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Date:   Mon, 30 Mar 2020 20:15:27 +0530
From:   kgunda@codeaurora.org
To:     Daniel Thompson <daniel.thompson@linaro.org>
Cc:     bjorn.andersson@linaro.org, jingoohan1@gmail.com,
        lee.jones@linaro.org, b.zolnierkie@samsung.com,
        dri-devel@lists.freedesktop.org, jacek.anaszewski@gmail.com,
        pavel@ucw.cz, robh+dt@kernel.org, mark.rutland@arm.com,
        linux-leds@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Andy Gross <agross@kernel.org>,
        linux-arm-msm@vger.kernel.org, linux-fbdev@vger.kernel.org
Subject: Re: [PATCH V4 2/4] backlight: qcom-wled: Add callback functions
In-Reply-To: <20200325153036.zyor2srbkdhmr2zj@holly.lan>
References: <1584985618-25689-1-git-send-email-kgunda@codeaurora.org>
 <1584985618-25689-3-git-send-email-kgunda@codeaurora.org>
 <20200325153036.zyor2srbkdhmr2zj@holly.lan>
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On 2020-03-25 21:00, Daniel Thompson wrote:
> On Mon, Mar 23, 2020 at 11:16:56PM +0530, Kiran Gunda wrote:
>> Add wled_cabc_config, wled_sync_toggle, wled_ovp_fault_status
>> and wled_ovp_delay callback functions to prepare the driver for
>> adding WLED5 support.
>> 
>> wled_cabc_config() ===> Used to configure the cabc register.
>>                          It is applicable for wled4 and wled5.
>> 
>> wled_sync_toggle() ===> used to toggle the Sync register bit for the
>>                         brightness update to take place.
>>                         It is applicable for WLED3, WLED4 and WLED5.
>> 
>> wled_ovp_fault_status() ===> Used to determine if the OVP fault is 
>> triggered.
>>                              It is applicable for WLED4 and WLED5.
>> 
>> wled_ovp_delay() ===> Provides the time to wait before checking the 
>> OVP status
>>                         after wled module enable.
>>                         It is applicable for WLED4 and WLED5.
> 
> These look like comments to me. Move them out of the patch header and
> make them into real comments!
> 
Sure. Will do it in next post.
> 
>> Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
> 
> This patch does not compile. Please fix this.
> 
> 
Sorry for that. Some how it didn't show up in my compilation.
Will fix it in next post.
>> ---
>>  drivers/video/backlight/qcom-wled.c | 188 
>> ++++++++++++++++++++++--------------
>>  1 file changed, 118 insertions(+), 70 deletions(-)
>> 
>> diff --git a/drivers/video/backlight/qcom-wled.c 
>> b/drivers/video/backlight/qcom-wled.c
>> index 3d276b3..a3daf9e 100644
>> --- a/drivers/video/backlight/qcom-wled.c
>> +++ b/drivers/video/backlight/qcom-wled.c
>> @@ -147,6 +147,7 @@ struct wled {
>>  	u32 max_brightness;
>>  	u32 short_count;
>>  	u32 auto_detect_count;
>> +	u32 version;
> 
> Why does some of the changes here use function pointers and other parts
> use if/else networks (wled->version == X) ?
> 
There is one place (in auto_string_detection) where we have to add the
if (version == 4) because the per string modulator_enable is present 
only
for WLED4 and there is no equivalent functionality available for WLED5.

There is another place, that i can convert it to the function pointer 
(auto_detection_required).

> Overall I almost wonder if the reduced clarify that comes from function
> pointers is actually adding much value?
> 
I believe adding the function pointer makes it cleaner and the same 
approach is used for
WLED4/WLED3 also.

