u-boot/drivers/pwm/pwm-imx.c
Axel Lin 16b0c0ce83 pwm: imx: Prevent NULL pointer dereference
pwm_id_to_reg() can return NULL, so add NULL testing to prevent NULL pointer
dereference.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Stefano Babic <sbabic@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>
2015-05-26 14:13:09 +02:00

71 lines
1.3 KiB
C

/*
* (C) Copyright 2014
* Heiko Schocher, DENX Software Engineering, hs@denx.de.
*
* Basic support for the pwm modul on imx6.
*
* 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>
#include "pwm-imx-util.h"
int pwm_init(int pwm_id, int div, int invert)
{
struct pwm_regs *pwm = (struct pwm_regs *)pwm_id_to_reg(pwm_id);
if (!pwm)
return -1;
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 period_cycles, duty_cycles, prescale;
u32 cr;
if (!pwm)
return -1;
pwm_imx_get_parms(period_ns, duty_ns, &period_cycles, &duty_cycles,
&prescale);
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);
if (!pwm)
return -1;
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);
if (!pwm)
return;
clrbits_le32(&pwm->cr, PWMCR_EN);
}