Re: [PATCH 2/3] w1: MAX1721x Stanalone Fuel Gauge - add 1-Wire slave drivers

[Sebastian Reichel <sebastian.reichel@collabora.co.uk>]

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Hi,

On Fri, Jun 02, 2017 at 10:06:28AM +0300, Alex A. Mihaylov wrote:
> Add support for Maxim Semiconductor MAX17211/MAX17215
> Standlone Fuel Gauge chips (1-Wire family 0x26)

I think this is pretty pointless after the w1 subsystem
is available publically [0]. We can just instantiate the w1
device in power-supply and skip registration of another
platform-device.

The registers and helper functions should also be added directly
to the power-supply driver.

[0] https://www.spinics.net/lists/kernel/msg2524566.html

-- Sebastian

> ---
>  drivers/w1/slaves/Kconfig       |  12 +++++
>  drivers/w1/slaves/Makefile      |   1 +
>  drivers/w1/slaves/w1_max1721x.c |  73 ++++++++++++++++++++++++++++
>  drivers/w1/slaves/w1_max1721x.h | 102 ++++++++++++++++++++++++++++++++++++++++
>  drivers/w1/w1_family.h          |   1 +
>  5 files changed, 189 insertions(+)
>  create mode 100644 drivers/w1/slaves/w1_max1721x.c
>  create mode 100644 drivers/w1/slaves/w1_max1721x.h
> 
> diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
> index 0ef9f2663d..06a63a1021 100644
> --- a/drivers/w1/slaves/Kconfig
> +++ b/drivers/w1/slaves/Kconfig
> @@ -86,6 +86,18 @@ config W1_SLAVE_DS2433_CRC
>  	  Each block has 30 bytes of data and a two byte CRC16.
>  	  Full block writes are only allowed if the CRC is valid.
>  
> +config W1_SLAVE_MAX1721X
> +	tristate "Maxim MAX17211/MAX17215 battery monitor chip"
> +	help
> +	  If you enable this you will have the MAX17211/MAX17215 battery
> +	  monitor chip support.
> +
> +	  The battery monitor chip is used in many batteries/devices
> +	  as the one who is responsible for charging/discharging/monitoring
> +	  Li+ batteries.
> +
> +	  If you are unsure, say N.
> +
>  config W1_SLAVE_DS2760
>  	tristate "Dallas 2760 battery monitor chip (HP iPAQ & others)"
>  	help
> diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
> index b4a358955e..967329a4b8 100644
> --- a/drivers/w1/slaves/Makefile
> +++ b/drivers/w1/slaves/Makefile
> @@ -11,6 +11,7 @@ obj-$(CONFIG_W1_SLAVE_DS2406)	+= w1_ds2406.o
>  obj-$(CONFIG_W1_SLAVE_DS2423)	+= w1_ds2423.o
>  obj-$(CONFIG_W1_SLAVE_DS2431)	+= w1_ds2431.o
>  obj-$(CONFIG_W1_SLAVE_DS2433)	+= w1_ds2433.o
> +obj-$(CONFIG_W1_SLAVE_MAX1721X)	+= w1_max1721x.o
>  obj-$(CONFIG_W1_SLAVE_DS2760)	+= w1_ds2760.o
>  obj-$(CONFIG_W1_SLAVE_DS2780)	+= w1_ds2780.o
>  obj-$(CONFIG_W1_SLAVE_DS2781)	+= w1_ds2781.o
> diff --git a/drivers/w1/slaves/w1_max1721x.c b/drivers/w1/slaves/w1_max1721x.c
> new file mode 100644
> index 0000000000..017ec3e159
> --- /dev/null
> +++ b/drivers/w1/slaves/w1_max1721x.c
> @@ -0,0 +1,73 @@
> +/*
> + * 1-Wire implementation for Maxim Semiconductor
> + * MAX17211/MAX17215 standalone fuel gauge chip
> + *
> + * Copyright (C) 2017 OAO Radioavionica
> + * Author: Alex A. Mihaylov <minimumlaw@rambler.ru>
> + *
> + * Use consistent with the GNU GPL is permitted,
> + * provided that this copyright notice is
> + * preserved in its entirety in all copies and derived works.
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/types.h>
> +#include <linux/platform_device.h>
> +#include <linux/mutex.h>
> +#include <linux/idr.h>
> +#include <linux/gfp.h>
> +
> +#include "../w1.h"
> +#include "../w1_int.h"
> +#include "../w1_family.h"
> +#include "w1_max1721x.h"
> +
> +static int w1_max17211_add_device(struct w1_slave *sl)
> +{
> +	int ret;
> +	struct platform_device *pdev;
> +
> +	pdev = platform_device_alloc("max1721x-battery", PLATFORM_DEVID_AUTO);
> +	if (!pdev)
> +		return -ENOMEM;
> +	pdev->dev.parent = &sl->dev;
> +
> +	ret = platform_device_add(pdev);
> +	if (ret)
> +		goto pdev_add_failed;
> +
> +	dev_set_drvdata(&sl->dev, pdev);
> +
> +	return 0;
> +
> +pdev_add_failed:
> +	platform_device_put(pdev);
> +
> +	return ret;
> +}
> +
> +static void w1_max17211_remove_device(struct w1_slave *sl)
> +{
> +	struct platform_device *pdev = dev_get_drvdata(&sl->dev);
> +
> +	platform_device_unregister(pdev);
> +}
> +
> +static struct w1_family_ops w1_max17211_fops = {
> +	.add_slave    = w1_max17211_add_device,
> +	.remove_slave = w1_max17211_remove_device,
> +};
> +
