[PATCH v3 0/2] Add MediaTek display PWM driver

[PATCH v3 0/2] Add MediaTek display PWM driver

[YH Huang]

This patch series add the use of display PWM driver and documentation 
for Mediatek SoCs. The driver is used to support the backlight of 
the panel. This is based on v4.1-rc1.

Change in v3:
1. Add suspend/resume function
2. Fix the formula for high_width calculation
3. Rewrite some code to make it easier to read
4. Add more information in the commit message

[PATCH v3 1/2] dt-bindings: pwm: add MediaTek display PWM bindings

[YH Huang]

Document the device-tree binding of MediatTek display PWM.
The clock "main" and "mm" are used to generate PWM signals.
The PWM has one channel to control the backlight brightness for display.
It supports MT8173 and MT6595.

Change-Id: I194ca88b4e4cd01a28b8701e07e86ea6941e5292
Signed-off-by: YH Huang <yh.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
 .../devicetree/bindings/pwm/pwm-mtk-disp.txt       | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt

diff --git a/Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt b/Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt
new file mode 100644
index 0000000..355b755
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt
@@ -0,0 +1,24 @@
+MediaTek display PWM controller
+
+Required properties:
+ - compatible: should be "mediatek,<name>-disp-pwm"
+   - "mediatek,mt8173-disp-pwm": found on mt8173 SoC
+   - "mediatek,mt6595-disp-pwm": found on mt6595 SoC
+ - reg: physical base address and length of the controller's registers
+ - #pwm-cells: must be 2. See pwm.txt in this directory for a description of
+   the cell format
+ - clocks: phandle and clock specifier of the PWM reference clock
+ - clock-names: must contain the following
+   - "main": clock used to generate PWM signals
+   - "mm": sync signals from the modules of mmsys
+
+Example:
+	pwm0: pwm@1401e000 {
+		compatible = "mediatek,mt8173-disp-pwm",
+			     "mediatek,mt6595-disp-pwm";
+		reg = <0 0x1401e000 0 0x1000>;
+		#pwm-cells = <2>;
+		clocks = <&mmsys MM_DISP_PWM026M>,
+			 <&mmsys MM_DISP_PWM0MM>;
+		clock-names = "main", "mm";
+	};
-- 
1.8.1.1.dirty

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v3 2/2] pwm: add MediaTek display PWM driver support

[YH Huang]

Add display PWM driver support to modify backlight for MT8173 and MT6595.
The PWM has one channel to control the brightness of the display.
When the (high_width / period) is closer to 1, the screen is brighter; otherwise, it is darker.

Change-Id: Ie85b295e2dddd90b4163af1c906df977f79b59d6
Signed-off-by: YH Huang <yh.huang@mediatek.com>
---
 drivers/pwm/Kconfig        |  10 ++
 drivers/pwm/Makefile       |   1 +
 drivers/pwm/pwm-mtk-disp.c | 256 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 267 insertions(+)
 create mode 100644 drivers/pwm/pwm-mtk-disp.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index b1541f4..90e3c079 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -211,6 +211,16 @@ config PWM_LPSS_PLATFORM
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-lpss-platform.
 
