Re: [PATCH v3 13/19] clk: at91: add PMC programmable clocks

[Nicolas Ferre <nicolas.ferre-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>]

On 08/08/2013 09:12, Boris BREZILLON :
> This patch adds new at91 programmable clocks implementation using common clk
> framework.
> A programmable clock is a clock which can be exported on a given pin to clock
> external devices.
> Each programmable clock is given an id (from 0 to 8).
> The number of available programmable clocks depends on the SoC you're using.
> Programmable clock driver only implements the clock setting (clock rate and
> parent setting). It must be chained to a system clock in order to
> enable/disable the generated clock.
> The PCKX pins used to output the clock signals must be assigned to the
> appropriate peripheral (see atmel's datasheets).
>
> Signed-off-by: Boris BREZILLON <b.brezillon-ZNYIgs0QAGpBDgjK7y7TUQ@public.gmane.org>
> ---
>   drivers/clk/at91/Makefile           |    2 +
>   drivers/clk/at91/clk-programmable.c |  419 +++++++++++++++++++++++++++++++++++
>   drivers/clk/at91/pmc.c              |   15 ++
>   drivers/clk/at91/pmc.h              |    9 +
>   4 files changed, 445 insertions(+)
>   create mode 100644 drivers/clk/at91/clk-programmable.c
>
> diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
> index 04deba3..3873b62 100644
> --- a/drivers/clk/at91/Makefile
> +++ b/drivers/clk/at91/Makefile
> @@ -5,3 +5,5 @@
>   obj-y += pmc.o
>   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
> diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
> new file mode 100644
> index 0000000..f40de6a
> --- /dev/null
> +++ b/drivers/clk/at91/clk-programmable.c
> @@ -0,0 +1,419 @@
> +/*
> + * drivers/clk/at91/clk-programmable.c
> + *
> + *  Copyright (C) 2013 Boris BREZILLON <b.brezillon-ZNYIgs0QAGpBDgjK7y7TUQ@public.gmane.org>
> + *
> + * 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/of_irq.h>
> +#include <linux/io.h>
> +#include <linux/wait.h>
> +#include <linux/sched.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +
> +#include "pmc.h"
> +
> +#define PROG_SOURCE_MAX		5
> +#define PROG_MAX		8
> +
> +struct clk_programmable_layout {
> +	u8 pres_shift;
> +	u8 css_mask;
> +	u8 have_slck_mck;
> +};
> +
> +#define to_clk_programmable(hw) container_of(hw, struct clk_programmable, hw)
> +struct clk_programmable {
> +	struct clk_hw hw;
> +	struct at91_pmc *pmc;
> +	unsigned int irq;
> +	wait_queue_head_t wait;
> +	u8 id;
> +	u8 css;
> +	u8 pres;
> +	u8 slckmck;
> +	const struct clk_programmable_layout *layout;
> +};
> +
> +static irqreturn_t clk_programmable_irq_handler(int irq, void *dev_id)
> +{
> +	struct clk_programmable *prog = (struct clk_programmable *)dev_id;
> +
> +	wake_up(&prog->wait);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int clk_programmable_prepare(struct clk_hw *hw)
> +{
> +	u32 tmp;
> +	struct clk_programmable *prog = to_clk_programmable(hw);
> +	struct at91_pmc *pmc = prog->pmc;
> +	const struct clk_programmable_layout *layout = prog->layout;
> +
> +	tmp = prog->css | (prog->pres << layout->pres_shift);
> +	if (layout->have_slck_mck && prog->slckmck)
> +		tmp |= 1 << 8;

;-) => define constants

> +
> +	pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp);
> +
> +	while (!(pmc_read(pmc, AT91_PMC_SR) & (1 << (prog->id + 8))))

- create a macro
- is creating an event for each iteration of the while loop a good idea?
- for the while() loop, I would like a timeout and a a non-active wait 
function...

