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charset="Windows-1252" Content-ID: <99E66F5B8BE2DA4286674328B9814AAB@namprd11.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: DM8PR11MB5687.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 613b1b96-3034-4e88-d1d0-08d942c04f02 X-MS-Exchange-CrossTenant-originalarrivaltime: 09 Jul 2021 09:59:57.5359 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 3f4057f3-b418-4d4e-ba84-d55b4e897d88 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: Fh9/b2++vzrf2CkE8aA6Xj24pXnUQrosvCAKyPTAoLmDch9gfNupLCq1Cg53Gkdazy1pGc6fDl034apM+mGcoWvGdfTc+WSBuCc9stX1cJ0= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM8PR11MB5686 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09.07.2021 12:21, Nicolas Ferre wrote: > On 07/07/2021 at 15:12, Codrin Ciubotariu wrote: >> On clk_generated_determine_rate(), the requested rate could be outside >> of clk's range. Limit the rate to the clock's range to not return an >> error. >=20 > Isn't it saner for the user to return an error code instead of=20 > automatically restrain the dynamics requested without notice? >=20 > Can you elaborate the use case where returning an error is not convenient= ? The way I see it, if the user requests a rate that is out of clock's=20 range, the driver's determine_rate() should return min/max, not an=20 error. That is actually the closest rate supported by the clock, which=20 is what determine_rate() should accomplish. The user has no clk API to=20 get clock's range, so there is no way to call clk_round_rate() only for=20 values within our range. The use cause is with sam9x60's I2S driver, which has to try different=20 rates to get the closest one to what it needs. There is no 'perfect'=20 rate, because there is no AUDIO PLL and we have to try different values=20 for our internal dividers to find the closest one. https://elixir.bootlin.com/linux/latest/source/sound/soc/atmel/mchp-i2s-mcc= .c#L416 Best regards, Codrin