diff mbox series

input: tegra: Use of_property_read_variable_u32_array() and of_property_present()

Message ID 20240731201407.1838385-6-robh@kernel.org
State Superseded
Headers show
Series input: tegra: Use of_property_read_variable_u32_array() and of_property_present() | expand

Commit Message

Rob Herring (Arm) July 31, 2024, 8:14 p.m. UTC 
There's no need to get the length of an DT array property before
parsing the array. of_property_read_variable_u32_array() takes a
minimum and maximum length and returns the actual length (or error
code).

This is part of a larger effort to remove callers of of_get_property()
and similar functions. of_get_property() leaks the DT property data
pointer which is a problem for dynamically allocated nodes which may
be freed.
---
 drivers/input/keyboard/tegra-kbc.c | 72 +++++++++++-------------------
 1 file changed, 27 insertions(+), 45 deletions(-)

Comments

Thierry Reding Aug. 27, 2024, 2:23 p.m. UTC | #1 
On Wed, Jul 31, 2024 at 02:14:01PM GMT, Rob Herring (Arm) wrote:
> There's no need to get the length of an DT array property before
> parsing the array. of_property_read_variable_u32_array() takes a
> minimum and maximum length and returns the actual length (or error
> code).
> 
> This is part of a larger effort to remove callers of of_get_property()
> and similar functions. of_get_property() leaks the DT property data
> pointer which is a problem for dynamically allocated nodes which may
> be freed.
> ---
>  drivers/input/keyboard/tegra-kbc.c | 72 +++++++++++-------------------
>  1 file changed, 27 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c
> index a1765ed8c825..53f39fc155ea 100644
> --- a/drivers/input/keyboard/tegra-kbc.c
> +++ b/drivers/input/keyboard/tegra-kbc.c
> @@ -491,12 +491,10 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
>  	struct device_node *np = kbc->dev->of_node;
>  	u32 prop;
>  	int i;
> -	u32 num_rows = 0;
> -	u32 num_cols = 0;
> +	int num_rows;
> +	int num_cols;
>  	u32 cols_cfg[KBC_MAX_GPIO];
>  	u32 rows_cfg[KBC_MAX_GPIO];
> -	int proplen;
> -	int ret;
>  
>  	if (!of_property_read_u32(np, "nvidia,debounce-delay-ms", &prop))
>  		kbc->debounce_cnt = prop;
> @@ -510,56 +508,23 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
>  	    of_property_read_bool(np, "nvidia,wakeup-source")) /* legacy */
>  		kbc->wakeup = true;
>  
> -	if (!of_get_property(np, "nvidia,kbc-row-pins", &proplen)) {
> -		dev_err(kbc->dev, "property nvidia,kbc-row-pins not found\n");
> -		return -ENOENT;
> -	}
> -	num_rows = proplen / sizeof(u32);
> -
> -	if (!of_get_property(np, "nvidia,kbc-col-pins", &proplen)) {
> -		dev_err(kbc->dev, "property nvidia,kbc-col-pins not found\n");
> -		return -ENOENT;
> -	}
> -	num_cols = proplen / sizeof(u32);
> -
> -	if (num_rows > kbc->hw_support->max_rows) {
> -		dev_err(kbc->dev,
> -			"Number of rows is more than supported by hardware\n");
> -		return -EINVAL;
> -	}
> -
> -	if (num_cols > kbc->hw_support->max_columns) {
> -		dev_err(kbc->dev,
> -			"Number of cols is more than supported by hardware\n");
> -		return -EINVAL;
> -	}
> -
> -	if (!of_get_property(np, "linux,keymap", &proplen)) {
> +	if (!of_property_present(np, "linux,keymap")) {
>  		dev_err(kbc->dev, "property linux,keymap not found\n");
>  		return -ENOENT;
>  	}
>  
> -	if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
> -		dev_err(kbc->dev,
> -			"keypad rows/columns not properly specified\n");
> -		return -EINVAL;
> -	}
> -
>  	/* Set all pins as non-configured */
>  	for (i = 0; i < kbc->num_rows_and_columns; i++)
>  		kbc->pin_cfg[i].type = PIN_CFG_IGNORE;
>  
> -	ret = of_property_read_u32_array(np, "nvidia,kbc-row-pins",
> -				rows_cfg, num_rows);
> -	if (ret < 0) {
> +	num_rows = of_property_read_variable_u32_array(np, "nvidia,kbc-row-pins",
> +				rows_cfg, 1, KBC_MAX_GPIO);
> +	if (num_rows < 0) {
>  		dev_err(kbc->dev, "Rows configurations are not proper\n");
> -		return -EINVAL;
> -	}
> -
> -	ret = of_property_read_u32_array(np, "nvidia,kbc-col-pins",
> -				cols_cfg, num_cols);
> -	if (ret < 0) {
> -		dev_err(kbc->dev, "Cols configurations are not proper\n");
> +		return num_rows;
> +	} else if (num_rows > kbc->hw_support->max_rows) {
> +		dev_err(kbc->dev,
> +			"Number of rows is more than supported by hardware\n");
>  		return -EINVAL;
>  	}
>  
> @@ -568,11 +533,28 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
>  		kbc->pin_cfg[rows_cfg[i]].num = i;
>  	}
>  
> +	num_cols = of_property_read_variable_u32_array(np, "nvidia,kbc-col-pins",
> +				cols_cfg, 1, KBC_MAX_GPIO);
> +	if (num_cols < 0) {
> +		dev_err(kbc->dev, "Cols configurations are not proper\n");
> +		return num_cols;
> +	} else if (num_cols > kbc->hw_support->max_columns) {
> +		dev_err(kbc->dev,
> +			"Number of cols is more than supported by hardware\n");
> +		return -EINVAL;
> +	}
> +
>  	for (i = 0; i < num_cols; i++) {
>  		kbc->pin_cfg[cols_cfg[i]].type = PIN_CFG_COL;
>  		kbc->pin_cfg[cols_cfg[i]].num = i;
>  	}
>  
> +	if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
> +		dev_err(kbc->dev,
> +			"keypad rows/columns not properly specified\n");
> +		return -EINVAL;
> +	}