> +		wait_event(prog->wait,
> +			   pmc_read(pmc, AT91_PMC_SR) & (1 << (prog->id + 8)));
> +
> +	return 0;
> +}
> +
> +static int clk_programmable_is_ready(struct clk_hw *hw)
> +{
> +	struct clk_programmable *prog = to_clk_programmable(hw);
> +	struct at91_pmc *pmc = prog->pmc;
> +
> +	return !!(pmc_read(pmc, AT91_PMC_SR) & (1 << (prog->id + 8)));

Ditto

> +}
> +
> +static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
> +						  unsigned long parent_rate)
> +{
> +	u32 tmp;
> +	struct clk_programmable *prog = to_clk_programmable(hw);
> +	struct at91_pmc *pmc = prog->pmc;
> +	const struct clk_programmable_layout *layout = prog->layout;
> +
> +	tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
> +	prog->pres = (tmp >> layout->pres_shift) & 0x7;

define constants

> +
> +	return parent_rate >> prog->pres;
> +}
> +
> +static long clk_programmable_round_rate(struct clk_hw *hw, unsigned long rate,
> +					unsigned long *parent_rate)
> +{
> +	unsigned long best_rate = *parent_rate;
> +	unsigned long best_diff;
> +	unsigned long new_diff;
> +	unsigned long cur_rate;
> +	int shift = shift;
> +
> +	if (rate > *parent_rate)
> +		return *parent_rate;
> +	else
> +		best_diff = *parent_rate - rate;
> +
> +	if (!best_diff)
> +		return best_rate;
> +
> +	for (shift = 1; shift < 7; shift++) {

Ditto

> +		cur_rate = *parent_rate >> shift;
> +
> +		if (cur_rate > rate)
> +			new_diff = cur_rate - rate;
> +		else
> +			new_diff = rate - cur_rate;
> +
> +		if (!new_diff)
> +			return cur_rate;
> +
> +		if (new_diff < best_diff) {
> +			best_diff = new_diff;
> +			best_rate = cur_rate;
> +		}
> +
> +		if (rate > cur_rate)
> +			break;
> +
> +	}
> +
> +	return best_rate;
> +}
> +
> +static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)
> +{
> +	struct clk_programmable *prog = to_clk_programmable(hw);
> +	const struct clk_programmable_layout *layout = prog->layout;
> +	if (index > layout->css_mask) {
> +		if (index == 4 && layout->have_slck_mck) {

define "4"

> +			prog->css = 0;
> +			prog->slckmck = 1;
> +			return 0;
> +		} else

Style: add the "{"

> +			return -EINVAL;

and "}"

> +	}
> +
> +	prog->css = index;
> +	return 0;
> +}
> +
> +static u8 clk_programmable_get_parent(struct clk_hw *hw)
> +{
> +	u32 tmp;
> +	u8 ret;
> +	struct clk_programmable *prog = to_clk_programmable(hw);
> +	struct at91_pmc *pmc = prog->pmc;
> +	const struct clk_programmable_layout *layout = prog->layout;
> +
> +	tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
> +	prog->css = tmp & layout->css_mask;
> +	ret = prog->css;
> +	if (layout->have_slck_mck) {
> +		prog->slckmck = !!(tmp & (1 << 8));

Ditto

> +		if (prog->slckmck && !ret)
> +			ret = 4;

Ditto

> +	}
> +
> +	return ret;
> +}
> +
> +static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
> +				     unsigned long parent_rate)
> +{
> +	struct clk_programmable *prog = to_clk_programmable(hw);
> +	unsigned long best_rate = parent_rate;
> +	unsigned long best_diff;
> +	unsigned long new_diff;
> +	unsigned long cur_rate;
> +	int shift = 0;
> +
> +	if (rate > parent_rate)
> +		return parent_rate;
> +	else
> +		best_diff = parent_rate - rate;
> +
> +	if (!best_diff) {
> +		prog->pres = shift;
> +		return 0;
> +	}
> +
> +	for (shift = 1; shift < 7; shift++) {

