[U-Boot] [PATCH v3 3/6] pwm, imx6: add support for pwm modul on imx6

[Stefano Babic <sbabic@denx.de>]

Hi Heiko,

On 16/07/2014 10:51, Heiko Schocher wrote:
> add basic support for the pwm modul found on imx6.
> 
> Signed-off-by: Heiko Schocher <hs@denx.de>
> Cc: Stefano Babic <sbabic@denx.de>
> 
> ---
> - changes for v3:
>   new in v3, as Stefano Babic suggested
> 
>  README                |   4 ++
>  drivers/Makefile      |   1 +
>  drivers/pwm/Makefile  |  13 ++++++
>  drivers/pwm/pwm-imx.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 127 insertions(+)
>  create mode 100644 drivers/pwm/Makefile
>  create mode 100644 drivers/pwm/pwm-imx.c
> 
> diff --git a/README b/README
> index 1eecba6..9f07831 100644
> --- a/README
> +++ b/README
> @@ -1377,6 +1377,10 @@ The following options need to be configured:
>  			CONFIG_SH_ETHER_CACHE_WRITEBACK
>  			If this option is set, the driver enables cache flush.
>  
> +- PWM Support:
> +		CONFIG_PWM_IMX
> +		Support for PWM modul on the imx6.
> +
>  - TPM Support:
>  		CONFIG_TPM
>  		Support TPM devices.
> diff --git a/drivers/Makefile b/drivers/Makefile
> index b23076f..b22b109 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -15,3 +15,4 @@ obj-y += video/
>  obj-y += watchdog/
>  obj-$(CONFIG_QE) += qe/
>  obj-y += memory/
> +obj-y += pwm/
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> new file mode 100644
> index 0000000..3173e20
> --- /dev/null
> +++ b/drivers/pwm/Makefile
> @@ -0,0 +1,13 @@
> +#
> +# (C) Copyright 2006
> +# Wolfgang Denk, DENX Software Engineering, wd at denx.de.
> +#
> +# (C) Copyright 2001
> +# Erik Theisen, Wave 7 Optics, etheisen at mindspring.com.
> +#
> +# SPDX-License-Identifier:	GPL-2.0+
> +#
> +
> +#ccflags-y += -DDEBUG
> +
> +obj-$(CONFIG_PWM_IMX) += pwm-imx.o
> diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
> new file mode 100644
> index 0000000..c70e150
> --- /dev/null
> +++ b/drivers/pwm/pwm-imx.c
> @@ -0,0 +1,109 @@
> +/*
> + * (C) Copyright 2014
> + * Heiko Schocher, DENX Software Engineering, hs at denx.de.
> + *
> + * Basic support for the pwm modul on imx6.
> + *
> + * Based on linux:drivers/pwm/pwm-imx.c
> + * from
> + * Sascha Hauer <s.hauer@pengutronix.de>
> + *
> + * SPDX-License-Identifier:	GPL-2.0+
> + */
> +
> +#include <common.h>
> +#include <div64.h>
> +#include <pwm.h>
> +#include <asm/arch/imx-regs.h>
> +#include <asm/io.h>
> +
> +/* pwm_id from 0..3 */
> +static struct pwm_regs *pwm_id_to_reg(int pwm_id)
> +{
> +	switch (pwm_id) {
> +	case 0:
> +		return (struct pwm_regs *)PWM1_BASE_ADDR;
> +		break;
> +	case 1:
> +		return (struct pwm_regs *)PWM2_BASE_ADDR;
> +		break;
> +	case 2:
> +		return (struct pwm_regs *)PWM3_BASE_ADDR;
> +		break;
> +	case 3:
> +		return (struct pwm_regs *)PWM4_BASE_ADDR;
> +		break;
> +	default:
> +		printf("unknown pwm_id: %d\n", pwm_id);
> +		break;
> +	}
> +	return NULL;
> +}
> +
> +int pwm_init(int pwm_id, int div, int invert)
> +{
> +	struct pwm_regs *pwm = (struct pwm_regs *)pwm_id_to_reg(pwm_id);
> +
> +	writel(0, &pwm->ir);
> +	return 0;
> +}
> +
> +int pwm_config(int pwm_id, int duty_ns, int period_ns)
> +{
> +	struct pwm_regs *pwm = (struct pwm_regs *)pwm_id_to_reg(pwm_id);
> +	unsigned long long c;
> +	unsigned long period_cycles, duty_cycles, prescale;
> +	u32 cr;
> +
> +	/*
> +	 * we have not yet a clock framework for imx6, so add the clock
> +	 * value here as a define. Replace it when we have the clock
> +	 * framework.
> +	 */
> +	c = CONFIG_IMX6_PWM_PER_CLK;
> +	c = c * period_ns;
> +	do_div(c, 1000000000);
> +	period_cycles = c;
> +
> +	prescale = period_cycles / 0x10000 + 1;
> +
> +	period_cycles /= prescale;
> +	c = (unsigned long long)period_cycles * duty_ns;
> +	do_div(c, period_ns);
> +	duty_cycles = c;
> +
> +	/*
> +	 * according to imx pwm RM, the real period value should be
> +	 * PERIOD value in PWMPR plus 2.
> +	 */
> +	if (period_cycles > 2)
> +		period_cycles -= 2;
> +	else
> +		period_cycles = 0;
> +
> +	cr = PWMCR_PRESCALER(prescale) |
> +		PWMCR_DOZEEN | PWMCR_WAITEN |
> +		PWMCR_DBGEN | PWMCR_CLKSRC_IPG_HIGH;
> +
> +	writel(cr, &pwm->cr);
> +	/* set duty cycles */
> +	writel(duty_cycles, &pwm->sar);
> +	/* set period cycles */
> +	writel(period_cycles, &pwm->pr);
> +	return 0;
> +}
> +
> +int pwm_enable(int pwm_id)
> +{
> +	struct pwm_regs *pwm = (struct pwm_regs *)pwm_id_to_reg(pwm_id);
> +
> +	setbits_le32(&pwm->cr, PWMCR_EN);
> +	return 0;
> +}
> +
> +void pwm_disable(int pwm_id)
> +{
> +	struct pwm_regs *pwm = (struct pwm_regs *)pwm_id_to_reg(pwm_id);
> +
> +	clrbits_le32(&pwm->cr, PWMCR_EN);
> +}
> 

Nice ! Should we also add in the commit message that the code is
directly taken from kernel driver ?

Acked-by: Stefano Babic <sbabic@denx.de>

Best regards,
Stefano Babic

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