path: root/ina260.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for Texas Instruments INA260 power monitor chip
 * Datasheet: https://www.ti.com/lit/gpn/INA260
 *
 * Copyright (C) 2023 GUEGAN Loic <loic.guegan@mailbox.org>
 */

#include "linux/module.h"
#include "linux/uaccess.h"
#include "linux/i2c.h"
#include "linux/kobject.h"
#include "linux/slab.h"
#include "linux/kernel.h"
#include <linux/sysfs.h>

// INA260 registers
#define INA260_REG_CONFIGURATION 0x00
#define INA260_REG_CURRENT 0x01
#define INA260_REG_VOLTAGE 0x02
#define INA260_REG_POWER 0x03
#define INA260_REG_MASKENABLE 0x06
#define INA260_REG_ALERTLIMIT 0x07
#define INA260_REG_MANUFACTURER 0xFE
#define INA260_REG_DIE 0xFF

#define INA260_IS_ATTR(_name) (strcmp(attr->attr.name, #_name) == 0)

// ina260 average modes list
static int ina260_avgs[8]={
    1,4,16,64,128,256,512,1024
};

// ina260 operating modes list
static char ina260_modes[8][42]={
    "Power-Down (or Shutdown)","Shunt Current, Triggered",
    "Bus Voltage, Triggered","Shunt Current and Bus Voltage, Triggered", 
    "Power-Down (or Shutdown)","Shunt Current, Continuous","Bus Voltage, Continuous",
    "Shunt Current and Bus Voltage, Continuous"
};

// ina260 conversion times list
static char ina260_ishcts_vbusct[8][9]={
    "140 µs", "204 µs","332 µs", "588 µs","1.1 ms", "2.116 ms","4.156 ms","8.244 ms"
};

// Driver root
static struct kobject* ina260_kobj;

// Data attached to i2c clients
struct client_data {
    struct kobject kobj;
    struct i2c_client *client;
    unsigned char reg; // Slave selected register
};

static const struct i2c_device_id ina260_ids[] = {
    { "ina260", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c,ina260_ids);

/**
 * @brief Read from ina260 registers
 * 
 * @param cdata client data to use to communicate
 * @param reg register to read
 * @param value register content output
 * @return int 0 on success, 1 on communication errors
 */
static int ina260_read_register(struct client_data* cdata, unsigned char reg, int *value){
    unsigned char bytes[2];
    if(cdata->reg == reg){
        if(i2c_master_recv(cdata->client,bytes,2)<0)
            return 1;
    } else {
        if(i2c_master_send(cdata->client,&reg,1)<0)
            return 1;
        cdata->reg = reg;
        if(i2c_master_recv(cdata->client,bytes,2)<0)
            return 1;
    }
    *value=(bytes[0]<<8) | bytes[1];
    return 0;
}

/**
 * @brief Write to ina260 registers
 * 
 * @param cdata client data to use to communicate
 * @param reg register to write to
 * @param value value to write in @a reg
 * @return int 0 on success, 1 on communication errors
 */
static int ina260_write_register(struct client_data* cdata, unsigned char reg, int value){
    unsigned char data[3];
    data[0]=reg;
    data[1]=(value>>8) & 0xFF; // MSB
    data[2]=value & 0xFF;   // LSB
    if(i2c_master_send(cdata->client,data,3)<0)
        return 1;
    return 0;
}

static ssize_t attr_show(struct kobject *_kobj, 
                    struct kobj_attribute *attr,
                    char *buf)
{
    int rvalue;
    struct client_data *cdata=container_of(_kobj,struct client_data,kobj);
    unsigned char reg=INA260_REG_POWER;

    if(!INA260_IS_ATTR(power)){
        if (INA260_IS_ATTR(current)){
            reg=INA260_REG_CURRENT;
        } else if(INA260_IS_ATTR(bus_voltage)) {
            reg=INA260_REG_VOLTAGE;
        } else if(INA260_IS_ATTR(mask_enable)) {
            reg=INA260_REG_MASKENABLE;
        } else if(INA260_IS_ATTR(alert_limit)) {
            reg=INA260_REG_ALERTLIMIT;
        } else if(INA260_IS_ATTR(configuration)) {
            reg=INA260_REG_CONFIGURATION;
        } else if(INA260_IS_ATTR(manufacturer_id)) {
            reg=INA260_REG_MANUFACTURER;
        } else {
            reg=INA260_REG_DIE;
        }
    }

