[U-Boot] [PATCH] armv7: s5p: pwm driver support
Donghwa Lee
dh09.lee at samsung.com
Wed Mar 2 02:44:42 CET 2011
Dear Minkyu Kang,
On 2011-02-28 8:36 Minkyu Kang wrote:
> Dear Donghwa Lee,
>
> On 24 February 2011 16:56, Donghwa Lee <dh09.lee at samsung.com> wrote:
>> This is common pwm driver of S5P.
>>
>> Signed-off-by: Donghwa Lee <dh09.lee at samsung.com>
>> Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
>>
>> ---
>> arch/arm/cpu/armv7/s5p-common/Makefile | 1 +
>> arch/arm/cpu/armv7/s5p-common/pwm.c | 214 +++++++++++++++++++++++++++++++
>> arch/arm/include/asm/arch-s5pc1xx/pwm.h | 14 ++
>> arch/arm/include/asm/arch-s5pc2xx/pwm.h | 14 ++
>> include/pwm.h | 21 +++
>> 5 files changed, 264 insertions(+), 0 deletions(-)
>> create mode 100644 arch/arm/cpu/armv7/s5p-common/pwm.c
>> create mode 100644 include/pwm.h
>>
>> diff --git a/arch/arm/cpu/armv7/s5p-common/pwm.c b/arch/arm/cpu/armv7/s5p-common/pwm.c
>> new file mode 100644
>> index 0000000..eed2206
>> --- /dev/null
>> +++ b/arch/arm/cpu/armv7/s5p-common/pwm.c
>> @@ -0,0 +1,214 @@
>> +/*
>> + * Copyright (C) 2011 Samsung Electronics
>> + *
>> + * Donghwa Lee <dh09.lee at samsung.com>
>> + *
>> + * See file CREDITS for list of people who contributed to this
>> + * project.
>> + *
>> + * 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.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, write to the Free Software
>> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
>> + * MA 02111-1307 USA
>> + */
>> +
>> +#include <common.h>
>> +#include <errno.h>
>> +#include <pwm.h>
>> +#include <asm/io.h>
>> +#include <asm/arch/pwm.h>
>> +#include <asm/arch/clk.h>
>> +
>> +#define PRESCALER_0 (8 - 1) /* prescaler of timer 0, 1 */
>> +#define PRESCALER_1 (16 - 1) /* prescaler of timer 2, 3, 4 */
>> +#define MUX_DIV_1 0 /* 1/1 period */
>> +#define MUX_DIV_2 1 /* 1/2 period */
>> +#define MUX_DIV_4 2 /* 1/4 period */
>> +#define MUX_DIV_8 3 /* 1/8 period */
>> +#define MUX_DIV_16 4 /* 1/16 period */
>> +
>> +#define MUX_DIV_SHIFT(x) ((x) * 4)
>> +
>> +#define TCON0_TIMER_SHIFT 0
>> +#define TCON_TIMER_SHIFT(x) (8 + ((x - 1) * 4))
>> +
>> +
> please remove this space
>
Yes, I will remove it.
>> +int pwm_enable(int pwm_id)
>> +{
>> + const struct s5p_timer *pwm = (struct s5p_timer *)samsung_get_base_timer();
>> + unsigned long tcon;
>> +
>> + tcon = readl(&pwm->tcon);
>> +
>> + if (pwm_id == 0)
>> + tcon |= TCON0_START;
>> + else
>> + tcon |= TCON_START(pwm_id);
>> + writel(tcon, &pwm->tcon);
>> +
>> + return 0;
>> +}
>> +
>> +void pwm_disable(int pwm_id)
>> +{
>> + const struct s5p_timer *pwm = (struct s5p_timer *)samsung_get_base_timer();
>> + unsigned long tcon;
>> +
>> + tcon = readl(&pwm->tcon);
>> + if (pwm_id == 0)
>> + tcon &= ~TCON0_START;
>> + else
>> + tcon &= ~TCON_START(pwm_id);
>> +
>> + writel(tcon, &pwm->tcon);
>> +
> please remove this space
>
Yes, I will remove it.
>> +}
>> +
>> +static unsigned long pwm_calc_tin(int pwm_id, unsigned long freq)
>> +{
>> + unsigned long tin_parent_rate;
>> + unsigned int div;
>> +
>> + tin_parent_rate = get_pwm_clk();
>> +
>> + for (div = 2; div <= 16; div *= 2) {
>> + if ((tin_parent_rate / (div << 16)) < freq)
>> + return tin_parent_rate / div;
>> + }
>> +
>> + return tin_parent_rate / 16;
>> +}
>> +
>> +#define NS_IN_HZ (1000000000UL)
>> +
>> +int pwm_config(int pwm_id, int duty_ns, int period_ns)
>> +{
>> + const struct s5p_timer *pwm = (struct s5p_timer *)samsung_get_base_timer();
>> + unsigned int offset;
>> + unsigned long tin_rate;
>> + unsigned long tin_ns;
>> + unsigned long period;
>> + unsigned long tcon;
>> + unsigned long tcnt;
>> + unsigned long timer_rate_hz;
>> +
> please remove this space
>
Yes, I will remove it.
>> + long tcmp;
> unsigned long?
>
Yes, I will fix it next version.
