[PATCH v3 0/4] Add hstimer support for H616 and T113-S3

[PATCH v3 0/4] Add hstimer support for H616 and T113-S3

[Michal Piekos]

Add support for Allwinner D1 high speed timer in sun5i hstimer driver
and describe corresponding nodes in dts for H616 and T113-S3 SoC's.

D1 and H616 uses same model as existing driver except register shift
compared to older variants. 

Added register layout abstraction in the driver, extended the binding
with new compatibles and wired up dts nodes for T113-S3 and H616 which
uses D1 as fallback compatible.

Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
---
Changes in v3:
- Removed left over dead code from v1
- Link to v2: https://lore.kernel.org/r/20260426-h616-t113s-hstimer-v2-0-e65e9dc0c9da@mmpsystems.pl

Changes in v2:
- Change driver handling of different offsets to using quirks
- Change from t113s to d1 as the fallback compatible string
- Fix conditional compatible matching
- Link to v1: https://lore.kernel.org/r/20260419-h616-t113s-hstimer-v1-0-1af74ebef7c5@mmpsystems.pl

To: Daniel Lezcano <daniel.lezcano@kernel.org>
To: Thomas Gleixner <tglx@kernel.org>
To: Rob Herring <robh@kernel.org>
To: Krzysztof Kozlowski <krzk+dt@kernel.org>
To: Conor Dooley <conor+dt@kernel.org>
To: Chen-Yu Tsai <wens@kernel.org>
To: Jernej Skrabec <jernej.skrabec@gmail.com>
To: Samuel Holland <samuel@sholland.org>
To: Maxime Ripard <mripard@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@lists.linux.dev
Cc: Andre Przywara <andre.przywara@arm.com>

---
Michal Piekos (4):
      dt-bindings: timer: allwinner,sun5i-a13-hstimer: add H616 and D1
      clocksource/drivers/sun5i: add D1 hstimer support
      arm: dts: allwinner: t113s: add hstimer node
      arm64: dts: allwinner: h616: add hstimer node

 .../timer/allwinner,sun5i-a13-hstimer.yaml         |  9 ++-
 arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi       | 11 +++
 arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi     | 10 +++
 drivers/clocksource/timer-sun5i.c                  | 84 +++++++++++++++++-----
 4 files changed, 94 insertions(+), 20 deletions(-)
---
base-commit: dca922e019dd758b4c1b4bec8f1d509efddeaab4
change-id: 20260413-h616-t113s-hstimer-62939948f91c

Best regards,
--  
Michal Piekos <michal.piekos@mmpsystems.pl>

[PATCH v3 1/4] dt-bindings: timer: allwinner,sun5i-a13-hstimer: add H616 and D1

[Michal Piekos]

D1 is similar to existing sun5i, but with different register offsets.
H616 uses same offsets as D1.

Add allwinner,sun20i-d1-hstimer
Add allwinner,sun50i-h616-hstimer with fallback to
allwinner,sun20i-d1-hstimer
Extend schema condition for interrupts to cover D1 compatible variant.

Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
---
 .../devicetree/bindings/timer/allwinner,sun5i-a13-hstimer.yaml   | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/timer/allwinner,sun5i-a13-hstimer.yaml b/Documentation/devicetree/bindings/timer/allwinner,sun5i-a13-hstimer.yaml
index f1853daec2f9..3e2725c56995 100644
--- a/Documentation/devicetree/bindings/timer/allwinner,sun5i-a13-hstimer.yaml
+++ b/Documentation/devicetree/bindings/timer/allwinner,sun5i-a13-hstimer.yaml
@@ -15,9 +15,13 @@ properties:
     oneOf:
       - const: allwinner,sun5i-a13-hstimer
       - const: allwinner,sun7i-a20-hstimer
+      - const: allwinner,sun20i-d1-hstimer
       - items:
           - const: allwinner,sun6i-a31-hstimer
           - const: allwinner,sun7i-a20-hstimer
+      - items:
+          - const: allwinner,sun50i-h616-hstimer
+          - const: allwinner,sun20i-d1-hstimer
 
   reg:
     maxItems: 1
@@ -45,7 +49,10 @@ required:
 if:
   properties:
     compatible:
-      const: allwinner,sun5i-a13-hstimer
+      anyOf:
+        - const: allwinner,sun5i-a13-hstimer
+        - contains:
+            const: allwinner,sun20i-d1-hstimer
 
 then:
   properties:

-- 
2.43.0

[PATCH v3 2/4] clocksource/drivers/sun5i: add D1 hstimer support

[Michal Piekos]

D1 high speed timer differs from existing timer-sun5i by register base
offset.

