[RCF 1/3] hwmon: Add ads1118 driver
From: Joshua Clayton
Date: Fri Jul 15 2016 - 20:18:47 EST
Add new driver for Texas Instruments ADS1118 and and ADS1018.
This driver works with ADS1018, because of code borrowed
from asd1015, which is similar, but I can only test ADS1118
Signed-off-by: Joshua Clayton <stillcompiling@xxxxxxxxx>
---
drivers/hwmon/Kconfig | 11 ++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/ads1118.c | 516 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 528 insertions(+)
create mode 100644 drivers/hwmon/ads1118.c
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index ff94007..cadde38 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1459,6 +1459,17 @@ config SENSORS_ADS1015
This driver can also be built as a module. If so, the module
will be called ads1015.
+config SENSORS_ADS1118
+ tristate "Texas Instruments ADS1018/ADS1118"
+ depends on SPI
+ help
+ If you say yes here you get support for Texas Instruments
+ ADS1118 16-bit 4-input ADC device and temperature sensor,
+ and the 12-bit ADS1018.
+
+ This driver can also be built as a module. If so, the module
+ will be called ads1118.
+
config SENSORS_ADS7828
tristate "Texas Instruments ADS7828 and compatibles"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 2ef5b7c..a3b4b2e 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_SENSORS_ADM1029) += adm1029.o
obj-$(CONFIG_SENSORS_ADM1031) += adm1031.o
obj-$(CONFIG_SENSORS_ADM9240) += adm9240.o
obj-$(CONFIG_SENSORS_ADS1015) += ads1015.o
+obj-$(CONFIG_SENSORS_ADS1118) += ads1118.o
obj-$(CONFIG_SENSORS_ADS7828) += ads7828.o
obj-$(CONFIG_SENSORS_ADS7871) += ads7871.o
obj-$(CONFIG_SENSORS_ADT7X10) += adt7x10.o
diff --git a/drivers/hwmon/ads1118.c b/drivers/hwmon/ads1118.c
new file mode 100644
index 0000000..65ee337
--- /dev/null
+++ b/drivers/hwmon/ads1118.c
@@ -0,0 +1,516 @@
+/*
+ * ads1118.c - hwmon driver for Texas Instruments ADS1118 16-bit 4-input ADC
+ * / temperature sensor, and Texas Instruments ADS1018, a faster, 12-bit
+ * chip of the same family.
+ *
+ * Author: Joshua Clayton
+ *
+ * Loosely based on ads1015.c by Dirk Eibach and others
+ *
+ * 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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/spi/spi.h>
+
+struct ads_table {
+ unsigned int rates[8];
+ unsigned int divisor;
+};
+
+struct ads_channel {
+ unsigned int delay_ms;
+ int pga;
+ u16 cfg;
+ bool enabled;
+};
+
+/* PGA fullscale voltages in microvolts */
+static const unsigned int fullscale_table[8] = {
+ 6144000, 4096000, 2048000, 1024000, 512000, 256000, 256000, 256000 };
+
+static const struct ads_table ads1018_table = {
+ .rates = {128, 250, 490, 920, 1600, 2400, 3300, 3300},
+ .divisor = 0x7ff0,
+};
+
+static const struct ads_table ads1118_table = {
+ .rates = {8, 16, 32, 64, 128, 250, 475, 860},
+ .divisor = 0x7fff,
+};
+
+#define ADS1118_NUM_CHANS 5
+#define ADS1118_TEMP_CHAN 4
+
+struct ads1118 {
+ struct device *hwmon_dev;
+ struct device *dev;
+ struct mutex update_lock; /* mutex protect updates */
+ struct ads_channel channel_data[ADS1118_NUM_CHANS];
+ const struct ads_table *ref;
+};
+
+/*
+ * NOTE: the bit offsets in the datasheet are 16 bit big
+ * endian. I've swapped upper and lower bytes in the defines
+ * so no twiddling is needed when sending the cfg to the device.
