linux-kernel - RE: [PATCH v2 1/2] leds-lm3530: set the value of max

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Message-ID: <B567DBAB974C0544994013492B949F8E3812CD3F53@EXMAIL03.scwf.nsc.com>
Date:	Wed, 25 Jan 2012 01:40:37 -0800
From:	"Kim, Milo" <Milo.Kim@...com>
To:	"Lars-Peter Clausen" <lars@...afoo.de>
cc:	"Linus Walleij" <linus.walleij@...aro.org>,
	"shreshthakumar.sahu@...ricsson.com" 
	<shreshthakumar.sahu@...ricsson.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"rpurdie@...ys.net" <rpurdie@...ys.net>
Subject: RE: [PATCH v2 1/2] leds-lm3530: set the value of max_brightness
 to 127

Only 7 bits are used for the brightness. (register address : A0h)
So the max_brightness property of lm3530 should be set to 127.

On initializing registers, maximum initial brightness is limited to 'max_brightness'.

Division-by-two is removed on updating the value of brightness.
This arithmetic is not necessary because the range of brightness is 0 ~ 127.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@...com>
---
 drivers/leds/leds-lm3530.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/leds/leds-lm3530.c b/drivers/leds/leds-lm3530.c
index 4d7ce76..7005a5f 100644
--- a/drivers/leds/leds-lm3530.c
+++ b/drivers/leds/leds-lm3530.c
@@ -80,6 +80,9 @@
 #define LM3530_DEF_ZT_3			(0x66)
 #define LM3530_DEF_ZT_4			(0x7F)
 
+/* 7 bits are used for the brightness : LM3530_BRT_CTRL_REG */
+#define MAX_BRIGHTNESS			(127)
+
 struct lm3530_mode_map {
 	const char *mode;
 	enum lm3530_mode mode_val;
@@ -184,6 +187,9 @@ static int lm3530_init_registers(struct lm3530_data *drvdata)
 	else
 		brightness = drvdata->brightness = pltfm->brt_val;
 
+	if (brightness > drvdata->led_dev.max_brightness)
+		brightness = drvdata->led_dev.max_brightness;
+
 	reg_val[0] = gen_config;	/* LM3530_GEN_CONFIG */
 	reg_val[1] = als_config;	/* LM3530_ALS_CONFIG */
 	reg_val[2] = brt_ramp;		/* LM3530_BRT_RAMP_RATE */
@@ -241,12 +247,12 @@ static void lm3530_brightness_set(struct led_classdev *led_cdev,
 
 		/* set the brightness in brightness control register*/
 		err = i2c_smbus_write_byte_data(drvdata->client,
-				LM3530_BRT_CTRL_REG, brt_val / 2);
+				LM3530_BRT_CTRL_REG, brt_val);
 		if (err)
 			dev_err(&drvdata->client->dev,
 				"Unable to set brightness: %d\n", err);
 		else
-			drvdata->brightness = brt_val / 2;
+			drvdata->brightness = brt_val;
 
 		if (brt_val == 0) {
 			err = regulator_disable(drvdata->regulator);
@@ -340,6 +346,7 @@ static int __devinit lm3530_probe(struct i2c_client *client,
 	drvdata->enable = false;
 	drvdata->led_dev.name = LM3530_LED_DEV;
 	drvdata->led_dev.brightness_set = lm3530_brightness_set;
+	drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
 
 	i2c_set_clientdata(client, drvdata);
 
-- 
1.7.4.1


Best Regards,
Milo (Woogyom) Kim


-----Original Message-----
From: Lars-Peter Clausen [mailto:lars@...afoo.de] 
Sent: Wednesday, January 25, 2012 4:53 PM
To: Kim, Milo
Cc: Linus Walleij; shreshthakumar.sahu@...ricsson.com; linux-kernel@...r.kernel.org; rpurdie@...ys.net
Subject: Re: [PATCH v2 1/2] leds-lm3530: set the value of max_brightness to 127

On 01/25/2012 02:51 AM, Kim, Milo wrote:
>> Only 7 bits are used for the brightness. (register address : A0h)
>> So the max_brightness property of lm3530 should be set to 127.
>> 
>> On initializing registers, maximum initial brightness is limited to 'max_brightness'.
>> 
>> Division-by-two is removed on updating the value of brightness.
>> This arithmetic is not necessary because the range of brightness is 0 ~ 127.
>> 
>> Signed-off-by: Milo(Woogyom) Kim <milo.kim@...com>
>> ---
>>  drivers/leds/leds-lm3530.c |   22 +++++++++++-----------
>>  1 files changed, 11 insertions(+), 11 deletions(-)
>> 

> Looks like something went wrong, this is the same patch as 2/2

Sorry for confusing you. Wrong patch was sent.

Best Regards,
Milo -


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