Add sunxi quirks to handle D1 specific offset.
Add D1 compatible string to OF match table.

Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
---
 drivers/clocksource/timer-sun5i.c | 84 ++++++++++++++++++++++++++++++---------
 1 file changed, 65 insertions(+), 19 deletions(-)

diff --git a/drivers/clocksource/timer-sun5i.c b/drivers/clocksource/timer-sun5i.c
index f827d3f98f60..517c048a4870 100644
--- a/drivers/clocksource/timer-sun5i.c
+++ b/drivers/clocksource/timer-sun5i.c
@@ -18,21 +18,30 @@
 #include <linux/slab.h>
 #include <linux/platform_device.h>
 
-#define TIMER_IRQ_EN_REG		0x00
+#define TIMER_IRQ_EN_REG			0x00
 #define TIMER_IRQ_EN(val)			BIT(val)
-#define TIMER_IRQ_ST_REG		0x04
-#define TIMER_CTL_REG(val)		(0x20 * (val) + 0x10)
+#define TIMER_IRQ_ST_REG			0x04
+#define TIMER_CTL_REG(val, offset)		(0x20 * (val) + 0x10 + (offset))
 #define TIMER_CTL_ENABLE			BIT(0)
 #define TIMER_CTL_RELOAD			BIT(1)
 #define TIMER_CTL_CLK_PRES(val)			(((val) & 0x7) << 4)
 #define TIMER_CTL_ONESHOT			BIT(7)
-#define TIMER_INTVAL_LO_REG(val)	(0x20 * (val) + 0x14)
-#define TIMER_INTVAL_HI_REG(val)	(0x20 * (val) + 0x18)
-#define TIMER_CNTVAL_LO_REG(val)	(0x20 * (val) + 0x1c)
-#define TIMER_CNTVAL_HI_REG(val)	(0x20 * (val) + 0x20)
+#define TIMER_INTVAL_LO_REG(val, offset)	(0x20 * (val) + 0x14 + (offset))
+#define TIMER_INTVAL_HI_REG(val, offset)	(0x20 * (val) + 0x18 + (offset))
+#define TIMER_CNTVAL_LO_REG(val, offset)	(0x20 * (val) + 0x1c + (offset))
+#define TIMER_CNTVAL_HI_REG(val, offset)	(0x20 * (val) + 0x20 + (offset))
 
 #define TIMER_SYNC_TICKS	3
 
+/**
+ * struct sunxi_timer_quirks - Differences between SoC variants.
+ *
+ * @from_ctl_base_offset: offset applied from ctl register onwards
+ */
+struct sunxi_timer_quirks {
+	u32 from_ctl_base_offset;
+};
+
 struct sun5i_timer {
 	void __iomem		*base;
 	struct clk		*clk;
@@ -40,6 +49,7 @@ struct sun5i_timer {
 	u32			ticks_per_jiffy;
 	struct clocksource	clksrc;
 	struct clock_event_device	clkevt;
+	const struct sunxi_timer_quirks *quirks;
 };
 
 #define nb_to_sun5i_timer(x) \
@@ -57,28 +67,36 @@ struct sun5i_timer {
  */
 static void sun5i_clkevt_sync(struct sun5i_timer *ce)
 {
-	u32 old = readl(ce->base + TIMER_CNTVAL_LO_REG(1));
+	u32 offset = ce->quirks->from_ctl_base_offset;
+	u32 old = readl(ce->base + TIMER_CNTVAL_LO_REG(1, offset));
 
-	while ((old - readl(ce->base + TIMER_CNTVAL_LO_REG(1))) < TIMER_SYNC_TICKS)
+	while ((old - readl(ce->base + TIMER_CNTVAL_LO_REG(1, offset))) <
+	       TIMER_SYNC_TICKS)
 		cpu_relax();
 }
 
 static void sun5i_clkevt_time_stop(struct sun5i_timer *ce, u8 timer)
 {
-	u32 val = readl(ce->base + TIMER_CTL_REG(timer));
-	writel(val & ~TIMER_CTL_ENABLE, ce->base + TIMER_CTL_REG(timer));
+	u32 offset = ce->quirks->from_ctl_base_offset;
+	u32 val = readl(ce->base + TIMER_CTL_REG(timer, offset));
+
+	writel(val & ~TIMER_CTL_ENABLE,
+	       ce->base + TIMER_CTL_REG(timer, offset));
 