    if(ina260_read_register(cdata,reg,&rvalue))
        return -1;

    return sprintf(buf, "%x\n", rvalue);
}
 
 
static ssize_t attr_store(struct kobject *_kobj, 
                       struct kobj_attribute *attr,
               const char *buf, size_t count)
{
    int uvalue;
    struct client_data *cdata=container_of(_kobj,struct client_data,kobj);
    unsigned char reg=INA260_REG_CONFIGURATION;
    
    if(kstrtoint(buf, 0,&uvalue))
        return -EINVAL;

    if (INA260_IS_ATTR(mask_enable)){
        reg=INA260_REG_MASKENABLE;
    } else if (INA260_IS_ATTR(alert_limit)){
        reg=INA260_REG_ALERTLIMIT;
    }

    if(ina260_write_register(cdata, reg, uvalue))
        return -1;

    return count;
}

static ssize_t attr_metric_show(struct kobject *_kobj,
                    struct kobj_attribute *attr,
                    char *buf)
{
    int rvalue;
    int op1, op2;
    struct client_data *cdata=container_of(_kobj,struct client_data,kobj);

    if(INA260_IS_ATTR(power)){
        if(ina260_read_register(cdata, INA260_REG_POWER,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", 10*rvalue);
    } else if(INA260_IS_ATTR(voltage)){
        if(ina260_read_register(cdata, INA260_REG_VOLTAGE,&rvalue))
            return -1;
        op1=rvalue*25/100 + rvalue;
        op2=rvalue*25%100;
        return sprintf(buf, "%d.%03d%d\n",(op1)/1000,(op1)%1000,op2);
    } else if(INA260_IS_ATTR(current)){
        if(ina260_read_register(cdata, INA260_REG_CURRENT,&rvalue))
            return -1;
        op1=rvalue*25/100 + rvalue;
        op2=rvalue*25%100;
        return sprintf(buf, "%d.%03d%d\n",(op1)/1000,(op1)%1000,op2);
    }

    return -1;
}

static ssize_t attr_field_show(struct kobject *_kobj, 
                      struct kobj_attribute *attr,
                     char *buf)
{
    int rvalue;
    struct client_data *cdata=container_of(_kobj,struct client_data,kobj);
    if(INA260_IS_ATTR(avg)){
        if(ina260_read_register(cdata, INA260_REG_CONFIGURATION,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", ina260_avgs[(rvalue>>9)&0x7]);
    } else if (INA260_IS_ATTR(mode)){
        if(ina260_read_register(cdata, INA260_REG_CONFIGURATION,&rvalue))
            return -1;
        return sprintf(buf, "%s\n", ina260_modes[rvalue&0x7]);
    } else if (INA260_IS_ATTR(ishct)){
        if(ina260_read_register(cdata, INA260_REG_CONFIGURATION,&rvalue))
            return -1;
        return sprintf(buf, "%s\n", ina260_ishcts_vbusct[(rvalue>>3)&0x7]);
    } else if (INA260_IS_ATTR(vbusct)){
        if(ina260_read_register(cdata, INA260_REG_CONFIGURATION,&rvalue))
            return -1;
        return sprintf(buf, "%s\n", ina260_ishcts_vbusct[(rvalue>>6)&0x7]);
    } else if (INA260_IS_ATTR(aff)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", (rvalue>>4)&0x1);
    } else if (INA260_IS_ATTR(cvrf)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", (rvalue>>3)&0x1);
    } else if (INA260_IS_ATTR(ocl)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", (rvalue>>15)&0x1);
    }else if (INA260_IS_ATTR(ucl)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", (rvalue>>14)&0x1);
    }else if (INA260_IS_ATTR(bol)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", (rvalue>>13)&0x1);
    }else if (INA260_IS_ATTR(bul)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", (rvalue>>12)&0x1);
    }else if (INA260_IS_ATTR(pol)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", (rvalue>>11)&0x1);
    }else if (INA260_IS_ATTR(cnvr)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", (rvalue>>10)&0x1);
    }else if (INA260_IS_ATTR(ovf)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", (rvalue>>2)&0x1);
    }else if (INA260_IS_ATTR(apol)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", (rvalue>>1)&0x1);
    }else if (INA260_IS_ATTR(len)){
        if(ina260_read_register(cdata, INA260_REG_MASKENABLE,&rvalue))
            return -1;
        return sprintf(buf, "%d\n", rvalue&0x1);
    }else if (INA260_IS_ATTR(did)){
        if(ina260_read_register(cdata, INA260_REG_DIE,&rvalue))
            return -1;
        return sprintf(buf, "0x%x\n", (rvalue>>4));
    }else if (INA260_IS_ATTR(rid)){
        if(ina260_read_register(cdata, INA260_REG_DIE,&rvalue))
            return -1;
        return sprintf(buf, "0x%x\n", rvalue&0x7);
    }else if (INA260_IS_ATTR(reset)){
        return sprintf(buf, "0\n");
    }
    return 0;
}