+ */
+#define ADS1118_MODE 0 /* single shot mode */
+#define ADS1118_PGA 1 /* programmmed gain */
+#define ADS1118_MUX 4 /* input channel */
+#define ADS1118_SS 7 /* start a conversion */
+#define ADS1118_NOP 8 /* validation pattern */
+#define ADS1118_PULL_UP 11 /* pullup resistor on MISO */
+#define ADS1118_TS_MODE 12 /* temperature sensor mode */
+#define ADS1118_DR 13 /* data rate table index */
+
+#define ADS1118_ADC_CFG (BIT(ADS1118_MODE) | BIT(ADS1118_SS) | \
+ (0x3 << ADS1118_NOP) | BIT(ADS1118_PULL_UP))
+#define ADS1118_TEMP_CFG (ADS1118_ADC_CFG | BIT(ADS1118_TS_MODE))
+
+/* MUX values for AINN (second input or ground) */
+#define ADS1118_MUX_AINN1 0
+#define ADS1118_MUX_AINN3 1
+#define ADS1118_MUX_AINN_GND 4
+
+#define ADS1118_DEFAULT_PGA 0
+#define ADS1118_DEFAULT_DR 7
+
+static inline void ads1118_set_cfg(u16 *cfg, u16 value, int offset)
+{
+ *cfg &= ~(0x07 << offset);
+ *cfg |= ((value & 0x07) << offset);
+}
+
+static int ads1118_channel_set_pga(struct ads_channel *chan, u32 fullscale)
+{
+ int i;
+
+ for (i = 7; i >= 0; --i)
+ if (fullscale_table[i] == fullscale)
+ break;
+
+ if (i < 0)
+ return -EINVAL;
+
+ chan->pga = fullscale / 1000;
+ ads1118_set_cfg(&chan->cfg, i, ADS1118_PGA);
+
+ return 0;
+}
+
+static int ads1118_chan_set_mux(struct ads_channel *chan, u16 in1, u16 in2)
+{
+ switch (in1) {
+ case 0:
+ if (in2 == ADS1118_MUX_AINN1)
+ break;
+ case 1:
+ case 2:
+ if (in2 == ADS1118_MUX_AINN3)
+ break;
+ case 3:
+ if (in2 == ADS1118_MUX_AINN_GND)
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ads1118_set_cfg(&chan->cfg, in1 + in2, ADS1118_MUX);
+
+ return 0;
+}
+
+static int ads1118_chan_set_rate(struct ads1118 *ads,
+ struct ads_channel *chan, u32 rate)
+{
+ int i;
+
+ for (i = 7; i >= 0; --i)
+ if (ads->ref->rates[i] == rate)
+ break;
+
+ if (i < 0)
+ return -EINVAL;
+
+ chan->delay_ms = DIV_ROUND_UP(1000, rate);
+ ads1118_set_cfg(&chan->cfg, i, ADS1118_DR);
+
+ return 0;
+}
+
+static int ads1118_read_adc(struct ads1118 *ads, struct ads_channel *chan,
+ s16 *value)
+{
+ int ret;
+ u16 buf;
+ struct spi_device *spi = to_spi_device(ads->dev);
+
+ mutex_lock(&ads->update_lock);
+
+ ret = spi_write(spi, &chan->cfg, sizeof(chan->cfg));
+ if (ret < 0)
+ goto err_unlock;
+
+ /* wait until conversion finished */
+ msleep(chan->delay_ms);
+
+ ret = spi_read(spi, &buf, sizeof(buf));
+ if (ret)
+ dev_info(&spi->dev, "error reading: %d\n", ret);
+
+ *value = (s16)be16_to_cpu(buf);
+
+err_unlock:
+ mutex_unlock(&ads->update_lock);
+ return ret;
+}
+
+static ssize_t show_in(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ struct ads1118 *ads = dev_get_drvdata(dev);
+ struct ads_channel *chan = &ads->channel_data[attr->index];
+ s16 read_value;
+ int microvolts;
+ int ret;
+
+ ret = ads1118_read_adc(ads, chan, &read_value);
+ if (ret < 0)
+ return ret;
+
+ microvolts = DIV_ROUND_CLOSEST(read_value * chan->pga,
+ ads->ref->divisor);
+
+ return sprintf(buf, "%d\n", microvolts);
+}
+
+static ssize_t show_temp(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ struct ads1118 *ads = dev_get_drvdata(dev);
+ struct ads_channel *chan = &ads->channel_data[attr->index];
+ s16 read_value;
+ int ret;
+
+ ret = ads1118_read_adc(ads, chan, &read_value);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * The ads1118 datasheet indicates 32nds of degree steps, but
+ * 14 bits left justified means a divisor of 128.
