Re: [PATCH v2] Input: keyboard - add device tree bindings for simple key matrixes

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Olof,

On Thu, Dec 29, 2011 at 10:42:26AM -0800, Olof Johansson wrote:
> This adds a simple device tree binding for simple key matrix data.
> 
> Changes since v1:
>  * Removed samsung-style binding support
>  * Added linux,fn-keymap and linux,fn-key optional properties
> 

This looks very reasonable to me, a few comments though.

> Signed-off-by: Olof Johansson <olof@lixom.net>
> ---
>  .../devicetree/bindings/input/matrix-keymap.txt    |   25 ++++++
>  drivers/input/keyboard/Makefile                    |    1 +
>  drivers/input/keyboard/keymap.c                    |   78 ++++++++++++++++++++
>  include/linux/input/matrix_keypad.h                |   34 +++++----
>  4 files changed, 123 insertions(+), 15 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/input/matrix-keymap.txt
>  create mode 100644 drivers/input/keyboard/keymap.c
> 
> diff --git a/Documentation/devicetree/bindings/input/matrix-keymap.txt b/Documentation/devicetree/bindings/input/matrix-keymap.txt
> new file mode 100644
> index 0000000..480ca46
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/matrix-keymap.txt
> @@ -0,0 +1,25 @@
> +For matrix keyboards there are two kinds of layout bindings using
> +linux key codes.
> +
> +Required properties:
> +- compatible: "matrix-keyboard-controller"
> +- linux,keymap: an array of 3-cell entries containing the equivalent
> +  of the three separate properties above: row, column and linux
> +  key-code.
> +
> +Optional properties:
> +- linux,fn-keymap: A separate array of 3-cell entries similar to
> +  linux,keymap but only to be used when the function key modifier is
> +  active. This is used for keyboards that have a software-based modifier
> +  key for 'Fn' but that need to describe the custom layout that should
> +  be used when said modifier key is active.
> +
> +- linux,fn-key: a 2-cell entry containing the < row column > of the
> +  function modifier key used to switch to the above linux,fn-keymap
> +  layout.
> +
> +Example:
> +	linux,keymap = < 0 3 2
> +			 0 4 5 >;
> +	linux,fn-key = < 2 1 >;
> +	linux,fn-keymap = < 0 3 1 >;
> diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
> index df7061f..83e6eed 100644
> --- a/drivers/input/keyboard/Makefile
> +++ b/drivers/input/keyboard/Makefile
> @@ -4,6 +4,7 @@
>  
>  # Each configuration option enables a list of files.
>  
> +obj-$(CONFIG_INPUT_KEYBOARD)		+= keymap.o

I do not think we should restrict it keyboard devices only; there could
be users in input/misc as well, so I'd rather have it as
drivers/input/matrix-keymap.c

I'd start with just matrix_keyboard_of_build_keymap() there and moved
matrix_keypad_build_keymap() as a follow-up patch as drivers using it
should 'select' it.

>  obj-$(CONFIG_KEYBOARD_ADP5520)		+= adp5520-keys.o
>  obj-$(CONFIG_KEYBOARD_ADP5588)		+= adp5588-keys.o
>  obj-$(CONFIG_KEYBOARD_ADP5589)		+= adp5589-keys.o
> diff --git a/drivers/input/keyboard/keymap.c b/drivers/input/keyboard/keymap.c
> new file mode 100644
> index 0000000..80d1074
> --- /dev/null
> +++ b/drivers/input/keyboard/keymap.c
> @@ -0,0 +1,78 @@
> +#include <linux/kernel.h>
> +#include <linux/types.h>
> +#include <linux/input.h>
> +#include <linux/of.h>
> +#include <linux/input/matrix_keypad.h>
> +#include <linux/export.h>
> +#include <linux/gfp.h>
> +#include <linux/slab.h>
> +
> +void matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
> +				unsigned int row_shift,
> +				unsigned short *keymap, unsigned long *keybit)
> +{
> +	int i;
> +
> +	for (i = 0; i < keymap_data->keymap_size; i++) {
> +		unsigned int key = keymap_data->keymap[i];
> +		unsigned int row = KEY_ROW(key);
> +		unsigned int col = KEY_COL(key);
> +		unsigned short code = KEY_VAL(key);
> +
> +		keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
> +		__set_bit(code, keybit);
> +	}
> +	__clear_bit(KEY_RESERVED, keybit);
> +}
> +EXPORT_SYMBOL_GPL(matrix_keypad_build_keymap);
> +
> +#ifdef CONFIG_OF
> +struct matrix_keymap_data *

Instead of allocating keymap data why don't we populate keymap and
keybits directly, like matrix_keypad_build_keymap() does?

