From patchwork Tue Apr 22 13:12:32 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris BREZILLON X-Patchwork-Id: 4031681 Return-Path: X-Original-To: patchwork-linux-arm@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 72A5B9F391 for ; Tue, 22 Apr 2014 13:15:48 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D6749201ED for ; Tue, 22 Apr 2014 13:15:43 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AF6C5201F7 for ; Tue, 22 Apr 2014 13:15:37 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WcaVs-0005GA-Ec; Tue, 22 Apr 2014 13:13:28 +0000 Received: from top.free-electrons.com ([176.31.233.9] helo=mail.free-electrons.com) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WcaVY-0004w3-0x for linux-arm-kernel@lists.infradead.org; Tue, 22 Apr 2014 13:13:10 +0000 Received: by mail.free-electrons.com (Postfix, from userid 106) id 349F69C4; Tue, 22 Apr 2014 15:12:58 +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=-2.5 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from localhost.localdomain (col31-4-88-188-83-94.fbx.proxad.net [88.188.83.94]) by mail.free-electrons.com (Postfix) with ESMTPSA id 6C79C986; Tue, 22 Apr 2014 15:12:57 +0200 (CEST) From: Boris BREZILLON To: Nicolas Ferre , Mike Turquette Subject: [PATCH v3 03/11] clk: at91: add slow clks driver Date: Tue, 22 Apr 2014 15:12:32 +0200 Message-Id: <1398172360-7837-4-git-send-email-boris.brezillon@free-electrons.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1398172360-7837-1-git-send-email-boris.brezillon@free-electrons.com> References: <1398172360-7837-1-git-send-email-boris.brezillon@free-electrons.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140422_061308_529339_F9CFFBBC X-CRM114-Status: GOOD ( 20.70 ) X-Spam-Score: 0.3 (/) Cc: devicetree@vger.kernel.org, Jean-Jacques Hiblot , linux-doc@vger.kernel.org, Boris BREZILLON , linux-kernel@vger.kernel.org, Alexandre Belloni , Jean-Christophe PLAGNIOL-VILLARD , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP AT91 slow clk is a clk multiplexer. In some SoCs (sam9x5, sama5, sam9g45 families) this multiplexer can choose among 2 sources: an internal RC oscillator circuit and an oscillator using an external crystal. In other Socs (sam9260 family) the multiplexer source is hardcoded with the OSCSEL signal. Signed-off-by: Boris BREZILLON --- drivers/clk/at91/Makefile | 4 +- drivers/clk/at91/clk-slow.c | 467 +++++++++++++++++++++++++++++++++++++++++++ drivers/clk/at91/pmc.c | 5 + drivers/clk/at91/pmc.h | 3 + drivers/clk/at91/sckc.c | 57 ++++++ drivers/clk/at91/sckc.h | 22 ++ include/linux/clk/at91_pmc.h | 1 + 7 files changed, 557 insertions(+), 2 deletions(-) create mode 100644 drivers/clk/at91/clk-slow.c create mode 100644 drivers/clk/at91/sckc.c create mode 100644 drivers/clk/at91/sckc.h diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile index 46c1d3d..4998aee 100644 --- a/drivers/clk/at91/Makefile +++ b/drivers/clk/at91/Makefile @@ -2,8 +2,8 @@ # Makefile for at91 specific clk # -obj-y += pmc.o -obj-y += clk-main.o clk-pll.o clk-plldiv.o clk-master.o +obj-y += pmc.o sckc.o +obj-y += clk-slow.o clk-main.o clk-pll.o clk-plldiv.o clk-master.o obj-y += clk-system.o clk-peripheral.o clk-programmable.o obj-$(CONFIG_HAVE_AT91_UTMI) += clk-utmi.o diff --git a/drivers/clk/at91/clk-slow.c b/drivers/clk/at91/clk-slow.c new file mode 100644 index 0000000..fc2d54c --- /dev/null +++ b/drivers/clk/at91/clk-slow.c @@ -0,0 +1,467 @@ +/* + * drivers/clk/at91/clk-slow.c + * + * Copyright (C) 2013 