* [PATCH] pinctrl: meson: fix G12A ao pull registers base address @ 2018-12-03 3:05 Xingyu Chen 2018-12-03 10:27 ` Neil Armstrong 0 siblings, 1 reply; 5+ messages in thread From: Xingyu Chen @ 2018-12-03 3:05 UTC (permalink / raw) To: linus.walleij, linux-gpio Cc: narmstrong, jbrunet, khilman, carlo, martin.blumenstingl, robh, xingyu.chen, jianxin.pan, linux-amlogic, linux-arm-kernel, linux-kernel Since Meson G12A SoC, Introduce new ao registers AO_RTI_PULL_UP_EN_REG and AO_GPIO_O. These bits of controlling output level are remapped to the new register AO_GPIO_O, and the AO_GPIO_O_EN_N support only controlling output enable. These bits of controlling pull enable are remapped to the new register AO_RTI_PULL_UP_EN_REG, and the AO_RTI_PULL_UP_REG support only controlling pull type(up/down). The new layout of ao gpio/pull registers is as follows: - AO_GPIO_O_EN_N [offset: 0x9 << 2] - AO_GPIO_I [offset: 0xa << 2] - AO_RTI_PULL_UP_REG [offset: 0xb << 2] - AO_RTI_PULL_UP_EN_REG [offset: 0xc << 2] - AO_GPIO_O [offset: 0xd << 2] >From above, we can see ao GPIO registers region has been separated by the ao pull registers. In order to ensure the continuity of the region on software, the ao GPIO and ao pull registers use the same base address, but can be identified by the offset. Fixes: 29ae0952e85f ("pinctrl: meson-g12a: add pinctrl driver support") Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com> Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com> --- drivers/pinctrl/meson/pinctrl-meson.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c index 53d449076dee..7ff40cd7a0cb 100644 --- a/drivers/pinctrl/meson/pinctrl-meson.c +++ b/drivers/pinctrl/meson/pinctrl-meson.c @@ -31,6 +31,9 @@ * In some cases the register ranges for pull enable and pull * direction are the same and thus there are only 3 register ranges. * + * Since Meson G12A SoC, the ao register ranges for gpio, pull enable + * and pull direction are the same, so there are only 2 register ranges. + * * For the pull and GPIO configuration every bank uses a contiguous * set of bits in the register sets described above; the same register * can be shared by more banks with different offsets. @@ -487,23 +490,22 @@ static int meson_pinctrl_parse_dt(struct meson_pinctrl *pc, return PTR_ERR(pc->reg_mux); } - pc->reg_pull = meson_map_resource(pc, gpio_np, "pull"); - if (IS_ERR(pc->reg_pull)) { - dev_err(pc->dev, "pull registers not found\n"); - return PTR_ERR(pc->reg_pull); + pc->reg_gpio = meson_map_resource(pc, gpio_np, "gpio"); + if (IS_ERR(pc->reg_gpio)) { + dev_err(pc->dev, "gpio registers not found\n"); + return PTR_ERR(pc->reg_gpio); } + pc->reg_pull = meson_map_resource(pc, gpio_np, "pull"); + /* Use gpio region if pull one is not present */ + if (IS_ERR(pc->reg_pull)) + pc->reg_pull = pc->reg_gpio; + pc->reg_pullen = meson_map_resource(pc, gpio_np, "pull-enable"); /* Use pull region if pull-enable one is not present */ if (IS_ERR(pc->reg_pullen)) pc->reg_pullen = pc->reg_pull; - pc->reg_gpio = meson_map_resource(pc, gpio_np, "gpio"); - if (IS_ERR(pc->reg_gpio)) { - dev_err(pc->dev, "gpio registers not found\n"); - return PTR_ERR(pc->reg_gpio); - } - return 0; } -- 2.19.2 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] pinctrl: meson: fix G12A ao pull registers base address 2018-12-03 3:05 [PATCH] pinctrl: meson: fix G12A ao pull registers base address