Ditto

> +		cur_rate = parent_rate >> shift;
> +
> +		if (cur_rate > rate)
> +			new_diff = cur_rate - rate;
> +		else
> +			new_diff = rate - cur_rate;
> +
> +		if (!new_diff)
> +			break;
> +
> +		if (new_diff < best_diff) {
> +			best_diff = new_diff;
> +			best_rate = cur_rate;
> +		}
> +
> +		if (rate > cur_rate)
> +			break;
> +
> +	}
> +
> +	prog->pres = shift;
> +	return 0;
> +}
> +
> +static const struct clk_ops programmable_ops = {
> +	.prepare = clk_programmable_prepare,
> +	.is_prepared = clk_programmable_is_ready,
> +	.recalc_rate = clk_programmable_recalc_rate,
> +	.round_rate = clk_programmable_round_rate,
> +	.get_parent = clk_programmable_get_parent,
> +	.set_parent = clk_programmable_set_parent,
> +	.set_rate = clk_programmable_set_rate,
> +};
> +
> +static struct clk * __init
> +at91_clk_register_programmable(struct at91_pmc *pmc, unsigned int irq,
> +			       const char *name, const char **parent_names,
> +			       u8 num_parents, u8 id,
> +			       const struct clk_programmable_layout *layout)
> +{
> +	int ret;
> +	struct clk_programmable *prog;
> +	struct clk *clk = NULL;
> +	struct clk_init_data init;
> +	char irq_name[11];
> +
> +	id &= 7;

Ditto

> +
> +	prog = kzalloc(sizeof(*prog), GFP_KERNEL);
> +	if (!prog)
> +		return ERR_PTR(-ENOMEM);
> +
> +	init.name = name;
> +	init.ops = &programmable_ops;
> +	init.parent_names = parent_names;
> +	init.num_parents = num_parents;
> +	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
> +
> +	prog->id = id;
> +	prog->layout = layout;
> +	prog->hw.init = &init;
> +	prog->pmc = pmc;
> +	prog->irq = irq;
> +	init_waitqueue_head(&prog->wait);
> +	irq_set_status_flags(prog->irq, IRQ_NOAUTOEN);
> +	snprintf(irq_name, sizeof(irq_name), "clk-prog%d", id);
> +	ret = request_irq(prog->irq, clk_programmable_irq_handler,
> +			  IRQF_TRIGGER_HIGH, irq_name, prog);
> +	if (ret)
> +		return ERR_PTR(ret);
> +
> +	clk = clk_register(NULL, &prog->hw);
> +

