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charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org cy_huang(=E9=BB=83=E5=95=9F=E5=8E=9F) =E6=96=BC 2021= =E5=B9=B46=E6=9C=884=E6=97=A5 =E9=80=B1=E4=BA=94 =E4=B8=8B=E5=8D=882:29=E5= =AF=AB=E9=81=93=EF=BC=9A > > > =E6=96=BC =E4=BA=94=EF=BC=8C2021-06-04 =E6=96=BC 13:59 +0800=EF=BC=8CAxel= Lin =E6=8F=90=E5=88=B0=EF=BC=9A > > cy_huang(=E9=BB=83=E5=95=9F=E5=8E=9F) =E6=96=BC 20= 21=E5=B9=B46=E6=9C=884=E6=97=A5 =E9=80=B1=E4=BA=94 =E4=B8=8B=E5=8D=881:48= =E5=AF=AB=E9=81=93=EF=BC=9A > > > > > =E6=96=BC =E4=BA=94=EF=BC=8C2021-06-04 =E6=96=BC 11:30 +0800=EF=BC=8CAxel= Lin =E6=8F=90=E5=88=B0=EF=BC=9A > > cy_huang(=E9=BB=83=E5=95=9F=E5=8E=9F) =E6=96=BC 20= 21=E5=B9=B46=E6=9C=884=E6=97=A5 =E9=80=B1=E4=BA=94 =E4=B8=8A=E5=8D=8810:26= =E5=AF=AB=E9=81=93=EF=BC=9A > > > > > cy_huang(=E9=BB=83=E5=95=9F=E5=8E=9F) =E6=96=BC 20= 21=E5=B9=B46=E6=9C=883=E6=97=A5 =E9=80=B1=E5=9B=9B =E4=B8=8B=E5=8D=8811:18= =E5=AF=AB=E9=81=93=EF=BC=9A > > > Hi,> > > > > cy_huang(=E9=BB=83=E5=95=9F=E5=8E=9F) =E6=96=BC 20= 21=E5=B9=B46=E6=9C=883=E6=97=A5 =E9=80=B1=E5=9B=9B =E4=B8=8B=E5=8D=886:20= =E5=AF=AB=E9=81=93=EF=BC=9A > > > > > Hi, Axel:> Use regulator_set_ramp_delay_regmap instead of open-coded. > > > > > > There's some reason. > You can refer to https://lkml.org/lkml/2021/6/1/1145. > > It's because our ramp value order is from small to large, not large to > small. > It conflicts with find_closest_bigger value chosen logic. > > I have verified the rt6160_set_ramp_delay() behavior exactly the same as > regulator_set_ramp_delay_regmap. (both functions get the same selector > for a given delay) > > Could you check if this patch works? > > Sure. > > After my test sample code, below's the result. > ascending [1000 2500 5000 10000] > target =3D 1000 =3D>sel =3D 0 > target =3D 2500 =3D>sel =3D 1 > target =3D 5000 =3D>sel =3D 2 > target =3D 10000 =3D>sel =3D 3 > target =3D 1700 =3D>sel =3D 1 > target =3D 2750 =3D>sel =3D 2 > target =3D 7500 =3D>sel =3D 3 > target =3D 15000 =3D>failed to find best select, sel =3D 3 > target =3D 0 =3D>sel =3D 0 > descending [10000 5000 2500 1000] > target =3D 1000 =3D>sel =3D 3 > target =3D 2500 =3D>sel =3D 2 > target =3D 5000 =3D>sel =3D 1 > target =3D 10000 =3D>sel =3D 0 > target =3D 1700 =3D>sel =3D 2 > target =3D 2750 =3D>sel =3D 1 > target =3D 7500 =3D>sel =3D 0 > target =3D 15000 =3D>failed to find best select, sel =3D 0 > target =3D 0 =3D>sel =3D 3 > > > It means when target is in range or even over, the result are all correct= . > But like as the ramp target is equal to 0, the selection will only choose= the minimum one. > When the ramp target is equal to 0, it means the user want to disable the= rammpping function. > > As I know, if target is equal to 0, it must find the fastest rampping val= ue as the best selection. > > > If your table is [1000 2500 5000 10000], find_closest_bigger() will > choose sel=3D0 when ramp_delay=3D0. > If your table is [10000 5000 2500 1000], find_closest_bigger() will > choose sel=3D3 when ramp_delay=3D0. > i.e. In both cases, find_closest_bigger() chooses the fastest ramping val= ue. > > This meets your exception. > > Actually, even if your table is [10000, 1000, 5000, 2500], > find_closest_bigger() still can choose the correct selector. > i.e. sel=3D1 when ramp_delay=3D0 in this case. > > This selection may be wrong. > ramp_delay=3D0 means ramp disabled, > If chip not support rampping disable, this selection must be configured a= s fastest rampping value, not the minimum one. > > > 0 does not mean ramp disable. > It could be explicitly set to zero or its unintialized (zero by default). > see > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit= /drivers/regulator/core.c?id=3D1653ccf4c52df6a4abe8ec2f33f2cb2896d129ea > > How about 'ramp_disable' falg is true? > > > My understanding is: > If the h/w does not support disabling ramp_delay, the regulator core > won't call ops->set_ramp_delay when ramp_delay=3D0. > If the h/w supports disabling ramp, i.e. ramp_disable flag is true, > the regulator core will > call ops->set_ramp_delay with ramp_delay=3D0. in this case, it should > have an exactly match and > write the register to disable ramp_delay. > > > If this can be guaranteed , to use the set_ramp_delay_regmap helper funct= ion would be better. Hi ChiYuan, Can you add Reviewed-by or Acked-by if this patch works. Regards, Axel