Previously we wouldn't try to initialize the columns when the
rows/columns were invalid, so this block could move before the last for
loop above.

But it doesn't really matter given that these are exceptions and really
shouldn't happen, so:

Acked-by: Thierry Reding <treding@nvidia.com>
Dmitry Torokhov Aug. 27, 2024, 3:36 p.m. UTC | #2 
On Tue, Aug 27, 2024 at 04:23:48PM +0200, Thierry Reding wrote:
> On Wed, Jul 31, 2024 at 02:14:01PM GMT, Rob Herring (Arm) wrote:
> > There's no need to get the length of an DT array property before
> > parsing the array. of_property_read_variable_u32_array() takes a
> > minimum and maximum length and returns the actual length (or error
> > code).
> > 
> > This is part of a larger effort to remove callers of of_get_property()
> > and similar functions. of_get_property() leaks the DT property data
> > pointer which is a problem for dynamically allocated nodes which may
> > be freed.
> > ---
> >  drivers/input/keyboard/tegra-kbc.c | 72 +++++++++++-------------------
> >  1 file changed, 27 insertions(+), 45 deletions(-)
> > 
> > diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c
> > index a1765ed8c825..53f39fc155ea 100644
> > --- a/drivers/input/keyboard/tegra-kbc.c
> > +++ b/drivers/input/keyboard/tegra-kbc.c
> > @@ -491,12 +491,10 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
> >  	struct device_node *np = kbc->dev->of_node;
> >  	u32 prop;
> >  	int i;
> > -	u32 num_rows = 0;
> > -	u32 num_cols = 0;
> > +	int num_rows;
> > +	int num_cols;
> >  	u32 cols_cfg[KBC_MAX_GPIO];
> >  	u32 rows_cfg[KBC_MAX_GPIO];
> > -	int proplen;
> > -	int ret;
> >  
> >  	if (!of_property_read_u32(np, "nvidia,debounce-delay-ms", &prop))
> >  		kbc->debounce_cnt = prop;
> > @@ -510,56 +508,23 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
> >  	    of_property_read_bool(np, "nvidia,wakeup-source")) /* legacy */
> >  		kbc->wakeup = true;
> >  
> > -	if (!of_get_property(np, "nvidia,kbc-row-pins", &proplen)) {
> > -		dev_err(kbc->dev, "property nvidia,kbc-row-pins not found\n");
> > -		return -ENOENT;
> > -	}
> > -	num_rows = proplen / sizeof(u32);
> > -
> > -	if (!of_get_property(np, "nvidia,kbc-col-pins", &proplen)) {
> > -		dev_err(kbc->dev, "property nvidia,kbc-col-pins not found\n");
> > -		return -ENOENT;
> > -	}
> > -	num_cols = proplen / sizeof(u32);
> > -
> > -	if (num_rows > kbc->hw_support->max_rows) {
> > -		dev_err(kbc->dev,
> > -			"Number of rows is more than supported by hardware\n");
> > -		return -EINVAL;
> > -	}
> > -
> > -	if (num_cols > kbc->hw_support->max_columns) {
> > -		dev_err(kbc->dev,
> > -			"Number of cols is more than supported by hardware\n");
> > -		return -EINVAL;
> > -	}
> > -