Xingyu Chen @ 2018-12-03 10:27 ` Neil Armstrong 2018-12-03 10:36 ` Jerome Brunet 2018-12-04 2:05 ` Xingyu Chen 0 siblings, 2 replies; 5+ messages in thread From: Neil Armstrong @ 2018-12-03 10:27 UTC (permalink / raw) To: Xingyu Chen, linus.walleij, linux-gpio Cc: jbrunet, khilman, carlo, martin.blumenstingl, robh, jianxin.pan, linux-amlogic, linux-arm-kernel, linux-kernel Hi Xingyu, On 03/12/2018 04:05, Xingyu Chen wrote: > Since Meson G12A SoC, Introduce new ao registers AO_RTI_PULL_UP_EN_REG > and AO_GPIO_O. > > These bits of controlling output level are remapped to the new register > AO_GPIO_O, and the AO_GPIO_O_EN_N support only controlling output enable. > > These bits of controlling pull enable are remapped to the new register > AO_RTI_PULL_UP_EN_REG, and the AO_RTI_PULL_UP_REG support only controlling > pull type(up/down). > > The new layout of ao gpio/pull registers is as follows: > - AO_GPIO_O_EN_N [offset: 0x9 << 2] > - AO_GPIO_I [offset: 0xa << 2] > - AO_RTI_PULL_UP_REG [offset: 0xb << 2] > - AO_RTI_PULL_UP_EN_REG [offset: 0xc << 2] > - AO_GPIO_O [offset: 0xd << 2] > > From above, we can see ao GPIO registers region has been separated by the > ao pull registers. In order to ensure the continuity of the region on > software, the ao GPIO and ao pull registers use the same base address, but > can be identified by the offset. > > Fixes: 29ae0952e85f ("pinctrl: meson-g12a: add pinctrl driver support") > Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com> > Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com> > --- > drivers/pinctrl/meson/pinctrl-meson.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c > index 53d449076dee..7ff40cd7a0cb 100644 > --- a/drivers/pinctrl/meson/pinctrl-meson.c > +++ b/drivers/pinctrl/meson/pinctrl-meson.c > @@ -31,6 +31,9 @@ > * In some cases the register ranges for pull enable and pull > * direction are the same and thus there are only 3 register ranges. > * > + * Since Meson G12A SoC, the ao register ranges for gpio, pull enable > + * and pull direction are the same, so there are only 2 register ranges. > + * > * For the pull and GPIO configuration every bank uses a contiguous > * set of bits in the register sets described above; the same register > * can be shared by more banks with different offsets. > @@ -487,23 +490,22 @@ static int meson_pinctrl_parse_dt(struct meson_pinctrl *pc, > return PTR_ERR(pc->reg_mux); > } > > - pc->reg_pull = meson_map_resource(pc, gpio_np, "pull"); > - if (IS_ERR(pc->reg_pull)) { > - dev_err(pc->dev, "pull registers not found\n"); > - return PTR_ERR(pc->reg_pull); > + pc->reg_gpio = meson_map_resource(pc, gpio_np, "gpio"); > + if (IS_ERR(pc->reg_gpio)) { > + dev_err(pc->dev, "gpio registers not found\n"); > + return PTR_ERR(pc->reg_gpio); > } > > + pc->reg_pull = meson_map_resource(pc, gpio_np, "pull"); > + /* Use gpio region if pull one is not present */ > + if (IS_ERR(pc->reg_pull)) > + pc->reg_pull = pc->reg_gpio; > + > pc->reg_pullen = meson_map_resource(pc, gpio_np, "pull-enable"); > /* Use pull region if pull-enable one is not present */ > if (IS_ERR(pc->reg_pullen)) > pc->reg_pullen = pc->reg_pull; > > - pc->reg_gpio = meson_map_resource(pc, gpio_np, "gpio"); > - if (IS_ERR(pc->reg_gpio)) { > - dev_err(pc->dev, "gpio registers not found\n"); > - return PTR_ERR(pc->reg_gpio); > - } > - > return 0; > } > > Doesn't it need an update of the