> +static struct w1_family w1_max17211_family = {
> +	.fid = W1_FAMILY_MAX17211,
> +	.fops = &w1_max17211_fops,
> +};
> +module_w1_family(w1_max17211_family);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Alex A. Mihaylov <minimumlaw@rambler.ru>");
> +MODULE_DESCRIPTION("1-wire Driver for MAX17211/MAX17215 battery monitor");
> +MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_MAX17211));
> diff --git a/drivers/w1/slaves/w1_max1721x.h b/drivers/w1/slaves/w1_max1721x.h
> new file mode 100644
> index 0000000000..47694d91dc
> --- /dev/null
> +++ b/drivers/w1/slaves/w1_max1721x.h
> @@ -0,0 +1,102 @@
> +/*
> + * 1-Wire implementation for Maxim Semiconductor
> + * MAX7211/MAX17215 stanalone fuel gauge chip
> + *
> + * Copyright (C) 2017 OAO Radioavionica
> + * Author: Alex A. Mihaylov <minimumlaw@rambler.ru>
> + *
> + * Use consistent with the GNU GPL is permitted,
> + * provided that this copyright notice is
> + * preserved in its entirety in all copies and derived works.
> + *
> + */
> +
> +#ifndef __w1_max17211_h__
> +#define __w1_max17211_h__
> +
> +/* Known commands to the MAX1721X chip */
> +#define W1_MAX1721X_READ_DATA		0x69
> +#define W1_MAX1721X_WRITE_DATA		0x6C
> +
> +/* Factory settings (nonvilatile registers) (W1 specific) */
> +
> +#define MAX1721X_REG_NRSENSE	0x1CF	/* RSense in 10^-5 Ohm */
> +/* Strings */
> +#define MAX1721X_REG_MFG_STR	0x1CC
> +#define MAX1721X_REG_MFG_NUMB	3
> +#define MAX1721X_REG_DEV_STR	0x1DB
> +#define MAX1721X_REG_DEV_NUMB	5
> +/* HEX Strings */
> +#define MAX1721X_REG_SER_HEX	0x1D8
> +
> +/* MAX1721X/MAX17215 Output Registers for I2C and W1 chips */
> +
> +#define MAX172XX_REG_STATUS	0x000	/* status reg */
> +#define MAX172XX_BAT_PRESENT	(1<<4)	/* battery connected bit */
> +#define MAX172XX_REG_DEVNAME	0x021	/* chip config */
> +#define MAX172XX_DEV_MASK	0x000F	/* chip type mask */
> +#define MAX172X1_DEV		0x0001
> +#define MAX172X5_DEV		0x0005
> +#define MAX172XX_REG_TEMP	0x008	/* Temperature */
> +#define MAX172XX_REG_BATT	0x0DA	/* Battery voltage */
> +#define MAX172XX_REG_CURRENT	0x00A	/* Actual current */
> +#define MAX172XX_REG_AVGCURRENT	0x00B	/* Average current */
> +#define MAX172XX_REG_REPSOC	0x006	/* Percentage of charge */
> +#define MAX172XX_REG_DESIGNCAP	0x018	/* Design capacity */
> +#define MAX172XX_REG_REPCAP	0x005	/* Average capacity */
> +#define MAX172XX_REG_TTE	0x011	/* Time to empty */
> +#define MAX172XX_REG_TTF	0x020	/* Time to full */
> +
> +/* Number of valid register addresses */
> +#define MAX1721X_MAX_REG_NR	0x1EF
> +
> +/* Convert regs value to power_supply units */
> +
> +static inline int max172xx_time_to_ps(unsigned int reg)
> +{
> +	return reg * 5625 / 1000;	/* in sec. */
> +}
> +
> +static inline int max172xx_percent_to_ps(unsigned int reg)
> +{
> +	return reg / 256;	/* in percent from 0 to 100 */
> +}
> +
> +static inline int max172xx_voltage_to_ps(unsigned int reg)
> +{
> +	return reg * 1250;	/* in uV */
> +}
> +
> +static inline int max172xx_capacity_to_ps(unsigned int reg)
> +{
> +	return reg * 500;	/* in uAh */
> +}
> +
> +/*
> + * Current and temperature is signed values, so unsigned regs
> + * value must be converted to signed type
> + */
> +
> +static inline int max172xx_temperature_to_ps(unsigned int reg)
> +{
> +	int val = (int16_t)(reg);
> +
> +	return val * 10 / 256; /* in tenths of deg. C */
> +}
> +
> +/*
> + * Calculating current registers resolution:
> + *
> + * RSense stored in 10^-5 Ohm, so mesaurment voltage must be
> + * in 10^-11 Volts for get current in uA.
> + * 16 bit current reg fullscale +/-51.2mV is 102400 uV.
> + * So: 102400 / 65535 * 10^5 = 156252
> + */
> +static inline int max172xx_current_to_voltage(unsigned int reg)
> +{
> +	int val = (int16_t)(reg);
> +
> +	return val * 156252;
> +}
> +
> +#endif /* !__w1_max17211_h__ */
> diff --git a/drivers/w1/w1_family.h b/drivers/w1/w1_family.h
> index c4a6b257a3..398adc9973 100644
> --- a/drivers/w1/w1_family.h
> +++ b/drivers/w1/w1_family.h
> @@ -29,6 +29,7 @@
>  #define W1_COUNTER_DS2423	0x1D
>  #define W1_THERM_DS1822  	0x22
>  #define W1_EEPROM_DS2433  	0x23
> +#define W1_FAMILY_MAX17211	0x26
>  #define W1_THERM_DS18B20 	0x28
>  #define W1_FAMILY_DS2408	0x29
>  #define W1_EEPROM_DS2431	0x2D
> -- 
> 2.13.0
> 

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