> +matrix_keyboard_of_fill_keymap(struct device_node *np)
> +{
> +	struct matrix_keymap_data *kd;
> +	struct device_node *knp;
> +	int proplen = 0, i;
> +	u32 *keymap, row, col, key_code;

Let's fail safely if np is NULL.

> +	const __be32 *prop = of_get_property(np, "linux,keymap", &proplen);
> +
> +	if (!of_device_is_compatible(np, "matrix-keyboard-controller"))
> +		return NULL;
> +
> +	kd = kmalloc(sizeof(*kd), GFP_KERNEL);
> +	if (!kd)
> +		return NULL;
> +	kd->keymap_size = proplen / 3;

Validate that proplen % 3 == 0?

> +
> +	keymap = kzalloc(kd->keymap_size * sizeof(u32), GFP_KERNEL);
> +	if (!keymap) {
> +		kfree(kd);
> +		return NULL;
> +	}
> +
> +	kd->keymap = keymap;
> +
> +	for (i = 0; i < kd->keymap_size; i++){
> +		/* property format is < row column keycode > */
> +		row = be32_to_cpup(prop++);
> +		col = be32_to_cpup(prop++);
> +		key_code = be32_to_cpup(prop++);
> +		*keymap++ = KEY(row, col, key_code);
> +	}
> +
> +	/* FIXME: Need to add handling of the linux,fn-keymap property here */
> +
> +	return kd;
> +}
> +EXPORT_SYMBOL_GPL(matrix_keyboard_of_fill_keymap);
> +
> +void matrix_keyboard_of_free_keymap(const struct matrix_keymap_data *kd)
> +{
> +	if (!kd)
> +		return;
> +	if (kd->keymap)
> +		kfree(kd->keymap);

If we decide to keep allocating kd then checking kd->keymap before
freeing is not necessary.

> +	kfree(kd);
> +}
> +EXPORT_SYMBOL_GPL(matrix_keyboard_of_free_keymap);
> +#endif
> diff --git a/include/linux/input/matrix_keypad.h b/include/linux/input/matrix_keypad.h
> index fe7c4b9..ac999c6 100644
> --- a/include/linux/input/matrix_keypad.h
> +++ b/include/linux/input/matrix_keypad.h
> @@ -3,6 +3,7 @@
>  
>  #include <linux/types.h>
>  #include <linux/input.h>
> +#include <linux/of.h>
>  
>  #define MATRIX_MAX_ROWS		32
>  #define MATRIX_MAX_COLS		32
> @@ -87,23 +88,26 @@ struct matrix_keypad_platform_data {
>   * an array of keycodes that is suitable for using in a standard matrix
>   * keyboard driver that uses row and col as indices.
>   */
> +void matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
> +				unsigned int row_shift,
> +				unsigned short *keymap, unsigned long *keybit);
> +
> +#ifdef CONFIG_OF
> +struct matrix_keymap_data *
> +matrix_keyboard_of_fill_keymap(struct device_node *np);
> +
> +void matrix_keyboard_of_free_keymap(const struct matrix_keymap_data *kd);
> +#else
> +static inline struct matrix_keymap_data *
> +matrix_keyboard_of_fill_keymap(struct device_node *np)
> +{
> +	return NULL;
> +}
> +
>  static inline void
> -matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
> -			   unsigned int row_shift,
> -			   unsigned short *keymap, unsigned long *keybit)
> +matrix_keyboard_of_free_keymap(const struct matrix_keymap_data *kd)
>  {
> -	int i;
> -
> -	for (i = 0; i < keymap_data->keymap_size; i++) {
> -		unsigned int key = keymap_data->keymap[i];
> -		unsigned int row = KEY_ROW(key);
> -		unsigned int col = KEY_COL(key);
> -		unsigned short code = KEY_VAL(key);
> -
> -		keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
> -		__set_bit(code, keybit);
> -	}
> -	__clear_bit(KEY_RESERVED, keybit);
>  }
> +#endif
>  
>  #endif /* _MATRIX_KEYPAD_H */
> -- 
> 1.7.8.GIT
> 

-- 
Dmitry