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[94.197.211.16]) by smtp.gmail.com with ESMTPSA id t5sm1747222wmi.32.2021.06.01.01.23.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Jun 2021 01:23:41 -0700 (PDT) Date: Tue, 1 Jun 2021 09:23:38 +0100 From: Torin Cooper-Bennun To: Marc Kleine-Budde Cc: linux-can@vger.kernel.org Subject: Re: [PATCH can-next 2/5] can: m_can: m_can_isr(): handle device-specific interrupts Message-ID: <20210601082338.b7t67oebywhcwcnd@bigthink> References: <20210526124747.674055-1-torin@maxiluxsystems.com> <20210526124747.674055-3-torin@maxiluxsystems.com> <20210526150705.s4ms7jhowsuts3yf@pengutronix.de> <20210526151833.5ppprex6zzrclr6u@pengutronix.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="hm6azvrphclzpj77" Content-Disposition: inline In-Reply-To: <20210526151833.5ppprex6zzrclr6u@pengutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org --hm6azvrphclzpj77 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, May 26, 2021 at 05:18:33PM +0200, Marc Kleine-Budde wrote: > On 26.05.2021 17:07:05, Marc Kleine-Budde wrote: > > On 26.05.2021 13:47:44, Torin Cooper-Bennun wrote: > > > + if (!ir) { > > > + /* Handle device-specific interrupts */ > > > + if (cdev->ops->handle_dev_interrupts) > > > + irq_ret =3D cdev->ops->handle_dev_interrupts(cdev, false); > > > + return irq_ret; > > > + } > > > + > > > + /* ACK M_CAN interrupts */ > > > + m_can_write(cdev, M_CAN_IR, ir); > > > =20 > > > + /* ACK device-specific interrupts */ > > > if (cdev->ops->handle_dev_interrupts) > > > cdev->ops->handle_dev_interrupts(cdev, true); > >=20 > > Why do you call a 2nd time the handle_dev_interrupts() callback? >=20 > I see, clear and no clear. Why are these two separate operations? As discussed here, https://lore.kernel.org/linux-can/20210514141012.3ehw4tosog3lreq4@pengutron= ix.de/ you previously recommended adding a 2nd parameter the callback to indicate that we only want to clear the device IR, not read it, in order to save an SPI transaction when M_CAN core interrupts were already handled. However, quoting from your previous mail, > On 26.05.2021 13:47:44, Torin Cooper-Bennun wrote: > > Device-specific interrupts are handled, if no M_CAN core interrupts were > > handled in the ISR call. >=20 > In case there are both core and device specific interrupts the kernel > IRQ handler will call the ISR a 2nd time - should be OK. this implies I should leave device IR totally alone unless no M_CAN interrupts are asserted, and do the following only: | ir =3D m_can_read(cdev, M_CAN_IR); | | if (!ir) { | /* Handle device-specific interrupts */ | if (cdev->ops->handle_dev_interrupts) | irq_ret =3D cdev->ops->handle_dev_interrupts(cdev, false); | return irq_ret; | } | | /* ACK M_CAN interrupts */ | m_can_write(cdev, M_CAN_IR, ir); I can probably also kill off the clear_only parameter. -- Regards, Torin Cooper-Bennun Software Engineer | maxiluxsystems.com --hm6azvrphclzpj77 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQGzBAABCgAdFiEEHoj68wxDgkT3Oo2Mj1jJmDXJkUgFAmC17ooACgkQj1jJmDXJ kUjoNwwAgKqzgOmOiOqDOg9y/basan6iksCH6DLCTScHP9CP5+Ua89Yyr7pcNkqZ F+MXJXixTBgr1PbS4ZF2u+E0DEWLcRY5UPEStNROkVaPggsYf522z0uNXyQnDRiG bP7Bv6iaiLEInLnFNnHmX2vUhaQI3vZ2ne/AefO2nkY/bfw0iXF2eI1fQHyBbsL0 ALNRzUhNmdlYDvYXIbUpQR6hTMmINWZPFp4IfLhViqV6QQdWB/rtE6d7flqdjfLe H9YI0w/uLtyUD8q/gL0fiMV/dhxiO9bJqUsDR7E3Acb2ABSoVtjEg1v3dZy4n7zl bMGNnYuzFaeKxk1/ecaYijAig7TOwjuLsxidvckgp/lxDykIPL6NEt2VQ53EChjl WDYXKG9QE7mzrKdWPo25CXwkUm0ans02oakVsD/QXsp+f6KzbnG/ORKXIpUbzwrJ gYWffHgLymXt3V98dk61HjOUfa/470GpJrPA+yluGdX3ZEiF0vxwq91J9dBaXvlg pk84EIDt =HPqz -----END PGP SIGNATURE----- --hm6azvrphclzpj77--