From patchwork Mon Aug 31 10:18:03 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sekhar Nori X-Patchwork-Id: 44851 Received: from bear.ext.ti.com (bear.ext.ti.com [192.94.94.41]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n7VAKx6o019373 for ; Mon, 31 Aug 2009 10:20:59 GMT Received: from dlep36.itg.ti.com ([157.170.170.91]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id n7VAJNiS019973; Mon, 31 Aug 2009 05:19:28 -0500 Received: from linux.omap.com (localhost [127.0.0.1]) by dlep36.itg.ti.com (8.13.8/8.13.8) with ESMTP id n7VAJML5007788; Mon, 31 Aug 2009 05:19:22 -0500 (CDT) Received: from linux.omap.com (localhost [127.0.0.1]) by linux.omap.com (Postfix) with ESMTP id 5C74D80654; Mon, 31 Aug 2009 05:19:05 -0500 (CDT) X-Original-To: davinci-linux-open-source@linux.davincidsp.com Delivered-To: davinci-linux-open-source@linux.davincidsp.com Received: from dbdp31.itg.ti.com (dbdp31.itg.ti.com [172.24.170.98]) by linux.omap.com (Postfix) with ESMTP id 1FBAB8062D for ; Mon, 31 Aug 2009 05:18:11 -0500 (CDT) Received: from psplinux051.india.ti.com (localhost [127.0.0.1]) by dbdp31.itg.ti.com (8.13.8/8.13.8) with ESMTP id n7VAI8eI001142; Mon, 31 Aug 2009 15:48:08 +0530 (IST) Received: from psplinux051.india.ti.com (localhost [127.0.0.1]) by psplinux051.india.ti.com (8.13.1/8.13.1) with ESMTP id n7VAI85p002999; Mon, 31 Aug 2009 15:48:08 +0530 Received: (from a0875516@localhost) by psplinux051.india.ti.com (8.13.1/8.13.1/Submit) id n7VAI8Bk002996; Mon, 31 Aug 2009 15:48:08 +0530 From: Sekhar Nori To: davinci-linux-open-source@linux.davincidsp.com Date: Mon, 31 Aug 2009 15:48:03 +0530 Message-Id: <1251713887-2824-6-git-send-email-nsekhar@ti.com> X-Mailer: git-send-email 1.6.2.4 In-Reply-To: <1251713887-2824-5-git-send-email-nsekhar@ti.com> References: <1251713887-2824-1-git-send-email-nsekhar@ti.com> <1251713887-2824-2-git-send-email-nsekhar@ti.com> <1251713887-2824-3-git-send-email-nsekhar@ti.com> <1251713887-2824-4-git-send-email-nsekhar@ti.com> <1251713887-2824-5-git-send-email-nsekhar@ti.com> Cc: Subject: [PATCH v4 06/10] davinci: support changing the clock rate in clock framework X-BeenThere: davinci-linux-open-source@linux.davincidsp.com X-Mailman-Version: 2.1.4 Precedence: list List-Id: davinci-linux-open-source.linux.davincidsp.com List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: davinci-linux-open-source-bounces@linux.davincidsp.com Errors-To: davinci-linux-open-source-bounces@linux.davincidsp.com clk_round_rate, clk_set_rate have been updated to handle dynamic frequency changes. The motivation behind the changes is to support dynamic CPU frequency change. davinci_set_pllrate() changes the PLL rate of a given PLL. This function has been presented as a generic function though it has been tested only on OMAP-L138 EVM. No other currently available DaVinci device will probably use this function, but any future device specific changes will hopefully be small enough to get taken care using a cpu_is_xxx() macro. Signed-off-by: Sekhar Nori --- arch/arm/mach-davinci/clock.c | 114 +++++++++++++++++++++++++++++++++++++++- arch/arm/mach-davinci/clock.h | 8 +++ 2 files changed, 119 insertions(+), 3 deletions(-) diff --git a/arch/arm/mach-davinci/clock.c b/arch/arm/mach-davinci/clock.c index 6de1e34..09e0e1c 100644 --- a/arch/arm/mach-davinci/clock.c +++ b/arch/arm/mach-davinci/clock.c @@ -19,6 +19,7 @@ #include #include #include +#include #include @@ -99,17 +100,44 @@ long clk_round_rate(struct clk *clk, unsigned long rate) if (clk == NULL || IS_ERR(clk)) return -EINVAL; + if (clk->round_rate) + return clk->round_rate(clk, rate); + return clk->rate; } EXPORT_SYMBOL(clk_round_rate); +/* Propagate rate to children */ +static void propagate_rate(struct clk *root) +{ + struct clk *clk; + + list_for_each_entry(clk, &root->children, childnode) { + if (clk->recalc) + clk->rate = clk->recalc(clk); + propagate_rate(clk); + } +} + int clk_set_rate(struct clk *clk, unsigned long rate) { + unsigned long flags; + int ret = -EINVAL; + if (clk == NULL || IS_ERR(clk)) - return -EINVAL; + return ret; - /* changing the clk rate is not supported */ - return -EINVAL; + spin_lock_irqsave(&clockfw_lock, flags); + if (clk->set_rate) + ret = clk->set_rate(clk, rate); + if (ret == 0) { + if (clk->recalc) + clk->rate = clk->recalc(clk); + propagate_rate(clk); + } + spin_unlock_irqrestore(&clockfw_lock, flags); + + return ret; } EXPORT_SYMBOL(clk_set_rate); @@ -296,6 +324,86 @@ static unsigned long clk_pllclk_recalc(struct clk *clk) return rate; } +/** + * davinci_set_pllrate - set the output rate of a given PLL. + * + * Note: Currently tested to work with OMAP-L138 only. + * + * @pll: pll whose rate needs to be changed. + * @prediv: The pre divider value. Passing 0 disables the pre-divider. + * @pllm: The multiplier value. Passing 0 leads to multiply-by-one. + * @postdiv: The post divider value. Passing 0 disables the post-divider. + */ +int davinci_set_pllrate(struct pll_data *pll, unsigned int prediv, + unsigned int mult, unsigned int postdiv) +{ + u32 ctrl; + unsigned int locktime; + + if (pll->base == NULL) + return -EINVAL; + + /* + * PLL lock time required per OMAP-L138 datasheet is + * (2000 * prediv)/sqrt(pllm) OSCIN cycles. We approximate sqrt(pllm) + * as 4 and OSCIN cycle as 25 MHz. + */ + if (prediv) { + locktime = ((2000 * prediv) / 100); + prediv = (prediv - 1) | PLLDIV_EN; + } else { + locktime = 20; + } + if (postdiv) + postdiv = (postdiv - 1) | PLLDIV_EN; + if (mult) + mult = mult - 1; + + ctrl = __raw_readl(pll->base + PLLCTL); + + /* Switch the PLL to bypass mode */ + ctrl &= ~(PLLCTL_PLLENSRC | PLLCTL_PLLEN); + __raw_writel(ctrl, pll->base + PLLCTL); + + /* + * Wait for 4 OSCIN/CLKIN cycles to ensure that the PLLC has switched + * to bypass mode. Delay of 1us ensures we are good for all > 4MHz + * OSCIN/CLKIN inputs. Typically the input is ~25MHz. + */ + udelay(1); + + /* Reset and enable PLL */ + ctrl &= ~(PLLCTL_PLLRST | PLLCTL_PLLDIS); + __raw_writel(ctrl, pll->base + PLLCTL); + + if (pll->flags & PLL_HAS_PREDIV) + __raw_writel(prediv, pll->base + PREDIV); + + __raw_writel(mult, pll->base + PLLM); + + if (pll->flags & PLL_HAS_POSTDIV) + __raw_writel(postdiv, pll->base + POSTDIV); + + /* + * Wait for PLL to reset properly, OMAP-L138 datasheet says + * 'min' time = 125ns + */ + udelay(1); + + /* Bring PLL out of reset */ + ctrl |= PLLCTL_PLLRST; + __raw_writel(ctrl, pll->base + PLLCTL); + + udelay(locktime); + + /* Remove PLL from bypass mode */ + ctrl |= PLLCTL_PLLEN; + __raw_writel(ctrl, pll->base + PLLCTL); + + return 0; +} +EXPORT_SYMBOL(davinci_set_pllrate); + int __init davinci_clk_init(struct davinci_clk *clocks) { struct davinci_clk *c; diff --git a/arch/arm/mach-davinci/clock.h b/arch/arm/mach-davinci/clock.h index 202b9ff..a75d3f7 100644 --- a/arch/arm/mach-davinci/clock.h +++ b/arch/arm/mach-davinci/clock.h @@ -22,6 +22,10 @@ /* PLL/Reset register offsets */ #define PLLCTL 0x100 #define PLLCTL_PLLEN BIT(0) +#define PLLCTL_PLLPWRDN BIT(1) +#define PLLCTL_PLLRST BIT(3) +#define PLLCTL_PLLDIS BIT(4) +#define PLLCTL_PLLENSRC BIT(5) #define PLLCTL_CLKMODE BIT(8) #define PLLM 0x110 @@ -74,6 +78,8 @@ struct clk { struct pll_data *pll_data; u32 div_reg; unsigned long (*recalc) (struct clk *); + int (*set_rate) (struct clk *clk, unsigned long rate); + int (*round_rate) (struct clk *clk, unsigned long rate); }; /* Clock flags */ @@ -97,6 +103,8 @@ struct davinci_clk { } int davinci_clk_init(struct davinci_clk *clocks); +int davinci_set_pllrate(struct pll_data *pll, unsigned int prediv, + unsigned int mult, unsigned int postdiv); extern struct platform_device davinci_wdt_device;