> > -	if (!of_get_property(np, "linux,keymap", &proplen)) {
> > +	if (!of_property_present(np, "linux,keymap")) {
> >  		dev_err(kbc->dev, "property linux,keymap not found\n");
> >  		return -ENOENT;
> >  	}
> >  
> > -	if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
> > -		dev_err(kbc->dev,
> > -			"keypad rows/columns not properly specified\n");
> > -		return -EINVAL;
> > -	}
> > -
> >  	/* Set all pins as non-configured */
> >  	for (i = 0; i < kbc->num_rows_and_columns; i++)
> >  		kbc->pin_cfg[i].type = PIN_CFG_IGNORE;
> >  
> > -	ret = of_property_read_u32_array(np, "nvidia,kbc-row-pins",
> > -				rows_cfg, num_rows);
> > -	if (ret < 0) {
> > +	num_rows = of_property_read_variable_u32_array(np, "nvidia,kbc-row-pins",
> > +				rows_cfg, 1, KBC_MAX_GPIO);
> > +	if (num_rows < 0) {
> >  		dev_err(kbc->dev, "Rows configurations are not proper\n");
> > -		return -EINVAL;
> > -	}
> > -
> > -	ret = of_property_read_u32_array(np, "nvidia,kbc-col-pins",
> > -				cols_cfg, num_cols);
> > -	if (ret < 0) {
> > -		dev_err(kbc->dev, "Cols configurations are not proper\n");
> > +		return num_rows;
> > +	} else if (num_rows > kbc->hw_support->max_rows) {
> > +		dev_err(kbc->dev,
> > +			"Number of rows is more than supported by hardware\n");
> >  		return -EINVAL;
> >  	}
> >  
> > @@ -568,11 +533,28 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
> >  		kbc->pin_cfg[rows_cfg[i]].num = i;
> >  	}
> >  
> > +	num_cols = of_property_read_variable_u32_array(np, "nvidia,kbc-col-pins",
> > +				cols_cfg, 1, KBC_MAX_GPIO);
> > +	if (num_cols < 0) {
> > +		dev_err(kbc->dev, "Cols configurations are not proper\n");
> > +		return num_cols;
> > +	} else if (num_cols > kbc->hw_support->max_columns) {
> > +		dev_err(kbc->dev,
> > +			"Number of cols is more than supported by hardware\n");
> > +		return -EINVAL;
> > +	}
> > +
> >  	for (i = 0; i < num_cols; i++) {
> >  		kbc->pin_cfg[cols_cfg[i]].type = PIN_CFG_COL;
> >  		kbc->pin_cfg[cols_cfg[i]].num = i;
> >  	}
> >  
> > +	if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
> > +		dev_err(kbc->dev,
> > +			"keypad rows/columns not properly specified\n");
> > +		return -EINVAL;
> > +	}
> 
> Previously we wouldn't try to initialize the columns when the
> rows/columns were invalid, so this block could move before the last for
> loop above.
> 
> But it doesn't really matter given that these are exceptions and really
> shouldn't happen, so:
> 
> Acked-by: Thierry Reding <treding@nvidia.com>

I don't quite like of_property_read_variable_u32_array() because it is
OF-specific. device_property_count_u32() will return the number of
elements in an array. But I guess this driver will only be used on an OF
system... 

