From: cy_huang <u0084500@gmail.com> To: robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, lee.jones@linaro.org, daniel.thompson@linaro.org, jingoohan1@gmail.com Cc: pavel@ucw.cz, deller@gmx.de, cy_huang@richtek.com, lucas_tsai@richtek.com, devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 2/2] backlight: rt4831: Apply ocp level from devicetree Date: Thu, 9 Jun 2022 10:22:19 +0800 [thread overview] Message-ID: <1654741339-12756-3-git-send-email-u0084500@gmail.com> (raw) In-Reply-To: <1654741339-12756-1-git-send-email-u0084500@gmail.com> From: ChiYuan Huang <cy_huang@richtek.com> Add 'richtek,bled-ocp-microamp' property parsing in device_property_init function. This value may configure prior to the kernel driver. If it's not specified in devicetree, keep the original setting. Else, use clamp to align the value in min/max range and also roundup to choose the best selector. Reported-by: Lucas Tsai <lucas_tsai@richtek.com> Signed-off-by: ChiYuan Huang <cy_huang@richtek.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> --- Since v2: - Prase the 'richtek,bled-ocp-microamp', clamp the value in min/max range, and roundup to get the best selector. --- drivers/video/backlight/rt4831-backlight.c | 33 +++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) diff --git a/drivers/video/backlight/rt4831-backlight.c b/drivers/video/backlight/rt4831-backlight.c index 42155c7..8c2001b 100644 --- a/drivers/video/backlight/rt4831-backlight.c +++ b/drivers/video/backlight/rt4831-backlight.c @@ -12,6 +12,7 @@ #define RT4831_REG_BLCFG 0x02 #define RT4831_REG_BLDIML 0x04 #define RT4831_REG_ENABLE 0x08 +#define RT4831_REG_BLOPT2 0x11 #define RT4831_BLMAX_BRIGHTNESS 2048 @@ -23,6 +24,11 @@ #define RT4831_BLDIML_MASK GENMASK(2, 0) #define RT4831_BLDIMH_MASK GENMASK(10, 3) #define RT4831_BLDIMH_SHIFT 3 +#define RT4831_BLOCP_MASK GENMASK(1, 0) + +#define RT4831_BLOCP_MINUA 900000 +#define RT4831_BLOCP_MAXUA 1800000 +#define RT4831_BLOCP_STEPUA 300000 struct rt4831_priv { struct device *dev; @@ -85,7 +91,7 @@ static int rt4831_parse_backlight_properties(struct rt4831_priv *priv, { struct device *dev = priv->dev; u8 propval; - u32 brightness; + u32 brightness, ocp_uA; unsigned int val = 0; int ret; @@ -120,6 +126,31 @@ static int rt4831_parse_backlight_properties(struct rt4831_priv *priv, if (ret) return ret; + /* + * This OCP level is used to protect and limit the inductor current. + * If inductor peak current reach the level, low-side MOSFET will be + * turned off. Meanwhile, the output channel current may be limited. + * To match the configured channel current, the inductor chosen must + * be higher than the OCP level. + * + * Not like the OVP level, the default 21V can be used in the most + * application. But if the chosen OCP level is smaller than needed, + * it will also affect the backlight channel output current to be + * smaller than the register setting. + */ + ret = device_property_read_u32(dev, "richtek,bled-ocp-microamp", + &ocp_uA); + if (!ret) { + ocp_uA = clamp_val(ocp_uA, RT4831_BLOCP_MINUA, + RT4831_BLOCP_MAXUA); + val = roundup(ocp_uA - RT4831_BLOCP_MINUA, + RT4831_BLOCP_STEPUA); + ret = regmap_update_bits(priv->regmap, RT4831_REG_BLOPT2, + RT4831_BLOCP_MASK, val); + if (ret) + return ret; + } + ret = device_property_read_u8(dev, "richtek,channel-use", &propval); if (ret) { dev_err(dev, "richtek,channel-use DT property missing\n"); -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: cy_huang <u0084500@gmail.com> To: robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, lee.jones@linaro.org, daniel.thompson@linaro.org, jingoohan1@gmail.com Cc: devicetree@vger.kernel.org, linux-fbdev@vger.kernel.org, lucas_tsai@richtek.com, deller@gmx.de, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, cy_huang@richtek.com, pavel@ucw.cz, linux-leds@vger.kernel.org