Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751440AbaFWEov (ORCPT ); Mon, 23 Jun 2014 00:44:51 -0400 Received: from mail-ve0-f181.google.com ([209.85.128.181]:44909 "EHLO mail-ve0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751299AbaFWEoq (ORCPT ); Mon, 23 Jun 2014 00:44:46 -0400 MIME-Version: 1.0 In-Reply-To: <20140618100404.GM19730@lukather> References: <1403016777-15121-1-git-send-email-wens@csie.org> <1403016777-15121-10-git-send-email-wens@csie.org> <20140618100404.GM19730@lukather> From: Chen-Yu Tsai Date: Mon, 23 Jun 2014 12:44:25 +0800 X-Google-Sender-Auth: tOZ5rS_FxPDMZPVFWxJqiOcxas0 Message-ID: Subject: Re: [PATCH v2 09/20] clk: sunxi: Add sun6i MBUS clock support To: Maxime Ripard Cc: Greg Kroah-Hartman , Samuel Ortiz , Lee Jones , Rob Herring , Mike Turquette , Emilio Lopez , Linus Walleij , linux-serial@vger.kernel.org, linux-arm-kernel , linux-sunxi , devicetree , linux-kernel , Boris BREZILLON , Luc Verhaegen Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 18, 2014 at 6:04 PM, Maxime Ripard wrote: > On Tue, Jun 17, 2014 at 10:52:46PM +0800, Chen-Yu Tsai wrote: >> Signed-off-by: Chen-Yu Tsai >> --- >> Documentation/devicetree/bindings/clock/sunxi.txt | 1 + >> drivers/clk/sunxi/clk-sunxi.c | 44 +++++++++++++++++++++++ >> 2 files changed, 45 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt >> index b9ec668..7b2ba41 100644 >> --- a/Documentation/devicetree/bindings/clock/sunxi.txt >> +++ b/Documentation/devicetree/bindings/clock/sunxi.txt >> @@ -40,6 +40,7 @@ Required properties: >> "allwinner,sun6i-a31-apb2-div-clk" - for the APB2 gates on A31 >> "allwinner,sun6i-a31-apb2-gates-clk" - for the APB2 gates on A31 >> "allwinner,sun4i-a10-mod0-clk" - for the module 0 family of clocks >> + "allwinner,sun6i-a31-mbus-clk" - for the MBUS clocks on A31 / A23 >> "allwinner,sun7i-a20-out-clk" - for the external output clocks >> "allwinner,sun7i-a20-gmac-clk" - for the GMAC clock module on A20/A31 >> "allwinner,sun4i-a10-usb-clk" - for usb gates + resets on A10 / A20 >> diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c >> index eca3c6e..a086b5b 100644 >> --- a/drivers/clk/sunxi/clk-sunxi.c >> +++ b/drivers/clk/sunxi/clk-sunxi.c >> @@ -307,6 +307,37 @@ static void sun4i_get_mod0_factors(u32 *freq, u32 parent_rate, >> >> >> /** >> + * sun6i_a31_get_mbus_factors() - calculates m factor for MBUS clocks >> + * MBUS rate is calculated as follows >> + * rate = parent_rate / (m + 1); >> + */ >> + >> +static void sun6i_a31_get_mbus_factors(u32 *freq, u32 parent_rate, >> + u8 *n, u8 *k, u8 *m, u8 *p) >> +{ >> + u8 div; >> + >> + /* These clocks can only divide, so we will never be able to achieve >> + * frequencies higher than the parent frequency */ >> + if (*freq > parent_rate) >> + *freq = parent_rate; >> + >> + div = DIV_ROUND_UP(parent_rate, *freq); >> + >> + if (div > 8) >> + div = 8; >> + >> + *freq = parent_rate / div; >> + >> + /* we were called to round the frequency, we can now return */ >> + if (n == NULL) > > s/n/m/ ? The factors clk driver passes all or none pointers. But I will change this to avoid the confusion. >> + return; >> + >> + *m = div - 1; >> +} >> + >> + >> +/** >> * sun7i_a20_get_out_factors() - calculates m, p factors for CLK_OUT_A/B >> * CLK_OUT rate is calculated as follows >> * rate = (parent_rate >> p) / (m + 1); >> @@ -447,6 +478,11 @@ static struct clk_factors_config sun4i_mod0_config = { >> .pwidth = 2, >> }; >> >> +static struct clk_factors_config sun6i_a31_mbus_config = { >> + .mshift = 0, >> + .mwidth = 3, > > Actually, the A31 has an extra N factor. > > So this mbus clock looks like it's only about the A23, and not the A31 > at all. I checked original sun6i code and sun6i code found in the A23 SDK. The original code uses the module 0 clock driver for mbus, so yes there's an extra N factor. The new code in the A23 SDK does not. Unfortunately I haven't been able to get my Hummingbird A31 up yet, so I can't poke around to check it. ChenYu -- 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/