[PATCH 2/4] misc: Add basic LM75 temperature driver
Sascha Hauer
s.hauer at pengutronix.de
Tue Dec 8 01:05:37 PST 2015
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
drivers/misc/Kconfig | 5 +
drivers/misc/Makefile | 1 +
drivers/misc/lm75.c | 262 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 268 insertions(+)
create mode 100644 drivers/misc/lm75.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 250b205..b95a7f6 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -22,4 +22,9 @@ config STATE_DRV
config IODEVICE
bool "IO device support"
+config LM75
+ tristate "LM75 driver"
+ depends on I2C
+ depends on IODEVICE
+
endmenu
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 127504e..a257dfb 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_JTAG) += jtag.o
obj-$(CONFIG_SRAM) += sram.o
obj-$(CONFIG_STATE_DRV) += state.o
obj-$(CONFIG_IODEVICE) += iodevice.o
+obj-$(CONFIG_LM75) += lm75.o
diff --git a/drivers/misc/lm75.c b/drivers/misc/lm75.c
new file mode 100644
index 0000000..d9e5580
--- /dev/null
+++ b/drivers/misc/lm75.c
@@ -0,0 +1,262 @@
+/*
+ * lm75.c - Part of lm_sensors, Linux kernel modules for hardware
+ * monitoring
+ * Copyright (c) 1998, 1999 Frodo Looijaard <frodol at dds.nl>
+ *
+ * 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 <common.h>
+#include <init.h>
+#include <driver.h>
+#include <xfuncs.h>
+#include <i2c/i2c.h>
+#include <iodevice.h>
+
+/*
+ * This driver handles the LM75 and compatible digital temperature sensors.
+ */
+
+/* straight from the datasheet */
+#define LM75_TEMP_MIN (-55000)
+#define LM75_TEMP_MAX 125000
+#define LM75_SHUTDOWN 0x01
+
+enum lm75_type { /* keep sorted in alphabetical order */
+ adt75,
+ ds1775,
+ ds75,
+ ds7505,
+ g751,
+ lm75,
+ lm75a,
+ lm75b,
+ max6625,
+ max6626,
+ mcp980x,
+ stds75,
+ tcn75,
+ tmp100,
+ tmp101,
+ tmp105,
+ tmp112,
+ tmp175,
+ tmp275,
+ tmp75,
+ tmp75c,
+};
+
+/* 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 device_d dev;
+ u8 resolution; /* In bits, between 9 and 12 */
+ struct iochannel iochan;
+ struct iodevice iodev;
+};
+
+static int lm75_read_value(struct lm75_data *data, u8 reg)
+{
+ if (reg == LM75_REG_CONF)
+ return i2c_smbus_read_byte_data(data->client, reg);
+ else
+ return i2c_smbus_read_word_swapped(data->client, reg);
+}
+
+static int lm75_write_value(struct lm75_data *data, u8 reg, u16 value)
+{
+ if (reg == LM75_REG_CONF)
+ return i2c_smbus_write_byte_data(data->client, reg, value);
+ else
+ return i2c_smbus_write_word_swapped(data->client, reg, value);
+}
+
+static long lm75_reg_to_mc(s16 temp, u8 resolution)
+{
+ return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
+}
+
+static int lm75_get_temp(struct iochannel *iochan, int *val)
+{
+ struct lm75_data *data = container_of(iochan, struct lm75_data, iochan);
+ int status;
+
+ status = lm75_read_value(data, LM75_REG_TEMP[0]);
+ if (status < 0) {
+ dev_err(&data->client->dev,
+ "LM75: Failed to read value: reg %d, error %d\n",
+ LM75_REG_TEMP[0], status);
+ return status;
+ }
+
+ *val = lm75_reg_to_mc(status, data->resolution);
+
+ return 0;
+}
+
+static int lm75_probe(struct device_d *dev)
+{
+ struct lm75_data *data;
+ int status;
+ u8 set_mask, clr_mask;
+ int new, ret;
+ enum lm75_type kind;
+
+ ret = dev_get_drvdata(dev, (const void **)&kind);
+ if (ret)
+ return ret;