Subject: [PATCH v3 2/2] backlight: rt4831: Apply ocp level from devicetree Date: Thu, 9 Jun 2022 10:22:19 +0800 [thread overview] Message-ID: <1654741339-12756-3-git-send-email-u0084500@gmail.com> (raw) In-Reply-To: <1654741339-12756-1-git-send-email-u0084500@gmail.com> From: ChiYuan Huang <cy_huang@richtek.com> Add 'richtek,bled-ocp-microamp' property parsing in device_property_init function. This value may configure prior to the kernel driver. If it's not specified in devicetree, keep the original setting. Else, use clamp to align the value in min/max range and also roundup to choose the best selector. Reported-by: Lucas Tsai <lucas_tsai@richtek.com> Signed-off-by: ChiYuan Huang <cy_huang@richtek.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> --- Since v2: - Prase the 'richtek,bled-ocp-microamp', clamp the value in min/max range, and roundup to get the best selector. --- drivers/video/backlight/rt4831-backlight.c | 33 +++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) diff --git a/drivers/video/backlight/rt4831-backlight.c b/drivers/video/backlight/rt4831-backlight.c index 42155c7..8c2001b 100644 --- a/drivers/video/backlight/rt4831-backlight.c +++ b/drivers/video/backlight/rt4831-backlight.c @@ -12,6 +12,7 @@ #define RT4831_REG_BLCFG 0x02 #define RT4831_REG_BLDIML 0x04 #define RT4831_REG_ENABLE 0x08 +#define RT4831_REG_BLOPT2 0x11 #define RT4831_BLMAX_BRIGHTNESS 2048 @@ -23,6 +24,11 @@ #define RT4831_BLDIML_MASK GENMASK(2, 0) #define RT4831_BLDIMH_MASK GENMASK(10, 3) #define RT4831_BLDIMH_SHIFT 3 +#define RT4831_BLOCP_MASK GENMASK(1, 0) + +#define RT4831_BLOCP_MINUA 900000 +#define RT4831_BLOCP_MAXUA 1800000 +#define RT4831_BLOCP_STEPUA 300000 struct rt4831_priv { struct device *dev; @@ -85,7 +91,7 @@ static int rt4831_parse_backlight_properties(struct rt4831_priv *priv, { struct device *dev = priv->dev; u8 propval; - u32 brightness; + u32 brightness, ocp_uA; unsigned int val = 0; int ret; @@ -120,6 +126,31 @@ static int rt4831_parse_backlight_properties(struct rt4831_priv *priv, if (ret) return ret; + /* + * This OCP level is used to protect and limit the inductor current. + * If inductor peak current reach the level, low-side MOSFET will be + * turned off. Meanwhile, the output channel current may be limited. + * To match the configured channel current, the inductor chosen must + * be higher than the OCP level. + * + * Not like the OVP level, the default 21V can be used in the most + * application. But if the chosen OCP level is smaller than needed, + * it will also affect the backlight channel output current to be + * smaller than the register setting. + */ + ret = device_property_read_u32(dev, "richtek,bled-ocp-microamp", + &ocp_uA); + if (!ret) { + ocp_uA = clamp_val(ocp_uA, RT4831_BLOCP_MINUA, + RT4831_BLOCP_MAXUA); + val = roundup(ocp_uA - RT4831_BLOCP_MINUA, + RT4831_BLOCP_STEPUA); + ret = regmap_update_bits(priv->regmap, RT4831_REG_BLOPT2, + RT4831_BLOCP_MASK, val); + if (ret) + return ret; + } + ret = device_property_read_u8(dev, "richtek,channel-use", &propval); if (ret) { dev_err(dev, "richtek,channel-use DT property missing\n"); -- 2.7.4
next prev parent reply other threads:[~2022-06-09 2:22 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-06-09 2:22 [PATCH v3 0/2] Add the property to make backlight OCP level selectable cy_huang 2022-06-09 2:22 ` cy_huang 2022-06-09 2:22 ` [PATCH v3 1/2] dt-bindings: backlight: rt4831: Add the new ocp level property cy_huang 2022-06-09 2:22 ` cy_huang 2022-06-09 9:26 ` Daniel Thompson 2022-06-09 9:26 ` Daniel Thompson 2022-06-09 10:31 ` Krzysztof Kozlowski 2022-06-09 10:31 ` Krzysztof Kozlowski 2022-06-09 2:22 ` cy_huang [this message] 2022-06-09 2:22 ` [PATCH v3 2/2] backlight: rt4831: Apply ocp level from devicetree cy_huang
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