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Message-ID: <5260093D.7090404@atmel.com>
Date: Thu, 17 Oct 2013 17:58:53 +0200
From: Nicolas Ferre <nicolas.ferre@...el.com>
To: Boris BREZILLON <b.brezillon@...rkiz.com>,
Rob Herring <rob.herring@...xeda.com>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Stephen Warren <swarren@...dotorg.org>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Rob Landley <rob@...dley.net>,
Andrew Victor <linux@...im.org.za>,
Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
Russell King <linux@....linux.org.uk>,
"Mike Turquette" <mturquette@...aro.org>,
Felipe Balbi <balbi@...com>,
"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
Grant Likely <grant.likely@...aro.org>,
Ludovic Desroches <ludovic.desroches@...el.com>,
Josh Wu <josh.wu@...el.com>,
Richard Genoud <richard.genoud@...il.com>
CC: <devicetree@...r.kernel.org>, <linux-doc@...r.kernel.org>,
<linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>, <linux-usb@...r.kernel.org>
Subject: Re: [PATCH v4 05/17] clk: at91: add PMC main clock
On 11/10/2013 10:44, Boris BREZILLON :
> This patch adds new at91 main oscillator clock implementation using common
> clk framework.
>
> If rate is not provided during clock registration it is calculated using
> the slow clock (main clk parent in this case) rate and MCFR register.
>
> Signed-off-by: Boris BREZILLON <b.brezillon@...rkiz.com>
Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>
> ---
> drivers/clk/at91/Makefile | 1 +
> drivers/clk/at91/clk-main.c | 189 +++++++++++++++++++++++++++++++++++++++++++
> drivers/clk/at91/pmc.c | 5 ++
> drivers/clk/at91/pmc.h | 3 +
> 4 files changed, 198 insertions(+)
> create mode 100644 drivers/clk/at91/clk-main.c
>
> diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
> index 1d4fb21..44105bd 100644
> --- a/drivers/clk/at91/Makefile
> +++ b/drivers/clk/at91/Makefile
> @@ -3,3 +3,4 @@
> #
>
> obj-y += pmc.o
> +obj-y += clk-main.o
> diff --git a/drivers/clk/at91/clk-main.c b/drivers/clk/at91/clk-main.c
> new file mode 100644
> index 0000000..905ceff
> --- /dev/null
> +++ b/drivers/clk/at91/clk-main.c
> @@ -0,0 +1,189 @@
> +/*
> + * drivers/clk/at91/clk-main.c
> + *
> + * Copyright (C) 2013 Boris BREZILLON <b.brezillon@...rkiz.com>
> + *
> + * 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 <linux/clk-provider.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk/at91_pmc.h>
> +#include <linux/delay.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/io.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/sched.h>
> +#include <linux/wait.h>
> +
> +#include "pmc.h"
> +
> +#define SLOW_CLOCK_FREQ 32768
> +#define MAINF_DIV 16
> +#define MAINFRDY_TIMEOUT (((MAINF_DIV + 1) * USEC_PER_SEC) / \
> + SLOW_CLOCK_FREQ)
> +#define MAINF_LOOP_MIN_WAIT (USEC_PER_SEC / SLOW_CLOCK_FREQ)
> +#define MAINF_LOOP_MAX_WAIT MAINFRDY_TIMEOUT
> +
> +struct clk_main {
> + struct clk_hw hw;
> + struct at91_pmc *pmc;
> + unsigned long rate;
> + unsigned int irq;
> + wait_queue_head_t wait;
> +};
> +
> +#define to_clk_main(hw) container_of(hw, struct clk_main, hw)
> +
> +static irqreturn_t clk_main_irq_handler(int irq, void *dev_id)
> +{
> + struct clk_main *clkmain = (struct clk_main *)dev_id;
> +
> + wake_up(&clkmain->wait);
> + disable_irq_nosync(clkmain->irq);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int clk_main_prepare(struct clk_hw *hw)
> +{
> + struct clk_main *clkmain = to_clk_main(hw);
> + struct at91_pmc *pmc = clkmain->pmc;
> + unsigned long halt_time, timeout;
> + u32 tmp;
> +
> + while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCS)) {
> + enable_irq(clkmain->irq);
> + wait_event(clkmain->wait,
> + pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCS);
> + }
> +
> + if (clkmain->rate)
> + return 0;
> +
> + timeout = jiffies + usecs_to_jiffies(MAINFRDY_TIMEOUT);
> + do {
> + halt_time = jiffies;
