Re: [PATCH v3 14/19] clk: at91: add PMC utmi clock

[Nicolas Ferre <nicolas.ferre@atmel.com>]

On 08/08/2013 09:14, Boris BREZILLON :
> This adds new at91 utmi clock implementation using common clk framework.
>
> This clock is a pll with a fixed factor (x40).
> It is used as a source for usb clock.
>
> Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
> ---
>   arch/arm/mach-at91/Kconfig  |    7 ++
>   drivers/clk/at91/Makefile   |    1 +
>   drivers/clk/at91/clk-utmi.c |  161 +++++++++++++++++++++++++++++++++++++++++++
>   drivers/clk/at91/pmc.c      |    7 ++
>   drivers/clk/at91/pmc.h      |    5 ++
>   5 files changed, 181 insertions(+)
>   create mode 100644 drivers/clk/at91/clk-utmi.c
>
> diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
> index 85b53a4..6ad37da 100644
> --- a/arch/arm/mach-at91/Kconfig
> +++ b/arch/arm/mach-at91/Kconfig
> @@ -1,5 +1,8 @@
>   if ARCH_AT91
>
> +config HAVE_AT91_UTMI
> +	bool
> +
>   config HAVE_AT91_DBGU0
>   	bool
>
> @@ -78,6 +81,7 @@ config SOC_SAMA5D3
>   	select HAVE_FB_ATMEL
>   	select HAVE_AT91_DBGU1
>   	select AT91_USE_OLD_CLK
> +	select HAVE_AT91_UTMI
>   	help
>   	  Select this if you are using one of Atmel's SAMA5D3 family SoC.
>   	  This support covers SAMA5D31, SAMA5D33, SAMA5D34, SAMA5D35.
> @@ -124,6 +128,7 @@ config SOC_AT91SAM9RL
>   	select HAVE_FB_ATMEL
>   	select SOC_AT91SAM9
>   	select AT91_USE_OLD_CLK
> +	select HAVE_AT91_UTMI
>
>   config SOC_AT91SAM9G45
>   	bool "AT91SAM9G45 or AT91SAM9M10 families"
> @@ -131,6 +136,7 @@ config SOC_AT91SAM9G45
>   	select HAVE_FB_ATMEL
>   	select SOC_AT91SAM9
>   	select AT91_USE_OLD_CLK
> +	select HAVE_AT91_UTMI
>   	help
>   	  Select this if you are using one of Atmel's AT91SAM9G45 family SoC.
>   	  This support covers AT91SAM9G45, AT91SAM9G46, AT91SAM9M10 and AT91SAM9M11.
> @@ -141,6 +147,7 @@ config SOC_AT91SAM9X5
>   	select HAVE_FB_ATMEL
>   	select SOC_AT91SAM9
>   	select AT91_USE_OLD_CLK
> +	select HAVE_AT91_UTMI
>   	help
>   	  Select this if you are using one of Atmel's AT91SAM9x5 family SoC.
>   	  This means that your SAM9 name finishes with a '5' (except if it is
> diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
> index 3873b62..a824883 100644
> --- a/drivers/clk/at91/Makefile
> +++ b/drivers/clk/at91/Makefile
> @@ -7,3 +7,4 @@ obj-y += clk-main.o clk-pll.o clk-plldiv.o clk-master.o
>   obj-y += clk-system.o clk-peripheral.o
>
>   obj-$(CONFIG_AT91_PROGRAMMABLE_CLOCKS)	+= clk-programmable.o
> +obj-$(CONFIG_HAVE_AT91_UTMI)		+= clk-utmi.o
> diff --git a/drivers/clk/at91/clk-utmi.c b/drivers/clk/at91/clk-utmi.c
> new file mode 100644
> index 0000000..244ff9e
> --- /dev/null
> +++ b/drivers/clk/at91/clk-utmi.c
> @@ -0,0 +1,161 @@
> +/*
> + * drivers/clk/at91/clk-utmi.c
> + *
> + *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.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/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/io.h>
> +#include <linux/sched.h>
> +#include <linux/wait.h>
> +
> +#include "pmc.h"
> +
> +#define to_clk_utmi(hw) container_of(hw, struct clk_utmi, hw)
> +
> +struct clk_utmi {
> +	struct clk_hw hw;
> +	struct at91_pmc *pmc;
> +	unsigned int irq;
> +	wait_queue_head_t wait;
> +};
> +
> +static irqreturn_t clk_utmi_irq_handler(int irq, void *dev_id)
> +{
> +	struct clk_utmi *utmi = (struct clk_utmi *)dev_id;
> +
> +	wake_up(&utmi->wait);
> +	disable_irq_nosync(utmi->irq);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int clk_utmi_prepare(struct clk_hw *hw)
> +{
> +	struct clk_utmi *utmi = to_clk_utmi(hw);
> +	struct at91_pmc *pmc = utmi->pmc;
> +	u32 tmp = at91_pmc_read(AT91_CKGR_UCKR) | AT91_PMC_UPLLEN |
> +		  AT91_PMC_UPLLCOUNT | AT91_PMC_BIASEN;
> +
> +	pmc_write(pmc, AT91_CKGR_UCKR, tmp);
> +
> +	while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU)) {
> +		enable_irq(utmi->irq);
> +		wait_event(utmi->wait,
> +			   pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU);
> +	}
> +
> +	return 0;
> +}
> +
> +static int clk_utmi_is_ready(struct clk_hw *hw)
> +{
> +	struct clk_utmi *utmi = to_clk_utmi(hw);
> +	struct at91_pmc *pmc = utmi->pmc;
> +
> +	return !!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU);
> +}
> +
> +static void clk_utmi_disable(struct clk_hw *hw)
> +{
> +	struct clk_utmi *utmi = to_clk_utmi(hw);
> +	struct at91_pmc *pmc = utmi->pmc;
> +	u32 tmp = at91_pmc_read(AT91_CKGR_UCKR) & ~AT91_PMC_UPLLEN;
> +
> +	pmc_write(pmc, AT91_CKGR_UCKR, tmp);
> +}
> +
> +static unsigned long clk_utmi_recalc_rate(struct clk_hw *hw,
> +					  unsigned long parent_rate)
> +{
> +	return parent_rate * 40;