Boris BREZILLON + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "pmc.h" +#include "sckc.h" + +#define SLOW_CLOCK_FREQ 32768 +#define SLOWCK_SW_CYCLES 5 +#define SLOWCK_SW_TIME_USEC ((SLOWCK_SW_CYCLES * USEC_PER_SEC) / \ + SLOW_CLOCK_FREQ) + +#define AT91_SCKC_CR 0x00 +#define AT91_SCKC_RCEN (1 << 0) +#define AT91_SCKC_OSC32EN (1 << 1) +#define AT91_SCKC_OSC32BYP (1 << 2) +#define AT91_SCKC_OSCSEL (1 << 3) + +struct clk_slow_osc { + struct clk_hw hw; + void __iomem *sckcr; + unsigned long startup_usec; +}; + +#define to_clk_slow_osc(hw) container_of(hw, struct clk_slow_osc, hw) + +struct clk_slow_rc_osc { + struct clk_hw hw; + void __iomem *sckcr; + unsigned long frequency; + unsigned long accuracy; + unsigned long startup_usec; +}; + +#define to_clk_slow_rc_osc(hw) container_of(hw, struct clk_slow_rc_osc, hw) + +struct clk_sam9260_slow { + struct clk_hw hw; + struct at91_pmc *pmc; +}; + +#define to_clk_sam9260_slow(hw) container_of(hw, struct clk_sam9260_slow, hw) + +struct clk_sam9x5_slow { + struct clk_hw hw; + void __iomem *sckcr; + u8 parent; +}; + +#define to_clk_sam9x5_slow(hw) container_of(hw, struct clk_sam9x5_slow, hw) + + +static int clk_slow_osc_prepare(struct clk_hw *hw) +{ + struct clk_slow_osc *osc = to_clk_slow_osc(hw); + void __iomem *sckcr = osc->sckcr; + u32 tmp = readl(sckcr); + + if (tmp & AT91_SCKC_OSC32BYP) + return 0; + + writel(tmp | AT91_SCKC_OSC32EN, sckcr); + + usleep_range(osc->startup_usec, osc->startup_usec + 1); + + return 0; +} + +static void clk_slow_osc_unprepare(struct clk_hw *hw) +{ + struct clk_slow_osc *osc = to_clk_slow_osc(hw); + void __iomem *sckcr = osc->sckcr; + u32 tmp = readl(sckcr); + + if (tmp & AT91_SCKC_OSC32BYP) + return; + + writel(tmp & ~AT91_SCKC_OSC32EN, sckcr); +} + +static int clk_slow_osc_is_prepared(struct clk_hw *hw) +{ + struct clk_slow_osc *osc = to_clk_slow_osc(hw); + void __iomem *sckcr = osc->sckcr; + u32 tmp = readl(sckcr); + + if (tmp & AT91_SCKC_OSC32BYP) + return 1; + + return !!(tmp & AT91_SCKC_OSC32EN); +} + +static const struct clk_ops slow_osc_ops = { + .prepare = clk_slow_osc_prepare, + .unprepare = clk_slow_osc_unprepare, + .is_prepared = clk_slow_osc_is_prepared, +}; + +static struct clk * __init +at91_clk_register_slow_osc(void __iomem *sckcr, + const char *name, + const char *parent_name, + unsigned long startup, + bool bypass) +{ + struct clk_slow_osc *osc; + struct clk *clk = NULL; + struct clk_init_data init; + + if (!sckcr || !name || !parent_name) + return ERR_PTR(-EINVAL); + + osc = kzalloc(sizeof(*osc), GFP_KERNEL); + if (!osc) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &slow_osc_ops; + init.parent_names = &parent_name; + init.num_parents = 1; + init.flags = 0; + + osc->hw.init = &init; + osc->sckcr = sckcr; + osc->startup_usec = startup; + + if (bypass) + writel((readl(sckcr) & ~AT91_SCKC_OSC32EN) | AT91_SCKC_OSC32BYP, + sckcr); + + clk = clk_register(NULL, &osc->hw); + if (IS_ERR(clk)) + kfree(osc); + + return clk; +} + +void __init of_at91sam9x5_clk_slow_osc_setup(struct device_node *np, + void __iomem *sckcr) +{ + struct clk *clk; + const char *parent_name; + const char *name = np->name; + u32 startup; + bool bypass; + + parent_name = of_clk_get_parent_name(np, 0); + of_property_read_string(np, "clock-output-names", &name); + of_property_read_u32(np, "atmel,startup-time-usec", &startup); + bypass = of_property_read_bool(np, "atmel,osc-bypass"); + + clk = at91_clk_register_slow_osc(sckcr, name, parent_name, startup, + bypass); + if (IS_ERR(clk)) + return; + + of_clk_add_provider(np, of_clk_src_simple_get, clk); +} + +static unsigned long clk_slow_rc_osc_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw); + + return osc->frequency; +} + +static unsigned long clk_slow_rc_osc_recalc_accuracy(struct clk_hw *hw, + unsigned long parent_acc) +{ + struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw); + + return osc->accuracy; +} + +static int clk_slow_rc_osc_prepare(struct clk_hw *hw) +{ + struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw); + void __iomem *sckcr = osc->sckcr; + + writel(readl(sckcr) | AT91_SCKC_RCEN, sckcr); + + usleep_range(osc->startup_usec, osc->startup_usec + 1); + + return 0; +} + +static void clk_slow_rc_osc_unprepare(struct clk_hw *hw) +{ + struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw); + void __iomem *sckcr = osc->sckcr; + + writel(readl(sckcr) & ~AT91_SCKC_RCEN, sckcr); +} + +static int clk_slow_rc_osc_is_prepared(struct clk_hw *hw) +{ + struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw); + + return !!(readl(osc->sckcr) & AT91_SCKC_RCEN); +} + +static const struct clk_ops slow_rc_osc_ops = { + .prepare = clk_slow_rc_osc_prepare, + .unprepare = clk_slow_rc_osc_unprepare, + .is_prepared = clk_slow_rc_osc_is_prepared, + .recalc_rate = clk_slow_rc_osc_recalc_rate, + .recalc_accuracy = clk_slow_rc_osc_recalc_accuracy, +}; + +static struct clk * __init +at91_clk_register_slow_rc_osc(void __iomem *sckcr, + const char *name, + unsigned long frequency, + unsigned long accuracy, + unsigned long startup) +{ + struct clk_slow_rc_osc *osc; + struct clk *clk = NULL; + struct clk_init_data init; + + if (!sckcr || !name) + return ERR_PTR(-EINVAL); + + osc = kzalloc(sizeof(*osc), GFP_KERNEL); + if (!osc) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &slow_rc_osc_ops; + init.parent_names = NULL; + init.num_parents = 0; + init.flags = CLK_IS_ROOT; + + osc->hw.init = &init; + osc->sckcr = sckcr; + osc->frequency = frequency; + osc->accuracy = accuracy; + osc->startup_usec = startup; + + clk = clk_register(NULL, &osc->hw); + if (IS_ERR(clk)) + kfree(osc); + + return clk; +} + +void __init of_at91sam9x5_clk_slow_rc_osc_setup(struct device_node *np, + void __iomem *sckcr) +{ + struct clk *clk; + u32 frequency = 0; + u32 accuracy = 0; + u32 startup = 0; + const char *name = np->name; + + of_property_read_string(np, "clock-output-names", &name); + of_property_read_u32(np, "clock-frequency", &frequency); + of_property_read_u32(np, "clock-accuracy", &accuracy); + of_property_read_u32(np, "atmel,startup-time-usec", &startup); + + clk = at91_clk_register_slow_rc_osc(sckcr, name, frequency, accuracy, + startup); + if (IS_ERR(clk)) + return; + + of_clk_add_provider(np, of_clk_src_simple_get, clk); +} + +static int clk_sam9x5_slow_set_parent(struct clk_hw *hw, u8 index) +{ + struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw); + void __iomem *sckcr = slowck->sckcr; + u32 tmp; + + if (index > 1) + return -EINVAL; + + tmp = readl(sckcr); + + if ((!index && !(tmp & AT91_SCKC_OSCSEL)) || + (index && (tmp & AT91_SCKC_OSCSEL))) + return 0; + + if (index) + tmp |= AT91_SCKC_OSCSEL; + else + tmp &= ~AT91_SCKC_OSCSEL; + + writel(tmp, sckcr); + + usleep_range(SLOWCK_SW_TIME_USEC, SLOWCK_SW_TIME_USEC + 1); + + return 0; +} + +static u8 clk_sam9x5_slow_get_parent(struct clk_hw *hw) +{ + struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw); + + return !!