Re: [PATCH v3 09/19] clk: at91: add PMC system clocks

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

On 08/08/2013 08:12, Boris BREZILLON :
> This patch adds new at91 system clock implementation using common clk
> framework.
>
> Some peripherals need to enable a "system" clock in order to work properly.
> Each system clock is given an id based on the bit position in SCER/SCDR
> registers.
>
> Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
> ---
>   drivers/clk/at91/Makefile     |    1 +
>   drivers/clk/at91/clk-system.c |  191 +++++++++++++++++++++++++++++++++++++++++
>   drivers/clk/at91/pmc.c        |    5 ++
>   drivers/clk/at91/pmc.h        |    3 +
>   4 files changed, 200 insertions(+)
>   create mode 100644 drivers/clk/at91/clk-system.c
>
> diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
> index e28fb2b..c2b7068 100644
> --- a/drivers/clk/at91/Makefile
> +++ b/drivers/clk/at91/Makefile
> @@ -4,3 +4,4 @@
>
>   obj-y += pmc.o
>   obj-y += clk-main.o clk-pll.o clk-plldiv.o clk-master.o
> +obj-y += clk-system.o
> diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c
> new file mode 100644
> index 0000000..11a3eb8
> --- /dev/null
> +++ b/drivers/clk/at91/clk-system.c
> @@ -0,0 +1,191 @@
> +/*
> + * drivers/clk/at91/clk-system.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/of.h>
> +#include <linux/of_address.h>
> +#include <linux/io.h>
> +
> +#include "pmc.h"
> +
> +#define SYSTEM_MAX		32
> +
> +#define to_clk_system(hw) container_of(hw, struct clk_system, hw)
> +struct clk_system {
> +	struct clk_hw hw;
> +	struct at91_pmc *pmc;
> +	u8 id;
> +};
> +
> +static int clk_system_enable(struct clk_hw *hw)
> +{
> +	struct clk_system *sys = to_clk_system(hw);
> +	struct at91_pmc *pmc = sys->pmc;
> +
> +	pmc_write(pmc, AT91_PMC_SCER, 1 << sys->id);
> +	return 0;
> +}
> +
> +static void clk_system_disable(struct clk_hw *hw)
> +{
> +	struct clk_system *sys = to_clk_system(hw);
> +	struct at91_pmc *pmc = sys->pmc;
> +
> +	pmc_write(pmc, AT91_PMC_SCDR, 1 << sys->id);
> +}
> +
> +static int clk_system_is_enabled(struct clk_hw *hw)
> +{
> +	struct clk_system *sys = to_clk_system(hw);
> +	struct at91_pmc *pmc = sys->pmc;
> +
> +	return !!(pmc_read(pmc, AT91_PMC_SCSR) & (1 << sys->id));
> +}
> +
> +static const struct clk_ops system_ops = {
> +	.enable = clk_system_enable,
> +	.disable = clk_system_disable,
> +	.is_enabled = clk_system_is_enabled,
> +};
> +
> +static struct clk * __init
> +at91_clk_register_system(struct at91_pmc *pmc, const char *name, u8 id)
> +{
> +	struct clk_system *sys;
> +	struct clk *clk = NULL;
> +	struct clk_init_data init;
> +
> +	id &= 31;

defined constant. Or event return an error instead of masking it (same 
for pll ids if I remember well).

> +
> +	sys = kzalloc(sizeof(*sys), GFP_KERNEL);
> +	if (!sys)
> +		return ERR_PTR(-ENOMEM);
> +
> +	init.name = name;
> +	init.ops = &system_ops;
> +	init.parent_names = NULL;
> +	init.num_parents = 0;
> +	/*
> +	 * CLK_IGNORE_UNUSED is used to avoid ddrck switch off.
> +	 * TODO : we should implement a driver supporting at91 ddr controller
> +	 * (see drivers/memory) which would request and enable the ddrck clock.
> +	 * When this is done we will be able to remove CLK_IGNORE_UNUSED flag.
> +	 */
> +	init.flags = CLK_IS_ROOT | CLK_IGNORE_UNUSED;

Is it a root clock? Usually clock parent for USB is UTMI or PLLB, LCD is 
usually the MCK. But I do not know how it interfere with your clock tree...

