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[ARM] S3C24XX: Support for PWM timer clocks via clk_* API 

Add support for the PWM timer clock routing via the
standard clk_ API.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Ben Dooks 2008-07-03 11:24:27 +01:00
parent b4b68f8cfa
commit b999f0db94
2 changed files with 438 additions and 0 deletions
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1
arch/arm/plat-s3c24xx/Makefile
View File

@ -19,6 +19,7 @@ obj-y += gpio.o
obj-y += gpiolib.o
obj-y += time.o
obj-y += clock.o
obj-y += pwm-clock.o
# Architecture dependant builds

437
arch/arm/plat-s3c24xx/pwm-clock.c Normal file
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@ -0,0 +1,437 @@
/* linux/arch/arm/plat-s3c24xx/pwm-clock.c
*
* Copyright (c) 2007 Simtec Electronics
* Copyright (c) 2007, 2008 Ben Dooks
* Ben Dooks <ben-linux@fluff.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.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <asm/hardware.h>
#include <asm/irq.h>
#include <asm/arch/regs-clock.h>
#include <asm/arch/regs-gpio.h>
#include <asm/plat-s3c24xx/clock.h>
#include <asm/plat-s3c24xx/cpu.h>
#include <asm/plat-s3c/regs-timer.h>
/* Each of the timers 0 through 5 go through the following
* clock tree, with the inputs depending on the timers.
*
* pclk ---- [ prescaler 0 ] -+---> timer 0
* +---> timer 1
*
* pclk ---- [ prescaler 1 ] -+---> timer 2
* +---> timer 3
* \---> timer 4
*
* Which are fed into the timers as so:
*
* prescaled 0 ---- [ div 2,4,8,16 ] ---\
* [mux] -> timer 0
* tclk 0 ------------------------------/
*
* prescaled 0 ---- [ div 2,4,8,16 ] ---\
* [mux] -> timer 1
* tclk 0 ------------------------------/
*
*
* prescaled 1 ---- [ div 2,4,8,16 ] ---\
* [mux] -> timer 2
* tclk 1 ------------------------------/
*
* prescaled 1 ---- [ div 2,4,8,16 ] ---\
* [mux] -> timer 3
* tclk 1 ------------------------------/
*
* prescaled 1 ---- [ div 2,4,8, 16 ] --\
* [mux] -> timer 4
* tclk 1 ------------------------------/
*
* Since the mux and the divider are tied together in the
* same register space, it is impossible to set the parent
* and the rate at the same time. To avoid this, we add an
* intermediate 'prescaled-and-divided' clock to select
* as the parent for the timer input clock called tdiv.
*
* prescaled clk --> pwm-tdiv ---\
* [ mux ] --> timer X
* tclk -------------------------/
*/
static unsigned long clk_pwm_scaler_getrate(struct clk *clk)
{
unsigned long tcfg0 = __raw_readl(S3C2410_TCFG0);
if (clk->id == 1) {
tcfg0 &= S3C2410_TCFG_PRESCALER1_MASK;
tcfg0 >>= S3C2410_TCFG_PRESCALER1_SHIFT;
} else {
tcfg0 &= S3C2410_TCFG_PRESCALER0_MASK;
}
return clk_get_rate(clk->parent) / (tcfg0 + 1);
}
/* TODO - add set rate calls. */
struct clk clk_timer_scaler[] = {
[0] = {
.name = "pwm-scaler0",
.id = -1,
.get_rate = clk_pwm_scaler_getrate,
},
[1] = {
.name = "pwm-scaler1",
.id = -1,
.get_rate = clk_pwm_scaler_getrate,
},
};
struct clk clk_timer_tclk[] = {
[0] = {
.name = "pwm-tclk0",
.id = -1,
},
[1] = {
.name = "pwm-tclk1",
.id = -1,
},
};
struct pwm_tdiv_clk {
struct clk clk;
unsigned int divisor;
};
static inline struct pwm_tdiv_clk *to_tdiv(struct clk *clk)
{
