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

Eduardo Valentin
2016-11-29T01:48:27Z

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
>