1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/hwmon/adcxx.c b/drivers/hwmon/adcxx.c
new file mode 100644
index 000000000..de37bce24
--- /dev/null
+++ b/drivers/hwmon/adcxx.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * adcxx.c
+ *
+ * The adcxx4s is an AD converter family from National Semiconductor (NS).
+ *
+ * Copyright (c) 2008 Marc Pignat <marc.pignat@hevs.ch>
+ *
+ * The adcxx4s communicates with a host processor via an SPI/Microwire Bus
+ * interface. This driver supports the whole family of devices with name
+ * ADC<bb><c>S<sss>, where
+ * * bb is the resolution in number of bits (8, 10, 12)
+ * * c is the number of channels (1, 2, 4, 8)
+ * * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500 kSPS
+ *   and 101 for 1 MSPS)
+ *
+ * Complete datasheets are available at National's website here:
+ * http://www.national.com/ds/DC/ADC<bb><c>S<sss>.pdf
+ *
+ * Handling of 8, 10 and 12 bits converters are the same, the
+ * unavailable bits are 0 :)
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/sysfs.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/mutex.h>
+#include <linux/mod_devicetable.h>
+#include <linux/spi/spi.h>
+
+#define DRVNAME		"adcxx"
+
+struct adcxx {
+	struct device *hwmon_dev;
+	struct mutex lock;
+	u32 channels;
+	u32 reference; /* in millivolts */
+};
+
+/* sysfs hook function */
+static ssize_t adcxx_show(struct device *dev,
+			  struct device_attribute *devattr, char *buf)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct adcxx *adc = spi_get_drvdata(spi);
+	u8 tx_buf[2];
+	u8 rx_buf[2];
+	int status;
+	u32 value;
+
+	if (mutex_lock_interruptible(&adc->lock))
+		return -ERESTARTSYS;
+
+	if (adc->channels == 1) {
+		status = spi_read(spi, rx_buf, sizeof(rx_buf));
+	} else {
+		tx_buf[0] = attr->index << 3; /* other bits are don't care */
+		status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),
+						rx_buf, sizeof(rx_buf));
+	}
+	if (status < 0) {
+		dev_warn(dev, "SPI synch. transfer failed with status %d\n",
+				status);
+		goto out;
+	}
+
+	value = (rx_buf[0] << 8) + rx_buf[1];
+	dev_dbg(dev, "raw value = 0x%x\n", value);
+
+	value = value * adc->reference >> 12;
+	status = sprintf(buf, "%d\n", value);
+out:
+	mutex_unlock(&adc->lock);
+	return status;
+}
+
+static ssize_t adcxx_min_show(struct device *dev,
+			      struct device_attribute *devattr, char *buf)
+{
+	/* The minimum reference is 0 for this chip family */
+	return sprintf(buf, "0\n");
+}
+
+static ssize_t adcxx_max_show(struct device *dev,
+			      struct device_attribute *devattr, char *buf)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	struct adcxx *adc = spi_get_drvdata(spi);
+	u32 reference;
+
+	if (mutex_lock_interruptible(&adc->lock))
+		return -ERESTARTSYS;
+
+	reference = adc->reference;
+
+	mutex_unlock(&adc->lock);
+
+	return sprintf(buf, "%d\n", reference);
+}
+
+static ssize_t adcxx_max_store(struct device *dev,
+			       struct device_attribute *devattr,
+			       const char *buf, size_t count)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	struct adcxx *adc = spi_get_drvdata(spi);
+	unsigned long value;
+
+	if (kstrtoul(buf, 10, &value))
+		return -EINVAL;
+
+	if (mutex_lock_interruptible(&adc->lock))
+		return -ERESTARTSYS;
+
+	adc->reference = value;
+
+	mutex_unlock(&adc->lock);
+
+	return count;
+}
+
+static ssize_t adcxx_name_show(struct device *dev,
+			       struct device_attribute *devattr, char *buf)
+{
+	return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
+}
+
+static struct sensor_device_attribute ad_input[] = {
+	SENSOR_ATTR_RO(name, adcxx_name, 0),
+	SENSOR_ATTR_RO(in_min, adcxx_min, 0),
+	SENSOR_ATTR_RW(in_max, adcxx_max, 0),
+	SENSOR_ATTR_RO(in0_input, adcxx, 0),
+	SENSOR_ATTR_RO(in1_input, adcxx, 1),
+	SENSOR_ATTR_RO(in2_input, adcxx, 2),
+	SENSOR_ATTR_RO(in3_input, adcxx, 3),
+	SENSOR_ATTR_RO(in4_input, adcxx, 4),
+	SENSOR_ATTR_RO(in5_input, adcxx, 5),
+	SENSOR_ATTR_RO(in6_input, adcxx, 6),
+	SENSOR_ATTR_RO(in7_input, adcxx, 7),
+};
+
+/*----------------------------------------------------------------------*/
+
+static int adcxx_probe(struct spi_device *spi)
+{
+	int channels = spi_get_device_id(spi)->driver_data;
+	struct adcxx *adc;
+	int status;
+	int i;
+
+	adc = devm_kzalloc(&spi->dev, sizeof(*adc), GFP_KERNEL);
+	if (!adc)
+		return -ENOMEM;
+
+	/* set a default value for the reference */
+	adc->reference = 3300;
+	adc->channels = channels;
+	mutex_init(&adc->lock);
+
+	mutex_lock(&adc->lock);
+
+	spi_set_drvdata(spi, adc);
+
+	for (i = 0; i < 3 + adc->channels; i++) {
+		status = device_create_file(&spi->dev, &ad_input[i].dev_attr);
+		if (status) {
+			dev_err(&spi->dev, "device_create_file failed.\n");
+			goto out_err;
+		}
+	}
+
+	adc->hwmon_dev = hwmon_device_register(&spi->dev);
+	if (IS_ERR(adc->hwmon_dev)) {
+		dev_err(&spi->dev, "hwmon_device_register failed.\n");
+		status = PTR_ERR(adc->hwmon_dev);
+		goto out_err;
+	}
+
+	mutex_unlock(&adc->lock);
+	return 0;
+
+out_err:
+	for (i--; i >= 0; i--)
+		device_remove_file(&spi->dev, &ad_input[i].dev_attr);
+
+	mutex_unlock(&adc->lock);
+	return status;
+}
+
+static void adcxx_remove(struct spi_device *spi)
+{
+	struct adcxx *adc = spi_get_drvdata(spi);
+	int i;
+
+	mutex_lock(&adc->lock);
+	hwmon_device_unregister(adc->hwmon_dev);
+	for (i = 0; i < 3 + adc->channels; i++)
+		device_remove_file(&spi->dev, &ad_input[i].dev_attr);
+
+	mutex_unlock(&adc->lock);
+}
+
+static const struct spi_device_id adcxx_ids[] = {
+	{ "adcxx1s", 1 },
+	{ "adcxx2s", 2 },
+	{ "adcxx4s", 4 },
+	{ "adcxx8s", 8 },
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, adcxx_ids);
+
+static struct spi_driver adcxx_driver = {
+	.driver = {
+		.name	= "adcxx",
+	},
+	.id_table = adcxx_ids,
+	.probe	= adcxx_probe,
+	.remove	= adcxx_remove,
+};
+
+module_spi_driver(adcxx_driver);
+
+MODULE_AUTHOR("Marc Pignat");
+MODULE_DESCRIPTION("National Semiconductor adcxx8sxxx Linux driver");
+MODULE_LICENSE("GPL");