> +
> +	sys->id = id;
> +	sys->hw.init = &init;
> +	sys->pmc = pmc;
> +
> +	clk = clk_register(NULL, &sys->hw);
> +
> +	if (IS_ERR(clk))
> +		kfree(sys);
> +
> +	return clk;
> +}
> +
> +struct clk_system_data {
> +	struct clk **clks;
> +	u8 *ids;
> +	unsigned int clk_num;
> +};
> +
> +static struct clk * __init
> +of_clk_src_system_get(struct of_phandle_args *clkspec, void *data)
> +{
> +	struct clk_system_data *clk_data = data;
> +	unsigned int id = clkspec->args[0];
> +	int i;
> +
> +	if (id >= SYSTEM_MAX)
> +		goto err;
> +
> +	for (i = 0; i < clk_data->clk_num; i++) {
> +		if (clk_data->ids[i] == id)
> +			return clk_data->clks[i];
> +	}
> +
> +err:
> +	pr_err("%s: invalid clock id %d\n", __func__, id);
> +	return ERR_PTR(-EINVAL);
> +}
> +
> +static void __init
> +of_at91_clk_sys_setup(struct device_node *np, struct at91_pmc *pmc)
> +{
> +	int i;
> +	int num;
> +	u32 id;
> +	struct clk *clk;
> +	u8 *ids;
> +	struct clk **clks;
> +	struct clk_system_data *clktab;
> +	const char *name;
> +	struct device_node *sysclknp;
> +
> +	num = of_get_child_count(np);
> +	if (num > SYSTEM_MAX)
> +		return;
> +
> +	clktab = kzalloc(sizeof(*clktab), GFP_KERNEL);
> +	if (!clktab)
> +		return;
> +
> +	ids = kzalloc(num * sizeof(*ids), GFP_KERNEL);
> +	if (!ids)
> +		goto out_free_clktab;
> +
> +	clks = kzalloc(num * sizeof(*clks), GFP_KERNEL);
> +	if (!clks)
> +		goto out_free_ids;
> +
> +	i = 0;
> +	for_each_child_of_node(np, sysclknp) {
> +		name = sysclknp->name;
> +
> +		if (of_property_read_u32(sysclknp, "atmel,clk-id", &id))
> +			goto out_free_clks;
> +		if (id >= SYSTEM_MAX)
> +			goto out_free_clks;
> +
> +		clk = at91_clk_register_system(pmc, name, id);
> +		if (IS_ERR(clk))
> +			goto out_free_clks;
> +
> +		clks[i] = clk;
> +		ids[i] = id;
> +
> +		i++;
> +	}
> +
> +	clktab->clk_num = num;
> +	clktab->clks = clks;
> +	clktab->ids = ids;
> +	of_clk_add_provider(np, of_clk_src_system_get, clktab);
> +	return;
> +
> +out_free_clks:
> +	kfree(clks);
> +out_free_ids:
> +	kfree(ids);
> +out_free_clktab:
> +	kfree(clktab);
> +}
> +
> +void __init of_at91rm9200_clk_sys_setup(struct device_node *np,
> +					struct at91_pmc *pmc)
> +{
> +	of_at91_clk_sys_setup(np, pmc);
> +}
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index 5258f1d..c674ef2 100644
> --- a/drivers/clk/at91/pmc.c
> +++ b/drivers/clk/at91/pmc.c
> @@ -251,6 +251,11 @@ static const struct of_device_id pmc_clk_ids[] __initdata = {
>   		.compatible = "atmel,at91sam9x5-clk-master",
>   		.data = of_at91sam9x5_clk_master_setup,
>   	},
> +	/* System clocks */
> +	{
> +		.compatible = "atmel,at91rm9200-clk-system",
> +		.data = of_at91rm9200_clk_sys_setup,
> +	},
>   	{ /*sentinel*/ }
>   };
>
> diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
> index 2e1dcb8..f88ef41 100644
> --- a/drivers/clk/at91/pmc.h
> +++ b/drivers/clk/at91/pmc.h
> @@ -74,4 +74,7 @@ extern void __init of_at91rm9200_clk_master_setup(struct device_node *np,
>   extern void __init of_at91sam9x5_clk_master_setup(struct device_node *np,
>   						  struct at91_pmc *pmc);
>
> +extern void __init of_at91rm9200_clk_sys_setup(struct device_node *np,
> +					       struct at91_pmc *pmc);
> +
>   #endif /* __PMC_H_ */
>


-- 
Nicolas Ferre