(readl(slowck->sckcr) & AT91_SCKC_OSCSEL); +} + +static const struct clk_ops sam9x5_slow_ops = { + .set_parent = clk_sam9x5_slow_set_parent, + .get_parent = clk_sam9x5_slow_get_parent, +}; + +static struct clk * __init +at91_clk_register_sam9x5_slow(void __iomem *sckcr, + const char *name, + const char **parent_names, + int num_parents) +{ + struct clk_sam9x5_slow *slowck; + struct clk *clk = NULL; + struct clk_init_data init; + + if (!sckcr || !name || !parent_names || !num_parents) + return ERR_PTR(-EINVAL); + + slowck = kzalloc(sizeof(*slowck), GFP_KERNEL); + if (!slowck) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &sam9x5_slow_ops; + init.parent_names = parent_names; + init.num_parents = num_parents; + init.flags = 0; + + slowck->hw.init = &init; + slowck->sckcr = sckcr; + slowck->parent = !!(readl(sckcr) & AT91_SCKC_OSCSEL); + + clk = clk_register(NULL, &slowck->hw); + if (IS_ERR(clk)) + kfree(slowck); + + return clk; +} + +void __init of_at91sam9x5_clk_slow_setup(struct device_node *np, + void __iomem *sckcr) +{ + struct clk *clk; + const char *parent_names[2]; + int num_parents; + const char *name = np->name; + int i; + + num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells"); + if (num_parents <= 0 || num_parents > 2) + return; + + for (i = 0; i < num_parents; ++i) { + parent_names[i] = of_clk_get_parent_name(np, i); + if (!parent_names[i]) + return; + } + + of_property_read_string(np, "clock-output-names", &name); + + clk = at91_clk_register_sam9x5_slow(sckcr, name, parent_names, + num_parents); + if (IS_ERR(clk)) + return; + + of_clk_add_provider(np, of_clk_src_simple_get, clk); +} + +static u8 clk_sam9260_slow_get_parent(struct clk_hw *hw) +{ + struct clk_sam9260_slow *slowck = to_clk_sam9260_slow(hw); + + return !!(pmc_read(slowck->pmc, AT91_PMC_SR) & AT91_PMC_OSCSEL); +} + +static const struct clk_ops sam9260_slow_ops = { + .get_parent = clk_sam9260_slow_get_parent, +}; + +static struct clk * __init +at91_clk_register_sam9260_slow(struct at91_pmc *pmc, + const char *name, + const char **parent_names, + int num_parents) +{ + struct clk_sam9260_slow *slowck; + struct clk *clk = NULL; + struct clk_init_data init; + + if (!pmc || !name) + return ERR_PTR(-EINVAL); + + if (!parent_names || !num_parents) + return ERR_PTR(-EINVAL); + + slowck = kzalloc(sizeof(*slowck), GFP_KERNEL); + if (!slowck) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &sam9260_slow_ops; + init.parent_names = parent_names; + init.num_parents = num_parents; + init.flags = 0; + + slowck->hw.init = &init; + slowck->pmc = pmc; + + clk = clk_register(NULL, &slowck->hw); + if (IS_ERR(clk)) + kfree(slowck); + + return clk; +} + +void __init of_at91sam9260_clk_slow_setup(struct device_node *np, + struct at91_pmc *pmc) +{ + struct clk *clk; + const char *parent_names[2]; + int num_parents; + const char *name = np->name; + int i; + + num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells"); + if (num_parents <= 0 || num_parents > 1) + return; + + for (i = 0; i < num_parents; ++i) { + parent_names[i] = of_clk_get_parent_name(np, i); + if (!parent_names[i]) + return; + } + + of_property_read_string(np, "clock-output-names", &name); + + clk = at91_clk_register_sam9260_slow(pmc, name, parent_names, + num_parents); + if (IS_ERR(clk)) + return; + + of_clk_add_provider(np, of_clk_src_simple_get, clk); +} diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c index dc5fdde..524196b 100644 --- a/drivers/clk/at91/pmc.c +++ b/drivers/clk/at91/pmc.c @@ -229,6 +229,11 @@ out_free_pmc: } static const struct of_device_id