Applied, thank you.
Thierry Reding Aug. 28, 2024, 3:05 p.m. UTC | #3 
On Tue, Aug 27, 2024 at 08:36:29AM GMT, Dmitry Torokhov wrote:
> On Tue, Aug 27, 2024 at 04:23:48PM +0200, Thierry Reding wrote:
> > On Wed, Jul 31, 2024 at 02:14:01PM GMT, Rob Herring (Arm) wrote:
> > > There's no need to get the length of an DT array property before
> > > parsing the array. of_property_read_variable_u32_array() takes a
> > > minimum and maximum length and returns the actual length (or error
> > > code).
> > > 
> > > This is part of a larger effort to remove callers of of_get_property()
> > > and similar functions. of_get_property() leaks the DT property data
> > > pointer which is a problem for dynamically allocated nodes which may
> > > be freed.
> > > ---
> > >  drivers/input/keyboard/tegra-kbc.c | 72 +++++++++++-------------------
> > >  1 file changed, 27 insertions(+), 45 deletions(-)
> > > 
> > > diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c
> > > index a1765ed8c825..53f39fc155ea 100644
> > > --- a/drivers/input/keyboard/tegra-kbc.c
> > > +++ b/drivers/input/keyboard/tegra-kbc.c
> > > @@ -491,12 +491,10 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
> > >  	struct device_node *np = kbc->dev->of_node;
> > >  	u32 prop;
> > >  	int i;
> > > -	u32 num_rows = 0;
> > > -	u32 num_cols = 0;
> > > +	int num_rows;
> > > +	int num_cols;
> > >  	u32 cols_cfg[KBC_MAX_GPIO];
> > >  	u32 rows_cfg[KBC_MAX_GPIO];
> > > -	int proplen;
> > > -	int ret;
> > >  
> > >  	if (!of_property_read_u32(np, "nvidia,debounce-delay-ms", &prop))
> > >  		kbc->debounce_cnt = prop;
> > > @@ -510,56 +508,23 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
> > >  	    of_property_read_bool(np, "nvidia,wakeup-source")) /* legacy */
> > >  		kbc->wakeup = true;
> > >  
> > > -	if (!of_get_property(np, "nvidia,kbc-row-pins", &proplen)) {
> > > -		dev_err(kbc->dev, "property nvidia,kbc-row-pins not found\n");
> > > -		return -ENOENT;
> > > -	}
> > > -	num_rows = proplen / sizeof(u32);
> > > -
> > > -	if (!of_get_property(np, "nvidia,kbc-col-pins", &proplen)) {
> > > -		dev_err(kbc->dev, "property nvidia,kbc-col-pins not found\n");
> > > -		return -ENOENT;
> > > -	}
> > > -	num_cols = proplen / sizeof(u32);
> > > -
> > > -	if (num_rows > kbc->hw_support->max_rows) {
> > > -		dev_err(kbc->dev,
> > > -			"Number of rows is more than supported by hardware\n");
> > > -		return -EINVAL;
> > > -	}
> > > -
> > > -	if (num_cols > kbc->hw_support->max_columns) {
> > > -		dev_err(kbc->dev,
> > > -			"Number of cols is more than supported by hardware\n");
> > > -		return -EINVAL;
> > > -	}
> > > -
> > > -	if (!of_get_property(np, "linux,keymap", &proplen)) {
> > > +	if (!of_property_present(np, "linux,keymap")) {