>> +
>> + /* We currently avoid using 64bit arithmetic by using the
>> + * fact that anything faster than 1GHz is easily representable
>> + * by 32bits. */
> Please keep multi-line comment rule.
> Please see chapter 8.
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/CodingStyle
>
Thank you, your comment. I will fix it.
>> + if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ)
>> + return -ERANGE;
>> +
>> + if (duty_ns > period_ns)
>> + return -EINVAL;
>> +
>> + period = NS_IN_HZ / period_ns;
>> +
>> + /* Check to see if we are changing the clock rate of the PWM */
>> + tin_rate = pwm_calc_tin(pwm_id, period);
>> + timer_rate_hz = tin_rate;
>> +
>> + tin_ns = NS_IN_HZ / tin_rate;
>> + tcnt = period_ns / tin_ns;
>> +
>> + /* Note, counters count down */
>> + tcmp = duty_ns / tin_ns;
>> + tcmp = tcnt - tcmp;
>> +
>> + /* the pwm hw only checks the compare register after a decrement,
>> + so the pin never toggles if tcmp = tcnt */
>> + if (tcmp == tcnt)
>> + tcmp--;
>> +
>> + if (tcmp < 0)
>> + tcmp = 0;
>> +
>> + /* Update the PWM register block. */
>> + writel(tcmp, &pwm->tcmpb0 + offset);
> offset is not initialized.
> And, timer4 doesn't have tcmpb register.
> Please check pwm_id.
>
offset variable was missed. I will add it next version and fix about timer 4.
>> + writel(tcnt, &pwm->tcntb0 + offset);
>> +
>> + tcon = readl(&pwm->tcon);
>> + if (pwm_id == 0) {
>> + tcon |= TCON0_UPDATE;
>> + tcon |= TCON0_AUTO_RELOAD;
>> + } else {
>> + tcon |= TCON_UPDATE(pwm_id);
>> + tcon |= TCON_AUTO_RELOAD(pwm_id);
>> + }
>> +
>> + writel(tcon, &pwm->tcon);
>> +
>> + if (pwm_id == 0)
>> + tcon &= ~TCON0_UPDATE;
>> + else
>> + tcon &= ~TCON_UPDATE(pwm_id);
>> +
>> + writel(tcon, &pwm->tcon);
>> +
>> + return 0;
>> +}
>> +
>> +int pwm_init(int pwm_id, int div, int invert)
>> +{
>> + u32 val;
>> + const struct s5p_timer *pwm = (struct s5p_timer *)samsung_get_base_timer();
>> + unsigned long timer_rate_hz;
>> + unsigned int offset, prescaler;
>> +
>> + /*
>> + * @ PWM Timer 0
> Timer 0 is right?
>
>> + * Timer Freq(HZ) =
>> + * PWM_CLK / { (prescaler_value + 1) * (divider_value) }
>> + */
>> +
>> + val = readl(&pwm->tcfg0);
>> + if (pwm_id < 2) {
>> + prescaler = PRESCALER_0;
>> + val &= ~0xff;
>> + val |= (prescaler & 0xff);
>> + } else {
>> + prescaler = PRESCALER_1;
>> + val &= ~(0xff << 8);
>> + val |= (prescaler & 0xff) << 8;
>> + }
>> + writel(val, &pwm->tcfg0);
>> + val = readl(&pwm->tcfg1);
>> + val &= ~(0xf << MUX_DIV_SHIFT(pwm_id));
>> + val |= (div & 0xf) << MUX_DIV_SHIFT(pwm_id);
>> + writel(val, &pwm->tcfg1);
>> +
>> + timer_rate_hz = get_pwm_clk() / ((prescaler + 1) *
>> + (div + 1));
>> +
>> + timer_rate_hz = timer_rate_hz / 100;
>> +
>> + /* set count value */
>> + offset = pwm_id * 0xc;
>> + writel(timer_rate_hz, &pwm->tcntb0 + offset);
>> +
>> + if (pwm_id == 0) {
>> + val = readl(&pwm->tcon) & ~(0xf << TCON0_TIMER_SHIFT);
>> + if (invert)
>> + val |= TCON0_INVERTER;
>> + } else {
>> + val = readl(&pwm->tcon) & ~(0xf << TCON_TIMER_SHIFT(pwm_id));
>> + if (invert)
>> + val |= TCON_INVERT(pwm_id);
> TCON0_INVERTER and TCON_INVERT()..
> inverter or invert?
> Please use same name.
>
Maybe I think INVERTER is right, I will fix it.
>> + }
>> +
>> + writel(val, &pwm->tcon);
> Pleas use tap instead of space.
>
>> + pwm_enable(pwm_id);
>> +
>> + return 0;
>> +}
>> diff --git a/include/pwm.h b/include/pwm.h
>> new file mode 100644
>> index 0000000..b09a02f
>> --- /dev/null
>> +++ b/include/pwm.h
>> @@ -0,0 +1,21 @@
>> +/*
>> + * header file for pwm driver.
>> + *
>> + * copyright (c) 2011 samsung electronics
>> + * donghwa lee <dh09.lee at samsung.com>
>> + *
>> + * this program is free software; you can redistribute it and/or modify
>> + * it under the terms of the gnu general public license version 2 as
>> + * published by the free software foundation.
> Please write full license.
>
Yes, I will add full license.
> Thanks
> Minkyu Kang
Thank you,
Donghwa Lee
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