+ */
+ return sprintf(buf, "%d\n", (((int)read_value) * 1000) >> 7);
+}
+
+static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, show_in, NULL, 0);
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, show_in, NULL, 1);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, show_in, NULL, 2);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, show_in, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL,
+ ADS1118_TEMP_CHAN);
+
+static struct attribute *ads1118_attributes[] = {
+ &sensor_dev_attr_in0_input.dev_attr.attr,
+ &sensor_dev_attr_in1_input.dev_attr.attr,
+ &sensor_dev_attr_in2_input.dev_attr.attr,
+ &sensor_dev_attr_in3_input.dev_attr.attr,
+
+ &sensor_dev_attr_temp1_input.dev_attr.attr,
+ NULL
+};
+
+static umode_t ads1118_attrs_visible(struct kobject *kobj,
+ struct attribute *attr, int n)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct ads1118 *ads = dev_get_drvdata(dev);
+
+ if (ads->channel_data[n].enabled)
+ return attr->mode;
+
+ return 0;
+}
+
+static const struct attribute_group ads1118_attr_group = {
+ .attrs = ads1118_attributes,
+ .is_visible = ads1118_attrs_visible,
+};
+
+static const struct attribute_group *groups[] = {
+ &ads1118_attr_group,
+ NULL
+};
+
+#ifdef CONFIG_OF
+static int ads1118_of_get_chan(struct device *dev, struct device_node *node)
+{
+ u32 chan_i;
+
+ if (!of_device_is_available(node))
+ return -EINVAL;
+
+ if (of_property_read_u32(node, "reg", &chan_i)) {
+ dev_err(dev, "reg value missing in %s\n", node->full_name);
+ return -EINVAL;
+ }
+
+ if (chan_i >= ADS1118_TEMP_CHAN) {
+ dev_err(dev, "reg value %d out of range in %s\n",
+ chan_i, node->full_name);
+ return -EINVAL;
+ }
+
+ return (int)chan_i;
+}
+
+static int ads1118_of_get_chan_pga(struct device *dev,
+ struct device_node *node,
+ struct ads_channel *chan)
+{
+ int ret;
+ u32 fullscale;
+
+ ret = of_property_read_u32(node, "ti,fullscale", &fullscale);
+ if (ret == -EINVAL) {
+ fullscale = fullscale_table[ADS1118_DEFAULT_PGA];
+ } else if (ret) {
+ dev_err(dev, "bad ti,fullscale on %s: should be u32\n",
+ node->full_name);
+ return ret;
+ }
+
+ ret = ads1118_channel_set_pga(chan, fullscale);
+ if (ret)
+ dev_err(dev, "bad ti,fullscale on %s: invalid value\n",
+ node->full_name);
+
+ return ret;
+}
+
+static int ads1118_of_get_chan_datarate(struct ads1118 *ads,
+ struct device_node *node,
+ struct ads_channel *chan)
+{
+ int ret;
+ u32 rate;
+
+ ret = of_property_read_u32(node, "ti,datarate", &rate);
+ if (ret == -EINVAL) {
+ rate = ads->ref->rates[ADS1118_DEFAULT_DR];
+ } else if (ret) {
+ dev_err(ads->dev, "bad ti,datarate on %s: should be u32\n",
+ node->full_name);
+ return ret;
+ }
+
+ ret = ads1118_chan_set_rate(ads, chan, rate);
+ if (ret)
+ dev_err(ads->dev, "bad ti,datarate on %s: invalid value\n",
+ node->full_name);
+
+ return ret;
+}
+
+static int ads1118_of_get_chan_mux(struct device *dev,
+ struct device_node *node,
+ struct ads_channel *chan,
+ int chan_i)
+{
+ int ret;
+ u32 de;
+ u16 in2;
+
+ ret = of_property_read_u32(node, "ti,differential-endpoint", &de);
+ if (ret == -EINVAL) {
+ in2 = ADS1118_MUX_AINN_GND;
+ goto set_mux;
+ } else if (ret) {
+ dev_err(dev, "bad ti,differential-endpoint on %s: should be a u32\n",
+ node->full_name);
+ return ret;
+ }
+
+ switch (de) {
+ case 1:
+ in2 = ADS1118_MUX_AINN1;
+ break;
+ case 3:
+ in2 = ADS1118_MUX_AINN3;
+ break;
+ default:
+ dev_err(dev, "bad ti,differential-endpoint %d on %s\n",
+ de, node->full_name);
+ return -EINVAL;
+ }
+
+set_mux:
+ ret = ads1118_chan_set_mux(chan, (u16)chan_i, in2);
