Re: [PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung SMDKV310

Re: [PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung SMDKV310

[JinGoo Han]

Hi, Banajit.
> -----Original Message-----
> From: linux-samsung-soc-owner@vger.kernel.org [mailto:linux-samsung-soc-
> owner@vger.kernel.org] On Behalf Of Banajit Goswami
> Sent: Wednesday, June 22, 2011 3:41 PM
> To: linux-samsung-soc@vger.kernel.org
> Cc: kgene.kim@samsung.com; ben-linux@fluff.org; linux-arm-
> kernel@lists.infradead.org; Banajit Goswami
> Subject: [PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung
> SMDKV310
> 
> This patch adds support for LCD backlight using PWM timer for
> Samsung SMDKV310 board.
> 
> Signed-off-by: Banajit Goswami <banajit.g@samsung.com>
> ---
>  arch/arm/mach-exynos4/Kconfig         |    1 +
>  arch/arm/mach-exynos4/mach-smdkv310.c |   43
> +++++++++++++++++++++++++++++++++
>  2 files changed, 44 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/mach-exynos4/Kconfig b/arch/arm/mach-exynos4/Kconfig
> index 1435fc3..9ab53bc 100644
> --- a/arch/arm/mach-exynos4/Kconfig
> +++ b/arch/arm/mach-exynos4/Kconfig
> @@ -128,6 +128,7 @@ config MACH_SMDKV310
>  	select S3C_DEV_HSMMC2
>  	select S3C_DEV_HSMMC3
>  	select SAMSUNG_DEV_KEYPAD
> +	select SAMSUNG_DEV_PWM
>  	select EXYNOS4_DEV_PD
>  	select EXYNOS4_DEV_SYSMMU
>  	select EXYNOS4_SETUP_I2C1
> diff --git a/arch/arm/mach-exynos4/mach-smdkv310.c b/arch/arm/mach-
> exynos4/mach-smdkv310.c
> index 7e3ee6c..b097ef6 100644
> --- a/arch/arm/mach-exynos4/mach-smdkv310.c
> +++ b/arch/arm/mach-exynos4/mach-smdkv310.c
> @@ -16,6 +16,7 @@
>  #include <linux/io.h>
>  #include <linux/i2c.h>
>  #include <linux/input.h>
> +#include <linux/pwm_backlight.h>
> 
>  #include <asm/mach/arch.h>
>  #include <asm/mach-types.h>
> @@ -29,6 +30,7 @@
>  #include <plat/sdhci.h>
>  #include <plat/iic.h>
>  #include <plat/pd.h>
> +#include <plat/gpio-cfg.h>
> 
>  #include <mach/map.h>
> 
> @@ -172,6 +174,45 @@ static struct i2c_board_info i2c_devs1[] __initdata =
> {
>  	{I2C_BOARD_INFO("wm8994", 0x1a),},
>  };
> 
> +static int smdkv310_backlight_init(struct device *dev)
> +{
> +	int ret = 0;
> +
> +	ret = gpio_request(EXYNOS4_GPD0(1), "Backlight");
> +	if (ret) {
> +		printk(KERN_ERR "failed to request GPD for PWM-OUT0\n");
> +		return ret;
> +	}
> +
> +	/* Configure GPIO pin with EXYNOS4_GPD_0_1_TOUT_0 */
> +	s3c_gpio_cfgpin(EXYNOS4_GPD0(1), S3C_GPIO_SFN(2));
> +
> +	return 0;
> +}
> +
> +static void smdkv310_backlight_exit(struct device *dev)
> +{
> +	s3c_gpio_cfgpin(EXYNOS4_GPD0(1), S3C_GPIO_OUTPUT);
> +	gpio_free(EXYNOS4_GPD0(1));
> +}
> +
> +static struct platform_pwm_backlight_data smdkv310_backlight_data = {
> +	.pwm_id		= 1,
> +	.max_brightness	= 255,
> +	.dft_brightness	= 255,
> +	.pwm_period_ns	= 78770,
Please use 1000 as pwm_period_ns instead of 78770 as follows:
-	.pwm_period_ns	= 78770,
+	.pwm_period_ns  = 1000,

The value '78770' makes noise related to resonance at LCD board.

I will explain how I get the value of PWM period.

