drivers/input/keyboard/st-keyscan.c

Source file repositories/reference/linux-study-clean/drivers/input/keyboard/st-keyscan.c

File Facts

System
Linux kernel
Corpus path
drivers/input/keyboard/st-keyscan.c
Extension
.c
Size
6499 bytes
Lines
272
Domain
Driver Families
Bucket
drivers/input
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct st_keyscan {
	void __iomem *base;
	int irq;
	struct clk *clk;
	struct input_dev *input_dev;
	unsigned long last_state;
	unsigned int n_rows;
	unsigned int n_cols;
	unsigned int debounce_us;
};

static irqreturn_t keyscan_isr(int irq, void *dev_id)
{
	struct st_keyscan *keypad = dev_id;
	unsigned short *keycode = keypad->input_dev->keycode;
	unsigned long state, change;
	int bit_nr;

	state = readl(keypad->base + KEYSCAN_MATRIX_STATE_OFF) & 0xffff;
	change = keypad->last_state ^ state;
	keypad->last_state = state;

	for_each_set_bit(bit_nr, &change, BITS_PER_LONG)
		input_report_key(keypad->input_dev,
				 keycode[bit_nr], state & BIT(bit_nr));

	input_sync(keypad->input_dev);

	return IRQ_HANDLED;
}

static int keyscan_start(struct st_keyscan *keypad)
{
	int error;

	error = clk_enable(keypad->clk);
	if (error)
		return error;

	writel(keypad->debounce_us * (clk_get_rate(keypad->clk) / 1000000),
	       keypad->base + KEYSCAN_DEBOUNCE_TIME_OFF);

	writel(((keypad->n_cols - 1) << KEYSCAN_MATRIX_DIM_X_SHIFT) |
	       ((keypad->n_rows - 1) << KEYSCAN_MATRIX_DIM_Y_SHIFT),
	       keypad->base + KEYSCAN_MATRIX_DIM_OFF);

	writel(KEYSCAN_CONFIG_ENABLE, keypad->base + KEYSCAN_CONFIG_OFF);

	return 0;
}

static void keyscan_stop(struct st_keyscan *keypad)
{
	writel(0, keypad->base + KEYSCAN_CONFIG_OFF);

	clk_disable(keypad->clk);
}

static int keyscan_open(struct input_dev *dev)
{
	struct st_keyscan *keypad = input_get_drvdata(dev);

	return keyscan_start(keypad);
}

static void keyscan_close(struct input_dev *dev)
{
	struct st_keyscan *keypad = input_get_drvdata(dev);

	keyscan_stop(keypad);
}

static int keypad_matrix_key_parse_dt(struct st_keyscan *keypad_data)
{
	struct device *dev = keypad_data->input_dev->dev.parent;
	struct device_node *np = dev->of_node;
	int error;

	error = matrix_keypad_parse_properties(dev, &keypad_data->n_rows,
					       &keypad_data->n_cols);
	if (error) {
		dev_err(dev, "failed to parse keypad params\n");
		return error;
	}

	of_property_read_u32(np, "st,debounce-us", &keypad_data->debounce_us);

	dev_dbg(dev, "n_rows=%d n_col=%d debounce=%d\n",
		keypad_data->n_rows, keypad_data->n_cols,
		keypad_data->debounce_us);

Annotation

Implementation Notes