static int ina260_write_field3(struct client_data *cdata, unsigned char reg, unsigned char n, int uvalue){
    int rvalue;
    if(!(uvalue>=0 && uvalue <8))
        return -EINVAL;
    // Fetch register value:
    if(ina260_read_register(cdata,reg,&rvalue))
        return 1;
    // Write bits:
    rvalue &= ~(0x7 << n); // clear bits
    rvalue |= (uvalue << n);
    // Write register value:
    if(ina260_write_register(cdata,reg,rvalue))
        return 1;
    return 0;
}

static int ina260_write_field1(struct client_data *cdata, unsigned char reg, unsigned char n, int uvalue){
    int rvalue;
    if(!(uvalue==0 || uvalue == 1))
        return -EINVAL;
    // Fetch register value:
    if(ina260_read_register(cdata,reg,&rvalue))
        return 1;
    // Set bit:
    rvalue &= ~(1<< n); // clear bit
    rvalue |= (uvalue << n);
    // Write register value
    if(ina260_write_register(cdata,reg,rvalue))
        return 1;
    return 0;
}

static ssize_t attr_field_store(struct kobject *_kobj, 
                       struct kobj_attribute *attr,
               const char __user *buf, size_t count)
{
    int uvalue, ret=0;
    struct client_data *cdata=container_of(_kobj,struct client_data,kobj);
    // Extract user supplied value:
    if(kstrtoint(buf, 0,&uvalue))
        return -EINVAL;
    // Store:
    if(INA260_IS_ATTR(reset) && uvalue!=0){
        ret=ina260_write_register(cdata, INA260_REG_CONFIGURATION, 0xFFFF); // Much quicker this way
    } else if(INA260_IS_ATTR(avg)){
      ret=ina260_write_field3(cdata,INA260_REG_CONFIGURATION,9,uvalue);
    } else if(INA260_IS_ATTR(mode)){
      ret=ina260_write_field3(cdata,INA260_REG_CONFIGURATION,0,uvalue);
    } else if(INA260_IS_ATTR(ishct)){
      ret=ina260_write_field3(cdata,INA260_REG_CONFIGURATION,3,uvalue);
    } else if(INA260_IS_ATTR(vbusct)){
      ret=ina260_write_field3(cdata,INA260_REG_CONFIGURATION,6,uvalue);
    } else if(INA260_IS_ATTR(ocl)){
      ret=ina260_write_field1(cdata,INA260_REG_MASKENABLE,15,uvalue);
    } else if(INA260_IS_ATTR(ucl)){
      ret=ina260_write_field1(cdata,INA260_REG_MASKENABLE,14,uvalue);
    } else if(INA260_IS_ATTR(bol)){
      ret=ina260_write_field1(cdata,INA260_REG_MASKENABLE,13,uvalue);
    } else if(INA260_IS_ATTR(bul)){
      ret=ina260_write_field1(cdata,INA260_REG_MASKENABLE,12,uvalue);
    } else if(INA260_IS_ATTR(pol)){
      ret=ina260_write_field1(cdata,INA260_REG_MASKENABLE,11,uvalue);
    } else if(INA260_IS_ATTR(cnvr)){
      ret=ina260_write_field1(cdata,INA260_REG_MASKENABLE,10,uvalue);
    } else if(INA260_IS_ATTR(apol)){
      ret=ina260_write_field1(cdata,INA260_REG_MASKENABLE,1,uvalue);
    } else if(INA260_IS_ATTR(len)){
      ret=ina260_write_field1(cdata,INA260_REG_MASKENABLE,0,uvalue);
    }
    return ret ? ret: count;
}