> 
>>  	bool disabled_by_short;
>>  	bool has_short_detect;
>>  	int short_irq;
>> @@ -155,6 +156,10 @@ struct wled {
>>  	struct wled_config cfg;
>>  	struct delayed_work ovp_work;
>>  	int (*wled_set_brightness)(struct wled *wled, u16 brightness);
>> +	int (*wled_cabc_config)(struct wled *wled, bool enable);
>> +	int (*wled_sync_toggle)(struct wled *wled);
>> +	int (*wled_ovp_fault_status)(struct wled *wled, bool *fault_set);
>> +	int (*wled_ovp_delay)(struct wled *wled);
>>  };
>> 
>>  static int wled3_set_brightness(struct wled *wled, u16 brightness)
>> @@ -237,7 +242,7 @@ static int wled_module_enable(struct wled *wled, 
>> int val)
>>  	return 0;
>>  }
>> 
>> -static int wled_sync_toggle(struct wled *wled)
>> +static int wled3_sync_toggle(struct wled *wled)
>>  {
>>  	int rc;
>>  	unsigned int mask = GENMASK(wled->max_string_count - 1, 0);
>> @@ -255,6 +260,46 @@ static int wled_sync_toggle(struct wled *wled)
>>  	return rc;
>>  }
>> 
>> +static int wled4_ovp_fault_status(struct wled *wled, bool *fault_set)
>> +{
>> +	int rc;
>> +	u32 int_rt_sts, fault_sts;
>> +
>> +	*fault_set = false;
>> +	rc = regmap_read(wled->regmap,
>> +			wled->ctrl_addr + WLED3_CTRL_REG_INT_RT_STS,
>> +			&int_rt_sts);
>> +	if (rc < 0) {
>> +		dev_err(wled->dev, "Failed to read INT_RT_STS rc=%d\n", rc);
>> +		return rc;
>> +	}
>> +
>> +	rc = regmap_read(wled->regmap,
>> +			wled->ctrl_addr + WLED3_CTRL_REG_FAULT_STATUS,
>> +			&fault_sts);
>> +	if (rc < 0) {
>> +		dev_err(wled->dev, "Failed to read FAULT_STATUS rc=%d\n", rc);
>> +		return rc;
>> +	}
>> +
>> +	if (int_rt_sts & WLED3_CTRL_REG_OVP_FAULT_STATUS)
>> +		*fault_set = true;
>> +
>> +	if (fault_sts & WLED3_CTRL_REG_OVP_FAULT_BIT)
>> +		*fault_set = true;
>> +
>> +	if (*fault_set)
>> +		dev_dbg(wled->dev, "WLED OVP fault detected, int_rt_sts=0x%x 
>> fault_sts=0x%x\n",
>> +			int_rt_sts, fault_sts);
>> +
>> +	return rc;
>> +}
>> +
>> +static int wled4_ovp_delay(struct wled *wled)
>> +{
>> +	return WLED_SOFT_START_DLY_US;
>> +}
>> +
>>  static int wled_update_status(struct backlight_device *bl)
>>  {
>>  	struct wled *wled = bl_get_data(bl);
>> @@ -275,7 +320,7 @@ static int wled_update_status(struct 
>> backlight_device *bl)
>>  			goto unlock_mutex;
>>  		}
>> 
>> -		rc = wled_sync_toggle(wled);
>> +		rc = wled->wled_sync_toggle(wled);
>>  		if (rc < 0) {
>>  			dev_err(wled->dev, "wled sync failed rc:%d\n", rc);
>>  			goto unlock_mutex;
>> @@ -298,6 +343,25 @@ static int wled_update_status(struct 
>> backlight_device *bl)
>>  	return rc;
>>  }
>> 
>> +static int wled4_cabc_config(struct wled *wled, bool enable)
>> +{
>> +	int i, j, rc;
>> +	u8 val;
>> +
>> +	for (i = 0; i < wled->cfg.num_strings; i++) {
>> +		j = wled->cfg.enabled_strings[i];
>> +
>> +		val = enable ? WLED4_SINK_REG_STR_CABC_MASK : 0;
