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https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git
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bf08749a6a
The adm1177 driver exposes the current alert threshold through
hwmon_curr_max_alarm. This violates the hwmon sysfs ABI, where
*_alarm attributes are read-only status flags and writable thresholds
must use currN_max.
The driver also stores the threshold internally in microamps, while
currN_max is defined in milliamps. Convert the threshold accordingly
on both the read and write paths.
Widen the cached threshold and related calculations to 64 bits so
that small shunt resistor values do not cause truncation or overflow.
Also use 64-bit arithmetic for the mA/uA conversions, clamp writes
to the range the hardware can represent, and propagate failures from
adm1177_write_alert_thr() instead of silently ignoring them.
Update the hwmon documentation to reflect the attribute rename and
the correct units returned by the driver.
Fixes: 09b08ac9e8 ("hwmon: (adm1177) Add ADM1177 Hot Swap Controller and Digital Power Monitor driver")
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20260325051246.28262-1-sanman.pradhan@hpe.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
274 lines
6.1 KiB
C
274 lines
6.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* ADM1177 Hot Swap Controller and Digital Power Monitor with Soft Start Pin
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*
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* Copyright 2015-2019 Analog Devices Inc.
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*/
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#include <linux/bits.h>
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#include <linux/device.h>
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#include <linux/hwmon.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/math64.h>
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#include <linux/minmax.h>
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#include <linux/module.h>
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#include <linux/regulator/consumer.h>
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/* Command Byte Operations */
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#define ADM1177_CMD_V_CONT BIT(0)
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#define ADM1177_CMD_I_CONT BIT(2)
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#define ADM1177_CMD_VRANGE BIT(4)
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/* Extended Register */
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#define ADM1177_REG_ALERT_TH 2
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#define ADM1177_BITS 12
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/**
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* struct adm1177_state - driver instance specific data
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* @client: pointer to i2c client
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* @r_sense_uohm: current sense resistor value
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* @alert_threshold_ua: current limit for shutdown
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* @vrange_high: internal voltage divider
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*/
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struct adm1177_state {
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struct i2c_client *client;
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u32 r_sense_uohm;
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u64 alert_threshold_ua;
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bool vrange_high;
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};
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static int adm1177_read_raw(struct adm1177_state *st, u8 num, u8 *data)
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{
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return i2c_master_recv(st->client, data, num);
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}
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static int adm1177_write_cmd(struct adm1177_state *st, u8 cmd)
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{
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return i2c_smbus_write_byte(st->client, cmd);
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}
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static int adm1177_write_alert_thr(struct adm1177_state *st,
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u64 alert_threshold_ua)
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{
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u64 val;
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int ret;
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val = 0xFFULL * alert_threshold_ua * st->r_sense_uohm;
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val = div_u64(val, 105840000U);
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val = div_u64(val, 1000U);
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if (val > 0xFF)
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val = 0xFF;
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ret = i2c_smbus_write_byte_data(st->client, ADM1177_REG_ALERT_TH,
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val);
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if (ret)
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return ret;
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st->alert_threshold_ua = alert_threshold_ua;
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return 0;
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}
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static int adm1177_read(struct device *dev, enum hwmon_sensor_types type,
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u32 attr, int channel, long *val)
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{
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struct adm1177_state *st = dev_get_drvdata(dev);
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u8 data[3];
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long dummy;
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int ret;
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switch (type) {
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case hwmon_curr:
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switch (attr) {
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case hwmon_curr_input:
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ret = adm1177_read_raw(st, 3, data);
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if (ret < 0)
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return ret;
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dummy = (data[1] << 4) | (data[2] & 0xF);
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/*
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* convert to milliamperes
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* ((105.84mV / 4096) x raw) / senseResistor(ohm)
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*/
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*val = div_u64((105840000ull * dummy),
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4096 * st->r_sense_uohm);
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return 0;
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case hwmon_curr_max:
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*val = div_u64(st->alert_threshold_ua, 1000);
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return 0;
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default:
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return -EOPNOTSUPP;
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}
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case hwmon_in:
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ret = adm1177_read_raw(st, 3, data);
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if (ret < 0)
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return ret;
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dummy = (data[0] << 4) | (data[2] >> 4);
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/*
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* convert to millivolts based on resistor devision
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* (V_fullscale / 4096) * raw
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*/
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if (st->vrange_high)
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dummy *= 26350;
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else
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dummy *= 6650;
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*val = DIV_ROUND_CLOSEST(dummy, 4096);
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return 0;
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default:
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return -EOPNOTSUPP;
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}
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}
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static int adm1177_write(struct device *dev, enum hwmon_sensor_types type,
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u32 attr, int channel, long val)
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{
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struct adm1177_state *st = dev_get_drvdata(dev);
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switch (type) {
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case hwmon_curr:
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switch (attr) {