// ----- Registers -----
static struct kobj_attribute configuration_attribute =
    __ATTR(configuration, 0664, attr_show, attr_store);
static struct kobj_attribute current_attribute = {
	.attr = {.name = "current", // current is a defined macro so need to do it manually
		 .mode = VERIFY_OCTAL_PERMISSIONS(0444) },
	.show	= attr_show,
	.store	= attr_store,
};
static struct kobj_attribute bus_voltage_attribute =
    __ATTR(bus_voltage, 0444, attr_show, attr_store);
static struct kobj_attribute power_attribute =
    __ATTR(power, 0444, attr_show, attr_store);
static struct kobj_attribute mask_enable_attribute =
    __ATTR(mask_enable, 0664, attr_show, attr_store);
static struct kobj_attribute alert_limit_attribute =
    __ATTR(alert_limit, 0664, attr_show, attr_store);
static struct kobj_attribute manufacturer_id_attribute =
    __ATTR(manufacturer_id, 0664, attr_show, attr_store);
static struct kobj_attribute die_id_attribute=
    __ATTR(die_id, 0664, attr_show, attr_store);
static struct attribute *registers_attrs[] = {
    &configuration_attribute.attr,
    &current_attribute.attr,
    &bus_voltage_attribute.attr,
    &power_attribute.attr,
    &mask_enable_attribute.attr,
    &alert_limit_attribute.attr,
    &manufacturer_id_attribute.attr,
    &die_id_attribute.attr,
    NULL,   
};
static const struct attribute_group registers_group = {
	.attrs = registers_attrs,
    .name = "registers"
};
// ----- Metrics -----
static struct kobj_attribute metric_power_attribute =
    __ATTR(power, 0444, attr_metric_show, NULL);
static struct kobj_attribute metric_voltage_attribute =
    __ATTR(voltage, 0444, attr_metric_show, NULL);
static struct kobj_attribute metric_current_attribute = {
	.attr = {.name = "current", // current is a defined macro so need to do it manually
		 .mode = VERIFY_OCTAL_PERMISSIONS(0444) },
	.show	= attr_metric_show,
	.store	= NULL
};
static struct attribute *metrics_attrs[] = {
    &metric_power_attribute.attr,
    &metric_voltage_attribute.attr,
    &metric_current_attribute.attr,
    NULL,   
};
static const struct attribute_group metrics_group = {
	.attrs = metrics_attrs
};
// ----- Fields -----
static struct kobj_attribute reset_field_attribute =
    __ATTR(reset, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute avg_field_attribute =
    __ATTR(avg, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute mode_field_attribute =
    __ATTR(mode, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute ishct_field_attribute =
    __ATTR(ishct, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute vbusct_field_attribute =
    __ATTR(vbusct, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute aff_field_attribute =
    __ATTR(aff, 0444, attr_field_show, attr_field_store);
static struct kobj_attribute cvrf_field_attribute =
    __ATTR(cvrf, 0444, attr_field_show, attr_field_store);
static struct kobj_attribute ocl_field_attribute =
    __ATTR(ocl, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute ucl_field_attribute =
    __ATTR(ucl, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute bol_field_attribute =
    __ATTR(bol, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute bul_field_attribute =
    __ATTR(bul, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute pol_field_attribute =
    __ATTR(pol, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute cnvr_field_attribute =
    __ATTR(cnvr, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute ovf_field_attribute =
    __ATTR(ovf, 0444, attr_field_show, attr_field_store);
static struct kobj_attribute apol_field_attribute =
    __ATTR(apol, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute len_field_attribute =
    __ATTR(len, 0664, attr_field_show, attr_field_store);
static struct kobj_attribute did_field_attribute =
    __ATTR(did, 0444, attr_field_show, attr_field_store);
static struct kobj_attribute rid_field_attribute =
    __ATTR(rid, 0444, attr_field_show, attr_field_store); 
static struct attribute *fields_attrs[] = {
    &reset_field_attribute.attr,
    &avg_field_attribute.attr,
    &mode_field_attribute.attr,
    &ishct_field_attribute.attr,
    &vbusct_field_attribute.attr,
    &aff_field_attribute.attr,
    &cvrf_field_attribute.attr,
    &ocl_field_attribute.attr,
    &ucl_field_attribute.attr,
    &bol_field_attribute.attr,
    &bul_field_attribute.attr,
    &pol_field_attribute.attr,
    &cnvr_field_attribute.attr,
    &ovf_field_attribute.attr,
    &apol_field_attribute.attr,
    &len_field_attribute.attr,
    &did_field_attribute.attr,
    &rid_field_attribute.attr,
    NULL,   
};
static const struct attribute_group fields_group = {
	.attrs = fields_attrs,
    .name = "fields"
};


