x00, /* input */ + 0x03, /* max */ + 0x02, /* hyst */ +}; + +/* Each client has this additional data */ +struct lm75_data { + struct i2c_client *client; + struct hwmon_sensor sensor; + + u8 resolution; /* In bits, between 9 and 12 */ +}; + +static inline struct lm75_data *to_lm75_data(struct hwmon_sensor *sensor) +{ + return container_of(sensor, struct lm75_data, sensor); +} + +/* + * All registers are word-sized, except for the configuration register. + * LM75 uses a high-byte first convention, which is exactly opposite to + * the SMBus standard. + */ +static s32 lm75_read_value(struct i2c_client *client, u8 reg) +{ + if (reg == LM75_REG_CONF) + return i2c_smbus_read_byte_data(client, reg); + else + return i2c_smbus_read_word_swapped(client, reg); +} + +static s32 lm75_write_value(struct i2c_client *client, u8 reg, u16 value) +{ + if (reg == LM75_REG_CONF) + return i2c_smbus_write_byte_data(client, reg, value); + else + return i2c_smbus_write_word_swapped(client, reg, value); +} + +static inline s32 lm75_reg_to_mc(s16 temp, u8 resolution) +{ + return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8); +} + +static int lm75_read_temp(struct hwmon_sensor *sensor, s32 *reading) +{ + struct lm75_data *data = to_lm75_data(sensor); + + s32 ret = lm75_read_value(data->client, LM75_REG_TEMP[0]); + + if (ret < 0) + return ret; + + *reading = lm75_reg_to_mc((s16)ret, data->resolution); + return 0; +} + +static int lm75_probe(struct device_d *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + struct lm75_data *data; + int err; + u8 set_mask, clr_mask; + int new; + enum lm75_type kind; + + err = dev_get_drvdata(dev, (const void **)&kind); + if (err) { + dev_err(dev, "Can't get driver data\n"); + return err; + } + + data = xzalloc(sizeof(struct lm75_data)); + if (!data) + return -ENOMEM; + + data->client = client; + + /* Set to LM75 resolution (9 bits, 1/2 degree C) and range. + * Then tweak to be more precise when appropriate. + */ + set_mask = 0; + clr_mask = LM75_SHUTDOWN; /* continuous conversions */ + + switch (kind) { + case lm75: + data->resolution = 9; + break; + } + + /* configure as specified */ + err = lm75_read_value(client, LM75_REG_CONF); + if (err < 0) { + dev_err(dev, "Can't read config? %d\n", err); + goto exit; + } + + new = err & ~clr_mask; + new |= set_mask; + if (err != new) + lm75_write_value(client, LM75_REG_CONF, new); + dev_dbg(dev, "Config %02x\n", new); + + if (!dev->device_node) { + dev_err(dev, "No device_node associated with the device\n"); + err = -EINVAL; + goto exit; + } + + data->sensor.name = of_get_property(dev->device_node, + "barebox,sensor-name", + NULL); + if (!data->sensor.name) { + dev_err(dev, "No sensor-name specified\n"); + err = -EINVAL; + goto exit; + } + + data->sensor.read = lm75_read_temp; + data->sensor.dev = dev; + + err = hwmon_sensor_register(&data->sensor); + +exit: + if (err) { + free(data); + return err; + } + + return 0; +} + +static const struct platform_device_id lm75_ids[] = { + { "lm75", lm75, }, + { /* LIST END */ } +}; + +static struct driver_d lm75_driver = { + .name = "lm75", + .probe = lm75_probe, + .id_table = lm75_ids, +}; + +static int lm75_init(void) +{ + return i2c_driver_register(&lm75_driver); +} +device_initcall(lm75_init); diff --git a/drivers/hwmon/lm75.h b/drivers/hwmon/lm75.h new file mode 100644 index 0000000..9ffe83e --- /dev/null +++ b/drivers/hwmon/lm75.h @@ -0,0 +1,48 @@ +/* + lm75.h - Part of lm_sensors, Linux kernel modules for hardware + monitoring + Copyright (c) 2003 Mark M. Hoffman + + 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. +*/ + +/* + This file contains common code for encoding/decoding LM75 type + temperature readings, which are emulated by many of the chips + we support. As the user is unlikely to load more than one driver + which contains this code, we don't worry about the wasted space. +*/ + + +/* straight from the datasheet */ +#define LM75_TEMP_MIN (-55000) +#define LM75_TEMP_MAX 125000 +#define LM75_SHUTDOWN 0x01 + +/* TEMP: 0.001C/bit (-55C to +125C) + REG: (0.5C/bit, two's complement) << 7 */ +static inline u16 LM75_TEMP_TO_REG(long temp) +{ + int ntemp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX); + ntemp += (ntemp < 0 ? -250 : 250); + return (u16)((ntemp / 500) << 7); +} + +static inline int LM75_TEMP_FROM_REG(u16 reg) +{ + /* use integer division instead of equivalent right shift to + guarantee arithmetic shift and preserve the sign */ + return ((s16)reg / 128) * 500; +} -- 2.5.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox