[PATCH v3 1/2] dt-bindings: input: cros-ec-keyb: Add a new property

[PATCH v3 1/2] dt-bindings: input: cros-ec-keyb: Add a new property

[Philip Chen]

This patch adds a new property `function-row-physmap` to the
device tree for the custom keyboard top row design.

The property describes the rows/columns of the top row keys
from left to right.

Signed-off-by: Philip Chen <philipchen@chromium.org>
---

(no changes since v2)

Changes in v2:
- add `function-row-physmap` instead of `google,custom-keyb-top-row`

 .../devicetree/bindings/input/google,cros-ec-keyb.yaml | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/google,cros-ec-keyb.yaml b/Documentation/devicetree/bindings/input/google,cros-ec-keyb.yaml
index 8e50c14a9d778..7acdb33781d30 100644
--- a/Documentation/devicetree/bindings/input/google,cros-ec-keyb.yaml
+++ b/Documentation/devicetree/bindings/input/google,cros-ec-keyb.yaml
@@ -31,6 +31,16 @@ properties:
       if the EC does not have its own logic or hardware for this.
     type: boolean
 
+  function-row-physmap:
+    $ref: '/schemas/types.yaml#/definitions/uint32-array'
+    description: |
+      An ordered u32 array describing the rows/columns (in the scan matrix)
+      of top row keys from physical left (KEY_F1) to right. Each entry
+      encodes the row/column as:
+      (((row) & 0xFF) << 24) | (((column) & 0xFF) << 16)
+      where the lower 16 bits are reserved. This property is specified only
+      when the keyboard has a custom design for the top row keys.
+
 required:
   - compatible
 
-- 
2.26.2

[PATCH v3 2/2] Input: cros-ec-keyb - Expose function row physical map to userspace

[Philip Chen]

The top-row keys in a keyboard usually have dual functionalities.
E.g. A function key "F1" is also an action key "Browser back".

Therefore, when an application receives an action key code from
a top-row key press, the application needs to know how to correlate
the action key code with the function key code and do the conversion
whenever necessary.

Since the userpace already knows the key scanlines (row/column)
associated with a received key code. Essentially, the userspace only
needs a mapping between the key row/column and the matching physical
location in the top row.

This patch enhances the cros-ec-keyb driver to create such a mapping
and expose it to userspace in the form of a function-row-physmap
attribute. The attribute would be a space separated ordered list of
row/column codes, for the keys in the function row, in a left-to-right
order.

The attribute will only be present when the device has a custom design
for the top-row keys.

Signed-off-by: Philip Chen <philipchen@chromium.org>
---

Changes in v3:
- parse `function-row-physmap` from DT earlier, when we probe
  cros_ec_keyb, and then store the extracted info in struct cros_ec_keyb.

Changes in v2:
- create function-row-physmap file in sysfs by parsing
  `function-row-physmap` property from DT
- assume the device already has a correct keymap to reflect the custom
  top-row keys (if they exist)

 drivers/input/keyboard/cros_ec_keyb.c | 82 +++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)

diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
index b379ed7628781..d804430d384d6 100644
--- a/drivers/input/keyboard/cros_ec_keyb.c
+++ b/drivers/input/keyboard/cros_ec_keyb.c
@@ -27,6 +27,8 @@
 
 #include <asm/unaligned.h>
 
+#define MAX_NUM_TOP_ROW_KEYS   15
+
 /**
  * struct cros_ec_keyb - Structure representing EC keyboard device
  *
@@ -42,6 +44,9 @@
  * @idev: The input device for the matrix keys.
  * @bs_idev: The input device for non-matrix buttons and switches (or NULL).
  * @notifier: interrupt event notifier for transport devices
+ * @function_row_physmap: An array of the encoded rows/columns for the top
+ *                        row function keys, in an order from left to right
+ * @num_function_row_keys: The number of top row keys in a custom keyboard
  */
 struct cros_ec_keyb {
 	unsigned int rows;
@@ -49,6 +54,7 @@ struct cros_ec_keyb {
 	int row_shift;
 	const struct matrix_keymap_data *keymap_data;
 	bool ghost_filter;
+	bool has_custom_top_row_keys;
 	uint8_t *valid_keys;
 	uint8_t *old_kb_state;
 
@@ -58,6 +64,9 @@ struct cros_ec_keyb {
 	struct input_dev *idev;
 	struct input_dev *bs_idev;
 	struct notifier_block notifier;
+
+	u16 function_row_physmap[MAX_NUM_TOP_ROW_KEYS];
+	u8 num_function_row_keys;
 };
 
 /**
@@ -527,6 +536,8 @@ static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
 	struct input_dev *idev;
 	const char *phys;
 	int err;
+	u32 top_row_key_pos[MAX_NUM_TOP_ROW_KEYS] = {0};
+	u8 i;
 
 	err = matrix_keypad_parse_properties(dev, &ckdev->rows, &ckdev->cols);
 	if (err)
@@ -578,6 +589,22 @@ static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
 	ckdev->idev = idev;
 	cros_ec_keyb_compute_valid_keys(ckdev);
 
+	if (of_property_read_variable_u32_array(dev->of_node,
+						"function-row-physmap",
+						top_row_key_pos,
+						0,
+						MAX_NUM_TOP_ROW_KEYS) > 0) {
+		for (i = 0; i < MAX_NUM_TOP_ROW_KEYS; i++) {
+			if (!top_row_key_pos[i])
+				break;
+			ckdev->function_row_physmap[i] = MATRIX_SCAN_CODE(
+						KEY_ROW(top_row_key_pos[i]),
+						KEY_COL(top_row_key_pos[i]),
+						ckdev->row_shift);
+		}
+		ckdev->num_function_row_keys = i;
+	}
+
 	err = input_register_device(ckdev->idev);
 	if (err) {
 		dev_err(dev, "cannot register input device\n");
@@ -587,6 +614,52 @@ static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev)
 	return 0;
 }
 
+static ssize_t function_row_physmap_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	ssize_t size = 0;
+	u8 i;
+	struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
+
+	if (!ckdev->num_function_row_keys)
+		return 0;
+
+	for (i = 0; i < ckdev->num_function_row_keys; i++)
+		size += scnprintf(buf + size, PAGE_SIZE - size, "%02X ",
+				  ckdev->function_row_physmap[i]);
+	size += scnprintf(buf + size, PAGE_SIZE - size, "\n");
+
+	return size;
+}
+
+static DEVICE_ATTR_RO(function_row_physmap);
+
+static struct attribute *cros_ec_keyb_attrs[] = {
+	&dev_attr_function_row_physmap.attr,
+	NULL,
+};
+
+static umode_t cros_ec_keyb_attr_is_visible(struct kobject *kobj,
+					    struct attribute *attr,
+					    int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct cros_ec_keyb *ckdev = dev_get_drvdata(dev);
+
+	if (attr == &dev_attr_function_row_physmap.attr &&
+	    !ckdev->num_function_row_keys)
+		return 0;
+
+	return attr->mode;
+}
+
+static const struct attribute_group cros_ec_keyb_attr_group = {
+	.is_visible = cros_ec_keyb_attr_is_visible,
+	.attrs = cros_ec_keyb_attrs,
+};
+
+
 static int cros_ec_keyb_probe(struct platform_device *pdev)
 {
 	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
@@ -617,6 +690,12 @@ static int cros_ec_keyb_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	err = sysfs_create_group(&dev->kobj, &cros_ec_keyb_attr_group);
+	if (err) {
+		dev_err(dev, "failed to create attributes. err=%d\n", err);
+		return err;
+	}
+
 	ckdev->notifier.notifier_call = cros_ec_keyb_work;
 	err = blocking_notifier_chain_register(&ckdev->ec->event_notifier,
 					       &ckdev->notifier);
@@ -632,6 +711,9 @@ static int cros_ec_keyb_probe(struct platform_device *pdev)
 static int cros_ec_keyb_remove(struct platform_device *pdev)
 {
 	struct cros_ec_keyb *ckdev = dev_get_drvdata(&pdev->dev);
+	struct device *dev = &pdev->dev;
+
+	sysfs_remove_group(&dev->kobj, &cros_ec_keyb_attr_group);
 
 	blocking_notifier_chain_unregister(&ckdev->ec->event_notifier,
 					   &ckdev->notifier);
-- 
2.26.2

Re: [PATCH v3 2/2] Input: cros-ec-keyb - Expose function row physical map to userspace

[Dmitry Torokhov]

Hi Philip,

On Mon, Jan 04, 2021 at 06:22:34PM -0800, Philip Chen wrote:
> The top-row keys in a keyboard usually have dual functionalities.
> E.g. A function key "F1" is also an action key "Browser back".
> 
> Therefore, when an application receives an action key code from
> a top-row key press, the application needs to know how to correlate
> the action key code with the function key code and do the conversion
> whenever necessary.
> 
> Since the userpace already knows the key scanlines (row/column)
> associated with a received key code. Essentially, the userspace only
> needs a mapping between the key row/column and the matching physical
> location in the top row.
> 
> This patch enhances the cros-ec-keyb driver to create such a mapping
> and expose it to userspace in the form of a function-row-physmap
> attribute. The attribute would be a space separated ordered list of
> row/column codes, for the keys in the function row, in a left-to-right
> order.
> 
> The attribute will only be present when the device has a custom design
> for the top-row keys.
> 
> Signed-off-by: Philip Chen <philipchen@chromium.org>
> ---
> 
> Changes in v3:
> - parse `function-row-physmap` from DT earlier, when we probe
>   cros_ec_keyb, and then store the extracted info in struct cros_ec_keyb.

Thank you for making the changes, much appreciated. Let's wait a bit to
see if Rob has any issues with this.

...

>  static int cros_ec_keyb_probe(struct platform_device *pdev)
>  {
>  	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
> @@ -617,6 +690,12 @@ static int cros_ec_keyb_probe(struct platform_device *pdev)
>  		return err;
>  	}
>  
> +	err = sysfs_create_group(&dev->kobj, &cros_ec_keyb_attr_group);
> +	if (err) {
> +		dev_err(dev, "failed to create attributes. err=%d\n", err);
> +		return err;
> +	}

Let's use devm_device_add_group() so that we do not need to remove it
manually in cros_ec_keyb_remove().

Thanks.

-- 
Dmitry