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

From: [email-masked] (Nicolas Ferre)
Date: Tue, 8 Oct 2013 18:06:37 +0200

On 08/10/2013 18:02, Nicolas Ferre :
> 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 <[email-masked]>
>> ---
>>    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 <[email-masked]>
>> + *
>> + * 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?

Oops, it is not "creating" it is "waiting" which is pretty different ;-)
So, do not consider this remark.

> - for the while() loop, I would like a timeout and a a non-active wait
> function...

Okay, this is also false: sorry for the noise.

>
>> +		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