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case hwmon_curr_max:
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val = clamp_val(val, 0,
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div_u64(105840000ULL, st->r_sense_uohm));
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return adm1177_write_alert_thr(st, (u64)val * 1000);
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default:
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return -EOPNOTSUPP;
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}
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default:
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return -EOPNOTSUPP;
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}
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}
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static umode_t adm1177_is_visible(const void *data,
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enum hwmon_sensor_types type,
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u32 attr, int channel)
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{
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const struct adm1177_state *st = data;
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switch (type) {
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case hwmon_in:
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switch (attr) {
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case hwmon_in_input:
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return 0444;
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}
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break;
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case hwmon_curr:
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switch (attr) {
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case hwmon_curr_input:
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if (st->r_sense_uohm)
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return 0444;
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return 0;
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case hwmon_curr_max:
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if (st->r_sense_uohm)
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return 0644;
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return 0;
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}
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break;
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default:
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break;
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}
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return 0;
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}
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static const struct hwmon_channel_info * const adm1177_info[] = {
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HWMON_CHANNEL_INFO(curr,
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HWMON_C_INPUT | HWMON_C_MAX),
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HWMON_CHANNEL_INFO(in,
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HWMON_I_INPUT),
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NULL
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};
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static const struct hwmon_ops adm1177_hwmon_ops = {
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.is_visible = adm1177_is_visible,
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.read = adm1177_read,
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.write = adm1177_write,
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};
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static const struct hwmon_chip_info adm1177_chip_info = {
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.ops = &adm1177_hwmon_ops,
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.info = adm1177_info,
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};
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static int adm1177_probe(struct i2c_client *client)
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{
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struct device *dev = &client->dev;
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struct device *hwmon_dev;
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struct adm1177_state *st;
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u64 alert_threshold_ua;
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u32 prop;
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int ret;
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st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
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if (!st)
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return -ENOMEM;
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st->client = client;
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ret = devm_regulator_get_enable_optional(&client->dev, "vref");
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if (ret == -EPROBE_DEFER)
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return -EPROBE_DEFER;
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if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
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&st->r_sense_uohm))
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st->r_sense_uohm = 0;
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if (!device_property_read_u32(dev, "adi,shutdown-threshold-microamp",
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&prop)) {
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alert_threshold_ua = prop;
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} else if (st->r_sense_uohm) {
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/*
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* set maximum default value from datasheet based on
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* shunt-resistor
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*/
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alert_threshold_ua = div_u64(105840000000ULL,
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st->r_sense_uohm);
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} else {
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alert_threshold_ua = 0;
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}
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st->vrange_high = device_property_read_bool(dev,
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"adi,vrange-high-enable");
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if (alert_threshold_ua && st->r_sense_uohm) {
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ret = adm1177_write_alert_thr(st, alert_threshold_ua);
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if (ret)
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return ret;
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}
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ret = adm1177_write_cmd(st, ADM1177_CMD_V_CONT |
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ADM1177_CMD_I_CONT |
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(st->vrange_high ? 0 : ADM1177_CMD_VRANGE));
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if (ret)
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return ret;
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hwmon_dev =
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devm_hwmon_device_register_with_info(dev, client->name, st,
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&adm1177_chip_info, NULL);
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return PTR_ERR_OR_ZERO(hwmon_dev);
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}
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static const struct i2c_device_id adm1177_id[] = {
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{"adm1177"},
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{}
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};
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MODULE_DEVICE_TABLE(i2c, adm1177_id);
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static const struct of_device_id adm1177_dt_ids[] = {
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{ .compatible = "adi,adm1177" },
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{},
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};
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MODULE_DEVICE_TABLE(of, adm1177_dt_ids);
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static struct i2c_driver adm1177_driver = {
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.driver = {
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.name = "adm1177",
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.of_match_table = adm1177_dt_ids,
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},
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.probe = adm1177_probe,
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.id_table = adm1177_id,
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};
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module_i2c_driver(adm1177_driver);
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MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
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MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
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MODULE_DESCRIPTION("Analog Devices ADM1177 ADC driver");
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MODULE_LICENSE("GPL v2");
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