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hwmon: Add RP1 ADC and temperature driver

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Signed-off-by: Phil Elwell <phil@raspberrypi.com>

drivers: hwmon: rp1-adc: check conversion validity before supplying value

The SAR ADC architecture may complete a conversion but instability in the
comparator can corrupt the result. Such corruption is signalled in the CS
ERR bit, asserted alongside each conversion result.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
This commit is contained in:
Phil Elwell
2023-03-02 18:04:42 +00:00
committed by Dom Cobley
parent f33d994dfe
commit 920dafbd50
3 changed files with 313 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/hwmon/Kconfig
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@@ -2629,6 +2629,13 @@ config SENSORS_INTEL_M10_BMC_HWMON
sensors monitor various telemetry data of different components on the
card, e.g. board temperature, FPGA core temperature/voltage/current.
config SENSORS_RP1_ADC
tristate "RP1 ADC and temperature sensor driver"
depends on MFD_RP1
help
Say yes here to enable support for the voltage and temperature
sensors of the Raspberry Pi RP1 peripheral chip.
if ACPI
comment "ACPI drivers"

1
drivers/hwmon/Makefile
View File

@@ -196,6 +196,7 @@ obj-$(CONFIG_SENSORS_PT5161L) += pt5161l.o
obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o
obj-$(CONFIG_SENSORS_QNAP_MCU_HWMON) += qnap-mcu-hwmon.o
obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o
obj-$(CONFIG_SENSORS_RP1_ADC) += rp1-adc.o
obj-$(CONFIG_SENSORS_SBTSI) += sbtsi_temp.o
obj-$(CONFIG_SENSORS_SBRMI) += sbrmi.o
obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o