+ if (ret)
+ dev_err(dev, "bad ti,differential-endpoint pair %d, %d on %s\n",
+ chan_i, de, node->full_name);
+
+ return ret;
+}
+
+static void ads1118_of_cfg_chan(struct ads1118 *ads, struct device_node *node)
+{
+ int ret;
+ int chan_i;
+ struct ads_channel *chan;
+
+ chan_i = ads1118_of_get_chan(ads->dev, node);
+ if (chan_i < 0)
+ return;
+
+ chan = &ads->channel_data[chan_i];
+ chan->cfg = ADS1118_ADC_CFG;
+ ret = ads1118_of_get_chan_pga(ads->dev, node, chan);
+ if (ret)
+ return;
+
+ ret = ads1118_of_get_chan_datarate(ads, node, chan);
+ if (ret)
+ return;
+
+ ret = ads1118_of_get_chan_mux(ads->dev, node, chan, chan_i);
+ if (ret)
+ return;
+
+ chan->enabled = true;
+}
+
+static void ads1118_of_get_pullup(struct ads1118 *ads)
+{
+ int i;
+
+ if (of_find_property(ads->dev->of_node, "ti,pullup-disable", NULL))
+ for (i = 0; i < ADS1118_NUM_CHANS; ++i)
+ ads->channel_data[i].cfg &= ~(BIT(ADS1118_PULL_UP));
+}
+#endif
+
+static void ads1118_temp_chan_enable(struct ads1118 *ads)
+{
+ struct ads_channel *chan = &ads->channel_data[ADS1118_TEMP_CHAN];
+ unsigned int rate = ads->ref->rates[ADS1118_DEFAULT_DR];
+
+ chan->cfg = ADS1118_TEMP_CFG;
+ ads1118_chan_set_rate(ads, chan, rate);
+ chan->enabled = true;
+}
+
+static int ads1118_get_cfg(struct ads1118 *ads)
+{
+ struct device_node *node;
+
+#ifndef CONFIG_OF
+ return -EINVAL;
+#else
+ if (!ads->dev->of_node
+ || !of_get_next_child(ads->dev->of_node, NULL))
+ return -EINVAL;
+
+ if (of_find_property(ads->dev->of_node, "ti,tempsensor", NULL))
+ ads1118_temp_chan_enable(ads);
+
+ ads1118_of_get_pullup(ads);
+
+ for_each_child_of_node(ads->dev->of_node, node) {
+ ads1118_of_cfg_chan(ads, node);
+ }
+
+ return 0;
+#endif
+}
+
+static void ads1118_enable_all(struct ads1118 *ads)
+{
+ unsigned int i;
+ unsigned int fullscale = fullscale_table[ADS1118_DEFAULT_PGA];
+ unsigned int rate = ads->ref->rates[ADS1118_DEFAULT_DR];
+
+ ads1118_temp_chan_enable(ads);
+
+ for (i = 0; i < ADS1118_TEMP_CHAN; ++i) {
+ struct ads_channel *chan = &ads->channel_data[i];
+
+ chan->cfg = ADS1118_ADC_CFG;
+ ads1118_channel_set_pga(chan, fullscale);
+ ads1118_chan_set_rate(ads, chan, rate);
+ ads1118_chan_set_mux(chan, (u16)i, ADS1118_MUX_AINN_GND);
+ chan->enabled = true;
+ }
+}
+
+static const struct of_device_id ads_1x18_ids[] = {
+ { .compatible = "ti,ads1018", .data = &ads1018_table, },
+ { .compatible = "ti,ads1118", .data = &ads1118_table, },
+ { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, ads_1x18_ids);
+
+static int ads1118_probe(struct spi_device *spi)
+{
+ const struct of_device_id *of_id;
+ struct ads1118 *ads;
+ int err;
+
+ ads = devm_kzalloc(&spi->dev, sizeof(struct ads1118),
+ GFP_KERNEL);
+ if (!ads)
+ return -ENOMEM;
+
+ of_id = of_match_device(ads_1x18_ids, &spi->dev);
+ if (!of_id)
+ return -EINVAL;
+
+ ads->ref = of_id->data;
+ ads->dev = &spi->dev;
+ mutex_init(&ads->update_lock);
+ err = ads1118_get_cfg(ads);
+ if (err)
+ ads1118_enable_all(ads);
+
+ ads->hwmon_dev =
+ devm_hwmon_device_register_with_groups(ads->dev, "ads11118",
+ ads, groups);
+ if (IS_ERR(ads->hwmon_dev)) {
+ err = PTR_ERR(ads->hwmon_dev);
+ dev_err(ads->dev, "error initializing hwmon: %d\n", err);
+ return err;
+ }
+
+ return 0;
+}
+
+static struct spi_driver ads1118_driver = {
+ .driver = {
+ .name = "ads1118",
+ .of_match_table = ads_1x18_ids,
+ },
+ .probe = ads1118_probe,
+};
+
+module_spi_driver(ads1118_driver);
+
+MODULE_AUTHOR("Joshua Clayton <stillcompiling@xxxxxxxxx>");
+MODULE_DESCRIPTION("ADS1118 driver");
+MODULE_LICENSE("GPL");
--
2.7.4