diff mbox

[v3,4/5] thermal: rockchip: optimize the conversion table

Message ID 1480331524-18741-5-git-send-email-wxt@rock-chips.com (mailing list archive)
State Changes Requested
Delegated to: Eduardo Valentin
Headers show

Commit Message

Caesar Wang Nov. 28, 2016, 11:12 a.m. UTC
In order to support the valid temperature can conver to analog value.
The rockchip thermal driver has not supported the all valid temperature
to convert the analog value. (e.g.: 61C, 62C, 63C....)

For example:
In some cases, we need adjust the trip point.
$cd /sys/class/thermal/thermal_zone*
$echo 68000 > trip_point_0_temp
That will return the max analogic value indicates the invalid before
posting this patch.

So, this patch will optimize the conversion table to support the other
cases.

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
---

Changes in v3: None
Changes in v2:
- improve the commit as Brian commnets on https://patchwork.kernel.org/patch/9440985

Changes in v1: None

 drivers/thermal/rockchip_thermal.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

Comments

Eduardo Valentin Nov. 29, 2016, 1:48 a.m. UTC | #1
On Mon, Nov 28, 2016 at 07:12:03PM +0800, Caesar Wang wrote:
> In order to support the valid temperature can conver to analog value.
> The rockchip thermal driver has not supported the all valid temperature
> to convert the analog value. (e.g.: 61C, 62C, 63C....)
> 
> For example:
> In some cases, we need adjust the trip point.
> $cd /sys/class/thermal/thermal_zone*
> $echo 68000 > trip_point_0_temp
> That will return the max analogic value indicates the invalid before
> posting this patch.
> 
> So, this patch will optimize the conversion table to support the other
> cases.
> 
> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> Reviewed-by: Brian Norris <briannorris@chromium.org>
> ---
> 
> Changes in v3: None
> Changes in v2:
> - improve the commit as Brian commnets on https://patchwork.kernel.org/patch/9440985
> 
> Changes in v1: None
> 
>  drivers/thermal/rockchip_thermal.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
> index ca1730e..660ed3b 100644
> --- a/drivers/thermal/rockchip_thermal.c
> +++ b/drivers/thermal/rockchip_thermal.c
> @@ -401,6 +401,8 @@ static u32 rk_tsadcv2_temp_to_code(const struct chip_tsadc_table *table,
>  				   int temp)
>  {
>  	int high, low, mid;
> +	unsigned long num;
> +	unsigned int denom;
>  	u32 error = table->data_mask;
>  
>  	low = 0;
> @@ -421,6 +423,27 @@ static u32 rk_tsadcv2_temp_to_code(const struct chip_tsadc_table *table,
>  		mid = (low + high) / 2;
>  	}
>  
> +	/*
> +	 * The conversion code granularity provided by the table. Let's
> +	 * assume that the relationship between temperature and
> +	 * analog value between 2 table entries is linear and interpolate
> +	 * to produce less granular result.
> +	 */
> +	num = abs(table->id[mid].code - table->id[mid + 1].code);
> +	num *= temp - table->id[mid].temp;
> +	denom = table->id[mid + 1].temp - table->id[mid].temp;
> +
> +	switch (table->mode) {
> +	case ADC_DECREMENT:
> +		return table->id[mid].code - (num / denom);
> +	case ADC_INCREMENT:
> +		return table->id[mid].code + (num / denom);
> +	default:
> +		pr_err("%s: invalid conversion table, mode=%d\n",

Is this really an invalid conversion table, or an invalid conversion mode?

> +		       __func__, table->mode);
> +		return error;
> +	}
> +
>  exit:
>  	pr_err("%s: invalid temperature, temp=%d error=%d\n",
>  	       __func__, temp, error);
> -- 
> 2.7.4
> 
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Eduardo Valentin Nov. 30, 2016, 6:29 a.m. UTC | #2
Hey,

On Mon, Nov 28, 2016 at 07:12:03PM +0800, Caesar Wang wrote:

<cut>

> +	num = abs(table->id[mid].code - table->id[mid + 1].code);
> +	num *= temp - table->id[mid].temp;
> +	denom = table->id[mid + 1].temp - table->id[mid].temp;


isn't the above 'mid + 1' off-by-one when mid ends being == table.length - 1?

You would be accessing table->id[table.length], which is wrong memory
access, no?

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Caesar Wang Dec. 12, 2016, 10:48 a.m. UTC | #3
在 2016年11月30日 14:29, Eduardo Valentin 写道:
> Hey,
>
> On Mon, Nov 28, 2016 at 07:12:03PM +0800, Caesar Wang wrote:
>
> <cut>
>
>> +	num = abs(table->id[mid].code - table->id[mid + 1].code);
>> +	num *= temp - table->id[mid].temp;
>> +	denom = table->id[mid + 1].temp - table->id[mid].temp;
>
> isn't the above 'mid + 1' off-by-one when mid ends being == table.length - 1?
>
> You would be accessing table->id[table.length], which is wrong memory
> access, no?

Yup, that's indeed a real issue for me.
FIxes on next version.

Thanks.

-Caesar

>
>
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip


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diff mbox

Patch

diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
index ca1730e..660ed3b 100644
--- a/drivers/thermal/rockchip_thermal.c
+++ b/drivers/thermal/rockchip_thermal.c
@@ -401,6 +401,8 @@  static u32 rk_tsadcv2_temp_to_code(const struct chip_tsadc_table *table,
 				   int temp)
 {
 	int high, low, mid;
+	unsigned long num;
+	unsigned int denom;
 	u32 error = table->data_mask;
 
 	low = 0;
@@ -421,6 +423,27 @@  static u32 rk_tsadcv2_temp_to_code(const struct chip_tsadc_table *table,
 		mid = (low + high) / 2;
 	}
 
+	/*
+	 * The conversion code granularity provided by the table. Let's
+	 * assume that the relationship between temperature and
+	 * analog value between 2 table entries is linear and interpolate
+	 * to produce less granular result.
+	 */
+	num = abs(table->id[mid].code - table->id[mid + 1].code);
+	num *= temp - table->id[mid].temp;
+	denom = table->id[mid + 1].temp - table->id[mid].temp;
+
+	switch (table->mode) {
+	case ADC_DECREMENT:
+		return table->id[mid].code - (num / denom);
+	case ADC_INCREMENT:
+		return table->id[mid].code + (num / denom);
+	default:
+		pr_err("%s: invalid conversion table, mode=%d\n",
+		       __func__, table->mode);
+		return error;
+	}
+
 exit:
 	pr_err("%s: invalid temperature, temp=%d error=%d\n",
 	       __func__, temp, error);