>> +		rc = regmap_update_bits(wled->regmap, wled->sink_addr +
>> +					WLED4_SINK_REG_STR_CABC(j),
>> +					WLED4_SINK_REG_STR_CABC_MASK, val);
>> +		if (rc < 0)
>> +			return rc;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>  #define WLED_SHORT_DLY_MS			20
>>  #define WLED_SHORT_CNT_MAX			5
>>  #define WLED_SHORT_RESET_CNT_DLY_US		USEC_PER_SEC
>> @@ -345,9 +409,10 @@ static irqreturn_t wled_short_irq_handler(int 
>> irq, void *_wled)
>> 
>>  static void wled_auto_string_detection(struct wled *wled)
>>  {
>> -	int rc = 0, i;
>> -	u32 sink_config = 0, int_sts;
>> +	int rc = 0, i, delay_time_us;
>> +	u32 sink_config = 0;
>>  	u8 sink_test = 0, sink_valid = 0, val;
>> +	bool fault_set;
>> 
>>  	/* Read configured sink configuration */
>>  	rc = regmap_read(wled->regmap, wled->sink_addr +
>> @@ -376,14 +441,9 @@ static void wled_auto_string_detection(struct 
>> wled *wled)
>>  	}
>> 
>>  	if (wled->cfg.cabc) {
>> -		for (i = 0; i < wled->cfg.num_strings; i++) {
>> -			rc = regmap_update_bits(wled->regmap, wled->sink_addr +
>> -						WLED4_SINK_REG_STR_CABC(i),
>> -						WLED4_SINK_REG_STR_CABC_MASK,
>> -						0);
>> -			if (rc < 0)
>> -				goto failed_detect;
>> -		}
>> +		rc = wled->wled_cabc_config(wled, 0);
> 
> Be consistent with the argument (elsewhere it is true/false).
> 
Will address in the next post.
> 
>> +		if (rc < 0)
>> +			goto failed_detect;
>>  	}
>> 
>>  	/* Disable all sinks */
>> @@ -427,18 +487,17 @@ static void wled_auto_string_detection(struct 
>> wled *wled)
>>  			goto failed_detect;
>>  		}
>> 
>> -		usleep_range(WLED_SOFT_START_DLY_US,
>> -			     WLED_SOFT_START_DLY_US + 1000);
>> +		delay_time_us = wled->wled_ovp_delay(wled);
>> +		usleep_range(delay_time_us, delay_time_us + 1000);
>> 
>> -		rc = regmap_read(wled->regmap, wled->ctrl_addr +
>> -				 WLED3_CTRL_REG_INT_RT_STS, &int_sts);
>> +		rc = wled->wled_ovp_fault_status(wled, &fault_set);
>>  		if (rc < 0) {
>> -			dev_err(wled->dev, "Error in reading WLED3_CTRL_INT_RT_STS 
>> rc=%d\n",
>> +			dev_err(wled->dev, "Error in getting OVP fault_sts, rc=%d\n",
>>  				rc);
>>  			goto failed_detect;
>>  		}
>> 
> 
> 
>> -		if (int_sts & WLED3_CTRL_REG_OVP_FAULT_STATUS)
>> +		if (fault_set)
>>  			dev_dbg(wled->dev, "WLED OVP fault detected with SINK %d\n",
>>  				i + 1);
>>  		else
>> @@ -478,30 +537,30 @@ static void wled_auto_string_detection(struct 
>> wled *wled)
>>  	}
>> 
>>  	/* Enable valid sinks */
>> -	for (i = 0; i < wled->cfg.num_strings; i++) {
>> -		if (wled->cfg.cabc) {
>> -			rc = regmap_update_bits(wled->regmap, wled->sink_addr +
>> -						WLED4_SINK_REG_STR_CABC(i),
>> -						WLED4_SINK_REG_STR_CABC_MASK,
>> -						WLED4_SINK_REG_STR_CABC_MASK);
>> -			if (rc < 0)
>> +	if (wled->version == 4) {
>> +		for (i = 0; i < wled->cfg.num_strings; i++) {