The SMDK boards use LT3591 as backlight LED driver of LTE480WV LCD
According to the LT3591 datasheet, the switching frequency should
be 1MHz. So, PWM period is calculated by following formula:
        PWM period = 1/switching frequency
                       = 1/1MHz
                       = 1000 ns

You can find LT3591 datasheet easily on the Internet. Please refer to it
for more information.
Good luck.
> +	.init		= smdkv310_backlight_init,
> +	.exit		= smdkv310_backlight_exit,
> +};
> +
> +static struct platform_device smdkv310_backlight_device = {
> +	.name		= "pwm-backlight",
> +	.dev		= {
> +		.parent		= &s3c_device_timer[1].dev,
> +		.platform_data	= &smdkv310_backlight_data,
> +	},
> +};
> +
>  static struct platform_device *smdkv310_devices[] __initdata = {
>  	&s3c_device_hsmmc0,
>  	&s3c_device_hsmmc1,
> @@ -195,6 +236,8 @@ static struct platform_device *smdkv310_devices[]
> __initdata = {
>  	&samsung_asoc_dma,
>  	&smdkv310_smsc911x,
>  	&smdkv310_pcm_device,
> +	&s3c_device_timer[1],
> +	&smdkv310_backlight_device,
>  };
> 
>  static void __init smdkv310_smsc911x_init(void)
> --
> 1.6.5.2
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-samsung-
> soc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung SMDKV310

[Banajit Goswami]

> From: JinGoo Han <jg1.han@samsung.com>
>
> Hi, Banajit.
Hi Jingoo,

>>
>> Signed-off-by: Banajit Goswami <banajit.g@samsung.com>
>> ---
...
<snip>
...
>> +     .pwm_period_ns  = 78770,
> Please use 1000 as pwm_period_ns instead of 78770 as follows:
> -       .pwm_period_ns  = 78770,
> +       .pwm_period_ns  = 1000,
>
Yes, I will modify the period value and send updated patch

> The value '78770' makes noise related to resonance at LCD board.
>
> I will explain how I get the value of PWM period.
>
> The SMDK boards use LT3591 as backlight LED driver of LTE480WV LCD
> According to the LT3591 datasheet, the switching frequency should
> be 1MHz. So, PWM period is calculated by following formula:
>        PWM period = 1/switching frequency
>                       = 1/1MHz
>                       = 1000 ns
>
Thanks for the explanation.

> You can find LT3591 datasheet easily on the Internet. Please refer to it
> for more information.
> Good luck.
Thanks you.

>> +     .init           = smdkv310_backlight_init,
...
<snip>
...
>

Regards,
Banajit

[PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung SMDKV310

[Banajit Goswami]

> From: JinGoo Han <jg1.han@samsung.com>
>
> Hi, Banajit.
Hi Jingoo,

>>
>> Signed-off-by: Banajit Goswami <banajit.g@samsung.com>
>> ---
...
<snip>
...
>> + ? ? .pwm_period_ns ?= 78770,
> Please use 1000 as pwm_period_ns instead of 78770 as follows:
> - ? ? ? .pwm_period_ns ?= 78770,
> + ? ? ? .pwm_period_ns ?= 1000,
>
Yes, I will modify the period value and send updated patch

> The value '78770' makes noise related to resonance at LCD board.
>
> I will explain how I get the value of PWM period.
>
> The SMDK boards use LT3591 as backlight LED driver of LTE480WV LCD
> According to the LT3591 datasheet, the switching frequency should
> be 1MHz. So, PWM period is calculated by following formula:
> ? ? ? ?PWM period = 1/switching frequency
> ? ? ? ? ? ? ? ? ? ? ? = 1/1MHz
> ? ? ? ? ? ? ? ? ? ? ? = 1000 ns
>
Thanks for the explanation.

> You can find LT3591 datasheet easily on the Internet. Please refer to it
> for more information.
> Good luck.
Thanks you.

>> + ? ? .init ? ? ? ? ? = smdkv310_backlight_init,
...
<snip>
...
>

Regards,
Banajit

RE: [PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung SMDKV310

[Kukjin Kim]

Banajit Goswami wrote:
> 
> > From: JinGoo Han <jg1.han@samsung.com>
> >
> > Hi, Banajit.
> Hi Jingoo,
> 
Hi all,

Hmm...
If the same code is required into each boards, please don't add them on both.

I think, we can avoid duplication...

Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim@samsung.com>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.

[PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung SMDKV310

[Kukjin Kim]

Banajit Goswami wrote:
> 
> > From: JinGoo Han <jg1.han@samsung.com>
> >
> > Hi, Banajit.
> Hi Jingoo,
> 
Hi all,

Hmm...
If the same code is required into each boards, please don't add them on both.

I think, we can avoid duplication...

Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim@samsung.com>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.

