From patchwork Tue Sep 25 16:33:38 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tero Kristo X-Patchwork-Id: 1505951 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 0002B40079 for ; Tue, 25 Sep 2012 16:34:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758073Ab2IYQe1 (ORCPT ); Tue, 25 Sep 2012 12:34:27 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:59748 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757997Ab2IYQeS (ORCPT ); Tue, 25 Sep 2012 12:34:18 -0400 Received: from dlelxv30.itg.ti.com ([172.17.2.17]) by devils.ext.ti.com (8.13.7/8.13.7) with ESMTP id q8PGYCIc014080; Tue, 25 Sep 2012 11:34:12 -0500 Received: from DFLE73.ent.ti.com (dfle73.ent.ti.com [128.247.5.110]) by dlelxv30.itg.ti.com (8.13.8/8.13.8) with ESMTP id q8PGYCDT000928; Tue, 25 Sep 2012 11:34:12 -0500 Received: from dlelxv22.itg.ti.com (172.17.1.197) by dfle73.ent.ti.com (128.247.5.110) with Microsoft SMTP Server id 14.1.323.3; Tue, 25 Sep 2012 11:34:12 -0500 Received: from localhost.localdomain (h64-6.vpn.ti.com [172.24.64.6]) by dlelxv22.itg.ti.com (8.13.8/8.13.8) with ESMTP id q8PGY1Bi005410; Tue, 25 Sep 2012 11:34:11 -0500 From: Tero Kristo To: , , CC: Subject: [PATCHv7 06/21] ARM: OMAP4: VC: calculate ramp times Date: Tue, 25 Sep 2012 19:33:38 +0300 Message-ID: <1348590833-12335-7-git-send-email-t-kristo@ti.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1348590833-12335-1-git-send-email-t-kristo@ti.com> References: <1348590833-12335-1-git-send-email-t-kristo@ti.com> MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org OMAP4 VC code now uses voltage deltas + slew rates for calculating actual ramp times for voltage changes. Both retention / sleep + off mode voltage ramp times are setup at the same time during initialization. Signed-off-by: Tero Kristo --- arch/arm/mach-omap2/vc.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 94 insertions(+), 0 deletions(-) diff --git a/arch/arm/mach-omap2/vc.c b/arch/arm/mach-omap2/vc.c index bba0d7c..26750fe 100644 --- a/arch/arm/mach-omap2/vc.c +++ b/arch/arm/mach-omap2/vc.c @@ -310,12 +310,106 @@ static void __init omap3_vc_init_channel(struct voltagedomain *voltdm) omap3_set_off_timings(voltdm); } +/** + * omap4_calc_volt_ramp - calculates voltage ramping delays on omap4 + * @voltdm: channel to calculate values for + * @voltage_diff: voltage difference in microvolts + * + * Calculates voltage ramp prescaler + counter values for a voltage + * difference on omap4. Returns a field value suitable for writing to + * VOLTSETUP register for a channel in following format: + * bits[8:9] prescaler ... bits[0:5] counter. See OMAP4 TRM for reference. + */ +static u32 omap4_calc_volt_ramp(struct voltagedomain *voltdm, u32 voltage_diff) +{ + u32 prescaler; + u32 cycles; + u32 time; + + time = voltage_diff / voltdm->pmic->slew_rate; + + cycles = voltdm->sys_clk.rate / 1000 * time / 1000; + + cycles /= 64; + prescaler = 0; + + /* shift to next prescaler until no overflow */ + + /* scale for div 256 = 64 * 4 */ + if (cycles > 63) { + cycles /= 4; + prescaler++; + } + + /* scale for div 512 = 256 * 2 */ + if (cycles > 63) { + cycles /= 2; + prescaler++; + } + + /* scale for div 2048 = 512 * 4 */ + if (cycles > 63) { + cycles /= 4; + prescaler++; + } + + /* check for overflow => invalid ramp time */ + if (cycles > 63) { + pr_warn("%s: invalid setuptime for vdd_%s\n", __func__, + voltdm->name); + return 0; + } + + cycles++; + + return (prescaler << OMAP4430_RAMP_UP_PRESCAL_SHIFT) | + (cycles << OMAP4430_RAMP_UP_COUNT_SHIFT); +} + +/** + * omap4_set_timings - set voltage ramp timings for a channel + * @voltdm: channel to configure + * @off_mode: whether off-mode values are used + * + * Calculates and sets the voltage ramp up / down values for a channel. + */ +static void omap4_set_timings(struct voltagedomain *voltdm, bool off_mode) +{ + u32 val; + u32 ramp; + int offset; + + if (off_mode) { + ramp = omap4_calc_volt_ramp(voltdm, + voltdm->vc_param->on - voltdm->vc_param->off); + offset = voltdm->vfsm->voltsetup_off_reg; + } else { + ramp = omap4_calc_volt_ramp(voltdm, + voltdm->vc_param->on - voltdm->vc_param->ret); + offset = voltdm->vfsm->voltsetup_reg; + } + + if (!ramp) + return; + + val = voltdm->read(offset); + + val |= ramp << OMAP4430_RAMP_DOWN_COUNT_SHIFT; + + val |= ramp << OMAP4430_RAMP_UP_COUNT_SHIFT; + + voltdm->write(val, offset); +} + /* OMAP4 specific voltage init functions */ static void __init omap4_vc_init_channel(struct voltagedomain *voltdm) { static bool is_initialized; u32 vc_val; + omap4_set_timings(voltdm, true); + omap4_set_timings(voltdm, false); + if (is_initialized) return;