[U-Boot] [PATCH] armv7: s5p: pwm driver support

[Donghwa Lee <dh09.lee@samsung.com>]

 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@samsung.com> wrote:
>> This is common pwm driver of S5P.
>>
>> Signed-off-by: Donghwa Lee <dh09.lee@samsung.com>
>> Signed-off-by: Kyungmin Park <kyungmin.park@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@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@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