Re: [PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung SMDKV310

[Banajit Goswami]

On Thu, Jun 23, 2011 at 5:14 PM, Kukjin Kim <kgene.kim@samsung.com> wrote:
> Banajit Goswami wrote:
>>
>> > From: JinGoo Han <jg1.han@samsung.com>
>> >
>> > Hi, Banajit.
>> Hi Jingoo,
>>
> Hi all,
Hello,

> Hmm...
> If the same code is required into each boards, please don't add them on both.
>
> I think, we can avoid duplication...
Yes, I have already started working on it.
I can send it by tomorrow.

> Thanks.
>
> Best regards,
> Kgene.

Thanks,
Banajit

[PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung SMDKV310

[Banajit Goswami]

On Thu, Jun 23, 2011 at 5:14 PM, Kukjin Kim <kgene.kim@samsung.com> wrote:
> Banajit Goswami wrote:
>>
>> > From: JinGoo Han <jg1.han@samsung.com>
>> >
>> > Hi, Banajit.
>> Hi Jingoo,
>>
> Hi all,
Hello,

> Hmm...
> If the same code is required into each boards, please don't add them on both.
>
> I think, we can avoid duplication...
Yes, I have already started working on it.
I can send it by tomorrow.

> Thanks.
>
> Best regards,
> Kgene.

Thanks,
Banajit

[PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung SMDKV310

[Banajit Goswami]

This patch adds support for LCD backlight using PWM timer for
Samsung SMDKV310 board.

Signed-off-by: Banajit Goswami <banajit.g@samsung.com>
---
 arch/arm/mach-exynos4/Kconfig         |    1 +
 arch/arm/mach-exynos4/mach-smdkv310.c |   43 +++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-exynos4/Kconfig b/arch/arm/mach-exynos4/Kconfig
index 1435fc3..9ab53bc 100644
--- a/arch/arm/mach-exynos4/Kconfig
+++ b/arch/arm/mach-exynos4/Kconfig
@@ -128,6 +128,7 @@ config MACH_SMDKV310
 	select S3C_DEV_HSMMC2
 	select S3C_DEV_HSMMC3
 	select SAMSUNG_DEV_KEYPAD
+	select SAMSUNG_DEV_PWM
 	select EXYNOS4_DEV_PD
 	select EXYNOS4_DEV_SYSMMU
 	select EXYNOS4_SETUP_I2C1
diff --git a/arch/arm/mach-exynos4/mach-smdkv310.c b/arch/arm/mach-exynos4/mach-smdkv310.c
index 7e3ee6c..b097ef6 100644
--- a/arch/arm/mach-exynos4/mach-smdkv310.c
+++ b/arch/arm/mach-exynos4/mach-smdkv310.c
@@ -16,6 +16,7 @@
 #include <linux/io.h>
 #include <linux/i2c.h>
 #include <linux/input.h>
+#include <linux/pwm_backlight.h>
 
 #include <asm/mach/arch.h>
 #include <asm/mach-types.h>
@@ -29,6 +30,7 @@
 #include <plat/sdhci.h>
 #include <plat/iic.h>
 #include <plat/pd.h>
+#include <plat/gpio-cfg.h>
 
 #include <mach/map.h>
 
@@ -172,6 +174,45 @@ static struct i2c_board_info i2c_devs1[] __initdata = {
 	{I2C_BOARD_INFO("wm8994", 0x1a),},
 };
 
+static int smdkv310_backlight_init(struct device *dev)
+{
+	int ret = 0;
+
+	ret = gpio_request(EXYNOS4_GPD0(1), "Backlight");
+	if (ret) {
+		printk(KERN_ERR "failed to request GPD for PWM-OUT0\n");
+		return ret;
+	}
+
+	/* Configure GPIO pin with EXYNOS4_GPD_0_1_TOUT_0 */
+	s3c_gpio_cfgpin(EXYNOS4_GPD0(1), S3C_GPIO_SFN(2));
+
+	return 0;
+}
+
+static void smdkv310_backlight_exit(struct device *dev)
+{
+	s3c_gpio_cfgpin(EXYNOS4_GPD0(1), S3C_GPIO_OUTPUT);
+	gpio_free(EXYNOS4_GPD0(1));
+}
+
+static struct platform_pwm_backlight_data smdkv310_backlight_data = {
+	.pwm_id		= 1,
+	.max_brightness	= 255,
+	.dft_brightness	= 255,
+	.pwm_period_ns	= 78770,
+	.init		= smdkv310_backlight_init,
+	.exit		= smdkv310_backlight_exit,
+};
+
+static struct platform_device smdkv310_backlight_device = {
+	.name		= "pwm-backlight",
+	.dev		= {
+		.parent		= &s3c_device_timer[1].dev,
+		.platform_data	= &smdkv310_backlight_data,
+	},
+};
+
 static struct platform_device *smdkv310_devices[] __initdata = {
 	&s3c_device_hsmmc0,
 	&s3c_device_hsmmc1,
@@ -195,6 +236,8 @@ static struct platform_device *smdkv310_devices[] __initdata = {
 	&samsung_asoc_dma,
 	&smdkv310_smsc911x,
 	&smdkv310_pcm_device,
+	&s3c_device_timer[1],
+	&smdkv310_backlight_device,
 };
 
 static void __init smdkv310_smsc911x_init(void)
-- 
1.6.5.2

[PATCH] ARM: EXYNOS4: Add PWM backlight support on Samsung SMDKV310

[Banajit Goswami]

