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// SPDX-License-Identifier: GPL-2.0-only
/*
* max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs
*
* Based on arch/arm/mach-pxa/corgi_ssp.c
*
* Copyright (C) 2004-2005 Richard Purdie
*
* Copyright (C) 2008 Marvell International Ltd.
* Eric Miao <eric.miao@marvell.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>
enum chips { max1110, max1111, max1112, max1113 };
#define MAX1111_TX_BUF_SIZE 1
#define MAX1111_RX_BUF_SIZE 2
/* MAX1111 Commands */
#define MAX1111_CTRL_PD0 (1u << 0)
#define MAX1111_CTRL_PD1 (1u << 1)
#define MAX1111_CTRL_SGL (1u << 2)
#define MAX1111_CTRL_UNI (1u << 3)
#define MAX1110_CTRL_SEL_SH (4)
#define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */
#define MAX1111_CTRL_STR (1u << 7)
struct max1111_data {
struct spi_device *spi;
struct device *hwmon_dev;
struct spi_message msg;
struct spi_transfer xfer[2];
uint8_t tx_buf[MAX1111_TX_BUF_SIZE];
uint8_t rx_buf[MAX1111_RX_BUF_SIZE];
struct mutex drvdata_lock;
/* protect msg, xfer and buffers from multiple access */
int sel_sh;
int lsb;
};
static int max1111_read(struct device *dev, int channel)
{
struct max1111_data *data = dev_get_drvdata(dev);
uint8_t v1, v2;
int err;
/* writing to drvdata struct is not thread safe, wait on mutex */
mutex_lock(&data->drvdata_lock);
data->tx_buf[0] = (channel << data->sel_sh) |
MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 |
MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR;
err = spi_sync(data->spi, &data->msg);
if (err < 0) {
dev_err(dev, "spi_sync failed with %d\n", err);
mutex_unlock(&data->drvdata_lock);
return err;
}
v1 = data->rx_buf[0];
v2 = data->rx_buf[1];
mutex_unlock(&data->drvdata_lock);
if ((v1 & 0xc0) || (v2 & 0x3f))
return -EINVAL;
return (v1 << 2) | (v2 >> 6);
}
#ifdef CONFIG_SHARPSL_PM
static struct max1111_data *the_max1111;
int max1111_read_channel(int channel);
int max1111_read_channel(int channel)
{
if (!the_max1111 || !the_max1111->spi)
return -ENODEV;
return max1111_read(&the_max1111->spi->dev, channel);
}
EXPORT_SYMBOL(max1111_read_channel);
#endif
/*
* NOTE: SPI devices do not have a default 'name' attribute, which is
* likely to be used by hwmon applications to distinguish between
* different devices, explicitly add a name attribute here.
*/
static ssize_t name_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
}
static ssize_t show_adc(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct max1111_data *data = dev_get_drvdata(dev);
int channel = to_sensor_dev_attr(attr)->index;
int ret;
ret = max1111_read(dev, channel);
if (ret < 0)
return ret;
/*
* Assume the reference voltage to be 2.048V or 4.096V, with an 8-bit
* sample. The LSB weight is 8mV or 16mV depending on the chip type.
*/
return sprintf(buf, "%d\n", ret * data->lsb);
}
#define MAX1111_ADC_ATTR(_id) \
SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id)
static DEVICE_ATTR_RO(name);
static MAX1111_ADC_ATTR(0);
static MAX1111_ADC_ATTR(1);
static MAX1111_ADC_ATTR(2);
static MAX1111_ADC_ATTR(3);
static MAX1111_ADC_ATTR(4);
static MAX1111_ADC_ATTR(5);
static MAX1111_ADC_ATTR(6);
static MAX1111_ADC_ATTR(7);
static struct attribute *max1111_attributes[] = {
&dev_attr_name.attr,
&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,
NULL,
};
static const struct attribute_group max1111_attr_group = {
.attrs = max1111_attributes,
};
static struct attribute *max1110_attributes[] = {
&sensor_dev_attr_in4_input.dev_attr.attr,
&sensor_dev_attr_in5_input.dev_attr.attr,
&sensor_dev_attr_in6_input.dev_attr.attr,
&sensor_dev_attr_in7_input.dev_attr.attr,
NULL,
};
static const struct attribute_group max1110_attr_group = {
.attrs = max1110_attributes,
};
static int setup_transfer(struct max1111_data *data)
{
struct spi_message *m;
struct spi_transfer *x;
m = &data->msg;
x = &data->xfer[0];
spi_message_init(m);
x->tx_buf = &data->tx_buf[0];
x->len = MAX1111_TX_BUF_SIZE;
spi_message_add_tail(x, m);
x++;
x->rx_buf = &data->rx_buf[0];
x->len = MAX1111_RX_BUF_SIZE;
spi_message_add_tail(x, m);
return 0;
}
static int max1111_probe(struct spi_device *spi)
{
enum chips chip = spi_get_device_id(spi)->driver_data;
struct max1111_data *data;
int err;
spi->bits_per_word = 8;
spi->mode = SPI_MODE_0;
err = spi_setup(spi);
if (err < 0)
return err;
data = devm_kzalloc(&spi->dev, sizeof(struct max1111_data), GFP_KERNEL);
if (data == NULL)
return -ENOMEM;
switch (chip) {
case max1110:
data->lsb = 8;
data->sel_sh = MAX1110_CTRL_SEL_SH;
break;
case max1111:
data->lsb = 8;
data->sel_sh = MAX1111_CTRL_SEL_SH;
break;
case max1112:
data->lsb = 16;
data->sel_sh = MAX1110_CTRL_SEL_SH;
break;
case max1113:
data->lsb = 16;
data->sel_sh = MAX1111_CTRL_SEL_SH;
break;
}
err = setup_transfer(data);
if (err)
return err;
mutex_init(&data->drvdata_lock);
data->spi = spi;
spi_set_drvdata(spi, data);
err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
if (err) {
dev_err(&spi->dev, "failed to create attribute group\n");
return err;
}
if (chip == max1110 || chip == max1112) {
err = sysfs_create_group(&spi->dev.kobj, &max1110_attr_group);
if (err) {
dev_err(&spi->dev,
"failed to create extended attribute group\n");
goto err_remove;
}
}
data->hwmon_dev = hwmon_device_register(&spi->dev);
if (IS_ERR(data->hwmon_dev)) {
dev_err(&spi->dev, "failed to create hwmon device\n");
err = PTR_ERR(data->hwmon_dev);
goto err_remove;
}
#ifdef CONFIG_SHARPSL_PM
the_max1111 = data;
#endif
return 0;
err_remove:
sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
return err;
}
static void max1111_remove(struct spi_device *spi)
{
struct max1111_data *data = spi_get_drvdata(spi);
#ifdef CONFIG_SHARPSL_PM
the_max1111 = NULL;
#endif
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
mutex_destroy(&data->drvdata_lock);
}
static const struct spi_device_id max1111_ids[] = {
{ "max1110", max1110 },
{ "max1111", max1111 },
{ "max1112", max1112 },
{ "max1113", max1113 },
{ },
};
MODULE_DEVICE_TABLE(spi, max1111_ids);
static struct spi_driver max1111_driver = {
.driver = {
.name = "max1111",
},
.id_table = max1111_ids,
.probe = max1111_probe,
.remove = max1111_remove,
};
module_spi_driver(max1111_driver);
MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver");
MODULE_LICENSE("GPL");
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