A constant or a little comment right here is necessary. As it is fixed 
by nature, I am not against such a number, but a comment is a must for 
this situation.

> +}
> +
> +static const struct clk_ops utmi_ops = {
> +	.prepare = clk_utmi_prepare,
> +	.is_prepared = clk_utmi_is_ready,
> +	.disable = clk_utmi_disable,
> +	.is_enabled = clk_utmi_is_ready,
> +	.recalc_rate = clk_utmi_recalc_rate,
> +};
> +
> +static struct clk * __init
> +at91_clk_register_utmi(struct at91_pmc *pmc, unsigned int irq,
> +		       const char *name, const char *parent_name)
> +{
> +	int ret;
> +	struct clk_utmi *utmi;
> +	struct clk *clk = NULL;
> +	struct clk_init_data init;
> +
> +	utmi = kzalloc(sizeof(*utmi), GFP_KERNEL);
> +	if (!utmi)
> +		return ERR_PTR(-ENOMEM);
> +
> +	init.name = name;
> +	init.ops = &utmi_ops;
> +	init.parent_names = parent_name ? &parent_name : NULL;
> +	init.num_parents = parent_name ? 1 : 0;
> +	init.flags = CLK_SET_RATE_GATE;
> +
> +	utmi->hw.init = &init;
> +	utmi->pmc = pmc;
> +	utmi->irq = irq;
> +	init_waitqueue_head(&utmi->wait);
> +	irq_set_status_flags(utmi->irq, IRQ_NOAUTOEN);
> +	ret = request_irq(utmi->irq, clk_utmi_irq_handler,
> +			  IRQF_TRIGGER_HIGH, "clk-utmi", utmi);
> +	if (ret)
> +		return ERR_PTR(ret);
> +
> +	clk = clk_register(NULL, &utmi->hw);
> +

..

> +	if (IS_ERR(clk))
> +		kfree(utmi);
> +
> +	return clk;
> +}
> +
> +static void __init
> +of_at91_clk_utmi_setup(struct device_node *np, struct at91_pmc *pmc)
> +{
> +	unsigned int irq;
> +	struct clk *clk;
> +	const char *parent_name;
> +	const char *name = np->name;
> +
> +	parent_name = of_clk_get_parent_name(np, 0);
> +
> +	of_property_read_string(np, "clock-output-names", &name);
> +
> +	irq = irq_of_parse_and_map(np, 0);
> +	if (!irq)
> +		return;
> +
> +	clk = at91_clk_register_utmi(pmc, irq, name, parent_name);
> +

..

> +	if (IS_ERR(clk))
> +		return;
> +
> +	of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +	return;
> +}
> +
> +void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np,
> +					 struct at91_pmc *pmc)
> +{
> +	of_at91_clk_utmi_setup(np, pmc);
> +}
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index 66a627d..238f0d2 100644
> --- a/drivers/clk/at91/pmc.c
> +++ b/drivers/clk/at91/pmc.c
> @@ -280,6 +280,13 @@ static const struct of_device_id pmc_clk_ids[] __initdata = {
>   		.data = of_at91sam9x5_clk_prog_setup,
>   	},
>   #endif
> +	/* UTMI clock */
> +#if defined(CONFIG_HAVE_AT91_UTMI)
> +	{
> +		.compatible = "atmel,at91sam9x5-clk-utmi",
> +		.data = of_at91sam9x5_clk_utmi_setup,
> +	},
> +#endif
>   	{ /*sentinel*/ }
>   };
>
> diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
> index 5f20dc1..3ba9503 100644
> --- a/drivers/clk/at91/pmc.h
> +++ b/drivers/clk/at91/pmc.h
> @@ -91,4 +91,9 @@ extern void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
>   						struct at91_pmc *pmc);
>   #endif
>
> +#if defined(CONFIG_HAVE_AT91_UTMI)
> +extern void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np,
> +						struct at91_pmc *pmc);
> +#endif
> +
>   #endif /* __PMC_H_ */
>


-- 
Nicolas Ferre