> -----Original Message----- > From: Tony Lindgren [mailto:tony@xxxxxxxxxxx] > Sent: Monday, April 08, 2013 11:00 PM > To: Hiremath, Vaibhav > Cc: linux-omap@xxxxxxxxxxxxxxx; khilman@xxxxxxxxxx; paul@xxxxxxxxx; > Nayak, Rajendra; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Subject: Re: [RFC PATCH 3/3] ARM: OMAP2+: Add command line parameter > for debugSS module control > > Hi, > > * hvaibhav@xxxxxx <hvaibhav@xxxxxx> [130304 03:40]: > > From: Vaibhav Hiremath <hvaibhav@xxxxxx> > > > > Currently there is no clean mechanism to control debugSS module and > > you have to always keep clocks enabled, either, > > > > - By enabling it during boot as part of clk_init function. > > Or > > - By having HWMOD_INIT_NO_IDLE flag in hwmod data. > > > > Based on the discussion, > > http://www.mail-archive.com/linux-omap@xxxxxxxxxxxxxxx/msg81771.html > > > > This patch introduces new kernel parameter "omap_debugss_en", > > which will allow user to control debugSS module enable/disable > > part during boot-time. > > I suggest you just make this part into a standard DT only > device driver. That way the command line parsing and clock > enabling can happen the normal way. > That’s good idea, as we are moving towards DT only boot support. Also, are you suggesting to have both command-line param and DT Property for this? > Is there any reason why this could not be a loadable module? > Because we want to keep it enabled before late_initcall. As part of late_initcall Clock/hwmod framework will start disabling unused modules, which will impact the Debugs as well. Consider the case where this debugss is loaded as a module, the user Will loose the JTAG connection until the module is loaded; and once module is Loaded, he has to again re-connect to the debugss. With only DT option the code will look like below, is this what you also have in your mind - arch/arm/boot/dts/am33xx.dtsi: debugss: debugss@4b000000 { compatible = "ti,debugss"; ti,hwmods = "debugss"; reg = <0x4b000000 1000000>; status = "disabled"; /* User need to enable it if he need JTAG connectivity*/ }; arch/arm/mach-omap2/debugss.c: static int __init _omap2_debugss_enable(void) { struct device_node *np; np = of_find_matching_node(oh_name); if (!node || ! of_device_is_available()) { pr_err("debugss device is not found\n"); return -ENODEV; } ... hwmod lookup./setup/enable along with optional clock enable. ... } device_initcall(_omap2_debugss_enable); Thanks, Vaibhav -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
