[PATCH v2 02/42] ARM: at91: add PMC main clock

[boris brezillon]

On 17/07/2013 15:40, Boris BREZILLON wrote:
> This is the at91 main oscillator clock implementation using common
> clk framework.
>
> If rate is not provided during clock registraction it is computed using
> the slow clock (main clk parent in this case) rate and the MCFR register.
>
> Signed-off-by: Boris BREZILLON <b.brezillon at overkiz.com>
> ---
>   drivers/clk/at91/Makefile   |    5 ++
>   drivers/clk/at91/clk-main.c |  106 +++++++++++++++++++++++++++++++++++++++++++
>   include/linux/clk/at91.h    |   10 ++++
>   3 files changed, 121 insertions(+)
>   create mode 100644 drivers/clk/at91/Makefile
>   create mode 100644 drivers/clk/at91/clk-main.c
>
> diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
> new file mode 100644
> index 0000000..42c084e
> --- /dev/null
> +++ b/drivers/clk/at91/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile for at91 specific clk
> +#
> +
> +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..738fa39
> --- /dev/null
> +++ b/drivers/clk/at91/clk-main.c
> @@ -0,0 +1,106 @@
> +/*
> + * drivers/clk/at91/clk-main.c
> + *
> + *  Copyright (C) 2013 Boris BREZILLON <b.brezillon at overkiz.com>
> + *
> + * This mainram 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.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/io.h>
> +
> +#define to_clk_main(hw) container_of(hw, struct clk_main, hw)
> +struct clk_main {
> +	struct clk_hw hw;
> +	unsigned long rate;
> +};
> +
> +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);
> +	if (clkmain->rate)
> +		return clkmain->rate;
> +	while ((tmp = at91_pmc_read(AT91_CKGR_MCFR)) & AT91_PMC_MAINRDY)
> +		;
wrong test here, should be:

while (!((tmp = at91_pmc_read(AT91_CKGR_MCFR)) & AT91_PMC_MAINRDY))
	;


> +	tmp &= AT91_PMC_MAINF;
> +	clkmain->rate = (tmp * parent_rate) / 16;
> +	return clkmain->rate;
> +}
> +
> +static const struct clk_ops main_ops = {
> +	.recalc_rate = clk_main_recalc_rate,
> +};
> +
> +struct clk * __init
> +at91_clk_register_main(const char *name,
> +		       const char *parent_name,
> +		       unsigned long rate)
> +{
> +	struct clk_main *clkmain;
> +	struct clk *clk = NULL;
> +	struct clk_init_data init;
> +
> +	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;
> +
> +	clk = clk_register(NULL, &clkmain->hw);
> +
> +	if (IS_ERR(clk))
> +		kfree(clkmain);
> +
> +	return clk;
> +}
> +
> +
> +
> +#if defined(CONFIG_OF)
> +static void __init
> +of_at91_clk_main_setup(struct device_node *np)
> +{
> +	struct clk *clk;
> +	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);
> +
> +	clk = at91_clk_register_main(name, parent_name, rate);
> +
> +	if (!IS_ERR(clk))
> +		return;
> +
> +	of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +}
> +
> +static void __init of_at91rm9200_clk_main_setup(struct device_node *np)
> +{
> +	of_at91_clk_main_setup(np);
> +}
> +CLK_OF_DECLARE(at91rm9200_clk_main, "atmel,at91rm9200-clk-main",
> +	       of_at91rm9200_clk_main_setup);
> +#endif
> diff --git a/include/linux/clk/at91.h b/include/linux/clk/at91.h
> index 0ce9586..8e83942 100644
> --- a/include/linux/clk/at91.h
> +++ b/include/linux/clk/at91.h
> @@ -16,6 +16,8 @@
>   #ifndef AT91_PMC_H
>   #define AT91_PMC_H
>   
> +#include <linux/clk-provider.h>
> +
>   #ifndef __ASSEMBLY__
>   extern void __iomem *at91_pmc_base;
>   
> @@ -187,4 +189,12 @@ extern void __iomem *at91_pmc_base;
>   #define			AT91_PMC_PCR_DIV8	0x3			/* Peripheral clock is MCK/8 */
>   #define		AT91_PMC_PCR_EN		(0x1  <<  28)		/* Enable */
>   
> +
> +
> +
> +struct clk * __init
> +at91_clk_register_main(const char *name,
> +		       const char *parent_name,
> +		       unsigned long rate);
> +
>   #endif