> > >  		dev_err(kbc->dev, "property linux,keymap not found\n");
> > >  		return -ENOENT;
> > >  	}
> > >  
> > > -	if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
> > > -		dev_err(kbc->dev,
> > > -			"keypad rows/columns not properly specified\n");
> > > -		return -EINVAL;
> > > -	}
> > > -
> > >  	/* Set all pins as non-configured */
> > >  	for (i = 0; i < kbc->num_rows_and_columns; i++)
> > >  		kbc->pin_cfg[i].type = PIN_CFG_IGNORE;
> > >  
> > > -	ret = of_property_read_u32_array(np, "nvidia,kbc-row-pins",
> > > -				rows_cfg, num_rows);
> > > -	if (ret < 0) {
> > > +	num_rows = of_property_read_variable_u32_array(np, "nvidia,kbc-row-pins",
> > > +				rows_cfg, 1, KBC_MAX_GPIO);
> > > +	if (num_rows < 0) {
> > >  		dev_err(kbc->dev, "Rows configurations are not proper\n");
> > > -		return -EINVAL;
> > > -	}
> > > -
> > > -	ret = of_property_read_u32_array(np, "nvidia,kbc-col-pins",
> > > -				cols_cfg, num_cols);
> > > -	if (ret < 0) {
> > > -		dev_err(kbc->dev, "Cols configurations are not proper\n");
> > > +		return num_rows;
> > > +	} else if (num_rows > kbc->hw_support->max_rows) {
> > > +		dev_err(kbc->dev,
> > > +			"Number of rows is more than supported by hardware\n");
> > >  		return -EINVAL;
> > >  	}
> > >  
> > > @@ -568,11 +533,28 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
> > >  		kbc->pin_cfg[rows_cfg[i]].num = i;
> > >  	}
> > >  
> > > +	num_cols = of_property_read_variable_u32_array(np, "nvidia,kbc-col-pins",
> > > +				cols_cfg, 1, KBC_MAX_GPIO);
> > > +	if (num_cols < 0) {
> > > +		dev_err(kbc->dev, "Cols configurations are not proper\n");
> > > +		return num_cols;
> > > +	} else if (num_cols > kbc->hw_support->max_columns) {
> > > +		dev_err(kbc->dev,
> > > +			"Number of cols is more than supported by hardware\n");
> > > +		return -EINVAL;
> > > +	}
> > > +
> > >  	for (i = 0; i < num_cols; i++) {
> > >  		kbc->pin_cfg[cols_cfg[i]].type = PIN_CFG_COL;
> > >  		kbc->pin_cfg[cols_cfg[i]].num = i;
> > >  	}
> > >  
> > > +	if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
> > > +		dev_err(kbc->dev,
> > > +			"keypad rows/columns not properly specified\n");
> > > +		return -EINVAL;
> > > +	}
> > 
> > Previously we wouldn't try to initialize the columns when the
> > rows/columns were invalid, so this block could move before the last for
> > loop above.
> > 
> > But it doesn't really matter given that these are exceptions and really
> > shouldn't happen, so:
> > 
> > Acked-by: Thierry Reding <treding@nvidia.com>
> 
> I don't quite like of_property_read_variable_u32_array() because it is
> OF-specific. device_property_count_u32() will return the number of
> elements in an array. But I guess this driver will only be used on an OF
> system... 