+config PWM_MTK_DISP
+	tristate "MediaTek display PWM driver"
+	depends on HAS_IOMEM
+	help
+	  Generic PWM framework driver for MediaTek disp-pwm device.
+	  The PWM is used to control the backlight brightness for display.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-mtk-disp.
+
 config PWM_MXS
 	tristate "Freescale MXS PWM support"
 	depends on ARCH_MXS && OF
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index ec50eb5..99c9e75 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_PWM_LPC32XX)	+= pwm-lpc32xx.o
 obj-$(CONFIG_PWM_LPSS)		+= pwm-lpss.o
 obj-$(CONFIG_PWM_LPSS_PCI)	+= pwm-lpss-pci.o
 obj-$(CONFIG_PWM_LPSS_PLATFORM)	+= pwm-lpss-platform.o
+obj-$(CONFIG_PWM_MTK_DISP)	+= pwm-mtk-disp.o
 obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o
 obj-$(CONFIG_PWM_PCA9685)	+= pwm-pca9685.o
 obj-$(CONFIG_PWM_PUV3)		+= pwm-puv3.o
diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
new file mode 100644
index 0000000..fb3a42e
--- /dev/null
+++ b/drivers/pwm/pwm-mtk-disp.c
@@ -0,0 +1,256 @@
+/*
+ * MediaTek display pulse-width-modulation controller driver.
+ * Copyright (c) 2015 MediaTek Inc.
+ * Author: YH Huang <yh.huang@mediatek.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pwm.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define DISP_PWM_EN		0x0
+#define PWM_ENABLE_MASK		0x1
+
+#define DISP_PWM_COMMIT		0x08
+#define PWM_COMMIT_MASK		0x1
+
+#define DISP_PWM_CON_0		0x10
+#define PWM_CLKDIV_SHIFT	16
+#define PWM_CLKDIV_MAX		0x3ff
+#define PWM_CLKDIV_MASK		(PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
+
+#define DISP_PWM_CON_1		0x14
+#define PWM_PERIOD_MASK		0xfff
+/* Shift log2(PWM_PERIOD_MASK + 1) as divisor */
+#define PWM_PERIOD_BIT_SHIFT	12
+
+#define PWM_HIGH_WIDTH_SHIFT	16
+#define PWM_HIGH_WIDTH_MASK	(0x1fff << PWM_HIGH_WIDTH_SHIFT)
+
+struct mtk_disp_pwm {
+	struct pwm_chip chip;
+	struct device *dev;
+	struct clk *clk_main;
+	struct clk *clk_mm;
+	void __iomem *base;
+};
+
+static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
+{
+	return container_of(chip, struct mtk_disp_pwm, chip);
+}
+
+static void mtk_disp_pwm_update_bits(void __iomem *address, u32 mask, u32 value)
+{
+	u32 val;
+
+	val = readl(address);
+	val &= ~mask;
+	val |= value;
+	writel(val, address);
+}
+
+static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			       int duty_ns, int period_ns)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	u64 div, rate;
+	u32 clk_div, period, high_width, value;
+
+	/*
+	 * Find period, high_width and clk_div to suit duty_ns and period_ns.
+	 * Calculate proper div value to keep period value in the bound.
+	 *
+	 * period_ns = 10^9 * (clk_div + 1) * (period + 1) / PWM_CLK_RATE
+	 * duty_ns = 10^9 * (clk_div + 1) * high_width / PWM_CLK_RATE
+	 *
+	 * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
+	 * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
+	 */
+	rate = clk_get_rate(mdp->clk_main);
+	clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
+			  PWM_PERIOD_BIT_SHIFT;
+	if (clk_div > PWM_CLKDIV_MAX)
+		return -EINVAL;
+
+	div = NSEC_PER_SEC * (clk_div + 1);
+	period = div64_u64(rate * period_ns, div);
+	if (period > 0)
+		period--;
+
+	high_width = div64_u64(rate * duty_ns, div);
+
+	mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_CON_0,
+				 PWM_CLKDIV_MASK, clk_div << PWM_CLKDIV_SHIFT);
+
+	value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
+	mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_CON_1,
+				 PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, value);
+
+	mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_COMMIT,
+				 PWM_COMMIT_MASK, 1);
+	mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_COMMIT,
+				 PWM_COMMIT_MASK, 0);
+
+	return 0;
+}
+
+static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+
+	mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_EN,
+				 PWM_ENABLE_MASK, 1);
+
+	return 0;
+}
+
+static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+
+	mtk_disp_pwm_update_bits(mdp->base + DISP_PWM_EN,
+				 PWM_ENABLE_MASK, 0);
+}
+
+static const struct pwm_ops mtk_disp_pwm_ops = {
+	.config = mtk_disp_pwm_config,
+	.enable = mtk_disp_pwm_enable,
+	.disable = mtk_disp_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int mtk_disp_pwm_probe(struct platform_device *pdev)
+{
+	struct mtk_disp_pwm *mdp;
+	struct resource *r;
+	int ret;
+
+	mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
+	if (!mdp)
+		return -ENOMEM;
+
+	mdp->dev = &pdev->dev;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mdp->base = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(mdp->base))
+		return PTR_ERR(mdp->base);
+
+	mdp->clk_main = devm_clk_get(&pdev->dev, "main");
+	if (IS_ERR(mdp->clk_main))
+		return PTR_ERR(mdp->clk_main);
+
+	mdp->clk_mm = devm_clk_get(&pdev->dev, "mm");
+	if (IS_ERR(mdp->clk_mm))
+		return PTR_ERR(mdp->clk_mm);
+
+	ret = clk_prepare_enable(mdp->clk_main);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_prepare_enable(mdp->clk_mm);
+	if (ret < 0)
+		goto disable_clk_main;
+
+	platform_set_drvdata(pdev, mdp);
+
+	mdp->chip.dev = &pdev->dev;
+	mdp->chip.ops = &mtk_disp_pwm_ops;
+	mdp->chip.base = -1;
+	mdp->chip.npwm = 1;
+
+	ret = pwmchip_add(&mdp->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+		goto disable_clk_mm;
+	}
+
+	return 0;
+
+disable_clk_mm:
+	clk_disable_unprepare(mdp->clk_mm);
+disable_clk_main:
+	clk_disable_unprepare(mdp->clk_main);
+	return ret;
+}
+
+static int mtk_disp_pwm_remove(struct platform_device *pdev)
+{
+	struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
+	int ret = pwmchip_remove(&mdp->chip);
+
+	clk_disable_unprepare(mdp->clk_main);
+	clk_disable_unprepare(mdp->clk_mm);
+
+	return ret;
+}
+
+static const struct of_device_id mtk_disp_pwm_of_match[] = {
+	{ .compatible = "mediatek,mt8173-disp-pwm" },
+	{ .compatible = "mediatek,mt6595-disp-pwm" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match);
+
+#ifdef CONFIG_PM_SLEEP
+static int mtk_disp_pwm_suspend(struct device *dev)
+{
+	struct mtk_disp_pwm *mdp = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(mdp->clk_main);
+	clk_disable_unprepare(mdp->clk_mm);
+
+	return 0;
+}
+
+static int mtk_disp_pwm_resume(struct device *dev)
+{
+	struct mtk_disp_pwm *mdp = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(mdp->clk_main);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_prepare_enable(mdp->clk_mm);
+	if (ret < 0) {
+		clk_disable_unprepare(mdp->clk_main);
+		return ret;
+	}
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(mtk_disp_pwm_pm_ops, mtk_disp_pwm_suspend,
+			 mtk_disp_pwm_resume);
+
+static struct platform_driver mtk_disp_pwm_driver = {
+	.driver = {
+		.name = "mediatek-disp-pwm",
+		.pm = &mtk_disp_pwm_pm_ops,
+		.of_match_table = mtk_disp_pwm_of_match,
+	},
+	.probe = mtk_disp_pwm_probe,
+	.remove = mtk_disp_pwm_remove,
+};
+module_platform_driver(mtk_disp_pwm_driver);
+
+MODULE_AUTHOR("YH Huang <yh.huang@mediatek.com>");
+MODULE_DESCRIPTION("MediaTek SoC display PWM driver");
+MODULE_LICENSE("GPL v2");
-- 
1.8.1.1.dirty

