Re: [PATCH v8 07/10] power: supply: bd70528: use linear ranges

[Sebastian Reichel <sebastian.reichel@collabora.com>]

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Hi,

On Fri, Apr 03, 2020 at 11:47:21AM +0300, Matti Vaittinen wrote:
> Change the bd70528 to use common linear_range code instead of
> implementing a copy of it in this driver.
> 
> Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
> ---

Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>

-- Sebastian

> 
> No changes since v7
> 
>  drivers/power/supply/Kconfig           |   1 +
>  drivers/power/supply/bd70528-charger.c | 144 ++++++++++---------------
>  2 files changed, 56 insertions(+), 89 deletions(-)
> 
> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
> index 9a5591ab90d0..8781c674ed07 100644
> --- a/drivers/power/supply/Kconfig
> +++ b/drivers/power/supply/Kconfig
> @@ -695,6 +695,7 @@ config CHARGER_UCS1002
>  config CHARGER_BD70528
>  	tristate "ROHM bd70528 charger driver"
>  	depends on MFD_ROHM_BD70528
> +	select LINEAR_RANGES
>  	default n
>  	help
>  	 Say Y here to enable support for getting battery status
> diff --git a/drivers/power/supply/bd70528-charger.c b/drivers/power/supply/bd70528-charger.c
> index 3b820110ecfa..7a805faeee83 100644
> --- a/drivers/power/supply/bd70528-charger.c
> +++ b/drivers/power/supply/bd70528-charger.c
> @@ -72,6 +72,7 @@
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
>  #include <linux/power_supply.h>
> +#include <linux/linear_range.h>
>  
>  #define CHG_STAT_SUSPEND	0x0
>  #define CHG_STAT_TRICKLE	0x1
> @@ -335,38 +336,37 @@ static int bd70528_get_present(struct bd70528_psy *bdpsy, int *val)
>  	return 0;
>  }
>  
> -struct bd70528_linear_range {
> -	int min;
> -	int step;
> -	int vals;
> -	int low_sel;
> -};
> -
> -static const struct bd70528_linear_range current_limit_ranges[] = {
> +static const struct linear_range current_limit_ranges[] = {
>  	{
>  		.min = 5,
>  		.step = 1,
> -		.vals = 36,
> -		.low_sel = 0,
> +		.min_sel = 0,
> +		.max_sel = 0x22,
>  	},
>  	{
>  		.min = 40,
>  		.step = 5,
> -		.vals = 5,
> -		.low_sel = 0x23,
> +		.min_sel = 0x23,
> +		.max_sel = 0x26,
>  	},
>  	{
>  		.min = 60,
>  		.step = 20,
> -		.vals = 8,
> -		.low_sel = 0x27,
> +		.min_sel = 0x27,
> +		.max_sel = 0x2d,
>  	},
>  	{
>  		.min = 200,
>  		.step = 50,
> -		.vals = 7,
> -		.low_sel = 0x2e,
> -	}
> +		.min_sel = 0x2e,
> +		.max_sel = 0x34,
> +	},
> +	{
> +		.min = 500,
> +		.step = 0,
> +		.min_sel = 0x35,
> +		.max_sel = 0x3f,
> +	},
>  };
>  
>  /*
> @@ -374,18 +374,18 @@ static const struct bd70528_linear_range current_limit_ranges[] = {
>   * voltage for low temperatures. The driver currently only reads
>   * the charge current at room temperature. We do set both though.
>   */
> -static const struct bd70528_linear_range warm_charge_curr[] = {
> +static const struct linear_range warm_charge_curr[] = {
>  	{
>  		.min = 10,
>  		.step = 10,
> -		.vals = 20,
> -		.low_sel = 0,
> +		.min_sel = 0,
> +		.max_sel = 0x12
>  	},
>  	{
>  		.min = 200,
>  		.step = 25,
> -		.vals = 13,
> -		.low_sel = 0x13,
> +		.min_sel = 0x13,
> +		.max_sel = 0x1f
>  	},
>  };
>  
> @@ -398,56 +398,6 @@ static const struct bd70528_linear_range warm_charge_curr[] = {
>  #define MAX_WARM_CHG_CURR_SEL 0x1f
>  #define MIN_CHG_CURR_SEL 0x0
>  
> -static int find_value_for_selector_low(const struct bd70528_linear_range *r,
> -				       int selectors, unsigned int sel,
> -				       unsigned int *val)
> -{
> -	int i;
> -
> -	for (i = 0; i < selectors; i++) {
> -		if (r[i].low_sel <= sel && r[i].low_sel + r[i].vals >= sel) {
> -			*val = r[i].min + (sel - r[i].low_sel) * r[i].step;
> -			return 0;
> -		}
> -	}
> -	return -EINVAL;
> -}
> -
> -/*
> - * For BD70528 voltage/current limits we happily accept any value which
> - * belongs the range. We could check if value matching the selector is
> - * desired by computing the range min + (sel - sel_low) * range step - but
> - * I guess it is enough if we use voltage/current which is closest (below)
> - * the requested?
> - */
> -static int find_selector_for_value_low(const struct bd70528_linear_range *r,
