From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [pm_wip/voltdm_nm][PATCH v2 2/3] OMAP4: PM: VC: introduce concept of default channel Date: Thu, 02 Jun 2011 16:45:15 -0700 Message-ID: <87pqmvn6gk.fsf@ti.com> References: <1306711180-8631-1-git-send-email-nm@ti.com> <1306711180-8631-3-git-send-email-nm@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from na3sys009aog117.obsmtp.com ([74.125.149.242]:57101 "EHLO na3sys009aog117.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752511Ab1FBXpT (ORCPT ); Thu, 2 Jun 2011 19:45:19 -0400 Received: by mail-pv0-f169.google.com with SMTP id 12so780701pvc.14 for ; Thu, 02 Jun 2011 16:45:18 -0700 (PDT) In-Reply-To: <1306711180-8631-3-git-send-email-nm@ti.com> (Nishanth Menon's message of "Sun, 29 May 2011 16:19:39 -0700") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Nishanth Menon Cc: linux-omap Nishanth Menon writes: > Due to a TRM bug, the current code assumes that channel0(core) is the default > channel. With the additional explanation provided by the hardware team, it is > clear that PRM_VC_CFG_CHANNEL register allows for flexibility of configuring > for various PMIC configurations. For example, the I2C slave address on TWL6030 > when using 4430 configuration could potentially use the same slave address for > all domains, while in 4460 configuration, we drive MPU using TPS; Core and IVA > using TWL6030. To allow this flexibility, we state in existing parameters using > a flag to indicate usage of default channel. > > In addition, the TRM update clears up the confusion on the fact that MPU is > infact the default channel on OMAP4. > > We update the same here. > > Signed-off-by: Nishanth Menon There's too much going on in this patch not described in the changelog (extra error checking, volt & cmd reg checking etc.) Also, I don't like the USE_DEFAULT_CHANNEL_I2C_PARAM, mainly because it adds clutter without any obvious value. To me, zero is a perfectly good value to signify "use default channel value", especially since that's the value used by the hardware. Incidentally, adding this doesn't actually change current behavior. Currently, I use zero (an unconfigured value in the VC settings) to signify it should use default settings. In your patch, you defined USE_DEFAULT_CHANNEL_I2C_PARAM as 0x10000 (17 bits) but assign it to 16 bit fields, which means they are just set to zero. :) So rather than take this patch, I'm just going to fold the following diff into "OMAP3+: VC: abstract out channel configuration" in voltdm_b. I'll also update the changelog noting that the TRM is wrong here in that it describes CORE as the default channel when it's in fact MPU. Kevin diff --git a/arch/arm/mach-omap2/vc.c b/arch/arm/mach-omap2/vc.c index fba352d..fa48944 100644 --- a/arch/arm/mach-omap2/vc.c +++ b/arch/arm/mach-omap2/vc.c @@ -33,21 +33,20 @@ * - command configuration address (RAC) and enable bit (RACEN) * - command values for ON, ONLP, RET and OFF (CMD) * - * This function currently only allows flexible configuration of - * the non-default channel (e.g. non-zero channels.) Starting with - * OMAP4, only the non-zero channels can be configured. Channel zero - * always uses the channel zero register values. Therefore, the - * same limitation is imposed on OMAP3 for consistency. + * This function currently only allows flexible configuration of the + * non-default channel. Starting with OMAP4, there are more than 2 + * channels, with one defined as the default (on OMAP4, it's MPU.) + * Only the non-default channel can be configured. */ static int omap_vc_config_channel(struct voltagedomain *voltdm) { struct omap_vc_channel *vc = voltdm->vc; /* - * For channel zero, the only configurable bit is RACEN. + * For default channel, the only configurable bit is RACEN. * All others must stay at zero (see function comment above.) */ - if (!vc->cfg_channel_sa_shift) + if (vc->is_default_channel) vc->cfg_channel &= CFG_CHANNEL_RACEN; voltdm->rmw(CFG_CHANNEL_MASK << vc->cfg_channel_sa_shift, diff --git a/arch/arm/mach-omap2/vc.h b/arch/arm/mach-omap2/vc.h index f0fb61f..c216b57 100644 --- a/arch/arm/mach-omap2/vc.h +++ b/arch/arm/mach-omap2/vc.h @@ -84,6 +84,8 @@ struct omap_vc_channel { u32 smps_cmdra_mask; u8 cmdval_reg; u8 cfg_channel_sa_shift; + + bool is_default_channel; }; extern struct omap_vc_channel omap3_vc_mpu; diff --git a/arch/arm/mach-omap2/vc44xx_data.c b/arch/arm/mach-omap2/vc44xx_data.c index fe4f4e5..5844b20 100644 --- a/arch/arm/mach-omap2/vc44xx_data.c +++ b/arch/arm/mach-omap2/vc44xx_data.c @@ -58,6 +58,7 @@ struct omap_vc_channel omap4_vc_mpu = { .smps_volra_mask = OMAP4430_VOLRA_VDD_MPU_L_MASK, .smps_cmdra_mask = OMAP4430_CMDRA_VDD_MPU_L_MASK, .cfg_channel_sa_shift = OMAP4430_SA_VDD_MPU_L_SHIFT, + .is_default_channel = true, }; struct omap_vc_channel omap4_vc_iva = {