+
+ data = xzalloc(sizeof(*data));
+
+ data->client = to_i2c_client(dev);
+
+ /* 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 adt75:
+ clr_mask |= 1 << 5; /* not one-shot mode */
+ data->resolution = 12;
+ break;
+ case ds1775:
+ case ds75:
+ case stds75:
+ clr_mask |= 3 << 5;
+ set_mask |= 2 << 5; /* 11-bit mode */
+ data->resolution = 11;
+ break;
+ case ds7505:
+ set_mask |= 3 << 5; /* 12-bit mode */
+ data->resolution = 12;
+ break;
+ case g751:
+ case lm75:
+ case lm75a:
+ data->resolution = 9;
+ break;
+ case lm75b:
+ data->resolution = 11;
+ break;
+ case max6625:
+ data->resolution = 9;
+ break;
+ case max6626:
+ data->resolution = 12;
+ break;
+ case tcn75:
+ data->resolution = 9;
+ break;
+ case mcp980x:
+ /* fall through */
+ case tmp100:
+ case tmp101:
+ set_mask |= 3 << 5; /* 12-bit mode */
+ data->resolution = 12;
+ clr_mask |= 1 << 7; /* not one-shot mode */
+ break;
+ case tmp112:
+ set_mask |= 3 << 5; /* 12-bit mode */
+ clr_mask |= 1 << 7; /* not one-shot mode */
+ data->resolution = 12;
+ break;
+ case tmp105:
+ case tmp175:
+ case tmp275:
+ case tmp75:
+ set_mask |= 3 << 5; /* 12-bit mode */
+ clr_mask |= 1 << 7; /* not one-shot mode */
+ data->resolution = 12;
+ break;
+ case tmp75c:
+ clr_mask |= 1 << 5; /* not one-shot mode */
+ data->resolution = 12;
+ break;
+ }
+
+ /* configure as specified */
+ status = lm75_read_value(data, LM75_REG_CONF);
+ if (status < 0) {
+ dev_dbg(dev, "Can't read config? %d\n", status);
+ return status;
+ }
+
+ new = status & ~clr_mask;
+ new |= set_mask;
+ if (status != new)
+ lm75_write_value(data, LM75_REG_CONF, new);
+
+ data->iodev.num_channels = 1;
+ data->iodev.hwdev = dev;
+ data->iodev.read = lm75_get_temp;
+ data->iodev.channels = xmalloc(sizeof(void *));
+ data->iodev.channels[0] = &data->iochan;
+ data->iochan.unit = "mC";
+
+ ret = iodevice_register(&data->iodev);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static const struct platform_device_id lm75_ids[] = {
+ { .name = "adt75", .driver_data = adt75, },
+ { .name = "ds1775", .driver_data = ds1775, },
+ { .name = "ds75", .driver_data = ds75, },
+ { .name = "ds7505", .driver_data = ds7505, },
+ { .name = "g751", .driver_data = g751, },
+ { .name = "lm75", .driver_data = lm75, },
+ { .name = "lm75a", .driver_data = lm75a, },
+ { .name = "lm75b", .driver_data = lm75b, },
+ { .name = "max6625", .driver_data = max6625, },
+ { .name = "max6626", .driver_data = max6626, },
+ { .name = "mcp980x", .driver_data = mcp980x, },
+ { .name = "stds75", .driver_data = stds75, },
+ { .name = "tcn75", .driver_data = tcn75, },
+ { .name = "tmp100", .driver_data = tmp100, },
+ { .name = "tmp101", .driver_data = tmp101, },
+ { .name = "tmp105", .driver_data = tmp105, },
+ { .name = "tmp112", .driver_data = tmp112, },
+ { .name = "tmp175", .driver_data = tmp175, },
+ { .name = "tmp275", .driver_data = tmp275, },
+ { .name = "tmp75", .driver_data = tmp75, },
+ { .name = "tmp75c", .driver_data = tmp75c, },
+ { /* LIST END */ }
+};
+
+static struct driver_d lm75_driver = {
+ .name = "lm75",
+ .probe = lm75_probe,
+ .id_table = lm75_ids,
+};
+
+static int lm75_init(void)
+{
+ i2c_driver_register(&lm75_driver);
+ return 0;
+}
+
+device_initcall(lm75_init);
\ No newline at end of file
--
2.6.2
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