 	sun5i_clkevt_sync(ce);
 }
 
 static void sun5i_clkevt_time_setup(struct sun5i_timer *ce, u8 timer, u32 delay)
 {
-	writel(delay, ce->base + TIMER_INTVAL_LO_REG(timer));
+	u32 offset = ce->quirks->from_ctl_base_offset;
+
+	writel(delay, ce->base + TIMER_INTVAL_LO_REG(timer, offset));
 }
 
 static void sun5i_clkevt_time_start(struct sun5i_timer *ce, u8 timer, bool periodic)
 {
-	u32 val = readl(ce->base + TIMER_CTL_REG(timer));
+	u32 offset = ce->quirks->from_ctl_base_offset;
+	u32 val = readl(ce->base + TIMER_CTL_REG(timer, offset));
 
 	if (periodic)
 		val &= ~TIMER_CTL_ONESHOT;
@@ -86,7 +104,7 @@ static void sun5i_clkevt_time_start(struct sun5i_timer *ce, u8 timer, bool perio
 		val |= TIMER_CTL_ONESHOT;
 
 	writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
-	       ce->base + TIMER_CTL_REG(timer));
+	       ce->base + TIMER_CTL_REG(timer, offset));
 }
 
 static int sun5i_clkevt_shutdown(struct clock_event_device *clkevt)
@@ -141,8 +159,9 @@ static irqreturn_t sun5i_timer_interrupt(int irq, void *dev_id)
 static u64 sun5i_clksrc_read(struct clocksource *clksrc)
 {
 	struct sun5i_timer *cs = clksrc_to_sun5i_timer(clksrc);
+	u32 offset = cs->quirks->from_ctl_base_offset;
 
-	return ~readl(cs->base + TIMER_CNTVAL_LO_REG(1));
+	return ~readl(cs->base + TIMER_CNTVAL_LO_REG(1, offset));
 }
 
 static int sun5i_rate_cb(struct notifier_block *nb,
@@ -173,12 +192,13 @@ static int sun5i_setup_clocksource(struct platform_device *pdev,
 				   unsigned long rate)
 {
 	struct sun5i_timer *cs = platform_get_drvdata(pdev);
+	u32 offset = cs->quirks->from_ctl_base_offset;
 	void __iomem *base = cs->base;
 	int ret;
 
-	writel(~0, base + TIMER_INTVAL_LO_REG(1));
+	writel(~0, base + TIMER_INTVAL_LO_REG(1, offset));
 	writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
-	       base + TIMER_CTL_REG(1));
+	       base + TIMER_CTL_REG(1, offset));
 
 	cs->clksrc.name = pdev->dev.of_node->name;
 	cs->clksrc.rating = 340;
@@ -237,6 +257,7 @@ static int sun5i_setup_clockevent(struct platform_device *pdev,
 
 static int sun5i_timer_probe(struct platform_device *pdev)
 {
+	const struct sunxi_timer_quirks *quirks;
 	struct device *dev = &pdev->dev;
 	struct sun5i_timer *st;
 	struct reset_control *rstc;
@@ -273,11 +294,18 @@ static int sun5i_timer_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	quirks = of_device_get_match_data(&pdev->dev);
+	if (!quirks) {
+		dev_err(&pdev->dev, "Failed to determine the quirks to use\n");
+		return -ENODEV;
+	}
+
 	st->base = timer_base;
 	st->ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
 	st->clk = clk;
 	st->clk_rate_cb.notifier_call = sun5i_rate_cb;
 	st->clk_rate_cb.next = NULL;
+	st->quirks = quirks;
 
 	ret = devm_clk_notifier_register(dev, clk, &st->clk_rate_cb);
 	if (ret) {
@@ -311,9 +339,27 @@ static void sun5i_timer_remove(struct platform_device *pdev)
 	clocksource_unregister(&st->clksrc);
 }
 
