Re: [PATCH 03/10] thermal: exynos: remove dead code for HW_MODE calibration

[Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>]

On Thursday, May 15, 2014 10:14:41 AM Eduardo Valentin wrote:
> Hello Bartlomiej

Hi,

> On Mon, May 05, 2014 at 01:15:32PM +0200, Bartlomiej Zolnierkiewicz wrote:
> > There should be no functional changes caused by this patch.
> > 
> 
> Please provide better explanation when removing features. For instance,
> based on the comment of commit introducing it, HW_MODE is a feature of
> 5540 samsung's SoC. Question is why now it is being removed?
> 
> commit 1928457ea6337043a06ca2acd9b4d01e75810a3f
> Author: Amit Daniel Kachhap <amit.daniel@samsung.com>
> Date:   Mon Jun 24 16:20:46 2013 +0530
> 
>     thermal: exynos: Add hardware mode thermal calibration support
>         
>     This patch adds support for h/w mode calibration in the TMU controller.
>     Soc's like 5440 support this features. The h/w bits needed for calibration
>     setting are same as that of enum calibration_type.

The commit above has added HW_MODE feature but it has never been enabled.
As such it has been a dead code for almost a year now and should be removed
from the kernel.  Morevoer if somebody would like to re-introduce it for
Exynos5440 (or other SoC) she/he should explain why it is needed and why it
is better than the software calibration that is used for all SoCs currently.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> Cheers,
> 
> 
> > Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> > ---
> >  drivers/thermal/samsung/exynos_tmu.c      | 33 +------------------------------
> >  drivers/thermal/samsung/exynos_tmu.h      | 13 ------------
> >  drivers/thermal/samsung/exynos_tmu_data.c |  3 ---
> >  drivers/thermal/samsung/exynos_tmu_data.h |  2 --
> >  4 files changed, 1 insertion(+), 50 deletions(-)
> > 
> > diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
> > index 0d96a51..9f2a5ee 100644
> > --- a/drivers/thermal/samsung/exynos_tmu.c
> > +++ b/drivers/thermal/samsung/exynos_tmu.c
> > @@ -76,9 +76,6 @@ static int temp_to_code(struct exynos_tmu_data *data, u8 temp)
> >  	struct exynos_tmu_platform_data *pdata = data->pdata;
> >  	int temp_code;
> >  
> > -	if (pdata->cal_mode == HW_MODE)
> > -		return temp;
> > -
> >  	if (data->soc == SOC_ARCH_EXYNOS4210)
> >  		/* temp should range between 25 and 125 */
> >  		if (temp < 25 || temp > 125) {
> > @@ -113,9 +110,6 @@ static int code_to_temp(struct exynos_tmu_data *data, u8 temp_code)
> >  	struct exynos_tmu_platform_data *pdata = data->pdata;
> >  	int temp;
> >  
> > -	if (pdata->cal_mode == HW_MODE)
> > -		return temp_code;
> > -
> >  	if (data->soc == SOC_ARCH_EXYNOS4210)
> >  		/* temp_code should range between 75 and 175 */
> >  		if (temp_code < 75 || temp_code > 175) {
> > @@ -164,9 +158,6 @@ static int exynos_tmu_initialize(struct platform_device *pdev)
> >  	if (TMU_SUPPORTS(pdata, TRIM_RELOAD))
> >  		__raw_writel(1, data->base + reg->triminfo_ctrl);
> >  
> > -	if (pdata->cal_mode == HW_MODE)
> > -		goto skip_calib_data;
> > -
> >  	/* Save trimming info in order to perform calibration */
> >  	if (data->soc == SOC_ARCH_EXYNOS5440) {
> >  		/*
> > @@ -202,7 +193,6 @@ static int exynos_tmu_initialize(struct platform_device *pdev)
> >  			(pdata->efuse_value >> reg->triminfo_85_shift) &
> >  			EXYNOS_TMU_TEMP_MASK;
> >  
> > -skip_calib_data:
> >  	if (pdata->max_trigger_level > MAX_THRESHOLD_LEVS) {
> >  		dev_err(&pdev->dev, "Invalid max trigger level\n");
> >  		ret = -EINVAL;
> > @@ -311,7 +301,7 @@ static void exynos_tmu_control(struct platform_device *pdev, bool on)
> >  	struct exynos_tmu_data *data = platform_get_drvdata(pdev);
> >  	struct exynos_tmu_platform_data *pdata = data->pdata;
> >  	const struct exynos_tmu_registers *reg = pdata->registers;
> > -	unsigned int con, interrupt_en, cal_val;
> > +	unsigned int con, interrupt_en;
> >  
> >  	mutex_lock(&data->lock);
> >  	clk_enable(data->clk);
> > @@ -337,27 +327,6 @@ static void exynos_tmu_control(struct platform_device *pdev, bool on)
> >  		con |= (pdata->noise_cancel_mode << reg->therm_trip_mode_shift);
> >  	}
> >  
> > -	if (pdata->cal_mode == HW_MODE) {
> > -		con &= ~(reg->calib_mode_mask << reg->calib_mode_shift);
> > -		cal_val = 0;