> + tmp = pmc_read(pmc, AT91_CKGR_MCFR);
> + if (tmp & AT91_PMC_MAINRDY)
> + return 0;
> + usleep_range(MAINF_LOOP_MIN_WAIT, MAINF_LOOP_MAX_WAIT);
> + } while (time_before(halt_time, timeout));
> +
> + return 0;
> +}
> +
> +static int clk_main_is_prepared(struct clk_hw *hw)
> +{
> + struct clk_main *clkmain = to_clk_main(hw);
> +
> + return !!(pmc_read(clkmain->pmc, AT91_PMC_SR) & AT91_PMC_MOSCS);
> +}
> +
> +static unsigned long clk_main_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + u32 tmp;
> + struct clk_main *clkmain = to_clk_main(hw);
> + struct at91_pmc *pmc = clkmain->pmc;
> +
> + if (clkmain->rate)
> + return clkmain->rate;
> +
> + tmp = pmc_read(pmc, AT91_CKGR_MCFR) & AT91_PMC_MAINF;
> + clkmain->rate = (tmp * parent_rate) / MAINF_DIV;
> +
> + return clkmain->rate;
> +}
> +
> +static const struct clk_ops main_ops = {
> + .prepare = clk_main_prepare,
> + .is_prepared = clk_main_is_prepared,
> + .recalc_rate = clk_main_recalc_rate,
> +};
> +
> +static struct clk * __init
> +at91_clk_register_main(struct at91_pmc *pmc,
> + unsigned int irq,
> + const char *name,
> + const char *parent_name,
> + unsigned long rate)
> +{
> + int ret;
> + struct clk_main *clkmain;
> + struct clk *clk = NULL;
> + struct clk_init_data init;
> +
> + if (!pmc || !irq || !name)
> + return ERR_PTR(-EINVAL);
> +
> + if (!rate && !parent_name)
> + return ERR_PTR(-EINVAL);
> +
> + clkmain = kzalloc(sizeof(*clkmain), GFP_KERNEL);
> + if (!clkmain)
> + return ERR_PTR(-ENOMEM);
> +
> + init.name = name;
> + init.ops = &main_ops;
> + init.parent_names = parent_name ? &parent_name : NULL;
> + init.num_parents = parent_name ? 1 : 0;
> + init.flags = parent_name ? 0 : CLK_IS_ROOT;
> +
> + clkmain->hw.init = &init;
> + clkmain->rate = rate;
> + clkmain->pmc = pmc;
> + clkmain->irq = irq;
> + init_waitqueue_head(&clkmain->wait);
> + irq_set_status_flags(clkmain->irq, IRQ_NOAUTOEN);
> + ret = request_irq(clkmain->irq, clk_main_irq_handler,
> + IRQF_TRIGGER_HIGH, "clk-main", clkmain);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + clk = clk_register(NULL, &clkmain->hw);
> + if (IS_ERR(clk)) {
> + free_irq(clkmain->irq, clkmain);
> + kfree(clkmain);
> + }
> +
> + return clk;
> +}
> +
> +
> +
> +static void __init
> +of_at91_clk_main_setup(struct device_node *np, struct at91_pmc *pmc)
> +{
> + struct clk *clk;
> + unsigned int irq;
> + const char *parent_name;
> + const char *name = np->name;
> + u32 rate = 0;
> +
> + parent_name = of_clk_get_parent_name(np, 0);
> + of_property_read_string(np, "clock-output-names", &name);
> + of_property_read_u32(np, "clock-frequency", &rate);
> + irq = irq_of_parse_and_map(np, 0);
> + if (!irq)
> + return;
> +
> + clk = at91_clk_register_main(pmc, irq, name, parent_name, rate);
> + if (IS_ERR(clk))
> + return;
> +
> + of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +}
> +
> +void __init of_at91rm9200_clk_main_setup(struct device_node *np,
> + struct at91_pmc *pmc)
> +{
> + of_at91_clk_main_setup(np, pmc);
> +}
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index d92e46c..ccfe506 100644
> --- a/drivers/clk/at91/pmc.c
> +++ b/drivers/clk/at91/pmc.c
> @@ -208,6 +208,11 @@ out_free_pmc:
> }
>
> static const struct of_device_id pmc_clk_ids[] __initdata = {
> + /* Main clock */
> + {
> + .compatible = "atmel,at91rm9200-clk-main",
> + .data = of_at91rm9200_clk_main_setup
> + },
> { /*sentinel*/ }
> };
>
> diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
> index b7e8397..294e230 100644
> --- a/drivers/clk/at91/pmc.h
> +++ b/drivers/clk/at91/pmc.h
> @@ -55,4 +55,7 @@ static inline void pmc_write(struct at91_pmc *pmc, int offset, u32 value)
> return writel_relaxed(value, pmc->regbase + offset);
> }
>
> +extern void __init of_at91rm9200_clk_main_setup(struct device_node *np,
> + struct at91_pmc *pmc);
> +
> #endif /* __PMC_H_ */
>
--
Nicolas Ferre
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