+static const struct sunxi_timer_quirks sun5i_sun7i_hstimer_quirks = {
+	.from_ctl_base_offset = 0x0,
+};
+
+static const struct sunxi_timer_quirks sun20i_d1_hstimer_quirks = {
+	.from_ctl_base_offset = 0x10,
+};
+
 static const struct of_device_id sun5i_timer_of_match[] = {
-	{ .compatible = "allwinner,sun5i-a13-hstimer" },
-	{ .compatible = "allwinner,sun7i-a20-hstimer" },
+	{
+		.compatible = "allwinner,sun5i-a13-hstimer",
+		.data = &sun5i_sun7i_hstimer_quirks,
+	},
+	{
+		.compatible = "allwinner,sun7i-a20-hstimer",
+		.data = &sun5i_sun7i_hstimer_quirks,
+	},
+	{
+		.compatible = "allwinner,sun20i-d1-hstimer",
+		.data = &sun20i_d1_hstimer_quirks,
+	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, sun5i_timer_of_match);

-- 
2.43.0

Re: [PATCH v3 2/4] clocksource/drivers/sun5i: add D1 hstimer support

[Chen-Yu Tsai]

On Wed, Apr 29, 2026 at 12:29 AM Michal Piekos
<michal.piekos@mmpsystems.pl> wrote:
>
> D1 high speed timer differs from existing timer-sun5i by register base
> offset.
>
> Add sunxi quirks to handle D1 specific offset.
> Add D1 compatible string to OF match table.
>
> Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>

Reviewed-by: Chen-Yu Tsai <wens@kernel.org>

[PATCH v3 3/4] arm: dts: allwinner: t113s: add hstimer node

[Michal Piekos]

Describe high speed timer block on Allwinner T113-S3.

Tested on LCPI-PC-T113/F113:
- hstimer is registered as clocksource
- switching clocksource at runtime works
- after rating increase hstimer operates as a broadcast clockevent device

Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
---
 arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi b/arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi
index 424f4a2487e2..40e76cfc8a1d 100644
--- a/arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi
+++ b/arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi
@@ -34,6 +34,17 @@ cpu1: cpu@1 {
 		};
 	};
 
+	soc {
+		hstimer@3008000 {
+			compatible = "allwinner,sun20i-d1-hstimer";
+			reg = <0x03008000 0x1000>;
+			interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 56 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&ccu CLK_BUS_HSTIMER>;
+			resets = <&ccu RST_BUS_HSTIMER>;
+		};
+	};
+
 	gic: interrupt-controller@1c81000 {
 		compatible = "arm,gic-400";
 		reg = <0x03021000 0x1000>,

-- 
2.43.0

Re: [PATCH v3 3/4] arm: dts: allwinner: t113s: add hstimer node

[Chen-Yu Tsai]

On Wed, Apr 29, 2026 at 12:29 AM Michal Piekos
<michal.piekos@mmpsystems.pl> wrote:
>
> Describe high speed timer block on Allwinner T113-S3.
>
> Tested on LCPI-PC-T113/F113:
> - hstimer is registered as clocksource
> - switching clocksource at runtime works
> - after rating increase hstimer operates as a broadcast clockevent device
>
> Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>

Reviewed-by: Chen-Yu Tsai <wens@kernel.org>

Re: [PATCH v3 3/4] arm: dts: allwinner: t113s: add hstimer node

[Chen-Yu Tsai]

On Wed, Apr 29, 2026 at 12:29 AM Michal Piekos
<michal.piekos@mmpsystems.pl> wrote:
>
> Describe high speed timer block on Allwinner T113-S3.
>
> Tested on LCPI-PC-T113/F113:
> - hstimer is registered as clocksource
> - switching clocksource at runtime works
> - after rating increase hstimer operates as a broadcast clockevent device
>
> Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
> ---
>  arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi b/arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi
> index 424f4a2487e2..40e76cfc8a1d 100644
> --- a/arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi
> +++ b/arch/arm/boot/dts/allwinner/sun8i-t113s.dtsi
> @@ -34,6 +34,17 @@ cpu1: cpu@1 {
>                 };
>         };
>
> +       soc {
> +               hstimer@3008000 {
> +                       compatible = "allwinner,sun20i-d1-hstimer";
> +                       reg = <0x03008000 0x1000>;
> +                       interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>,
> +                                    <GIC_SPI 56 IRQ_TYPE_LEVEL_HIGH>;
> +                       clocks = <&ccu CLK_BUS_HSTIMER>;
> +                       resets = <&ccu RST_BUS_HSTIMER>;
> +               };
> +       };
> +

Actually this could probably be added to the common risc-v dtsi file instead:

    arch/riscv/boot/dts/allwinner/sunxi-d1s-t113.dtsi

That way both the D1 and T113 / T113s benefit.

