Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162347AbaDCG3P (ORCPT ); Thu, 3 Apr 2014 02:29:15 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:56329 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933511AbaDCG3M (ORCPT ); Thu, 3 Apr 2014 02:29:12 -0400 Message-ID: <533CFFB3.9070201@ti.com> Date: Thu, 3 Apr 2014 09:29:07 +0300 From: Peter Ujfalusi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Tero Kristo , Mike Turquette CC: Tony Lindgren , , Subject: Re: [PATCH] clk: ti: clk-7xx: Correct ABE DPLL configuration References: <1396446525-20302-1-git-send-email-peter.ujfalusi@ti.com> <533C1AC2.1000307@ti.com> In-Reply-To: <533C1AC2.1000307@ti.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/02/2014 05:12 PM, Tero Kristo wrote: > On 04/02/2014 04:48 PM, Peter Ujfalusi wrote: >> ABE DPLL frequency need to be lowered from 361267200 >> to 180633600 to facilitate the ATL requironments. >> The dpll_abe_m2x2_ck clock need to be set to double >> of ABE DPLL rate in order to have correct clocks >> for audio. > > Do you have some sort of TRM reference for this? The ATL's max divider is 32. For audio purpose the clock coming out from the ATL instance should be 128 * fs. It is only possible to have 44.1KHz sampling rate with ABE DPLL set to 361267200 or 180633600. Which means: The atl generated clock should be 128 * 44100 = 5644800 >From ABE_DPLL 361267200 we would need to have 64 as divider (ATL can't do this). >From the suggested ABE_DPLL of 180633600 we can use ATL divider of 32, which is the maximum it can do. So the reason for the change is to have ATLPCLK clock which can be used for audio in the future, the 361267200 is just too high. > > -Tero > >> >> Signed-off-by: Peter Ujfalusi >> --- >> drivers/clk/ti/clk-7xx.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/clk/ti/clk-7xx.c b/drivers/clk/ti/clk-7xx.c >> index f7e40734c819..19a55bf407dd 100644 >> --- a/drivers/clk/ti/clk-7xx.c >> +++ b/drivers/clk/ti/clk-7xx.c >> @@ -16,7 +16,7 @@ >> #include >> #include >> >> -#define DRA7_DPLL_ABE_DEFFREQ 361267200 >> +#define DRA7_DPLL_ABE_DEFFREQ 180633600 >> #define DRA7_DPLL_GMAC_DEFFREQ 1000000000 >> >> >> @@ -322,6 +322,11 @@ int __init dra7xx_dt_clk_init(void) >> if (rc) >> pr_err("%s: failed to configure ABE DPLL!\n", __func__); >> >> + dpll_ck = clk_get_sys(NULL, "dpll_abe_m2x2_ck"); >> + rc = clk_set_rate(dpll_ck, DRA7_DPLL_ABE_DEFFREQ * 2); >> + if (rc) >> + pr_err("%s: failed to configure ABE DPLL m2x2!\n", __func__); >> + >> dpll_ck = clk_get_sys(NULL, "dpll_gmac_ck"); >> rc = clk_set_rate(dpll_ck, DRA7_DPLL_GMAC_DEFFREQ); >> if (rc) >> > -- P?ter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/