>> +			if (sink_config &
>> +			    BIT(WLED4_SINK_REG_CURR_SINK_SHFT + i))
>> +				val = WLED4_SINK_REG_STR_MOD_MASK;
>> +			else
>> +				/* Disable modulator_en for unused sink */
>> +				val = 0x0;
>> +
>> +			rc = regmap_write(wled->regmap, wled->sink_addr +
>> +					  WLED4_SINK_REG_STR_MOD_EN(i), val);
>> +			if (rc < 0) {
>> +				dev_err(wled->dev, "Failed to configure MODULATOR_EN rc=%d\n",
>> +					rc);
>>  				goto failed_detect;
>> -		}
>> -
>> -		if (sink_config & BIT(WLED4_SINK_REG_CURR_SINK_SHFT + i))
>> -			val = WLED4_SINK_REG_STR_MOD_MASK;
>> -		else
>> -			val = 0x0; /* Disable modulator_en for unused sink */
>> -
>> -		rc = regmap_write(wled->regmap, wled->sink_addr +
>> -				  WLED4_SINK_REG_STR_MOD_EN(i), val);
>> -		if (rc < 0) {
>> -			dev_err(wled->dev, "Failed to configure MODULATOR_EN rc=%d\n",
>> -				rc);
>> -			goto failed_detect;
>> +			}
>>  		}
>>  	}
>> 
>> +	/* Enable CABC if it needs to be enabled */
> 
> If it needs to be enabled?
> 
Ok. Actually Enable CABC should be enough. I will remove the latter part
in the next post.
> 
>> +	rc = wled->wled_cabc_config(wled, true);
>> +	if (rc < 0)
>> +		goto failed_detect;
>> +
>>  	/* Restore the feedback setting */
>>  	rc = regmap_write(wled->regmap,
>>  			  wled->ctrl_addr + WLED3_CTRL_REG_FEEDBACK_CONTROL, 0);
>> @@ -570,29 +629,19 @@ static bool wled_auto_detection_required(struct 
>> wled *wled)
>>  static int wled_auto_detection_at_init(struct wled *wled)
>>  {
>>  	int rc;
>> -	u32 fault_status, rt_status;
>> +	bool fault_set;
>> 
>>  	if (!wled->cfg.auto_detection_enabled)
>>  		return 0;
>> 
>> -	rc = regmap_read(wled->regmap,
>> -			 wled->ctrl_addr + WLED3_CTRL_REG_INT_RT_STS,
>> -			 &rt_status);
>> +	rc = wled->wled_ovp_fault_status(wled, &fault_set);
>>  	if (rc < 0) {
>> -		dev_err(wled->dev, "Failed to read RT status rc=%d\n", rc);
>> -		return rc;
>> -	}
>> -
>> -	rc = regmap_read(wled->regmap,
>> -			 wled->ctrl_addr + WLED3_CTRL_REG_FAULT_STATUS,
>> -			 &fault_status);
>> -	if (rc < 0) {
>> -		dev_err(wled->dev, "Failed to read fault status rc=%d\n", rc);
>> +		dev_err(wled->dev, "Error in getting OVP fault_sts, rc=%d\n",
>> +			rc);
>>  		return rc;
>>  	}
>> 
>> -	if ((rt_status & WLED3_CTRL_REG_OVP_FAULT_STATUS) ||
>> -	    (fault_status & WLED3_CTRL_REG_OVP_FAULT_BIT)) {
>> +	if (fault_set) {
>>  		mutex_lock(&wled->lock);
>>  		wled_auto_string_detection(wled);
>>  		mutex_unlock(&wled->lock);
>> @@ -811,17 +860,12 @@ static int wled4_setup(struct wled *wled)
>>  					wled->cfg.string_i_limit);
>>  		if (rc < 0)
>>  			return rc;
>> -
>> -		addr = wled->sink_addr +
>> -				WLED4_SINK_REG_STR_CABC(j);
>> -		rc = regmap_update_bits(wled->regmap, addr,
>> -					WLED4_SINK_REG_STR_CABC_MASK,
>> -					wled->cfg.cabc ?