bindings ? Neil ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] pinctrl: meson: fix G12A ao pull registers base address 2018-12-03 10:27 ` Neil Armstrong @ 2018-12-03 10:36 ` Jerome Brunet 2018-12-04 2:10 ` Xingyu Chen 2018-12-04 2:05 ` Xingyu Chen 1 sibling, 1 reply; 5+ messages in thread From: Jerome Brunet @ 2018-12-03 10:36 UTC (permalink / raw) To: Neil Armstrong, Xingyu Chen, linus.walleij, linux-gpio Cc: khilman, carlo, martin.blumenstingl, robh, jianxin.pan, linux-amlogic, linux-arm-kernel, linux-kernel On Mon, 2018-12-03 at 11:27 +0100, Neil Armstrong wrote: > Hi Xingyu, > > > On 03/12/2018 04:05, Xingyu Chen wrote: > > Since Meson G12A SoC, Introduce new ao registers AO_RTI_PULL_UP_EN_REG > > and AO_GPIO_O. > > > > These bits of controlling output level are remapped to the new register > > AO_GPIO_O, and the AO_GPIO_O_EN_N support only controlling output enable. > > > > These bits of controlling pull enable are remapped to the new register > > AO_RTI_PULL_UP_EN_REG, and the AO_RTI_PULL_UP_REG support only controlling > > pull type(up/down). > > > > The new layout of ao gpio/pull registers is as follows: > > - AO_GPIO_O_EN_N [offset: 0x9 << 2] > > - AO_GPIO_I [offset: 0xa << 2] > > - AO_RTI_PULL_UP_REG [offset: 0xb << 2] > > - AO_RTI_PULL_UP_EN_REG [offset: 0xc << 2] > > - AO_GPIO_O [offset: 0xd << 2] > > > > From above, we can see ao GPIO registers region has been separated by the > > ao pull registers. In order to ensure the continuity of the region on > > software, the ao GPIO and ao pull registers use the same base address, but > > can be identified by the offset. > > > > Fixes: 29ae0952e85f ("pinctrl: meson-g12a: add pinctrl driver support") > > Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com> > > Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com> > > --- > > drivers/pinctrl/meson/pinctrl-meson.c | 22 ++++++++++++---------- > > 1 file changed, 12 insertions(+), 10 deletions(-) > > > > diff --git a/drivers/pinctrl/meson/pinctrl-meson.c > > b/drivers/pinctrl/meson/pinctrl-meson.c > > index 53d449076dee..7ff40cd7a0cb 100644 > > --- a/drivers/pinctrl/meson/pinctrl-meson.c > > +++ b/drivers/pinctrl/meson/pinctrl-meson.c > > @@ -31,6 +31,9 @@ > > * In some cases the register ranges for pull enable and pull > > * direction are the same and thus there are only 3 register ranges. > > * > > + * Since Meson G12A SoC, the ao register ranges for gpio, pull enable > > + * and pull direction are the same, so there are only 2 register ranges. > > + * > > * For the pull and GPIO configuration every bank uses a contiguous > > * set of bits in the register sets described above; the same register > > * can be shared by more banks with different offsets. > > @@ -487,23 +490,22 @@ static int meson_pinctrl_parse_dt(struct > > meson_pinctrl *pc, > > return PTR_ERR(pc->reg_mux); > > } > > > > - pc->reg_pull = meson_map_resource(pc, gpio_np, "pull"); > > - if (IS_ERR(pc->reg_pull)) { > > - dev_err(pc->dev, "pull registers not found\n"); > > - return PTR_ERR(pc->reg_pull); > > + pc->reg_gpio = meson_map_resource(pc, gpio_np, "gpio"); > > + if (IS_ERR(pc->reg_gpio)) { > > + dev_err(pc->dev, "gpio registers not found\n"); > > + return PTR_ERR(pc->reg_gpio); > > } > > > > + pc->reg_pull = meson_map_resource(pc, gpio_np, "pull"); > > + /* Use gpio region if pull one is not present */ > > + if (IS_ERR(pc->reg_pull)) > > + pc->reg_pull = pc->reg_gpio; > > + > > pc->reg_pullen = meson_map_resource(pc, gpio_np, "pull-enable"); > > /* Use pull region if pull-enable one is not present */ > > if (IS_ERR(pc->reg_pullen)) > > pc->reg_pullen = pc->reg_pull; > > > > - pc->reg_gpio = meson_map_resource(pc, gpio_np, "gpio"); > > - if (IS_ERR(pc->reg_gpio)) { > > - dev_err(pc->dev, "gpio registers not found\n"); > > - return PTR_ERR(pc->reg_gpio); > > - } > > - > > return 0; > > } > > > > > Doesn't it need an update of the bindings ? Going even further, shouldn't we stop trying make multiple regions out of this, and have just one ? On all the Amlogic SoC we have seen so far, all the regions a very (VERY) close to each other. It seems very unlikely that there something unrelated to GPIO in between. It looks like everything is mostly there in the driver to deal with offset, so change would be minimal. Of course, for DT stability we will need to carry the legacy, but for newer SoC, such as the g12, does it really makes sense to have multiple regions ? > > Neil > ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] pinctrl: meson: fix G12A ao pull registers base address 2018-12-03 10:36 ` Jerome Brunet @ 2018-12-04 2:10 ` Xingyu Chen 0 siblings, 0 replies; 5+ messages in thread From: Xingyu Chen @ 2018-12-04 2:10 UTC (permalink / raw) To: Jerome Brunet, Neil Armstrong, linus.walleij, linux-gpio Cc: khilman, carlo, martin.blumenstingl, robh, jianxin.pan, linux-amlogic, linux-arm-kernel, linux-kernel, Xingyu Chen On 2018/12/3 18:36, Jerome Brunet wrote: > On Mon, 2018-12-03 at 11:27 +0100, Neil Armstrong wrote: >> Hi Xingyu, >> >> >> On 03/12/2018 04:05, Xingyu Chen wrote: >>> Since Meson G12A SoC, Introduce new ao registers AO_RTI_PULL_UP_EN_REG >>> and AO_GPIO_O. >>> >>> These bits of controlling output level are remapped to the new register >>> AO_GPIO_O, and the AO_GPIO_O_EN_N support only controlling output enable. >>> >>> These bits of controlling pull enable are remapped to the new register >>> AO_RTI_PULL_UP_EN_REG, and the AO_RTI_PULL_UP_REG support only controlling >>> pull type(up/down). >>> >>> The new layout of ao gpio/pull registers is as follows: >>> - AO_GPIO_O_EN_N [offset: 0x9 << 2] >>> - AO_GPIO_I [offset: 0xa << 2] >>> - AO_RTI_PULL_UP_REG [offset: 0xb << 2] >>> - AO_RTI_PULL_UP_EN_REG [offset: 0xc << 2] >>> - AO_GPIO_O [offset: 0xd << 2] >>> >>> From above, we can see ao GPIO registers region has been separated by the >>> ao pull registers. In order to ensure the continuity of the region on >>> software, the ao GPIO and ao pull registers use the same base address, but >>> can be identified by the offset. >>> >>> Fixes: 29ae0952e85f ("pinctrl: meson-g12a: add pinctrl driver support") >>> Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com> >>> Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com> >>> --- >>> drivers/pinctrl/meson/pinctrl-meson.c | 22 ++++++++++++---------- >>> 1 file changed, 12 insertions(+), 10 deletions(-) >>> >>> diff --git a/drivers/pinctrl/meson/pinctrl-meson.c >>> b/drivers/pinctrl/meson/pinctrl-meson.c >>> index 53d449076dee..7ff40cd7a0cb 100644 >>> --- a/drivers/pinctrl/meson/pinctrl-meson.c >>> +++ b/drivers/pinctrl/meson/pinctrl-meson.c >>> @@ -31,6 +31,9 @@ >>> * In some cases the register ranges for pull enable and pull >>> * direction are the same and thus there are only 3 register ranges. >>> * >>> + * Since