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Subject: Re: [PATCH 1/3] leds: lm3532: Fix brightness control for i2c mode
To:     Jacek Anaszewski <jacek.anaszewski@gmail.com>, <pavel@ucw.cz>,
        <tony@atomide.com>, <sre@kernel.org>, <nekit1000@gmail.com>,
        <mpartap@gmx.net>, <merlijn@wizzup.org>
CC:     <linux-leds@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20190801151421.21486-1-dmurphy@ti.com>
 <3e304b9a-e7fc-9294-1950-ee9bc5956305@gmail.com>
From:   Dan Murphy <dmurphy@ti.com>
Message-ID: <3716262b-64e5-e236-1c35-7cfe9e0d935a@ti.com>
Date:   Thu, 1 Aug 2019 14:17:14 -0500
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Jacek

On 8/1/19 1:52 PM, Jacek Anaszewski wrote:
> Hi Dan,
>
> Thank you for the patch set. Please find my comments
> in the code below.
>
> On 8/1/19 5:14 PM, Dan Murphy wrote:
>> Fix the brightness control for I2C mode.  Instead of
>> changing the full scale current register update the ALS target
>> register for the appropriate banks.
>>
>> In addition clean up some code errors and random misspellings found
>> during coding.
>>
>> Tested on Droid4 as well as LM3532 EVM connected to a BeagleBoneBlack
>>
>> Fixes: e37a7f8d77e1 ("leds: lm3532: Introduce the lm3532 LED driver")
>> Reported-by: Pavel Machek <pavel@ucw.cz>
>> Signed-off-by: Dan Murphy <dmurphy@ti.com>
>> ---
>>   drivers/leds/leds-lm3532.c | 78 ++++++++++++++++++++++++--------------
>>   1 file changed, 50 insertions(+), 28 deletions(-)
>>
>> diff --git a/drivers/leds/leds-lm3532.c b/drivers/leds/leds-lm3532.c
>> index 646100724971..ff197adb2f22 100644
>> --- a/drivers/leds/leds-lm3532.c
>> +++ b/drivers/leds/leds-lm3532.c
>> @@ -23,11 +23,11 @@
>>   #define LM3532_REG_PWM_B_CFG	0x14
>>   #define LM3532_REG_PWM_C_CFG	0x15
>>   #define LM3532_REG_ZONE_CFG_A	0x16
>> -#define LM3532_REG_CTRL_A_BRT	0x17
>> +#define LM3532_REG_CTRL_A_FS_CURR	0x17
>>   #define LM3532_REG_ZONE_CFG_B	0x18
>> -#define LM3532_REG_CTRL_B_BRT	0x19
>> +#define LM3532_REG_CTRL_B_FS_CURR	0x19
>>   #define LM3532_REG_ZONE_CFG_C	0x1a
>> -#define LM3532_REG_CTRL_C_BRT	0x1b
>> +#define LM3532_REG_CTRL_C_FS_CURR	0x1b
>>   #define LM3532_REG_ENABLE	0x1d
>>   #define LM3532_ALS_CONFIG	0x23
>>   #define LM3532_REG_ZN_0_HI	0x60
>> @@ -38,9 +38,12 @@
>>   #define LM3532_REG_ZN_2_LO	0x65
>>   #define LM3532_REG_ZN_3_HI	0x66
>>   #define LM3532_REG_ZN_3_LO	0x67
>> +#define LM3532_REG_ZONE_TRGT_A	0x70
>> +#define LM3532_REG_ZONE_TRGT_B	0x75
>> +#define LM3532_REG_ZONE_TRGT_C	0x7a
>>   #define LM3532_REG_MAX		0x7e
>>   
>> -/* Contorl Enable */
>> +/* Control Enable */
>>   #define LM3532_CTRL_A_ENABLE	BIT(0)
>>   #define LM3532_CTRL_B_ENABLE	BIT(1)
>>   #define LM3532_CTRL_C_ENABLE	BIT(2)
>> @@ -63,6 +66,8 @@
>>   #define LM3532_ZONE_2		BIT(3)
>>   #define LM3532_ZONE_3		(BIT(2) | BIT(3))
>>   #define LM3532_ZONE_4		BIT(4)
>> +#define LM3532_BRT_CFG_MASK	(LM3532_I2C_CTRL | LM3532_LINEAR_MAP | \