Yeah, this hardware only exists on fairly old Tegra devices and I know
of no plans to support anything other that DT on those.

Thierry
Rob Herring (Arm) Sept. 13, 2024, 8:06 p.m. UTC | #4 
On Fri, Sep 6, 2024 at 12:33 AM Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
>
> On Tue, Aug 27, 2024 at 10:53:38AM -0700, Dmitry Torokhov wrote:
> > >
> > > Applied, thank you.
> >
> > Oh, wait, can I get your SOB please?
>
> Rob, I am still waiting on your SOB please.

Oh, missed this. That's weird it is missing. New patch coming.

Rob
diff mbox series

Patch

diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c
index a1765ed8c825..53f39fc155ea 100644
--- a/drivers/input/keyboard/tegra-kbc.c
+++ b/drivers/input/keyboard/tegra-kbc.c
@@ -491,12 +491,10 @@  static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
 	struct device_node *np = kbc->dev->of_node;
 	u32 prop;
 	int i;
-	u32 num_rows = 0;
-	u32 num_cols = 0;
+	int num_rows;
+	int num_cols;
 	u32 cols_cfg[KBC_MAX_GPIO];
 	u32 rows_cfg[KBC_MAX_GPIO];
-	int proplen;
-	int ret;
 
 	if (!of_property_read_u32(np, "nvidia,debounce-delay-ms", &prop))
 		kbc->debounce_cnt = prop;
@@ -510,56 +508,23 @@  static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
 	    of_property_read_bool(np, "nvidia,wakeup-source")) /* legacy */
 		kbc->wakeup = true;
 
-	if (!of_get_property(np, "nvidia,kbc-row-pins", &proplen)) {
-		dev_err(kbc->dev, "property nvidia,kbc-row-pins not found\n");
-		return -ENOENT;
-	}
-	num_rows = proplen / sizeof(u32);
-
-	if (!of_get_property(np, "nvidia,kbc-col-pins", &proplen)) {
-		dev_err(kbc->dev, "property nvidia,kbc-col-pins not found\n");
-		return -ENOENT;
-	}
-	num_cols = proplen / sizeof(u32);
-
-	if (num_rows > kbc->hw_support->max_rows) {
-		dev_err(kbc->dev,
-			"Number of rows is more than supported by hardware\n");
-		return -EINVAL;
-	}
-
-	if (num_cols > kbc->hw_support->max_columns) {
-		dev_err(kbc->dev,
-			"Number of cols is more than supported by hardware\n");
-		return -EINVAL;
-	}
-
-	if (!of_get_property(np, "linux,keymap", &proplen)) {
+	if (!of_property_present(np, "linux,keymap")) {
 		dev_err(kbc->dev, "property linux,keymap not found\n");
 		return -ENOENT;
 	}
 
-	if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
-		dev_err(kbc->dev,
-			"keypad rows/columns not properly specified\n");
-		return -EINVAL;
-	}
-
 	/* Set all pins as non-configured */
 	for (i = 0; i < kbc->num_rows_and_columns; i++)
 		kbc->pin_cfg[i].type = PIN_CFG_IGNORE;
 
-	ret = of_property_read_u32_array(np, "nvidia,kbc-row-pins",
-				rows_cfg, num_rows);
-	if (ret < 0) {
+	num_rows = of_property_read_variable_u32_array(np, "nvidia,kbc-row-pins",
+				rows_cfg, 1, KBC_MAX_GPIO);
+	if (num_rows < 0) {
 		dev_err(kbc->dev, "Rows configurations are not proper\n");
-		return -EINVAL;
-	}
-
-	ret = of_property_read_u32_array(np, "nvidia,kbc-col-pins",
-				cols_cfg, num_cols);
-	if (ret < 0) {
-		dev_err(kbc->dev, "Cols configurations are not proper\n");
+		return num_rows;
+	} else if (num_rows > kbc->hw_support->max_rows) {
+		dev_err(kbc->dev,
+			"Number of rows is more than supported by hardware\n");
 		return -EINVAL;
 	}
 
@@ -568,11 +533,28 @@  static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
 		kbc->pin_cfg[rows_cfg[i]].num = i;
 	}
 
+	num_cols = of_property_read_variable_u32_array(np, "nvidia,kbc-col-pins",
+				cols_cfg, 1, KBC_MAX_GPIO);
+	if (num_cols < 0) {
+		dev_err(kbc->dev, "Cols configurations are not proper\n");
+		return num_cols;
+	} else if (num_cols > kbc->hw_support->max_columns) {
+		dev_err(kbc->dev,
+			"Number of cols is more than supported by hardware\n");
+		return -EINVAL;
+	}
+
 	for (i = 0; i < num_cols; i++) {
 		kbc->pin_cfg[cols_cfg[i]].type = PIN_CFG_COL;
 		kbc->pin_cfg[cols_cfg[i]].num = i;
 	}
 
+	if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
+		dev_err(kbc->dev,
+			"keypad rows/columns not properly specified\n");
+		return -EINVAL;
+	}
+
 	return 0;
 }