Re: [PATCH v3 1/2] dt-bindings: pwm: add MediaTek display PWM bindings

[YH Huang]

I am sorry for forgetting to remove Change-Id in [PATCH v3 1/2] and
[PATCH v3 1/2].

Regards,
YH Huang

On Mon, 2015-06-29 at 23:03 +0800, YH Huang wrote:
> Document the device-tree binding of MediatTek display PWM.
> The clock "main" and "mm" are used to generate PWM signals.
> The PWM has one channel to control the backlight brightness for display.
> It supports MT8173 and MT6595.
> 
> Change-Id: I194ca88b4e4cd01a28b8701e07e86ea6941e5292
> Signed-off-by: YH Huang <yh.huang@mediatek.com>
> ---
>  .../devicetree/bindings/pwm/pwm-mtk-disp.txt       | 24 ++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt
> 
> diff --git a/Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt b/Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt
> new file mode 100644
> index 0000000..355b755
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt
> @@ -0,0 +1,24 @@
> +MediaTek display PWM controller
> +
> +Required properties:
> + - compatible: should be "mediatek,<name>-disp-pwm"
> +   - "mediatek,mt8173-disp-pwm": found on mt8173 SoC
> +   - "mediatek,mt6595-disp-pwm": found on mt6595 SoC
> + - reg: physical base address and length of the controller's registers
> + - #pwm-cells: must be 2. See pwm.txt in this directory for a description of
> +   the cell format
> + - clocks: phandle and clock specifier of the PWM reference clock
> + - clock-names: must contain the following
> +   - "main": clock used to generate PWM signals
> +   - "mm": sync signals from the modules of mmsys
> +
> +Example:
> +	pwm0: pwm@1401e000 {
> +		compatible = "mediatek,mt8173-disp-pwm",
> +			     "mediatek,mt6595-disp-pwm";
> +		reg = <0 0x1401e000 0 0x1000>;
> +		#pwm-cells = <2>;
> +		clocks = <&mmsys MM_DISP_PWM026M>,
> +			 <&mmsys MM_DISP_PWM0MM>;
> +		clock-names = "main", "mm";
> +	};