>> -					WLED4_SINK_REG_STR_CABC_MASK : 0);
>> -		if (rc < 0)
>> -			return rc;
>>  	}
>> 
>> +	rc = wled4_cabc_config(wled, wled->cfg.en_cabc);
>> +	if (rc < 0)
>> +		return rc;
>> +
>>  	rc = regmap_update_bits(wled->regmap, wled->ctrl_addr +
>>  				WLED3_CTRL_REG_MOD_EN,
>>  				WLED3_CTRL_REG_MOD_EN_MASK,
>> @@ -835,7 +879,7 @@ static int wled4_setup(struct wled *wled)
>>  	if (rc < 0)
>>  		return rc;
>> 
>> -	rc = wled_sync_toggle(wled);
>> +	rc = wled->wled_sync_toggle(wled);
>>  	if (rc < 0) {
>>  		dev_err(wled->dev, "Failed to toggle sync reg rc:%d\n", rc);
>>  		return rc;
>> @@ -951,7 +995,7 @@ static u32 wled_values(const struct wled_var_cfg 
>> *cfg, u32 idx)
>>  	return idx;
>>  }
>> 
>> -static int wled_configure(struct wled *wled, int version)
>> +static int wled_configure(struct wled *wled)
>>  {
>>  	struct wled_config *cfg = &wled->cfg;
>>  	struct device *dev = wled->dev;
>> @@ -1035,12 +1079,13 @@ static int wled_configure(struct wled *wled, 
>> int version)
>>  	if (rc)
>>  		wled->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", 
>> dev->of_node);
>> 
>> -	switch (version) {
>> +	switch (wled->version) {
>>  	case 3:
>>  		u32_opts = wled3_opts;
>>  		size = ARRAY_SIZE(wled3_opts);
>>  		*cfg = wled3_config_defaults;
>>  		wled->wled_set_brightness = wled3_set_brightness;
>> +		wled->wled_sync_toggle = wled3_sync_toggle;
>>  		wled->max_string_count = 3;
>>  		wled->sink_addr = wled->ctrl_addr;
>>  		break;
>> @@ -1050,6 +1095,10 @@ static int wled_configure(struct wled *wled, 
>> int version)
>>  		size = ARRAY_SIZE(wled4_opts);
>>  		*cfg = wled4_config_defaults;
>>  		wled->wled_set_brightness = wled4_set_brightness;
>> +		wled->wled_sync_toggle = wled3_sync_toggle;
>> +		wled->wled_cabc_config = wled4_cabc_config;
>> +		wled->wled_ovp_fault_status = wled4_ovp_fault_status;
>> +		wled->wled_ovp_delay = wled4_ovp_delay;
>>  		wled->max_string_count = 4;
>> 
>>  		prop_addr = of_get_address(dev->of_node, 1, NULL, NULL);
>> @@ -1186,7 +1235,6 @@ static int wled_probe(struct platform_device 
>> *pdev)
>>  	struct backlight_device *bl;
>>  	struct wled *wled;
>>  	struct regmap *regmap;
>> -	int version;
>>  	u32 val;
>>  	int rc;
>> 
>> @@ -1203,18 +1251,18 @@ static int wled_probe(struct platform_device 
>> *pdev)
>>  	wled->regmap = regmap;
>>  	wled->dev = &pdev->dev;
>> 
>> -	version = (uintptr_t)of_device_get_match_data(&pdev->dev);
>> -	if (!version) {
>> +	wled->version = (uintptr_t)of_device_get_match_data(&pdev->dev);
>> +	if (!wled->version) {
>>  		dev_err(&pdev->dev, "Unknown device version\n");
>>  		return -ENODEV;
>>  	}
>> 
>>  	mutex_init(&wled->lock);
>> -	rc = wled_configure(wled, version);
>> +	rc = wled_configure(wled);
>>  	if (rc)
>>  		return rc;
>> 
>> -	switch (version) {
>> +	switch (wled->version) {
>>  	case 3:
>>  		wled->cfg.auto_detection_enabled = false;
>>  		rc = wled3_setup(wled);
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
>> Forum,
>>  a Linux Foundation Collaborative Project