^^

> +	if (IS_ERR(clk))
> +		kfree(prog);
> +
> +	return clk;
> +}
> +
> +static const struct clk_programmable_layout at91rm9200_programmable_layout = {
> +	.pres_shift = 2,
> +	.css_mask = 0x3,
> +	.have_slck_mck = 0,
> +};
> +
> +static const struct clk_programmable_layout at91sam9g45_programmable_layout = {
> +	.pres_shift = 2,
> +	.css_mask = 0x3,
> +	.have_slck_mck = 1,
> +};
> +
> +static const struct clk_programmable_layout at91sam9x5_programmable_layout = {
> +	.pres_shift = 4,
> +	.css_mask = 0x7,
> +	.have_slck_mck = 0,
> +};
> +
> +struct clk_prog_data {
> +	struct clk **clks;
> +	u8 *ids;
> +	unsigned int clk_num;
> +};
> +
> +static struct clk * __init
> +of_clk_src_periph_get(struct of_phandle_args *clkspec, void *data)
> +{
> +	struct clk_prog_data *clk_data = data;
> +	unsigned int id = clkspec->args[0];
> +	int i;
> +
> +	if (id >= PROG_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_prog_setup(struct device_node *np, struct at91_pmc *pmc,
> +		       const struct clk_programmable_layout *layout)
> +{
> +	int num;
> +	u32 id;
> +	int i;
> +	unsigned int irq;
> +	struct clk *clk;
> +	int num_parents;
> +	u8 *ids;
> +	struct clk **clks;
> +	struct clk_prog_data *clktab;
> +	const char *parent_names[PROG_SOURCE_MAX];
> +	const char *name;
> +	struct device_node *progclknp;
> +
> +	num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
> +	if (num_parents <= 0 || num_parents > PROG_SOURCE_MAX)
> +		return;
> +
> +	for (i = 0; i < num_parents; ++i) {
> +		parent_names[i] = of_clk_get_parent_name(np, i);
> +		if (!parent_names[i])
> +			return;
> +	}
> +
> +	num = of_get_child_count(np);
> +	if (!num || num > PROG_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, progclknp) {
> +		name = progclknp->name;
> +
> +		if (of_property_read_u32(progclknp, "atmel,clk-id", &id))
> +			goto out_free_clks;
> +		if (id >= PROG_MAX)
> +			goto out_free_clks;
> +
> +		irq = irq_of_parse_and_map(np, 0);
> +		if (!irq)
> +			goto out_free_clks;
> +
> +		clk = at91_clk_register_programmable(pmc, irq, name,
> +						     parent_names, num_parents,
> +						     id, layout);
> +		if (IS_ERR(clk))
> +			goto out_free_clks;
> +
> +		clks[i] = clk;
> +		ids[i++] = id;
> +	}
> +
> +	clktab->clk_num = num;
> +	clktab->clks = clks;
> +	clktab->ids = ids;
> +	of_clk_add_provider(np, of_clk_src_periph_get, clktab);
> +	return;
> +
> +out_free_clks:
> +	kfree(clks);
> +out_free_ids:
> +	kfree(ids);
> +out_free_clktab:
> +	kfree(clktab);
> +}
> +
> +
> +void __init of_at91rm9200_clk_prog_setup(struct device_node *np,
> +					 struct at91_pmc *pmc)
> +{
> +	of_at91_clk_prog_setup(np, pmc, &at91rm9200_programmable_layout);
> +}
> +
> +void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,
> +					  struct at91_pmc *pmc)
> +{
> +	of_at91_clk_prog_setup(np, pmc, &at91sam9g45_programmable_layout);
> +}
> +
> +void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
> +					 struct at91_pmc *pmc)
> +{
> +	of_at91_clk_prog_setup(np, pmc, &at91sam9x5_programmable_layout);
> +}
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index 1a56f1c..66a627d 100644
> --- a/drivers/clk/at91/pmc.c
> +++ b/drivers/clk/at91/pmc.c
> @@ -265,6 +265,21 @@ static const struct of_device_id pmc_clk_ids[] __initdata = {
>   		.compatible = "atmel,at91sam9x5-clk-peripheral",
>   		.data = of_at91sam9x5_clk_periph_setup,
>   	},
> +	/* Programmable clocks */
> +#if defined(CONFIG_AT91_PROGRAMMABLE_CLOCKS)
> +	{
> +		.compatible = "atmel,at91rm9200-clk-programmable",
> +		.data = of_at91rm9200_clk_prog_setup,
> +	},
> +	{
> +		.compatible = "atmel,at91sam9g45-clk-programmable",
> +		.data = of_at91sam9g45_clk_prog_setup,
> +	},
> +	{
> +		.compatible = "atmel,at91sam9x5-clk-programmable",
> +		.data = of_at91sam9x5_clk_prog_setup,
> +	},
> +#endif
>   	{ /*sentinel*/ }
>   };
>
> diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
> index 08c30fb..5f20dc1 100644
> --- a/drivers/clk/at91/pmc.h
> +++ b/drivers/clk/at91/pmc.h
> @@ -82,4 +82,13 @@ extern void __init of_at91rm9200_clk_periph_setup(struct device_node *np,
>   extern void __init of_at91sam9x5_clk_periph_setup(struct device_node *np,
>   						  struct at91_pmc *pmc);
>
> +#if defined(CONFIG_AT91_PROGRAMMABLE_CLOCKS)
> +extern void __init of_at91rm9200_clk_prog_setup(struct device_node *np,
> +						struct at91_pmc *pmc);
> +extern void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,
> +						 struct at91_pmc *pmc);
> +extern void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
> +						struct at91_pmc *pmc);
> +#endif
> +
>   #endif /* __PMC_H_ */
>


-- 
Nicolas Ferre
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