Re: [PATCH v3 0/2] Add MediaTek display PWM driver

[Daniel Kurtz]

Hi YH,

Please also include a patch that adds PWM bindings to mt8173.dtsi.
The clock definitions (CLK_MM_DISP_PWM*) are added by James LIao's patch:
  clk: mediatek: Add subsystem clocks of MT8173

I think it is ok to mention in the cover-letter that the PWM .dtsi
change depends on that other patch.

Also, cover-letters usually contain a "shortlog" and diffstatm that
gives summary of patches and changed files, generated along with the
patches using:
 git format-patch --cover-letter

Thanks,
-Daniel

On Mon, Jun 29, 2015 at 11:03 PM, YH Huang <yh.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> wrote:
> This patch series add the use of display PWM driver and documentation
> for Mediatek SoCs. The driver is used to support the backlight of
> the panel. This is based on v4.1-rc1.
>
> Change in v3:
> 1. Add suspend/resume function
> 2. Fix the formula for high_width calculation
> 3. Rewrite some code to make it easier to read
> 4. Add more information in the commit message
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v3 2/2] pwm: add MediaTek display PWM driver support

[Daniel Kurtz]

On Mon, Jun 29, 2015 at 11:03 PM, YH Huang <yh.huang@mediatek.com> wrote:
> Add display PWM driver support to modify backlight for MT8173 and MT6595.
> The PWM has one channel to control the brightness of the display.
> When the (high_width / period) is closer to 1, the screen is brighter; otherwise, it is darker.
>
> Change-Id: Ie85b295e2dddd90b4163af1c906df977f79b59d6
> Signed-off-by: YH Huang <yh.huang@mediatek.com>
> ---
>  drivers/pwm/Kconfig        |  10 ++
>  drivers/pwm/Makefile       |   1 +
>  drivers/pwm/pwm-mtk-disp.c | 256 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 267 insertions(+)
>  create mode 100644 drivers/pwm/pwm-mtk-disp.c
>
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index b1541f4..90e3c079 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -211,6 +211,16 @@ config PWM_LPSS_PLATFORM
>           To compile this driver as a module, choose M here: the module
>           will be called pwm-lpss-platform.
>
> +config PWM_MTK_DISP
> +       tristate "MediaTek display PWM driver"
> +       depends on HAS_IOMEM

depends on ARCH_MEDIATEK || COMPILE_TEST

> +       help
> +         Generic PWM framework driver for MediaTek disp-pwm device.
> +         The PWM is used to control the backlight brightness for display.
> +
> +         To compile this driver as a module, choose M here: the module
> +         will be called pwm-mtk-disp.
> +
>  config PWM_MXS
>         tristate "Freescale MXS PWM support"
>         depends on ARCH_MXS && OF
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index ec50eb5..99c9e75 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -18,6 +18,7 @@ obj-$(CONFIG_PWM_LPC32XX)     += pwm-lpc32xx.o
>  obj-$(CONFIG_PWM_LPSS)         += pwm-lpss.o
>  obj-$(CONFIG_PWM_LPSS_PCI)     += pwm-lpss-pci.o
>  obj-$(CONFIG_PWM_LPSS_PLATFORM)        += pwm-lpss-platform.o
> +obj-$(CONFIG_PWM_MTK_DISP)     += pwm-mtk-disp.o
>  obj-$(CONFIG_PWM_MXS)          += pwm-mxs.o
>  obj-$(CONFIG_PWM_PCA9685)      += pwm-pca9685.o
>  obj-$(CONFIG_PWM_PUV3)         += pwm-puv3.o
> diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c
> new file mode 100644
> index 0000000..fb3a42e
> --- /dev/null
> +++ b/drivers/pwm/pwm-mtk-disp.c
> @@ -0,0 +1,256 @@
> +/*
> + * MediaTek display pulse-width-modulation controller driver.
> + * Copyright (c) 2015 MediaTek Inc.
> + * Author: YH Huang <yh.huang@mediatek.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/pwm.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#define DISP_PWM_EN            0x0
> +#define PWM_ENABLE_MASK                0x1

