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linux/drivers/hwmon/ltc4245.c
Uwe Kleine-König d8a66f3621 hwmon: Drop explicit initialization of struct i2c_device_id::driver_data to 0 
These drivers don't use the driver_data member of struct i2c_device_id,
so don't explicitly initialize this member.

This prepares putting driver_data in an anonymous union which requires
either no initialization or named designators. But it's also a nice
cleanup on its own.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20240430085654.1028864-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-05-01 07:47:49 -07:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
*
* Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
*
* This driver is based on the ds1621 and ina209 drivers.
*
* Datasheet:
* http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
#include <linux/platform_data/ltc4245.h>
/* Here are names of the chip's registers (a.k.a. commands) */
enum ltc4245_cmd {
LTC4245_STATUS = 0x00, /* readonly */
LTC4245_ALERT = 0x01,
LTC4245_CONTROL = 0x02,
LTC4245_ON = 0x03,
LTC4245_FAULT1 = 0x04,
LTC4245_FAULT2 = 0x05,
LTC4245_GPIO = 0x06,
LTC4245_ADCADR = 0x07,
LTC4245_12VIN = 0x10,
LTC4245_12VSENSE = 0x11,
LTC4245_12VOUT = 0x12,
LTC4245_5VIN = 0x13,
LTC4245_5VSENSE = 0x14,
LTC4245_5VOUT = 0x15,
LTC4245_3VIN = 0x16,
LTC4245_3VSENSE = 0x17,
LTC4245_3VOUT = 0x18,
LTC4245_VEEIN = 0x19,
LTC4245_VEESENSE = 0x1a,
LTC4245_VEEOUT = 0x1b,
LTC4245_GPIOADC = 0x1c,
};
struct ltc4245_data {
struct i2c_client *client;
struct mutex update_lock;
bool valid;
unsigned long last_updated; /* in jiffies */
/* Control registers */
u8 cregs[0x08];
/* Voltage registers */
u8 vregs[0x0d];
/* GPIO ADC registers */
bool use_extra_gpios;
int gpios[3];
};
/*
* Update the readings from the GPIO pins. If the driver has been configured to
* sample all GPIO's as analog voltages, a round-robin sampling method is used.
* Otherwise, only the configured GPIO pin is sampled.
*
* LOCKING: must hold data->update_lock
*/
static void ltc4245_update_gpios(struct device *dev)
{
struct ltc4245_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
u8 gpio_curr, gpio_next, gpio_reg;
int i;
/* no extra gpio support, we're basically done */
if (!data->use_extra_gpios) {
data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10];
return;
}
/*
* If the last reading was too long ago, then we mark all old GPIO
* readings as stale by setting them to -EAGAIN
*/
if (time_after(jiffies, data->last_updated + 5 * HZ)) {
for (i = 0; i < ARRAY_SIZE(data->gpios); i++)
data->gpios[i] = -EAGAIN;
}
/*
* Get the current GPIO pin
*
* The datasheet calls these GPIO[1-3], but we'll calculate the zero
* based array index instead, and call them GPIO[0-2]. This is much
* easier to think about.
