From patchwork Thu Jul 17 09:08:52 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Ripard X-Patchwork-Id: 4573941 Return-Path: X-Original-To: patchwork-linux-mmc@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 602F49F3B4 for ; Thu, 17 Jul 2014 09:10:34 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 50F06201BB for ; Thu, 17 Jul 2014 09:10:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 29B27201B9 for ; Thu, 17 Jul 2014 09:10:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755746AbaGQJKX (ORCPT ); Thu, 17 Jul 2014 05:10:23 -0400 Received: from top.free-electrons.com ([176.31.233.9]:41397 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754585AbaGQJKT (ORCPT ); Thu, 17 Jul 2014 05:10:19 -0400 Received: by mail.free-electrons.com (Postfix, from userid 106) id 3641FD68; Thu, 17 Jul 2014 11:10:18 +0200 (CEST) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from localhost (col31-4-88-188-83-94.fbx.proxad.net [88.188.83.94]) by mail.free-electrons.com (Postfix) with ESMTPSA id 6028968A; Thu, 17 Jul 2014 11:10:17 +0200 (CEST) From: Maxime Ripard To: Mike Turquette , Hans de Goede , Emilio Lopez , chris@printf.net, david.lanzendoerfer@o2s.ch, ulf.hansson@linaro.org Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mmc@vger.kernel.org, Maxime Ripard Subject: [PATCH 12/14] clk: sunxi: mod0: Introduce MMC proper phase handling Date: Thu, 17 Jul 2014 11:08:52 +0200 Message-Id: <1405588134-2396-13-git-send-email-maxime.ripard@free-electrons.com> X-Mailer: git-send-email 2.0.1 In-Reply-To: <1405588134-2396-1-git-send-email-maxime.ripard@free-electrons.com> References: <1405588134-2396-1-git-send-email-maxime.ripard@free-electrons.com> Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The MMC clock we thought we had until now are actually not one but three different clocks. The main one is unchanged, and will have three outputs: - The clock fed into the MMC - a sample and output clocks, to deal with when should we output/sample data to/from the MMC bus The phase control we had are actually controlling the two latter clocks, but the main MMC one is unchanged. We can adjust the phase with a 3 bits value, from 0 to 7, 0 meaning a 180 phase shift, and the other values being the number of periods from the MMC parent clock to outphase the clock of. Signed-off-by: Maxime Ripard --- Documentation/devicetree/bindings/clock/sunxi.txt | 2 + drivers/clk/sunxi/clk-mod0.c | 189 ++++++++++++++++++++++ 2 files changed, 191 insertions(+) diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt index 112d8525b6e0..d3786ab9b7a7 100644 --- a/Documentation/devicetree/bindings/clock/sunxi.txt +++ b/Documentation/devicetree/bindings/clock/sunxi.txt @@ -47,6 +47,8 @@ Required properties: "allwinner,sun6i-a31-apb2-gates-clk" - for the APB2 gates on A31 "allwinner,sun8i-a23-apb2-gates-clk" - for the APB2 gates on A23 "allwinner,sun4i-a10-mbus-clk" - for the MBUS clock on A10 + "allwinner,sun4i-a10-mmc-output-clk" - for the MMC output clock on A10 + "allwinner,sun4i-a10-mmc-sample-clk" - for the MMC sample clock on A10 "allwinner,sun4i-a10-mod0-clk" - for the module 0 family of clocks "allwinner,sun7i-a20-out-clk" - for the external output clocks "allwinner,sun7i-a20-gmac-clk" - for the GMAC clock module on A20/A31 diff --git a/drivers/clk/sunxi/clk-mod0.c b/drivers/clk/sunxi/clk-mod0.c index a179299ec79d..d72cb7ff1356 100644 --- a/drivers/clk/sunxi/clk-mod0.c +++ b/drivers/clk/sunxi/clk-mod0.c @@ -16,6 +16,7 @@ #include #include +#include #include "clk-factors.h" @@ -92,3 +93,191 @@ static void __init sun4i_a10_mbus_setup(struct device_node *node) clk_prepare_enable(mbus); } CLK_OF_DECLARE(sun4i_a10_mbus, "allwinner,sun4i-a10-mbus-clk", sun4i_a10_mbus_setup); + +struct mmc_phase_data { + u8 offset; +}; + +struct mmc_phase { + struct clk_hw hw; + void __iomem *reg; + struct mmc_phase_data *data; + spinlock_t *lock; +}; + +#define to_mmc_phase(_hw) container_of(_hw, struct mmc_phase, hw) + +static int mmc_get_phase(struct clk_hw *hw) +{ + struct clk *mmc, *mmc_parent, *clk = hw->clk; + struct mmc_phase *phase = to_mmc_phase(hw); + unsigned int mmc_rate, mmc_parent_rate; + u16 step, mmc_div; + u32 value; + u8 delay; + + value = readl(phase->reg); + delay = (value >> phase->data->offset) & 0x3; + + if (!delay) + return 180; + + /* Get the main MMC clock */ + mmc = clk_get_parent(clk); + if (!mmc) + return -EINVAL; + + /* And its rate */ + mmc_rate = clk_get_rate(mmc); + if (!mmc_rate) + return -EINVAL; + + /* Now, get the MMC parent (most likely some PLL) */ + mmc_parent = clk_get_parent(mmc); + if (!mmc_parent) + return -EINVAL; + + /* And its rate */ + mmc_parent_rate = clk_get_rate(mmc_parent); + if (!mmc_parent_rate) + return -EINVAL; + + /* Get MMC clock divider */ + mmc_div = mmc_parent_rate / mmc_rate; + + step = DIV_ROUND_CLOSEST(360, mmc_div); + return delay * step; +} + +static int mmc_set_phase(struct clk_hw *hw, int degrees) +{ + struct clk *mmc, *mmc_parent, *clk = hw->clk; + struct mmc_phase *phase = to_mmc_phase(hw); + unsigned int mmc_rate, mmc_parent_rate; + unsigned long flags; + u32 value; + u8 delay; + + /* Get the main MMC clock */ + mmc = clk_get_parent(clk); + if (!mmc) + return -EINVAL; + + /* And its rate */ + mmc_rate = clk_get_rate(mmc); + if (!mmc_rate) + return -EINVAL; + + /* Now, get the MMC parent (most likely some PLL) */ + mmc_parent = clk_get_parent(mmc); + if (!mmc_parent) + return -EINVAL; + + /* And its rate */ + mmc_parent_rate = clk_get_rate(mmc_parent); + if (!mmc_parent_rate) + return -EINVAL; + + if (degrees != 180) { + u16 step, mmc_div; + + /* Get MMC clock divider */ + mmc_div = mmc_parent_rate / mmc_rate; + + /* + * We can only outphase the clocks by multiple of the + * PLL's period. + * + * Since the MMC clock in only a divider, and the + * formula to get the outphasing in degrees is deg = + * 360 * delta / period + * + * If we simplify this formula, we can see that the + * only thing that we're concerned about is the number + * of period we want to outphase our clock from, and + * the divider set by the MMC clock. + */ + step = DIV_ROUND_CLOSEST(360, mmc_div); + delay = DIV_ROUND_CLOSEST(degrees, step); + } else { + delay = 0; + } + + spin_lock_irqsave(phase->lock, flags); + value = readl(phase->reg); + value &= ~GENMASK(phase->data->offset + 3, phase->data->offset); + value |= delay << phase->data->offset; + writel(value, phase->reg); + spin_unlock_irqrestore(phase->lock, flags); + + return 0; +} + +static const struct clk_ops mmc_clk_ops = { + .get_phase = mmc_get_phase, + .set_phase = mmc_set_phase, +}; + +static void __init sun4i_a10_mmc_phase_setup(struct device_node *node, + struct mmc_phase_data *data) +{ + const char *parent_names[1] = { of_clk_get_parent_name(node, 0) }; + struct clk_init_data init = { + .num_parents = 1, + .parent_names = parent_names, + .ops = &mmc_clk_ops, + }; + + struct mmc_phase *phase; + struct clk *clk; + + phase = kmalloc(sizeof(*phase), GFP_KERNEL); + if (!phase) + return; + + phase->hw.init = &init; + + phase->reg = of_iomap(node, 0); + if (!phase->reg) + goto err_free; + + phase->data = data; + phase->lock = &sun4i_a10_mod0_lock; + + if (of_property_read_string(node, "clock-output-names", &init.name)) + init.name = node->name; + + clk = clk_register(NULL, &phase->hw); + if (IS_ERR(clk)) + goto err_unmap; + + of_clk_add_provider(node, of_clk_src_simple_get, clk); + + return; + +err_unmap: + iounmap(phase->reg); +err_free: + kfree(phase); +} + + +static struct mmc_phase_data mmc_output_clk = { + .offset = 8, +}; + +static struct mmc_phase_data mmc_sample_clk = { + .offset = 20, +}; + +static void __init sun4i_a10_mmc_output_setup(struct device_node *node) +{ + sun4i_a10_mmc_phase_setup(node, &mmc_output_clk); +} +CLK_OF_DECLARE(sun4i_a10_mmc_output, "allwinner,sun4i-a10-mmc-output-clk", sun4i_a10_mmc_output_setup); + +static void __init sun4i_a10_mmc_sample_setup(struct device_node *node) +{ + sun4i_a10_mmc_phase_setup(node, &mmc_sample_clk); +} +CLK_OF_DECLARE(sun4i_a10_mmc_sample, "allwinner,sun4i-a10-mmc-sample-clk", sun4i_a10_mmc_sample_setup);