For one bit fields like this, it is nicer to use: BIT()

Thanks!
-Dan

Re: [PATCH v3 1/2] dt-bindings: pwm: add MediaTek display PWM bindings

[Daniel Kurtz]

On Mon, Jun 29, 2015 at 11:24 PM, YH Huang <yh.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> wrote:
> I am sorry for forgetting to remove Change-Id in [PATCH v3 1/2] and
> [PATCH v3 1/2].
>
> Regards,
> YH Huang
>
> On Mon, 2015-06-29 at 23:03 +0800, YH Huang wrote:
>> Document the device-tree binding of MediatTek display PWM.
>> The clock "main" and "mm" are used to generate PWM signals.
>> The PWM has one channel to control the backlight brightness for display.
>> It supports MT8173 and MT6595.
>>
>> Change-Id: I194ca88b4e4cd01a28b8701e07e86ea6941e5292
>> Signed-off-by: YH Huang <yh.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
>> ---
>>  .../devicetree/bindings/pwm/pwm-mtk-disp.txt       | 24 ++++++++++++++++++++++
>>  1 file changed, 24 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt
>>
>> diff --git a/Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt b/Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt
>> new file mode 100644
>> index 0000000..355b755
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt
>> @@ -0,0 +1,24 @@
>> +MediaTek display PWM controller
>> +
>> +Required properties:
>> + - compatible: should be "mediatek,<name>-disp-pwm"
>> +   - "mediatek,mt8173-disp-pwm": found on mt8173 SoC
>> +   - "mediatek,mt6595-disp-pwm": found on mt6595 SoC
>> + - reg: physical base address and length of the controller's registers
>> + - #pwm-cells: must be 2. See pwm.txt in this directory for a description of
>> +   the cell format
>> + - clocks: phandle and clock specifier of the PWM reference clock
>> + - clock-names: must contain the following
>> +   - "main": clock used to generate PWM signals
>> +   - "mm": sync signals from the modules of mmsys
>> +
>> +Example:
>> +     pwm0: pwm@1401e000 {
>> +             compatible = "mediatek,mt8173-disp-pwm",
>> +                          "mediatek,mt6595-disp-pwm";
>> +             reg = <0 0x1401e000 0 0x1000>;
>> +             #pwm-cells = <2>;
>> +             clocks = <&mmsys MM_DISP_PWM026M>,
>> +                      <&mmsys MM_DISP_PWM0MM>;

These should be CLK_MM_DISP...

Thanks!
-Dan

>> +             clock-names = "main", "mm";
>> +     };
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH v3 0/2] Add MediaTek display PWM driver

[YH Huang]

Hi Daniel,

I will add PWM dtsi in the next patch and also fix the code with your
suggestions in other mails.

Regards,
YH Huang

On Tue, 2015-06-30 at 14:35 +0800, Daniel Kurtz wrote:
> Hi YH,
> 
> Please also include a patch that adds PWM bindings to mt8173.dtsi.
> The clock definitions (CLK_MM_DISP_PWM*) are added by James LIao's patch:
>   clk: mediatek: Add subsystem clocks of MT8173
> 
> I think it is ok to mention in the cover-letter that the PWM .dtsi
> change depends on that other patch.
> 
> Also, cover-letters usually contain a "shortlog" and diffstatm that
> gives summary of patches and changed files, generated along with the
> patches using:
>  git format-patch --cover-letter
> 
> Thanks,
> -Daniel
> 
> On Mon, Jun 29, 2015 at 11:03 PM, YH Huang <yh.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> wrote:
> > This patch series add the use of display PWM driver and documentation
> > for Mediatek SoCs. The driver is used to support the backlight of
> > the panel. This is based on v4.1-rc1.
> >
> > Change in v3:
> > 1. Add suspend/resume function
> > 2. Fix the formula for high_width calculation
> > 3. Rewrite some code to make it easier to read
> > 4. Add more information in the commit message
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at  http://www.tux.org/lkml/


--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html