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>

diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index 40bf0275437fefbd4deaecd6934e2b4ccb2392aa..47799fc0d1fb87c5c5ffb95967264d231825d4b9 100644 (file)
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -18,6 +18,9 @@ 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;
 }
@@ -28,6 +31,9 @@ int pwm_config(int pwm_id, int duty_ns, int period_ns)
        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);
 
@@ -47,6 +53,9 @@ 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;
 }
@@ -55,5 +64,8 @@ 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);
 }