ChenYu

>         gic: interrupt-controller@1c81000 {
>                 compatible = "arm,gic-400";
>                 reg = <0x03021000 0x1000>,
>
> --
> 2.43.0
>
>

[PATCH v3 4/4] arm64: dts: allwinner: h616: add hstimer node

[Michal Piekos]

Describe high speed timer block on Allwinner H616.

Tested on Orange Pi Zero 3:
- hstimer is registered as clocksource
- switching clocksource at runtime works
- after rating increase hstimer operates as a broadcast clockevent device

Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
---
 arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi
index bf054869e78b..1356e5df2562 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi
@@ -237,6 +237,16 @@ timer0: timer@3009000 {
 			clocks = <&osc24M>;
 		};
 
+		hstimer@3005000 {
+			compatible = "allwinner,sun50i-h616-hstimer",
+				     "allwinner,sun20i-d1-hstimer";
+			reg = <0x03005000 0x1000>;
+			interrupts = <GIC_SPI 45 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 46 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&ccu CLK_BUS_HSTIMER>;
+			resets = <&ccu RST_BUS_HSTIMER>;
+		};
+
 		watchdog: watchdog@30090a0 {
 			compatible = "allwinner,sun50i-h616-wdt",
 				     "allwinner,sun6i-a31-wdt";

-- 
2.43.0

Re: [PATCH v3 4/4] arm64: dts: allwinner: h616: add hstimer node

[Chen-Yu Tsai]

On Wed, Apr 29, 2026 at 12:29 AM Michal Piekos
<michal.piekos@mmpsystems.pl> wrote:
>
> Describe high speed timer block on Allwinner H616.
>
> Tested on Orange Pi Zero 3:
> - hstimer is registered as clocksource
> - switching clocksource at runtime works
> - after rating increase hstimer operates as a broadcast clockevent device
>
> Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>

Reviewed-by: Chen-Yu Tsai <wens@kernel.org>

Re: [PATCH v3 0/4] Add hstimer support for H616 and T113-S3

[Daniel Lezcano]

On 4/28/26 18:26, Michal Piekos wrote:
> Add support for Allwinner D1 high speed timer in sun5i hstimer driver
> and describe corresponding nodes in dts for H616 and T113-S3 SoC's.
> 
> D1 and H616 uses same model as existing driver except register shift
> compared to older variants.
> 
> Added register layout abstraction in the driver, extended the binding
> with new compatibles and wired up dts nodes for T113-S3 and H616 which
> uses D1 as fallback compatible.
> 
> Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
> ---

Applied patches 1 and 2

Thanks

Re: [PATCH v3 0/4] Add hstimer support for H616 and T113-S3

[Michal Piekos]

On Wed, May 06, 2026 at 01:28:22PM +0200, Daniel Lezcano wrote:
> On 4/28/26 18:26, Michal Piekos wrote:
> > Add support for Allwinner D1 high speed timer in sun5i hstimer driver
> > and describe corresponding nodes in dts for H616 and T113-S3 SoC's.
> > 
> > D1 and H616 uses same model as existing driver except register shift
> > compared to older variants.
> > 
> > Added register layout abstraction in the driver, extended the binding
> > with new compatibles and wired up dts nodes for T113-S3 and H616 which
> > uses D1 as fallback compatible.
> > 
> > Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
> > ---
> 
> Applied patches 1 and 2
> 
> Thanks

Thank you.
I will spin shortly next version with suggested correction for patch 3.

Re: [PATCH v3 0/4] Add hstimer support for H616 and T113-S3

[Daniel Lezcano]

On 5/6/26 16:41, Michal Piekos wrote:
> On Wed, May 06, 2026 at 01:28:22PM +0200, Daniel Lezcano wrote:
>> On 4/28/26 18:26, Michal Piekos wrote:
>>> Add support for Allwinner D1 high speed timer in sun5i hstimer driver
>>> and describe corresponding nodes in dts for H616 and T113-S3 SoC's.
>>>
>>> D1 and H616 uses same model as existing driver except register shift
>>> compared to older variants.
>>>
>>> Added register layout abstraction in the driver, extended the binding
>>> with new compatibles and wired up dts nodes for T113-S3 and H616 which
>>> uses D1 as fallback compatible.
>>>
>>> Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
>>> ---
>>
>> Applied patches 1 and 2
>>
>> Thanks
> 
> Thank you.
> I will spin shortly next version with suggested correction for patch 3.

So patch 1 and 2 are unchanged in v4 ? (missing reviewed-by: Chen-Yu BTW)