>> +				LM3532_ZONE_MASK)
>>   
>>   #define LM3532_ENABLE_ALS	BIT(3)
>>   #define LM3532_ALS_SEL_SHIFT	6
>> @@ -127,6 +132,7 @@ struct lm3532_led {
>>   	int control_bank;
>>   	int mode;
>>   	int num_leds;
>> +	int ctrl_brt_pointer;
>>   	u32 led_strings[LM3532_MAX_CONTROL_BANKS];
>>   	char label[LED_MAX_NAME_SIZE];
>>   };
>> @@ -161,18 +167,18 @@ struct lm3532_data {
>>   };
>>   
>>   static const struct reg_default lm3532_reg_defs[] = {
>> -	{LM3532_REG_OUTPUT_CFG, 0xe4},
>> +	{LM3532_REG_OUTPUT_CFG, 0x24},
>>   	{LM3532_REG_STARTSHUT_RAMP, 0xc0},
>>   	{LM3532_REG_RT_RAMP, 0xc0},
>>   	{LM3532_REG_PWM_A_CFG, 0x82},
>>   	{LM3532_REG_PWM_B_CFG, 0x82},
>>   	{LM3532_REG_PWM_C_CFG, 0x82},
>>   	{LM3532_REG_ZONE_CFG_A, 0xf1},
>> -	{LM3532_REG_CTRL_A_BRT, 0xf3},
>> +	{LM3532_REG_CTRL_A_FS_CURR, 0x13},
>>   	{LM3532_REG_ZONE_CFG_B, 0xf1},
>> -	{LM3532_REG_CTRL_B_BRT, 0xf3},
>> +	{LM3532_REG_CTRL_B_FS_CURR, 0x13},
>>   	{LM3532_REG_ZONE_CFG_C, 0xf1},
>> -	{LM3532_REG_CTRL_C_BRT, 0xf3},
>> +	{LM3532_REG_CTRL_C_FS_CURR, 0x13},
>>   	{LM3532_REG_ENABLE, 0xf8},
>>   	{LM3532_ALS_CONFIG, 0x44},
>>   	{LM3532_REG_ZN_0_HI, 0x35},
>> @@ -302,7 +308,7 @@ static int lm3532_led_disable(struct lm3532_led *led_data)
>>   	int ret;
>>   
>>   	ret = regmap_update_bits(led_data->priv->regmap, LM3532_REG_ENABLE,
>> -					 ctrl_en_val, ~ctrl_en_val);
>> +					 ctrl_en_val, 0);
>>   	if (ret) {
>>   		dev_err(led_data->priv->dev, "Failed to set ctrl:%d\n", ret);
>>   		return ret;
>> @@ -321,7 +327,7 @@ static int lm3532_brightness_set(struct led_classdev *led_cdev,
>>   
>>   	mutex_lock(&led->priv->lock);
>>   
>> -	if (led->mode == LM3532_BL_MODE_ALS) {
>> +	if (led->mode == LM3532_ALS_CTRL) {
>>   		if (brt_val > LED_OFF)
>>   			ret = lm3532_led_enable(led);
>>   		else
>> @@ -339,11 +345,9 @@ static int lm3532_brightness_set(struct led_classdev *led_cdev,
>>   	if (ret)
>>   		goto unlock;
>>   
>> -	brightness_reg = LM3532_REG_CTRL_A_BRT + led->control_bank * 2;
>> -	brt_val = brt_val / LM3532_BRT_VAL_ADJUST;
>> -
>> +	brightness_reg = LM3532_REG_ZONE_TRGT_A + led->control_bank * 5 +
>> +			 (led->ctrl_brt_pointer >> 2);
>>   	ret = regmap_write(led->priv->regmap, brightness_reg, brt_val);
>> -
>>   unlock:
>>   	mutex_unlock(&led->priv->lock);
>>   	return ret;
>> @@ -356,8 +360,29 @@ static int lm3532_init_registers(struct lm3532_led *led)
>>   	unsigned int output_cfg_val = 0;
>>   	unsigned int output_cfg_shift = 0;
>>   	unsigned int output_cfg_mask = 0;
>> +	int brightness_config_reg;
>> +	int brightness_config_val;
>>   	int ret, i;
>>   
>> +	if (drvdata->enable_gpio)
>> +		gpiod_direction_output(drvdata->enable_gpio, 1);
>> +
>> +	brightness_config_reg = LM3532_REG_ZONE_CFG_A + led->control_bank * 2;
>> +	/* This could be hard coded to the default value but the control
> Coding style issue:
>
>          /*
>           * This is the preferred style for multi-line comments