static struct kobj_type ina260_ktype = {
	.sysfs_ops	= &kobj_sysfs_ops,
};

/**
 * @brief Compare on ina260 register to a supplied value
 * 
 * @param client i2c client to use for communications
 * @param reg register to use for comparison
 * @param value register expected value
 * @return int 0 if register contains value and 1 otherwise
 */
static int ina260_probe_register(struct i2c_client *client, unsigned char reg, int value){
    unsigned char bytes[2];
    if(i2c_master_send(client,&reg,1)<0)
        return 1;
    if(i2c_master_recv(client,bytes,2)<0)
        return 1;
    return ((bytes[0]<<8) | bytes[1])!=value;
}

static int ina260_probe_new(struct i2c_client *client){
    struct client_data *p;
    // Attempt device discovery:
    if(ina260_probe_register(client,INA260_REG_MANUFACTURER,0x5449) ||
       ina260_probe_register(client,INA260_REG_DIE,0x2270)){
        printk("ina260 probe fails bus=%d address=0x%02x\n",client->adapter->nr,client->addr);
        return 1;
    }
    // Initialize client data:
    printk("ina260 detected bus=%d address=0x%02x\n",client->adapter->nr,client->addr);
    p=kzalloc(sizeof(struct client_data),GFP_KERNEL);
    kobject_init(&p->kobj,&ina260_ktype);
    // Setup sysfs root kobject:
    if(kobject_add(&p->kobj,ina260_kobj,client->dev.kobj.name)){
        kobject_put(&p->kobj);
        kfree(p);
        return 1;
    }
    p->client=client;
    p->reg=INA260_REG_DIE; // Maintain cache coherence
    i2c_set_clientdata(client,p);
    // Setup sysfs groups:
    if(sysfs_create_group(&p->kobj,&registers_group)||
       sysfs_create_group(&p->kobj,&metrics_group)||
       sysfs_create_group(&p->kobj,&fields_group)){
        kobject_put(&p->kobj);
        kfree(p);
        return 1;
    }
    return 0;
}

static void ina260_remove(struct i2c_client *client){
    struct client_data *p=i2c_get_clientdata(client);
    kobject_put(&p->kobj);
    kfree(p);
    printk("ina260 removed bus=%d address=0x%02x\n",client->adapter->nr,client->addr);
}

static struct i2c_driver ina260_driver = {
	.driver = {
		.name = "ina260"
	},
	.probe_new = ina260_probe_new,
	.remove = ina260_remove,
	.id_table = ina260_ids
};

static int __init ina260_init(void){
    ina260_kobj = kobject_create_and_add("ina260",kernel_kobj);
    i2c_add_driver(&ina260_driver);
    return 0;
}

static void __exit ina260_exit(void){
    i2c_del_driver(&ina260_driver);
    kobject_put(ina260_kobj);
}

module_init(ina260_init);
module_exit(ina260_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Loïc Guegan");
MODULE_DESCRIPTION("INA260 Texas Instruments");
MODULE_VERSION("1.0");