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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2021-2026 Axiado Corporation
*
* Driver for the Axiado on-chip temperature sensor (TSADC)
*/
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
/* TSADC register offsets */
#define AXIADO_TSADC_MODE 0x0000
#define AXIADO_TSADC_FUNC_CTRL 0x0004
#define AXIADO_TSADC_AVG_DOUT 0x000c
#define AXIADO_TSADC_INTR_MASK 0x0010
#define AXIADO_TSADC_ANA_REG 0x0020
#define AXIADO_TSADC_SEL 0x0028
#define AXIADO_TSADC_TSEN_EN 0x002c
#define AXIADO_TSADC_EN 0x0030
/* TSADC mode register: continuous conversion */
#define AXIADO_TSADC_MODE_CONT 0x2
/*
* TSADC functional control register: bit 0 starts the conversion and
* bits [31:16] specify the number of samples. Average over 16 samples.
*/
#define AXIADO_TSADC_FUNC_CTRL_START BIT(0)
#define AXIADO_TSADC_FUNC_CTRL_NUM_SAMPLES GENMASK(31, 16)
#define AXIADO_TSADC_FUNC_CTRL_CLR 0x0
#define AXIADO_TSADC_FUNC_CTRL_SET \
(FIELD_PREP(AXIADO_TSADC_FUNC_CTRL_NUM_SAMPLES, 16) | \
AXIADO_TSADC_FUNC_CTRL_START)
/* TSADC average output register: 12-bit ADC result */
#define AXIADO_TSADC_AVG_DOUT_MASK GENMASK(11, 0)
/* Interrupt mask bits */
#define AXIADO_TSADC_INTR_BIST_DONE BIT(0)
#define AXIADO_TSADC_INTR_LOOP_DONE BIT(1)
#define AXIADO_TSADC_INTR_THRESHOLD BIT(2)
#define AXIADO_TSADC_INTR_MASK_ALL \
(AXIADO_TSADC_INTR_BIST_DONE | \
AXIADO_TSADC_INTR_LOOP_DONE | \
AXIADO_TSADC_INTR_THRESHOLD)
/* TSADC analog block configuration required for temperature measurement */
#define AXIADO_TSADC_ANA_REG_INIT 0x6
/* TSADC SEL: select temperature measurement */
#define AXIADO_TSADC_SEL_TEMP 0x00
/* TSADC EN / TSEN_EN field values */
#define AXIADO_TSADC_DIS 0x00
#define AXIADO_TSADC_ENA 0x01
struct axiado_tsadc {
void __iomem *regs;
};
/*
* Lookup table: raw ADC output (12-bit) vs temperature in millidegrees
* Celsius. Raw values decrease as temperature increases, from -40°C
* to 125°C in 5°C steps.
*/
struct axiado_tsadc_point {
u32 raw;
int temp_mc;
};
static const struct axiado_tsadc_point axiado_tsadc_table[] = {
{ .raw = 2776, .temp_mc = -40000 },
{ .raw = 2748, .temp_mc = -35000 },
{ .raw = 2721, .temp_mc = -30000 },
{ .raw = 2694, .temp_mc = -25000 },
{ .raw = 2667, .temp_mc = -20000 },
{ .raw = 2640, .temp_mc = -15000 },
{ .raw = 2612, .temp_mc = -10000 },
{ .raw = 2584, .temp_mc = -5000 },
{ .raw = 2556, .temp_mc = 0 },
{ .raw = 2528, .temp_mc = 5000 },
{ .raw = 2500, .temp_mc = 10000 },
{ .raw = 2472, .temp_mc = 15000 },
{ .raw = 2444, .temp_mc = 20000 },
{ .raw = 2416, .temp_mc = 25000 },
{ .raw = 2389, .temp_mc = 30000 },
{ .raw = 2362, .temp_mc = 35000 },
{ .raw = 2335, .temp_mc = 40000 },
{ .raw = 2307, .temp_mc = 45000 },
{ .raw = 2279, .temp_mc = 50000 },
{ .raw = 2251, .temp_mc = 55000 },
{ .raw = 2223, .temp_mc = 60000 },
{ .raw = 2195, .temp_mc = 65000 },
{ .raw = 2167, .temp_mc = 70000 },
{ .raw = 2138, .temp_mc = 75000 },
{ .raw = 2110, .temp_mc = 80000 },
{ .raw = 2081, .temp_mc = 85000 },
{ .raw = 2052, .temp_mc = 90000 },
{ .raw = 2024, .temp_mc = 95000 },
{ .raw = 1996, .temp_mc = 100000 },
{ .raw = 1967, .temp_mc = 105000 },
{ .raw = 1938, .temp_mc = 110000 },
{ .raw = 1909, .temp_mc = 115000 },
{ .raw = 1880, .temp_mc = 120000 },
{ .raw = 1852, .temp_mc = 125000 },
};
/* Convert raw ADC code to millidegrees Celsius with linear interpolation. */
static int axiado_tsadc_raw_to_mc(u32 raw, long *val)
{
int i, n = ARRAY_SIZE(axiado_tsadc_table);
long num, denom;
if (raw >= axiado_tsadc_table[0].raw) {
*val = axiado_tsadc_table[0].temp_mc;
return 0;
}
if (raw <= axiado_tsadc_table[n - 1].raw) {
*val = axiado_tsadc_table[n - 1].temp_mc;
return 0;
}
/* Find i such that axiado_tsadc_table[i].raw >= raw > axiado_tsadc_table[i+1].raw */