> -				       int selectors, unsigned int val,
> -				       unsigned int *sel, bool *found)
> -{
> -	int i;
> -	int ret = -EINVAL;
> -
> -	*found = false;
> -	for (i = 0; i < selectors; i++) {
> -		if (r[i].min <= val) {
> -			if (r[i].min + r[i].step * r[i].vals >= val) {
> -				*found = true;
> -				*sel = r[i].low_sel + (val - r[i].min) /
> -				       r[i].step;
> -				ret = 0;
> -				break;
> -			}
> -			/*
> -			 * If the range max is smaller than requested
> -			 * we can set the max supported value from range
> -			 */
> -			*sel = r[i].low_sel + r[i].vals;
> -			ret = 0;
> -		}
> -	}
> -	return ret;
> -}
> -
>  static int get_charge_current(struct bd70528_psy *bdpsy, int *ma)
>  {
>  	unsigned int sel;
> @@ -463,9 +413,9 @@ static int get_charge_current(struct bd70528_psy *bdpsy, int *ma)
>  
>  	sel &= BD70528_MASK_CHG_CHG_CURR;
>  
> -	ret = find_value_for_selector_low(&warm_charge_curr[0],
> -					  ARRAY_SIZE(warm_charge_curr), sel,
> -					  ma);
> +	ret = linear_range_get_value_array(&warm_charge_curr[0],
> +					   ARRAY_SIZE(warm_charge_curr),
> +					   sel, ma);
>  	if (ret) {
>  		dev_err(bdpsy->dev,
>  			"Unknown charge current value 0x%x\n",
> @@ -491,10 +441,9 @@ static int get_current_limit(struct bd70528_psy *bdpsy, int *ma)
>  
>  	sel &= BD70528_MASK_CHG_DCIN_ILIM;
>  
> -	ret = find_value_for_selector_low(&current_limit_ranges[0],
> -					  ARRAY_SIZE(current_limit_ranges), sel,
> -					  ma);
> -
> +	ret = linear_range_get_value_array(&current_limit_ranges[0],
> +					   ARRAY_SIZE(current_limit_ranges),
> +					   sel, ma);
>  	if (ret) {
>  		/* Unspecified values mean 500 mA */
>  		*ma = 500;
> @@ -588,15 +537,28 @@ static int set_charge_current(struct bd70528_psy *bdpsy, int ma)
>  		goto set;
>  	}
>  
> -	ret = find_selector_for_value_low(&warm_charge_curr[0],
> -					  ARRAY_SIZE(warm_charge_curr), ma,
> -					  &reg, &found);
> +/*
> + * For BD70528 voltage/current limits we happily accept any value which
> + * belongs the range. We could check if value matching the selector is
> + * desired by computing the range min + (sel - sel_low) * range step - but
> + * I guess it is enough if we use voltage/current which is closest (below)
> + * the requested?
> + */
> +
> +	ret = linear_range_get_selector_low_array(warm_charge_curr,
> +						  ARRAY_SIZE(warm_charge_curr),
> +						  ma, &reg, &found);
>  	if (ret) {
> +		dev_err(bdpsy->dev,
> +			 "Unsupported charge current %u mA\n", ma);
>  		reg = MIN_CHG_CURR_SEL;
>  		goto set;
>  	}
>  	if (!found) {
> -		/* There was a gap in supported values and we hit it */
> +		/*
> +		 * There was a gap in supported values and we hit it.
> +		 * Yet a smaller value was found so we use it.
> +		 */
>  		dev_warn(bdpsy->dev,
>  			 "Unsupported charge current %u mA\n", ma);
>  	}
> @@ -648,17 +610,21 @@ static int set_current_limit(struct bd70528_psy *bdpsy, int ma)
>  		goto set;
>  	}
>  
> -	ret = find_selector_for_value_low(&current_limit_ranges[0],
> -					  ARRAY_SIZE(current_limit_ranges), ma,
> -					  &reg, &found);
> +	ret = linear_range_get_selector_low_array(current_limit_ranges,
> +					ARRAY_SIZE(current_limit_ranges),
> +					ma, &reg, &found);
>  	if (ret) {
> +		dev_err(bdpsy->dev, "Unsupported current limit %umA\n", ma);
>  		reg = MIN_CURR_LIMIT_SEL;
>  		goto set;
>  	}
>  	if (!found) {
> -		/* There was a gap in supported values and we hit it ?*/
> -		dev_warn(bdpsy->dev, "Unsupported current limit %umA\n",
> -			 ma);
> +		/*
> +		 * There was a gap in supported values and we hit it.
> +		 * We found a smaller value from ranges and use it.
> +		 * Warn user though.
> +		 */
> +		dev_warn(bdpsy->dev, "Unsupported current limit %umA\n", ma);
>  	}
>  
>  set:
> -- 
> 2.21.0
> 
> 
> -- 
> Matti Vaittinen, Linux device drivers
> ROHM Semiconductors, Finland SWDC
> Kiviharjunlenkki 1E
> 90220 OULU
> FINLAND
> 
> ~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
> Simon says - in Latin please.
> ~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
> Thanks to Simon Glass for the translation =] 

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