*/
gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
if (gpio_curr > 0)
gpio_curr -= 1;
/* Read the GPIO voltage from the GPIOADC register */
data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10];
/* Find the next GPIO pin to read */
gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios);
/*
* Calculate the correct setting for the GPIO register so it will
* sample the next GPIO pin
*/
gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6);
/* Update the GPIO register */
i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
/* Update saved data */
data->cregs[LTC4245_GPIO] = gpio_reg;
}
static struct ltc4245_data *ltc4245_update_device(struct device *dev)
{
struct ltc4245_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
s32 val;
int i;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
/* Read control registers -- 0x00 to 0x07 */
for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
val = i2c_smbus_read_byte_data(client, i);
if (unlikely(val < 0))
data->cregs[i] = 0;
else
data->cregs[i] = val;
}
/* Read voltage registers -- 0x10 to 0x1c */
for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
val = i2c_smbus_read_byte_data(client, i+0x10);
if (unlikely(val < 0))
data->vregs[i] = 0;
else
data->vregs[i] = val;
}
/* Update GPIO readings */
ltc4245_update_gpios(dev);
data->last_updated = jiffies;
data->valid = true;
}
mutex_unlock(&data->update_lock);
return data;
}
/* Return the voltage from the given register in millivolts */
static int ltc4245_get_voltage(struct device *dev, u8 reg)
{
struct ltc4245_data *data = ltc4245_update_device(dev);
const u8 regval = data->vregs[reg - 0x10];
u32 voltage = 0;
switch (reg) {
case LTC4245_12VIN:
case LTC4245_12VOUT:
voltage = regval * 55;
break;
case LTC4245_5VIN:
case LTC4245_5VOUT:
voltage = regval * 22;
break;
case LTC4245_3VIN:
case LTC4245_3VOUT:
voltage = regval * 15;
break;
case LTC4245_VEEIN:
case LTC4245_VEEOUT:
voltage = regval * -55;
break;
case LTC4245_GPIOADC:
voltage = regval * 10;
break;
default:
/* If we get here, the developer messed up */
WARN_ON_ONCE(1);
break;
}
return voltage;
}
/* Return the current in the given sense register in milliAmperes */
static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
{
struct ltc4245_data *data = ltc4245_update_device(dev);
const u8 regval = data->vregs[reg - 0x10];
unsigned int voltage;
unsigned int curr;
/*
* The strange looking conversions that follow are fixed-point
* math, since we cannot do floating point in the kernel.
*
* Step 1: convert sense register to microVolts
* Step 2: convert voltage to milliAmperes
*
* If you play around with the V=IR equation, you come up with
* the following: X uV / Y mOhm == Z mA
*
* With the resistors that are fractions of a milliOhm, we multiply
* the voltage and resistance by 10, to shift the decimal point.
* Now we can use the normal division operator again.
*/
switch (reg) {
case LTC4245_12VSENSE:
voltage = regval * 250; /* voltage in uV */
curr = voltage / 50; /* sense resistor 50 mOhm */
break;
case LTC4245_5VSENSE:
voltage = regval * 125; /* voltage in uV */
curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
break;
case LTC4245_3VSENSE:
voltage = regval * 125; /* voltage in uV */
curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
break;
case LTC4245_VEESENSE:
voltage = regval * 250; /* voltage in uV */
curr = voltage / 100; /* sense resistor 100 mOhm */
break;
default:
/* If we get here, the developer messed up */
WARN_ON_ONCE(1);
curr = 0;
break;
}
return curr;
}
/* Map from voltage channel index to voltage register */
static const s8 ltc4245_in_regs[] = {
LTC4245_12VIN, LTC4245_5VIN, LTC4245_3VIN, LTC4245_VEEIN,
LTC4245_12VOUT, LTC4245_5VOUT, LTC4245_3VOUT, LTC4245_VEEOUT,
};
/* Map from current channel index to current register */
static const s8 ltc4245_curr_regs[] = {
LTC4245_12VSENSE, LTC4245_5VSENSE, LTC4245_3VSENSE, LTC4245_VEESENSE,
};
static int ltc4245_read_curr(struct device *dev, u32 attr, int channel,
long *val)
{
struct ltc4245_data *data = ltc4245_update_device(dev);
switch (attr) {
case hwmon_curr_input:
*val = ltc4245_get_current(dev, ltc4245_curr_regs[channel]);