return container_of(clk, struct pwm_tdiv_clk, clk);
}
static inline unsigned long tcfg_to_divisor(unsigned long tcfg1)
{
return 1 << (1 + tcfg1);
}
static unsigned long clk_pwm_tdiv_get_rate(struct clk *clk)
{
unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
unsigned int divisor;
tcfg1 >>= S3C2410_TCFG1_SHIFT(clk->id);
tcfg1 &= S3C2410_TCFG1_MUX_MASK;
if (tcfg1 == S3C2410_TCFG1_MUX_TCLK)
divisor = to_tdiv(clk)->divisor;
else
divisor = tcfg_to_divisor(tcfg1);
return clk_get_rate(clk->parent) / divisor;
}
static unsigned long clk_pwm_tdiv_round_rate(struct clk *clk,
unsigned long rate)
{
unsigned long parent_rate;
unsigned long divisor;
parent_rate = clk_get_rate(clk->parent);
divisor = parent_rate / rate;
if (divisor <= 2)
divisor = 2;
else if (divisor <= 4)
divisor = 4;
else if (divisor <= 8)
divisor = 8;
else
divisor = 16;
return parent_rate / divisor;
}
static unsigned long clk_pwm_tdiv_bits(struct pwm_tdiv_clk *divclk)
{
unsigned long bits;
switch (divclk->divisor) {
case 2:
bits = S3C2410_TCFG1_MUX_DIV2;
break;
case 4:
bits = S3C2410_TCFG1_MUX_DIV4;
break;
case 8:
bits = S3C2410_TCFG1_MUX_DIV8;
break;
case 16:
default:
bits = S3C2410_TCFG1_MUX_DIV16;
break;
}
return bits;
}
static void clk_pwm_tdiv_update(struct pwm_tdiv_clk *divclk)
{
unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
unsigned long bits = clk_pwm_tdiv_bits(divclk);
unsigned long flags;
unsigned long shift = S3C2410_TCFG1_SHIFT(divclk->clk.id);
local_irq_save(flags);
tcfg1 = __raw_readl(S3C2410_TCFG1);
tcfg1 &= ~(S3C2410_TCFG1_MUX_MASK << shift);
tcfg1 |= bits << shift;
__raw_writel(tcfg1, S3C2410_TCFG1);
local_irq_restore(flags);
}
static int clk_pwm_tdiv_set_rate(struct clk *clk, unsigned long rate)
{
struct pwm_tdiv_clk *divclk = to_tdiv(clk);
unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
unsigned long parent_rate = clk_get_rate(clk->parent);
unsigned long divisor;
tcfg1 >>= S3C2410_TCFG1_SHIFT(clk->id);
tcfg1 &= S3C2410_TCFG1_MUX_MASK;
rate = clk_round_rate(clk, rate);
divisor = parent_rate / rate;
if (divisor > 16)
return -EINVAL;
divclk->divisor = divisor;
/* Update the current MUX settings if we are currently
* selected as the clock source for this clock. */
if (tcfg1 != S3C2410_TCFG1_MUX_TCLK)
clk_pwm_tdiv_update(divclk);
return 0;
}
struct pwm_tdiv_clk clk_timer_tdiv[] = {
[0] = {
.clk = {
.name = "pwm-tdiv",
.parent = &clk_timer_scaler[0],
.get_rate = clk_pwm_tdiv_get_rate,
.set_rate = clk_pwm_tdiv_set_rate,
.round_rate = clk_pwm_tdiv_round_rate,
},
},
[1] = {
.clk = {
.name = "pwm-tdiv",
.parent = &clk_timer_scaler[0],
.get_rate = clk_pwm_tdiv_get_rate,
.set_rate = clk_pwm_tdiv_set_rate,
.round_rate = clk_pwm_tdiv_round_rate,
}
},
[2] = {
.clk = {
.name = "pwm-tdiv",
.parent = &clk_timer_scaler[1],
.get_rate = clk_pwm_tdiv_get_rate,
.set_rate = clk_pwm_tdiv_set_rate,
.round_rate = clk_pwm_tdiv_round_rate,
},
},
[3] = {
.clk = {
.name = "pwm-tdiv",
.parent = &clk_timer_scaler[1],
.get_rate = clk_pwm_tdiv_get_rate,
.set_rate = clk_pwm_tdiv_set_rate,
.round_rate = clk_pwm_tdiv_round_rate,
},
},
[4] = {
.clk = {
.name = "pwm-tdiv",
.parent = &clk_timer_scaler[1],
.get_rate = clk_pwm_tdiv_get_rate,
.set_rate = clk_pwm_tdiv_set_rate,