305
drivers/hwmon/rp1-adc.c Normal file
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@@ -0,0 +1,305 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* Driver for the RP1 ADC and temperature sensor
* Copyright (C) 2023 Raspberry Pi Ltd.
*/
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#define MODULE_NAME "rp1-adc"
#define RP1_ADC_CS 0x00
#define RP1_ADC_RESULT 0x04
#define RP1_ADC_FCS 0x08
#define RP1_ADC_FIFO 0x0c
#define RP1_ADC_DIV 0x10
#define RP1_ADC_INTR 0x14
#define RP1_ADC_INTE 0x18
#define RP1_ADC_INTF 0x1c
#define RP1_ADC_INTS 0x20
#define RP1_ADC_RWTYPE_SET 0x2000
#define RP1_ADC_RWTYPE_CLR 0x3000
#define RP1_ADC_CS_RROBIN_MASK 0x1f
#define RP1_ADC_CS_RROBIN_SHIFT 16
#define RP1_ADC_CS_AINSEL_MASK 0x7
#define RP1_ADC_CS_AINSEL_SHIFT 12
#define RP1_ADC_CS_ERR_STICKY 0x400
#define RP1_ADC_CS_ERR 0x200
#define RP1_ADC_CS_READY 0x100
#define RP1_ADC_CS_START_MANY 0x8
#define RP1_ADC_CS_START_ONCE 0x4
#define RP1_ADC_CS_TS_EN 0x2
#define RP1_ADC_CS_EN 0x1
#define RP1_ADC_FCS_THRESH_MASK 0xf
#define RP1_ADC_FCS_THRESH_SHIFT 24
#define RP1_ADC_FCS_LEVEL_MASK 0xf
#define RP1_ADC_FCS_LEVEL_SHIFT 16
#define RP1_ADC_FCS_OVER 0x800
#define RP1_ADC_FCS_UNDER 0x400
#define RP1_ADC_FCS_FULL 0x200
#define RP1_ADC_FCS_EMPTY 0x100
#define RP1_ADC_FCS_DREQ_EN 0x8
#define RP1_ADC_FCS_ERR 0x4
#define RP1_ADC_FCS_SHIFR 0x2
#define RP1_ADC_FCS_EN 0x1
#define RP1_ADC_FIFO_ERR 0x8000
#define RP1_ADC_FIFO_VAL_MASK 0xfff
#define RP1_ADC_DIV_INT_MASK 0xffff
#define RP1_ADC_DIV_INT_SHIFT 8
#define RP1_ADC_DIV_FRAC_MASK 0xff
#define RP1_ADC_DIV_FRAC_SHIFT 0
struct rp1_adc_data {
void __iomem *base;
spinlock_t lock;
struct device *hwmon_dev;
int vref_mv;
};
static int rp1_adc_ready_wait(struct rp1_adc_data *data)
{
int retries = 10;
while (retries && !(readl(data->base + RP1_ADC_CS) & RP1_ADC_CS_READY))
retries--;
return retries ? 0 : -EIO;
}
static int rp1_adc_read(struct rp1_adc_data *data,
struct device_attribute *devattr, unsigned int *val)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
int channel = attr->index;
int ret;
spin_lock(&data->lock);
writel(RP1_ADC_CS_AINSEL_MASK << RP1_ADC_CS_AINSEL_SHIFT,
data->base + RP1_ADC_RWTYPE_CLR + RP1_ADC_CS);
writel(channel << RP1_ADC_CS_AINSEL_SHIFT,
data->base + RP1_ADC_RWTYPE_SET + RP1_ADC_CS);
writel(RP1_ADC_CS_START_ONCE,
data->base + RP1_ADC_RWTYPE_SET + RP1_ADC_CS);
ret = rp1_adc_ready_wait(data);
if (ret)
return ret;
/* Asserted if the completed conversion had a convergence error */
if (readl(data->base + RP1_ADC_CS) & RP1_ADC_CS_ERR)
return -EIO;
*val = readl(data->base + RP1_ADC_RESULT);
spin_unlock(&data->lock);
return ret;
}
static int rp1_adc_to_mv(struct rp1_adc_data *data, unsigned int val)
{
return ((u64)data->vref_mv * val) / 0xfff;
}
static ssize_t rp1_adc_show(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct rp1_adc_data *data = dev_get_drvdata(dev);
unsigned int val;
int ret;
ret = rp1_adc_read(data, devattr, &val);
if (ret)
return ret;
return sprintf(buf, "%d\n", rp1_adc_to_mv(data, val));
}
static ssize_t rp1_adc_temp_show(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct rp1_adc_data *data = dev_get_drvdata(dev);
unsigned int val;
int ret, mv, mc;
writel(RP1_ADC_CS_TS_EN,
data->base + RP1_ADC_RWTYPE_SET + RP1_ADC_CS);
ret = rp1_adc_read(data, devattr, &val);
if (ret)
return ret;
mv = rp1_adc_to_mv(data, val);
/* T = 27 - (ADC_voltage - 0.706)/0.001721 */
mc = 27000 - DIV_ROUND_CLOSEST((mv - 706) * (s64)1000000, 1721);
return sprintf(buf, "%d\n", mc);
}
static ssize_t rp1_adc_raw_show(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct rp1_adc_data *data = dev_get_drvdata(dev);
unsigned int val;
int ret = rp1_adc_read(data, devattr, &val);
if (ret)
return ret;
return sprintf(buf, "%u\n", val);
}
static ssize_t rp1_adc_temp_raw_show(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
struct rp1_adc_data *data = dev_get_drvdata(dev);
unsigned int val;
int ret = rp1_adc_read(data, devattr, &val);
if (ret)
return ret;
return sprintf(buf, "%u\n", val);
}
static SENSOR_DEVICE_ATTR_RO(in1_input, rp1_adc, 0);
static SENSOR_DEVICE_ATTR_RO(in2_input, rp1_adc, 1);
static SENSOR_DEVICE_ATTR_RO(in3_input, rp1_adc, 2);
static SENSOR_DEVICE_ATTR_RO(in4_input, rp1_adc, 3);
static SENSOR_DEVICE_ATTR_RO(temp1_input, rp1_adc_temp, 4);
static SENSOR_DEVICE_ATTR_RO(in1_raw, rp1_adc_raw, 0);
static SENSOR_DEVICE_ATTR_RO(in2_raw, rp1_adc_raw, 1);
static SENSOR_DEVICE_ATTR_RO(in3_raw, rp1_adc_raw, 2);
static SENSOR_DEVICE_ATTR_RO(in4_raw, rp1_adc_raw, 3);
static SENSOR_DEVICE_ATTR_RO(temp1_raw, rp1_adc_temp_raw, 4);
static struct attribute *rp1_adc_attrs[] = {
&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_in4_input.dev_attr.attr,
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_in1_raw.dev_attr.attr,
&sensor_dev_attr_in2_raw.dev_attr.attr,
&sensor_dev_attr_in3_raw.dev_attr.attr,
&sensor_dev_attr_in4_raw.dev_attr.attr,
&sensor_dev_attr_temp1_raw.dev_attr.attr,
NULL
};
static umode_t rp1_adc_is_visible(struct kobject *kobj,
struct attribute *attr, int index)
{
return 0444;
}
static const struct attribute_group rp1_adc_group = {
.attrs = rp1_adc_attrs,
.is_visible = rp1_adc_is_visible,
};
__ATTRIBUTE_GROUPS(rp1_adc);
static int __init rp1_adc_probe(struct platform_device *pdev)
{
struct rp1_adc_data *data;
struct regulator *reg;
struct clk *clk;
int vref_uv, ret;
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
spin_lock_init(&data->lock);
data->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(data->base))
return PTR_ERR(data->base);
platform_set_drvdata(pdev, data);
clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(clk))
return -ENODEV;
clk_set_rate(clk, 50000000);
clk_prepare_enable(clk);
reg = devm_regulator_get(&pdev->dev, "vref");
if (IS_ERR(reg))
return PTR_ERR(reg);
vref_uv = regulator_get_voltage(reg);
data->vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);
data->hwmon_dev =
devm_hwmon_device_register_with_groups(&pdev->dev,
"rp1_adc",
data,
rp1_adc_groups);
if (IS_ERR(data->hwmon_dev)) {
ret = PTR_ERR(data->hwmon_dev);
dev_err(&pdev->dev, "hwmon_device_register failed with %d.\n", ret);
goto err_register;
}
/* Disable interrupts */
writel(0, data->base + RP1_ADC_INTE);
/* Enable the block, clearing any sticky error */
writel(RP1_ADC_CS_EN | RP1_ADC_CS_ERR_STICKY, data->base + RP1_ADC_CS);
return 0;
err_register:
sysfs_remove_group(&pdev->dev.kobj, &rp1_adc_group);
return ret;
}
static void rp1_adc_remove(struct platform_device *pdev)
{
struct rp1_adc_data *data = platform_get_drvdata(pdev);
hwmon_device_unregister(data->hwmon_dev);
}
static const struct of_device_id rp1_adc_dt_ids[] = {
{ .compatible = "raspberrypi,rp1-adc", },
{ }
};
MODULE_DEVICE_TABLE(of, rp1_adc_dt_ids);
static struct platform_driver rp1_adc_driver = {
.remove = rp1_adc_remove,
.driver = {
.name = MODULE_NAME,
.of_match_table = rp1_adc_dt_ids,
},
};
module_platform_driver_probe(rp1_adc_driver, rp1_adc_probe);
MODULE_DESCRIPTION("RP1 ADC driver");
MODULE_AUTHOR("Phil Elwell <phil@raspberrypi.com>");
MODULE_LICENSE("GPL");