for (i = 0; i < n - 1; i++) {
if (raw >= axiado_tsadc_table[i + 1].raw)
break;
}
if (raw == axiado_tsadc_table[i].raw) {
*val = axiado_tsadc_table[i].temp_mc;
return 0;
}
/* Linear interpolation within the interval */
num = (long)(axiado_tsadc_table[i + 1].temp_mc - axiado_tsadc_table[i].temp_mc) *
(axiado_tsadc_table[i].raw - raw);
denom = axiado_tsadc_table[i].raw - axiado_tsadc_table[i + 1].raw;
*val = axiado_tsadc_table[i].temp_mc + num / denom;
return 0;
}
static int axiado_tsadc_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct axiado_tsadc *tsadc = dev_get_drvdata(dev);
u32 raw;
if (type != hwmon_temp)
return -EOPNOTSUPP;
switch (attr) {
case hwmon_temp_input:
if (ioread32(tsadc->regs + AXIADO_TSADC_SEL) != AXIADO_TSADC_SEL_TEMP ||
ioread32(tsadc->regs + AXIADO_TSADC_EN) != AXIADO_TSADC_ENA)
return -ENODATA;
raw = ioread32(tsadc->regs + AXIADO_TSADC_AVG_DOUT) &
AXIADO_TSADC_AVG_DOUT_MASK;
return axiado_tsadc_raw_to_mc(raw, val);
default:
return -EOPNOTSUPP;
}
}
static umode_t axiado_tsadc_is_visible(const void *data,
enum hwmon_sensor_types type, u32 attr,
int channel)
{
if (type == hwmon_temp) {
switch (attr) {
case hwmon_temp_input:
return 0444;
default:
break;
}
}
return 0;
}
static const struct hwmon_channel_info * const axiado_tsadc_info[] = {
HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
NULL
};
static const struct hwmon_ops axiado_tsadc_hwmon_ops = {
.is_visible = axiado_tsadc_is_visible,
.read = axiado_tsadc_read,
};
static const struct hwmon_chip_info axiado_tsadc_chip_info = {
.ops = &axiado_tsadc_hwmon_ops,
.info = axiado_tsadc_info,
};
static void axiado_tsadc_disable(void *data)
{
struct axiado_tsadc *tsadc = data;
iowrite32(AXIADO_TSADC_DIS, tsadc->regs + AXIADO_TSADC_TSEN_EN);
iowrite32(AXIADO_TSADC_DIS, tsadc->regs + AXIADO_TSADC_EN);
}
static int axiado_tsadc_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct axiado_tsadc *tsadc;
struct device *hwmon_dev;
struct clk *refclk;
int ret;
tsadc = devm_kzalloc(dev, sizeof(*tsadc), GFP_KERNEL);
if (!tsadc)
return -ENOMEM;
tsadc->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(tsadc->regs))
return dev_err_probe(dev, PTR_ERR(tsadc->regs),
"failed to map registers\n");
refclk = devm_clk_get_enabled(dev, NULL);
if (IS_ERR(refclk))
return dev_err_probe(dev, PTR_ERR(refclk),
"failed to enable reference clock\n");
/* Mask all interrupts before setup */
iowrite32(AXIADO_TSADC_INTR_MASK_ALL, tsadc->regs + AXIADO_TSADC_INTR_MASK);
iowrite32(AXIADO_TSADC_ANA_REG_INIT, tsadc->regs + AXIADO_TSADC_ANA_REG);
iowrite32(AXIADO_TSADC_ENA, tsadc->regs + AXIADO_TSADC_EN);
iowrite32(AXIADO_TSADC_SEL_TEMP, tsadc->regs + AXIADO_TSADC_SEL);
iowrite32(AXIADO_TSADC_MODE_CONT, tsadc->regs + AXIADO_TSADC_MODE);
iowrite32(AXIADO_TSADC_FUNC_CTRL_CLR, tsadc->regs + AXIADO_TSADC_FUNC_CTRL);
iowrite32(AXIADO_TSADC_FUNC_CTRL_SET, tsadc->regs + AXIADO_TSADC_FUNC_CTRL);
/* Enable the bandgap circuit once the block is fully configured */
iowrite32(AXIADO_TSADC_ENA, tsadc->regs + AXIADO_TSADC_TSEN_EN);
ret = devm_add_action_or_reset(dev, axiado_tsadc_disable, tsadc);
if (ret)
return ret;
hwmon_dev = devm_hwmon_device_register_with_info(dev, "axiado_tsadc",
tsadc,
&axiado_tsadc_chip_info,
NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct of_device_id axiado_tsadc_match[] = {
{ .compatible = "axiado,ax3000-tsadc" },
{ }
};
MODULE_DEVICE_TABLE(of, axiado_tsadc_match);
static struct platform_driver axiado_tsadc_driver = {
.driver = {
.name = "axiado-tsadc",
.of_match_table = axiado_tsadc_match,
},
.probe = axiado_tsadc_probe,
};
module_platform_driver(axiado_tsadc_driver);
MODULE_DESCRIPTION("Axiado TSADC temperature sensor driver");
MODULE_AUTHOR("Axiado Corporation");
MODULE_LICENSE("GPL");
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