.round_rate = clk_pwm_tdiv_round_rate,
},
},
};
static int __init clk_pwm_tdiv_register(unsigned int id)
{
struct pwm_tdiv_clk *divclk = &clk_timer_tdiv[id];
unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
tcfg1 >>= S3C2410_TCFG1_SHIFT(id);
tcfg1 &= S3C2410_TCFG1_MUX_MASK;
divclk->clk.id = id;
divclk->divisor = tcfg_to_divisor(tcfg1);
return s3c24xx_register_clock(&divclk->clk);
}
static inline struct clk *s3c24xx_pwmclk_tclk(unsigned int id)
{
return (id >= 2) ? &clk_timer_tclk[1] : &clk_timer_tclk[0];
}
static inline struct clk *s3c24xx_pwmclk_tdiv(unsigned int id)
{
return &clk_timer_tdiv[id].clk;
}
static int clk_pwm_tin_set_parent(struct clk *clk, struct clk *parent)
{
unsigned int id = clk->id;
unsigned long tcfg1;
unsigned long flags;
unsigned long bits;
unsigned long shift = S3C2410_TCFG1_SHIFT(id);
if (parent == s3c24xx_pwmclk_tclk(id))
bits = S3C2410_TCFG1_MUX_TCLK << shift;
else if (parent == s3c24xx_pwmclk_tdiv(id))
bits = clk_pwm_tdiv_bits(to_tdiv(clk)) << shift;
else
return -EINVAL;
clk->parent = parent;
local_irq_save(flags);
tcfg1 = __raw_readl(S3C2410_TCFG1);
tcfg1 &= ~(S3C2410_TCFG1_MUX_MASK << shift);
__raw_writel(tcfg1 | bits, S3C2410_TCFG1);
local_irq_restore(flags);
return 0;
}
static struct clk clk_tin[] = {
[0] = {
.name = "pwm-tin",
.id = 0,
.set_parent = clk_pwm_tin_set_parent,
},
[1] = {
.name = "pwm-tin",
.id = 1,
.set_parent = clk_pwm_tin_set_parent,
},
[2] = {
.name = "pwm-tin",
.id = 2,
.set_parent = clk_pwm_tin_set_parent,
},
[3] = {
.name = "pwm-tin",
.id = 3,
.set_parent = clk_pwm_tin_set_parent,
},
[4] = {
.name = "pwm-tin",
.id = 4,
.set_parent = clk_pwm_tin_set_parent,
},
};
static __init int clk_pwm_tin_register(struct clk *pwm)
{
unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
unsigned int id = pwm->id;
struct clk *parent;
int ret;
ret = s3c24xx_register_clock(pwm);
if (ret < 0)
return ret;
tcfg1 >>= S3C2410_TCFG1_SHIFT(id);
tcfg1 &= S3C2410_TCFG1_MUX_MASK;
if (tcfg1 == S3C2410_TCFG1_MUX_TCLK)
parent = s3c24xx_pwmclk_tclk(id);
else
parent = s3c24xx_pwmclk_tdiv(id);
return clk_set_parent(pwm, parent);
}
static __init int s3c24xx_pwmclk_init(void)
{
struct clk *clk_timers;
unsigned int clk;
int ret;
clk_timers = clk_get(NULL, "timers");
if (IS_ERR(clk_timers)) {
printk(KERN_ERR "%s: no parent clock\n", __func__);
return -EINVAL;
}
for (clk = 0; clk < ARRAY_SIZE(clk_timer_scaler); clk++) {
clk_timer_scaler[clk].parent = clk_timers;
ret = s3c24xx_register_clock(&clk_timer_scaler[clk]);
if (ret < 0) {
printk(KERN_ERR "error adding pwm scaler%d clock\n", clk);
goto err;
}
}
for (clk = 0; clk < ARRAY_SIZE(clk_timer_tclk); clk++) {
ret = s3c24xx_register_clock(&clk_timer_tclk[clk]);
if (ret < 0) {
printk(KERN_ERR "error adding pww tclk%d\n", clk);
goto err;
}
}
for (clk = 0; clk < ARRAY_SIZE(clk_timer_tdiv); clk++) {
ret = clk_pwm_tdiv_register(clk);
if (ret < 0) {
printk(KERN_ERR "error adding pwm%d tdiv clock\n", clk);
goto err;
}
}
for (clk = 0; clk < ARRAY_SIZE(clk_tin); clk++) {
ret = clk_pwm_tin_register(&clk_tin[clk]);
if (ret < 0) {
printk(KERN_ERR "error adding pwm%d tin clock\n", clk);
goto err;
}
}
return 0;
err:
return ret;
}
arch_initcall(s3c24xx_pwmclk_init);