From patchwork Tue Jul 31 10:20:09 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lucas Stach X-Patchwork-Id: 10550581 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 467421822 for ; Tue, 31 Jul 2018 10:20:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2A8772A79A for ; Tue, 31 Jul 2018 10:20:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1DECC2A7B1; Tue, 31 Jul 2018 10:20:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 812BC2A7C4 for ; Tue, 31 Jul 2018 10:20:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731503AbeGaL7w (ORCPT ); Tue, 31 Jul 2018 07:59:52 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:58945 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727409AbeGaL7w (ORCPT ); Tue, 31 Jul 2018 07:59:52 -0400 Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7] helo=dude.pengutronix.de.) by metis.ext.pengutronix.de with esmtp (Exim 4.89) (envelope-from ) id 1fkRlB-0006yg-Im; Tue, 31 Jul 2018 12:20:09 +0200 From: Lucas Stach To: Michael Turquette , Stephen Boyd , Rob Herring , Shawn Guo Cc: Fabio Estevam , kernel@pengutronix.de, linux-imx@nxp.com, linux-clk@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, patchwork-lst@pengutronix.de Subject: [PATCH 3/3] clk: imx6q: handle ENET PLL bypass Date: Tue, 31 Jul 2018 12:20:09 +0200 Message-Id: <20180731102009.6710-3-l.stach@pengutronix.de> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180731102009.6710-1-l.stach@pengutronix.de> References: <20180731102009.6710-1-l.stach@pengutronix.de> X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: l.stach@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-clk@vger.kernel.org Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The ENET PLL is different from the other i.MX6 PLLs, as it has multiple outputs with different post-dividers, which are all bypassed if the single bypass bit is activated. The hardware setup looks something like this: _ refclk-o---PLL---o----DIV1-----| \ | | |M |----OUT1 o-----------------------|_/ | | _ | o----DIV2-----| \ | | |M |----OUT2 o-----------------------|_/ | | _ | `----DIV3-----| \ | |M |----OUT3 `-----------------------|_/ The bypass bit not only bypasses the PLL, but also the attached post-dividers. This would be reasonbly straight forward to model with a single output, or with different bypass bits for each output, but sadly the HW guys decided that it would be good to actuate all 3 muxes with a single bit. So the need to have the PLL bypassed for one of the outputs always affects 2 other (in our model) independent branches of the clock tree. This means the decision to bypass this PLL is a system wide design choice and should not be changed on-the-fly, so we can treat any bapass configuration as static. As such we can just register the post-dividiers with a ratio that reflects the bypass status, which allows us to bypass the PLL without breaking our abstraction model and with it DT stability. Signed-off-by: Lucas Stach --- drivers/clk/imx/clk-imx6q.c | 63 +++++++++++++++++++++++++++++++++---- 1 file changed, 57 insertions(+), 6 deletions(-) diff --git a/drivers/clk/imx/clk-imx6q.c b/drivers/clk/imx/clk-imx6q.c index f64f0fe76658..c52294694273 100644 --- a/drivers/clk/imx/clk-imx6q.c +++ b/drivers/clk/imx/clk-imx6q.c @@ -231,6 +231,41 @@ static void of_assigned_ldb_sels(struct device_node *node, } } +static bool pll6_bypassed(struct device_node *node) +{ + int index, ret, num_clocks; + struct of_phandle_args clkspec; + + num_clocks = of_count_phandle_with_args(node, "assigned-clocks", + "#clock-cells"); + if (num_clocks < 0) + return false; + + for (index = 0; index < num_clocks; index++) { + ret = of_parse_phandle_with_args(node, "assigned-clocks", + "#clock-cells", index, + &clkspec); + if (ret < 0) + return false; + + if (clkspec.np == node && + clkspec.args[0] == IMX6QDL_PLL6_BYPASS) + break; + } + + /* PLL6 bypass is not part of the assigned clock list */ + if (index == num_clocks) + return false; + + ret = of_parse_phandle_with_args(node, "assigned-clock-parents", + "#clock-cells", index, &clkspec); + + if (clkspec.args[0] != IMX6QDL_CLK_PLL6) + return true; + + return false; +} + #define CCM_CCDR 0x04 #define CCM_CCSR 0x0c #define CCM_CS2CDR 0x2c @@ -510,16 +545,32 @@ static void __init imx6q_clocks_init(struct device_node *ccm_node) clk[IMX6QDL_CLK_USBPHY1_GATE] = imx_clk_gate("usbphy1_gate", "dummy", base + 0x10, 6); clk[IMX6QDL_CLK_USBPHY2_GATE] = imx_clk_gate("usbphy2_gate", "dummy", base + 0x20, 6); - clk[IMX6QDL_CLK_SATA_REF] = imx_clk_fixed_factor("sata_ref", "pll6_enet", 1, 5); - clk[IMX6QDL_CLK_PCIE_REF] = imx_clk_fixed_factor("pcie_ref", "pll6_enet", 1, 4); + /* + * The ENET PLL is special in that is has multiple outputs with + * different post-dividers that are all affected by the single bypass + * bit, so a single mux bit affects 3 independent branches of the clock + * tree. There is no good way to model this in the clock framework and + * dynamically changing the bypass bit, will yield unexpected results. + * So we treat any configuration that bypasses the ENET PLL as + * essentially static with the divider ratios refelcting the bypass + * status. + * + */ + if (!pll6_bypassed(ccm_node)) { + clk[IMX6QDL_CLK_SATA_REF] = imx_clk_fixed_factor("sata_ref", "pll6_enet", 1, 5); + clk[IMX6QDL_CLK_PCIE_REF] = imx_clk_fixed_factor("pcie_ref", "pll6_enet", 1, 4); + clk[IMX6QDL_CLK_ENET_REF] = clk_register_divider_table(NULL, "enet_ref", "pll6_enet", 0, + base + 0xe0, 0, 2, 0, clk_enet_ref_table, + &imx_ccm_lock); + } else { + clk[IMX6QDL_CLK_SATA_REF] = imx_clk_fixed_factor("sata_ref", "pll6_enet", 1, 1); + clk[IMX6QDL_CLK_PCIE_REF] = imx_clk_fixed_factor("pcie_ref", "pll6_enet", 1, 1); + clk[IMX6QDL_CLK_ENET_REF] = imx_clk_fixed_factor("enet_ref", "pll6_enet", 1, 1); + } clk[IMX6QDL_CLK_SATA_REF_100M] = imx_clk_gate("sata_ref_100m", "sata_ref", base + 0xe0, 20); clk[IMX6QDL_CLK_PCIE_REF_125M] = imx_clk_gate("pcie_ref_125m", "pcie_ref", base + 0xe0, 19); - clk[IMX6QDL_CLK_ENET_REF] = clk_register_divider_table(NULL, "enet_ref", "pll6_enet", 0, - base + 0xe0, 0, 2, 0, clk_enet_ref_table, - &imx_ccm_lock); - clk[IMX6QDL_CLK_LVDS1_SEL] = imx_clk_mux("lvds1_sel", base + 0x160, 0, 5, lvds_sels, ARRAY_SIZE(lvds_sels)); clk[IMX6QDL_CLK_LVDS2_SEL] = imx_clk_mux("lvds2_sel", base + 0x160, 5, 5, lvds_sels, ARRAY_SIZE(lvds_sels));