Meson G12A SoC, the ao register ranges for gpio, pull enable >>> + * and pull direction are the same, so there are only 2 register ranges. >>> + * >>> * For the pull and GPIO configuration every bank uses a contiguous >>> * set of bits in the register sets described above; the same register >>> * can be shared by more banks with different offsets. >>> @@ -487,23 +490,22 @@ static int meson_pinctrl_parse_dt(struct >>> meson_pinctrl *pc, >>> return PTR_ERR(pc->reg_mux); >>> } >>> >>> - pc->reg_pull = meson_map_resource(pc, gpio_np, "pull"); >>> - if (IS_ERR(pc->reg_pull)) { >>> - dev_err(pc->dev, "pull registers not found\n"); >>> - return PTR_ERR(pc->reg_pull); >>> + pc->reg_gpio = meson_map_resource(pc, gpio_np, "gpio"); >>> + if (IS_ERR(pc->reg_gpio)) { >>> + dev_err(pc->dev, "gpio registers not found\n"); >>> + return PTR_ERR(pc->reg_gpio); >>> } >>> >>> + pc->reg_pull = meson_map_resource(pc, gpio_np, "pull"); >>> + /* Use gpio region if pull one is not present */ >>> + if (IS_ERR(pc->reg_pull)) >>> + pc->reg_pull = pc->reg_gpio; >>> + >>> pc->reg_pullen = meson_map_resource(pc, gpio_np, "pull-enable"); >>> /* Use pull region if pull-enable one is not present */ >>> if (IS_ERR(pc->reg_pullen)) >>> pc->reg_pullen = pc->reg_pull; >>> >>> - pc->reg_gpio = meson_map_resource(pc, gpio_np, "gpio"); >>> - if (IS_ERR(pc->reg_gpio)) { >>> - dev_err(pc->dev, "gpio registers not found\n"); >>> - return PTR_ERR(pc->reg_gpio); >>> - } >>> - >>> return 0; >>> } >>> >>> >> Doesn't it need an update of the bindings ? > > Going even further, shouldn't we stop trying make multiple regions out of > this, and have just one ? > > On all the Amlogic SoC we have seen so far, all the regions a very (VERY) > close to each other. It seems very unlikely that there something unrelated to > GPIO in between. > > It looks like everything is mostly there in the driver to deal with offset, so > change would be minimal. > > Of course, for DT stability we will need to carry the legacy, but for newer > SoC, such as the g12, does it really makes sense to have multiple regions ? > Hi, Jerome the ee gpio, pull and pull-en register regions are discontinuous, some addresses are reserved between them and maybe used for other module. For example [G12A]: range of gpio register address offset: (0x010 << 2) - (0x022 << 2) range of pull register address offset: (0x03a << 2) - (0x03f << 2) range of pull-en register address offset: (0x048 << 2) - (0x04d << 2) keeping the multiple register regions seems to be more flexible and friendly for Meson Series SoCs at present. >> >> Neil >> > > > . > ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] pinctrl: meson: fix G12A ao pull registers base address 2018-12-03 10:27 ` Neil Armstrong 2018-12-03 10:36 ` Jerome Brunet @ 2018-12-04 2:05 ` Xingyu Chen 1 sibling, 0 replies; 5+ messages in thread From: Xingyu Chen @ 2018-12-04 2:05 UTC (permalink / raw) To: Neil Armstrong, linus.walleij, linux-gpio Cc: jbrunet, khilman, carlo, martin.blumenstingl, robh, jianxin.pan, linux-amlogic, linux-arm-kernel, linux-kernel On 2018/12/3 18:27, Neil Armstrong wrote: > Hi Xingyu, > > > On 03/12/2018 04:05, Xingyu Chen wrote: >> Since Meson G12A SoC, Introduce new ao registers AO_RTI_PULL_UP_EN_REG >> and AO_GPIO_O. >> >> These bits of controlling output level are remapped to the new register >> AO_GPIO_O, and the AO_GPIO_O_EN_N