pmc_clk_ids[] __initconst = { + /* Slow oscillator */ + { + .compatible = "atmel,at91sam9260-clk-slow", + .data = of_at91sam9260_clk_slow_setup, + }, /* Main clock */ { .compatible = "atmel,at91rm9200-clk-main-osc", diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h index 42cc7cc..6c76259 100644 --- a/drivers/clk/at91/pmc.h +++ b/drivers/clk/at91/pmc.h @@ -58,6 +58,9 @@ static inline void pmc_write(struct at91_pmc *pmc, int offset, u32 value) int of_at91_get_clk_range(struct device_node *np, const char *propname, struct clk_range *range); +extern void __init of_at91sam9260_clk_slow_setup(struct device_node *np, + struct at91_pmc *pmc); + extern void __init of_at91rm9200_clk_main_osc_setup(struct device_node *np, struct at91_pmc *pmc); extern void __init of_at91sam9x5_clk_main_rc_osc_setup(struct device_node *np, diff --git a/drivers/clk/at91/sckc.c b/drivers/clk/at91/sckc.c new file mode 100644 index 0000000..1184d76 --- /dev/null +++ b/drivers/clk/at91/sckc.c @@ -0,0 +1,57 @@ +/* + * drivers/clk/at91/sckc.c + * + * Copyright (C) 2013 Boris BREZILLON + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ + +#include +#include +#include +#include +#include + +#include "sckc.h" + +static const struct of_device_id sckc_clk_ids[] __initconst = { + /* Slow clock */ + { + .compatible = "atmel,at91sam9x5-clk-slow-osc", + .data = of_at91sam9x5_clk_slow_osc_setup, + }, + { + .compatible = "atmel,at91sam9x5-clk-slow-rc-osc", + .data = of_at91sam9x5_clk_slow_rc_osc_setup, + }, + { + .compatible = "atmel,at91sam9x5-clk-slow", + .data = of_at91sam9x5_clk_slow_setup, + }, + { /*sentinel*/ } +}; + +static void __init of_at91sam9x5_sckc_setup(struct device_node *np) +{ + struct device_node *childnp; + void (*clk_setup)(struct device_node *, void __iomem *); + const struct of_device_id *clk_id; + void __iomem *regbase = of_iomap(np, 0); + + if (!regbase) + return; + + for_each_child_of_node(np, childnp) { + clk_id = of_match_node(sckc_clk_ids, childnp); + if (!clk_id) + continue; + clk_setup = clk_id->data; + clk_setup(childnp, regbase); + } +} +CLK_OF_DECLARE(at91sam9x5_clk_sckc, "atmel,at91sam9x5-sckc", + of_at91sam9x5_sckc_setup); diff --git a/drivers/clk/at91/sckc.h b/drivers/clk/at91/sckc.h new file mode 100644 index 0000000..836fcf5 --- /dev/null +++ b/drivers/clk/at91/sckc.h @@ -0,0 +1,22 @@ +/* + * drivers/clk/at91/sckc.h + * + * Copyright (C) 2013 Boris BREZILLON + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#ifndef __AT91_SCKC_H_ +#define __AT91_SCKC_H_ + +extern void __init of_at91sam9x5_clk_slow_osc_setup(struct device_node *np, + void __iomem *sckcr); +extern void __init of_at91sam9x5_clk_slow_rc_osc_setup(struct device_node *np, + void __iomem *sckcr); +extern void __init of_at91sam9x5_clk_slow_setup(struct device_node *np, + void __iomem *sckcr); + +#endif /* __AT91_SCKC_H_ */ diff --git a/include/linux/clk/at91_pmc.h b/include/linux/clk/at91_pmc.h index a6911eb..de4268d 100644 --- a/include/linux/clk/at91_pmc.h +++ b/include/linux/clk/at91_pmc.h @@ -155,6 +155,7 @@ extern void __iomem *at91_pmc_base; #define AT91_PMC_LOCKB (1 << 2) /* PLLB Lock */ #define AT91_PMC_MCKRDY (1 << 3) /* Master Clock */ #define AT91_PMC_LOCKU (1 << 6) /* UPLL Lock [some SAM9] */ +#define AT91_PMC_OSCSEL (1 << 7) /* Slow Oscillator Selection [some SAM9] */ #define AT91_PMC_PCK0RDY (1 << 8) /* Programmable Clock 0 */ #define AT91_PMC_PCK1RDY (1 << 9) /* Programmable Clock 1 */ #define AT91_PMC_PCK2RDY (1 << 10) /* Programmable Clock 2 */