From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH-v5 RESEND 2/5] i2c: pxa: enable/disable i2c module across msg xfer Date: Fri, 11 Sep 2015 20:53:12 +0200 Message-ID: <20150911185312.GA1516@katana> References: <1440395978-9065-1-git-send-email-vaibhav.hiremath@linaro.org> <1440395978-9065-3-git-send-email-vaibhav.hiremath@linaro.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="4Ckj6UjgE2iN1+kY" Return-path: Content-Disposition: inline In-Reply-To: <1440395978-9065-3-git-send-email-vaibhav.hiremath-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Vaibhav Hiremath Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, robert.jarzmik-GANU6spQydw@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Yi Zhang List-Id: linux-i2c@vger.kernel.org --4Ckj6UjgE2iN1+kY Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Aug 24, 2015 at 11:29:35AM +0530, Vaibhav Hiremath wrote: > From: Yi Zhang >=20 > Enable i2c module/unit before transmission and disable when it > finishes. >=20 > why? > It's because the i2c bus may be disturbed if the slave device, > typically a touch, powers on. I am not convinced, "may disturb" is too weak for me. It would need a way more detailed description of the problem which makes clear that this mechanism is the only way to go forward. Can't you use Runtime PM for that? --4Ckj6UjgE2iN1+kY Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJV8yMYAAoJEBQN5MwUoCm2XG8QAI/cC6wWQMNF18RQYDLoHvBH R+6TYPM/Z5HodA+WPrDlI4XgI9Lzm5eAmBx5chG2KKKq2bpUwabYlQHQScxIeeNW SvQyF3AdUgTElKlg1ibA+TeNMyFDyRzNJ52V+tQ5QpSdV0eU1r0xZFGAr/26QHWs 6D/cL8v47Vd5grTsryK/oXI4ZR9PEk7lXjCLbIAhbv84vsckoid2+cYHxGjKfU0D 6GNQmYctBbfixSFIfSbavxS7F+ekq3j4lzOK8BiW8dQsUcWt6xkl/6wPqMNVULgs 26Ue+bWcAc8kBbaUrkLae0AqfzKR0lpLMF3ARF15ukLeybf9R2HJSy6kxM4cj95b SBeG50ExRea2sZHkOyyBPho4IMehDlAZCevpfxsi2qGqIBR56JDJX3MLwn/O+d3H s93WKFfAJj/7lQ5OMn8h9mc/OHAUbKKO2Xdj7raCSqDzRMKsjwfHs/TWCo4gETNV Iad2Dx+6OfveNKHT2DJhv/ZFLG33w4OsleVoof8T0y3UJnysy7CcxjL5L75ckQtZ BEd/LEr00QSKgjbFg21f64+zvfFj7QuuwNAshdu9KWCWk63vnaTUhTu8FbVdwwCd ZCr9An6lKj/n9C9lQUoPTUHuSiSm1pexC09YjVKKAHGkj1eO/+xp4weIHPfQaucs kKZIpw8a7hhH6OYBUpuF =7OSn -----END PGP SIGNATURE----- --4Ckj6UjgE2iN1+kY--