support only controlling output enable. >> >> These bits of controlling pull enable are remapped to the new register >> AO_RTI_PULL_UP_EN_REG, and the AO_RTI_PULL_UP_REG support only controlling >> pull type(up/down). >> >> The new layout of ao gpio/pull registers is as follows: >> - AO_GPIO_O_EN_N [offset: 0x9 << 2] >> - AO_GPIO_I [offset: 0xa << 2] >> - AO_RTI_PULL_UP_REG [offset: 0xb << 2] >> - AO_RTI_PULL_UP_EN_REG [offset: 0xc << 2] >> - AO_GPIO_O [offset: 0xd << 2] >> >> From above, we can see ao GPIO registers region has been separated by the >> ao pull registers. In order to ensure the continuity of the region on >> software, the ao GPIO and ao pull registers use the same base address, but >> can be identified by the offset. >> >> Fixes: 29ae0952e85f ("pinctrl: meson-g12a: add pinctrl driver support") >> Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com> >> Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com> >> --- >> drivers/pinctrl/meson/pinctrl-meson.c | 22 ++++++++++++---------- >> 1 file changed, 12 insertions(+), 10 deletions(-) >> >> diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c >> index 53d449076dee..7ff40cd7a0cb 100644 >> --- a/drivers/pinctrl/meson/pinctrl-meson.c >> +++ b/drivers/pinctrl/meson/pinctrl-meson.c >> @@ -31,6 +31,9 @@ >> * In some cases the register ranges for pull enable and pull >> * direction are the same and thus there are only 3 register ranges. >> * >> + * Since Meson G12A SoC, the ao register ranges for gpio, pull enable >> + * and pull direction are the same, so there are only 2 register ranges. >> + * >> * For the pull and GPIO configuration every bank uses a contiguous >> * set of bits in the register sets described above; the same register >> * can be shared by more banks with different offsets. >> @@ -487,23 +490,22 @@ static int meson_pinctrl_parse_dt(struct meson_pinctrl *pc, >> return PTR_ERR(pc->reg_mux); >> } >> >> - pc->reg_pull = meson_map_resource(pc, gpio_np, "pull"); >> - if (IS_ERR(pc->reg_pull)) { >> - dev_err(pc->dev, "pull registers not found\n"); >> - return PTR_ERR(pc->reg_pull); >> + pc->reg_gpio = meson_map_resource(pc, gpio_np, "gpio"); >> + if (IS_ERR(pc->reg_gpio)) { >> + dev_err(pc->dev, "gpio registers not found\n"); >> + return PTR_ERR(pc->reg_gpio); >> } >> >> + pc->reg_pull = meson_map_resource(pc, gpio_np, "pull"); >> + /* Use gpio region if pull one is not present */ >> + if (IS_ERR(pc->reg_pull)) >> + pc->reg_pull = pc->reg_gpio; >> + >> pc->reg_pullen = meson_map_resource(pc, gpio_np, "pull-enable"); >> /* Use pull region if pull-enable one is not present */ >> if (IS_ERR(pc->reg_pullen)) >> pc->reg_pullen = pc->reg_pull; >> >> - pc->reg_gpio = meson_map_resource(pc, gpio_np, "gpio"); >> - if (IS_ERR(pc->reg_gpio)) { >> - dev_err(pc->dev, "gpio registers not found\n"); >> - return PTR_ERR(pc->reg_gpio); >> - } >> - >> return 0; >> } >> >> > Doesn't it need an update of the bindings ? > > Neil > Thanks, I will update it in next patch > . > ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2018-12-04 2:10 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2018-12-03 3:05 [PATCH] pinctrl: meson: fix G12A ao pull registers base address Xingyu Chen 2018-12-03 10:27 ` Neil Armstrong 2018-12-03 10:36 ` Jerome Brunet 2018-12-04 2:10 ` Xingyu Chen 2018-12-04 2:05 ` Xingyu Chen
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