This patch adds support for LCD backlight using PWM timer for
Samsung SMDKV310 board.

Signed-off-by: Banajit Goswami <banajit.g@samsung.com>
---
 arch/arm/mach-exynos4/Kconfig         |    1 +
 arch/arm/mach-exynos4/mach-smdkv310.c |   43 +++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-exynos4/Kconfig b/arch/arm/mach-exynos4/Kconfig
index 1435fc3..9ab53bc 100644
--- a/arch/arm/mach-exynos4/Kconfig
+++ b/arch/arm/mach-exynos4/Kconfig
@@ -128,6 +128,7 @@ config MACH_SMDKV310
 	select S3C_DEV_HSMMC2
 	select S3C_DEV_HSMMC3
 	select SAMSUNG_DEV_KEYPAD
+	select SAMSUNG_DEV_PWM
 	select EXYNOS4_DEV_PD
 	select EXYNOS4_DEV_SYSMMU
 	select EXYNOS4_SETUP_I2C1
diff --git a/arch/arm/mach-exynos4/mach-smdkv310.c b/arch/arm/mach-exynos4/mach-smdkv310.c
index 7e3ee6c..b097ef6 100644
--- a/arch/arm/mach-exynos4/mach-smdkv310.c
+++ b/arch/arm/mach-exynos4/mach-smdkv310.c
@@ -16,6 +16,7 @@
 #include <linux/io.h>
 #include <linux/i2c.h>
 #include <linux/input.h>
+#include <linux/pwm_backlight.h>
 
 #include <asm/mach/arch.h>
 #include <asm/mach-types.h>
@@ -29,6 +30,7 @@
 #include <plat/sdhci.h>
 #include <plat/iic.h>
 #include <plat/pd.h>
+#include <plat/gpio-cfg.h>
 
 #include <mach/map.h>
 
@@ -172,6 +174,45 @@ static struct i2c_board_info i2c_devs1[] __initdata = {
 	{I2C_BOARD_INFO("wm8994", 0x1a),},
 };
 
+static int smdkv310_backlight_init(struct device *dev)
+{
+	int ret = 0;
+
+	ret = gpio_request(EXYNOS4_GPD0(1), "Backlight");
+	if (ret) {
+		printk(KERN_ERR "failed to request GPD for PWM-OUT0\n");
+		return ret;
+	}
+
+	/* Configure GPIO pin with EXYNOS4_GPD_0_1_TOUT_0 */
+	s3c_gpio_cfgpin(EXYNOS4_GPD0(1), S3C_GPIO_SFN(2));
+
+	return 0;
+}
+
+static void smdkv310_backlight_exit(struct device *dev)
+{
+	s3c_gpio_cfgpin(EXYNOS4_GPD0(1), S3C_GPIO_OUTPUT);
+	gpio_free(EXYNOS4_GPD0(1));
+}
+
+static struct platform_pwm_backlight_data smdkv310_backlight_data = {
+	.pwm_id		= 1,
+	.max_brightness	= 255,
+	.dft_brightness	= 255,
+	.pwm_period_ns	= 78770,
+	.init		= smdkv310_backlight_init,
+	.exit		= smdkv310_backlight_exit,
+};
+
+static struct platform_device smdkv310_backlight_device = {
+	.name		= "pwm-backlight",
+	.dev		= {
+		.parent		= &s3c_device_timer[1].dev,
+		.platform_data	= &smdkv310_backlight_data,
+	},
+};
+
 static struct platform_device *smdkv310_devices[] __initdata = {
 	&s3c_device_hsmmc0,
 	&s3c_device_hsmmc1,
@@ -195,6 +236,8 @@ static struct platform_device *smdkv310_devices[] __initdata = {
 	&samsung_asoc_dma,
 	&smdkv310_smsc911x,
 	&smdkv310_pcm_device,
+	&s3c_device_timer[1],
+	&smdkv310_backlight_device,
 };
 
 static void __init smdkv310_smsc911x_init(void)
-- 
1.6.5.2