OK checkpatch did not crib about it but I can change it.


>
>> +	 * brightness register may have changed during boot.
>> +	 */> +	ret = regmap_read(drvdata->regmap, brightness_config_reg,
>> +			  &led->ctrl_brt_pointer);
>> +	if (ret)
>> +		return ret;
>> +
>> +	led->ctrl_brt_pointer &= LM3532_ZONE_MASK;
> Could you shed more light on this hardware peculiarity?
> What kind of pointer is it?

The bits in the register are called Control A,B or C Brightness Pointer 
in the data sheet.

Basically BITS(4:2) control or points to which Zone target register will 
be used to control

the output current for the particular control bank

000 = Control A Zone Target 0
001 = Control A Zone Target 1
010 = Control A Zone Target 2
011 = Control A Zone Target 3
1XX = Control A Zone Target 4 (default)

I was trying to keep the variable and register bits name some what the same.

>
>> +	brightness_config_val = led->ctrl_brt_pointer | led->mode;
>> +	ret = regmap_write(drvdata->regmap, brightness_config_reg,
>> +			   brightness_config_val);
>> +	if (ret)
>> +		return ret;
>> +
>>   	for (i = 0; i < led->num_leds; i++) {
>>   		output_cfg_shift = led->led_strings[i] * 2;
>>   		output_cfg_val |= (led->control_bank << output_cfg_shift);
>> @@ -382,7 +407,6 @@ static int lm3532_als_configure(struct lm3532_data *priv,
>>   	struct lm3532_als_data *als = priv->als_data;
>>   	u32 als_vmin, als_vmax, als_vstep;
>>   	int zone_reg = LM3532_REG_ZN_0_HI;
>> -	int brightnes_config_reg;
>>   	int ret;
>>   	int i;
>>   
>> @@ -411,14 +435,7 @@ static int lm3532_als_configure(struct lm3532_data *priv,
>>   	als->config = (als->als_avrg_time | (LM3532_ENABLE_ALS) |
>>   		(als->als_input_mode << LM3532_ALS_SEL_SHIFT));
>>   
>> -	ret = regmap_write(priv->regmap, LM3532_ALS_CONFIG, als->config);
>> -	if (ret)
>> -		return ret;
>> -
>> -	brightnes_config_reg = LM3532_REG_ZONE_CFG_A + led->control_bank * 2;
>> -
>> -	return regmap_update_bits(priv->regmap, brightnes_config_reg,
>> -				  LM3532_I2C_CTRL, LM3532_ALS_CTRL);
>> +	return regmap_write(priv->regmap, LM3532_ALS_CONFIG, als->config);
>>   }
>>   
>>   static int lm3532_parse_als(struct lm3532_data *priv)
>> @@ -542,12 +559,14 @@ static int lm3532_parse_node(struct lm3532_data *priv)
>>   		}
>>   
>>   		if (led->mode == LM3532_BL_MODE_ALS) {
>> +			led->mode = LM3532_ALS_CTRL;
>>   			ret = lm3532_parse_als(priv);
>>   			if (ret)
>>   				dev_err(&priv->client->dev, "Failed to parse als\n");
>>   			else
>>   				lm3532_als_configure(priv, led);
>> -		}
>> +		} else
>> +			led->mode = LM3532_I2C_CTRL;
> Coding style issue: you need curly braces around the body of "else"
> in this case as well.

No checkpatch complaint I will fix it.

Dan