return 0;
case hwmon_curr_max_alarm:
*val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel + 4));
return 0;
default:
return -EOPNOTSUPP;
}
}
static int ltc4245_read_in(struct device *dev, u32 attr, int channel, long *val)
{
struct ltc4245_data *data = ltc4245_update_device(dev);
switch (attr) {
case hwmon_in_input:
if (channel < 8) {
*val = ltc4245_get_voltage(dev,
ltc4245_in_regs[channel]);
} else {
int regval = data->gpios[channel - 8];
if (regval < 0)
return regval;
*val = regval * 10;
}
return 0;
case hwmon_in_min_alarm:
if (channel < 4)
*val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel));
else
*val = !!(data->cregs[LTC4245_FAULT2] &
BIT(channel - 4));
return 0;
default:
return -EOPNOTSUPP;
}
}
static int ltc4245_read_power(struct device *dev, u32 attr, int channel,
long *val)
{
unsigned long curr;
long voltage;
switch (attr) {
case hwmon_power_input:
(void)ltc4245_update_device(dev);
curr = ltc4245_get_current(dev, ltc4245_curr_regs[channel]);
voltage = ltc4245_get_voltage(dev, ltc4245_in_regs[channel]);
*val = abs(curr * voltage);
return 0;
default:
return -EOPNOTSUPP;
}
}
static int ltc4245_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
switch (type) {
case hwmon_curr:
return ltc4245_read_curr(dev, attr, channel, val);
case hwmon_power:
return ltc4245_read_power(dev, attr, channel, val);
case hwmon_in:
return ltc4245_read_in(dev, attr, channel - 1, val);
default:
return -EOPNOTSUPP;
}
}
static umode_t ltc4245_is_visible(const void *_data,
enum hwmon_sensor_types type,
u32 attr, int channel)
{
const struct ltc4245_data *data = _data;
switch (type) {
case hwmon_in:
if (channel == 0)
return 0;
switch (attr) {
case hwmon_in_input:
if (channel > 9 && !data->use_extra_gpios)
return 0;
return 0444;
case hwmon_in_min_alarm:
if (channel > 8)
return 0;
return 0444;
default:
return 0;
}
case hwmon_curr:
switch (attr) {
case hwmon_curr_input:
case hwmon_curr_max_alarm:
return 0444;
default:
return 0;
}
case hwmon_power:
switch (attr) {
case hwmon_power_input:
return 0444;
default:
return 0;
}
default:
return 0;
}
}
static const struct hwmon_channel_info * const ltc4245_info[] = {
HWMON_CHANNEL_INFO(in,
HWMON_I_INPUT,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT | HWMON_I_MIN_ALARM,
HWMON_I_INPUT,
HWMON_I_INPUT,
HWMON_I_INPUT),
HWMON_CHANNEL_INFO(curr,
HWMON_C_INPUT | HWMON_C_MAX_ALARM,
HWMON_C_INPUT | HWMON_C_MAX_ALARM,
HWMON_C_INPUT | HWMON_C_MAX_ALARM,
HWMON_C_INPUT | HWMON_C_MAX_ALARM),
HWMON_CHANNEL_INFO(power,
HWMON_P_INPUT,
HWMON_P_INPUT,
HWMON_P_INPUT,
HWMON_P_INPUT),
NULL
};
static const struct hwmon_ops ltc4245_hwmon_ops = {
.is_visible = ltc4245_is_visible,
.read = ltc4245_read,
};
static const struct hwmon_chip_info ltc4245_chip_info = {
.ops = &ltc4245_hwmon_ops,
.info = ltc4245_info,
};
static bool ltc4245_use_extra_gpios(struct i2c_client *client)
{
struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
struct device_node *np = client->dev.of_node;
/* prefer platform data */
if (pdata)
return pdata->use_extra_gpios;
/* fallback on OF */
if (of_property_read_bool(np, "ltc4245,use-extra-gpios"))
return true;
return false;
}
static int ltc4245_probe(struct i2c_client *client)
{
struct i2c_adapter *adapter = client->adapter;
struct ltc4245_data *data;
struct device *hwmon_dev;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
mutex_init(&data->update_lock);
data->use_extra_gpios = ltc4245_use_extra_gpios(client);
/* Initialize the LTC4245 chip */
i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
hwmon_dev = devm_hwmon_device_register_with_info(&client->dev,
client->name, data,
&ltc4245_chip_info,
NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id ltc4245_id[] = {
{ "ltc4245" },
{ }
};
MODULE_DEVICE_TABLE(i2c, ltc4245_id);
/* This is the driver that will be inserted */
static struct i2c_driver ltc4245_driver = {
.driver = {
.name = "ltc4245",
},
.probe = ltc4245_probe,
.id_table = ltc4245_id,
};
module_i2c_driver(ltc4245_driver);
MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
MODULE_DESCRIPTION("LTC4245 driver");
MODULE_LICENSE("GPL");
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