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Manresa" , Jizhou Tong , linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/4] media: i2c: Add ST VD55G0 global shutter sensor driver Message-ID: <20261109132746.22125-1-lsa.uz@pm.me> In-Reply-To: References: <20261109093353.3757-1-lsa.uz@pm.me> <20261109093353.3757-3-lsa.uz@pm.me> <20261109124610.85065-1-lsa.uz@pm.me> Feedback-ID: 113843758:user:proton X-Pm-Message-ID: a3bee21ddf5233bc865bcf357b8e7637d7aa5563 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi Sakari, On Mon, Nov 09, 2026 at 02:59:44PM +0200, Sakari Ailus wrote: >> >> +static const s64 vd55g0_ev_bias_menu[] =3D { >> >> +=09-3000, -2500, -2000, -1500, -1000, -500, >> >> +=09 0, >> >> +=09 500, 1000, 1500, 2000, 2500, 3000, >> > >> > Is this >> >> The sentence seems to have been cut off here. What did you mean? The >> table is vd55g1's, in the control's 0.001 EV units. > > Uh, yes. I meant to ask if this is a firmware limitation. I guess so? No, it is the driver's. The firmware has both a target and a compensation register (UM2829, 14.7.3, Table 39 [1]): AE_COMPENSATION VALUE 15:0 SFP 8.8 Compensation in EV AE_TARGET_PERCENTAGE VALUE 15:0 UI Percentage relative to satura= tion where "100 means saturated image". The driver writes the target from this table, 27 * 2^EV, as vd55g1 does: =09static const unsigned int index2exposure_target[] =3D { =09=093, 5, 7, 10, 14, 19, 27, 38, 54, 76, 108, 153, 216, =09}; So +2.5 and +3 EV ask for 153 and 216, above saturation; I have not tested what the AE does there. v4 keeps vd55g1's table, unless you or Benjamin prefer the compensation register. [1] https://www.st.com/resource/en/user_manual/um2829-how-to-integrate-and-= configure-the-vd55g0-device-from-a-hardware-and-software-perspective-stmicr= oelectronics.pdf Sergey