> > -		switch (pdata->cal_type) {
> > -		case TYPE_TWO_POINT_TRIMMING:
> > -			cal_val = 3;
> > -			break;
> > -		case TYPE_ONE_POINT_TRIMMING_85:
> > -			cal_val = 2;
> > -			break;
> > -		case TYPE_ONE_POINT_TRIMMING_25:
> > -			cal_val = 1;
> > -			break;
> > -		case TYPE_NONE:
> > -			break;
> > -		default:
> > -			dev_err(&pdev->dev, "Invalid calibration type, using none\n");
> > -		}
> > -		con |= cal_val << reg->calib_mode_shift;
> > -	}
> > -
> >  	if (on) {
> >  		con |= (1 << reg->core_en_shift);
> >  		interrupt_en =
> > diff --git a/drivers/thermal/samsung/exynos_tmu.h b/drivers/thermal/samsung/exynos_tmu.h
> > index 80dc899..e417af8 100644
> > --- a/drivers/thermal/samsung/exynos_tmu.h
> > +++ b/drivers/thermal/samsung/exynos_tmu.h
> > @@ -34,11 +34,6 @@ enum calibration_type {
> >  	TYPE_NONE,
> >  };
> >  
> > -enum calibration_mode {
> > -	SW_MODE,
> > -	HW_MODE,
> > -};
> > -
> >  enum soc_type {
> >  	SOC_ARCH_EXYNOS4210 = 1,
> >  	SOC_ARCH_EXYNOS4412,
> > @@ -92,10 +87,6 @@ enum soc_type {
> >   * @buf_slope_sel_shift: shift bits of amplifier gain value in tmu_ctrl
> >  	register.
> >   * @buf_slope_sel_mask: mask bits of amplifier gain value in tmu_ctrl register.
> > - * @calib_mode_shift: shift bits of calibration mode value in tmu_ctrl
> > -	register.
> > - * @calib_mode_mask: mask bits of calibration mode value in tmu_ctrl
> > -	register.
> >   * @core_en_shift: shift bits of TMU core enable bit in tmu_ctrl register.
> >   * @tmu_status: register drescribing the TMU status.
> >   * @tmu_cur_temp: register containing the current temperature of the TMU.
> > @@ -139,8 +130,6 @@ struct exynos_tmu_registers {
> >  	u32	therm_trip_en_shift;
> >  	u32	buf_slope_sel_shift;
> >  	u32	buf_slope_sel_mask;
> > -	u32	calib_mode_shift;
> > -	u32	calib_mode_mask;
> >  	u32	core_en_shift;
> >  
> >  	u32	tmu_status;
> > @@ -222,7 +211,6 @@ struct exynos_tmu_registers {
> >   * @default_temp_offset: default temperature offset in case of no trimming
> >   * @test_mux; information if SoC supports test MUX
> >   * @cal_type: calibration type for temperature
> > - * @cal_mode: calibration mode for temperature
> >   * @freq_clip_table: Table representing frequency reduction percentage.
> >   * @freq_tab_count: Count of the above table as frequency reduction may
> >   *	applicable to only some of the trigger levels.
> > @@ -253,7 +241,6 @@ struct exynos_tmu_platform_data {
> >  	u8 test_mux;
> >  
> >  	enum calibration_type cal_type;
> > -	enum calibration_mode cal_mode;
> >  	enum soc_type type;
> >  	struct freq_clip_table freq_tab[4];
> >  	unsigned int freq_tab_count;
> > diff --git a/drivers/thermal/samsung/exynos_tmu_data.c b/drivers/thermal/samsung/exynos_tmu_data.c
> > index 36d64d6..4b992d9 100644
> > --- a/drivers/thermal/samsung/exynos_tmu_data.c
> > +++ b/drivers/thermal/samsung/exynos_tmu_data.c
> > @@ -205,8 +205,6 @@ static const struct exynos_tmu_registers exynos5440_tmu_registers = {
> >  	.therm_trip_en_shift = EXYNOS_TMU_THERM_TRIP_EN_SHIFT,
> >  	.buf_slope_sel_shift = EXYNOS_TMU_BUF_SLOPE_SEL_SHIFT,
> >  	.buf_slope_sel_mask = EXYNOS_TMU_BUF_SLOPE_SEL_MASK,
> > -	.calib_mode_shift = EXYNOS_TMU_CALIB_MODE_SHIFT,
> > -	.calib_mode_mask = EXYNOS_TMU_CALIB_MODE_MASK,
> >  	.core_en_shift = EXYNOS_TMU_CORE_EN_SHIFT,
> >  	.tmu_status = EXYNOS5440_TMU_S0_7_STATUS,
> >  	.tmu_cur_temp = EXYNOS5440_TMU_S0_7_TEMP,
> > @@ -243,7 +241,6 @@ static const struct exynos_tmu_registers exynos5440_tmu_registers = {
> >  	.reference_voltage = 16, \
> >  	.noise_cancel_mode = 4, \
> >  	.cal_type = TYPE_ONE_POINT_TRIMMING, \
> > -	.cal_mode = 0, \
> >  	.efuse_value = 0x5b2d, \
> >  	.min_efuse_value = 16, \
> >  	.max_efuse_value = 76, \
> > diff --git a/drivers/thermal/samsung/exynos_tmu_data.h b/drivers/thermal/samsung/exynos_tmu_data.h
> > index d4eeddb..1fed00d 100644
> > --- a/drivers/thermal/samsung/exynos_tmu_data.h
> > +++ b/drivers/thermal/samsung/exynos_tmu_data.h
> > @@ -60,8 +60,6 @@
> >  #define EXYNOS_TMU_TRIP_MODE_SHIFT	13
> >  #define EXYNOS_TMU_TRIP_MODE_MASK	0x7
> >  #define EXYNOS_TMU_THERM_TRIP_EN_SHIFT	12
> > -#define EXYNOS_TMU_CALIB_MODE_SHIFT	4
> > -#define EXYNOS_TMU_CALIB_MODE_MASK	0x3
> >  
> >  #define EXYNOS_TMU_INTEN_RISE0_SHIFT	0
> >  #define EXYNOS_TMU_INTEN_RISE1_SHIFT	4