From mboxrd@z Thu Jan 1 00:00:00 1970 From: York Sun Subject: Re: clock driver Date: Tue, 26 May 2015 17:20:10 -0700 Message-ID: <55650DBA.5000304@freescale.com> References: <5564C58B.9050400@freescale.com> <20150526223829.GA26454@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150526223829.GA26454-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Guenter Roeck Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, andrey-MoRZu3FOBbXQT0dZR+AlfA@public.gmane.org, sebastian.hesselbarth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, rabeeh-UBr1pzP51AyaMJb+Lgu22Q@public.gmane.org List-Id: linux-i2c@vger.kernel.org On 05/26/2015 03:38 PM, Guenter Roeck wrote: > On Tue, May 26, 2015 at 12:12:11PM -0700, York Sun wrote: >> Linux experts, >> >> I have rewritten a driver for Silicon Labs SI5338 programmable clock chip. The >> original driver was written by Andrey (CC'ed), but was floatingn outside of the >> kernel. The driver was written to use sysfs as the interface, not the common >> clock framework. I wonder if I have to rewrite the driver following common clock >> framework. One concern is to support a feature to accept ClockBuilder (TM) >> output on sysfs. I don't see sysfs support on common clock framework. Please >> correct me if I am wrong. >> >> If not using common clock framework is acceptable, I would like to send a RFC >> patch for review. >> > My original driver for si570 was rejected because it didn't support the clock > framework, so you might face an uphill battle. > > SI provides a document for SI5338 describing how to configure it without > using clockbuilder [1]. Can that be used to implement generic code which > doesn't need clockbuilder ? > The driver is capable to handle the user's input and enable the clocks. Removing the support of importing is a step back. At least it is a feature I am using. I believe Andrey also used this feature when the driver was first drafted. That being said, my application relies on setting multiple clock chips on a PCIe device. That means I cannot put the configuration into device tree. There may be a way to fill device tree, but I am not ready to explore yet. Without a sysfs interface, can I change the configuration for each clock? I also found COMMON_CLK is a bool, not tristate. It is only selected by others. Is there a reason for doing so? My current platform (P1022DS) doesn't have CONFIG_COMMON_CLK enabled. York