Input: add driver for Broadcom keypad controller

Broadcom Keypad controller is used to interface a SoC with a matrix-type
keypad device. The keypad controller supports multiple row and column
lines. A key can be placed at each intersection of a unique row and a
unique column. The keypad controller can sense a key-press and key-release
and report the event using an interrupt to the CPU.

Reviewed-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

3 files changed, 470 insertions, 0 deletions

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index a89ba7cb96f1..17de1dcac637 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -686,4 +686,15 @@ config KEYBOARD_CAP11XX
 	  To compile this driver as a module, choose M here: the
 	  module will be called cap11xx.
 
+config KEYBOARD_BCM
+	tristate "Broadcom keypad driver"
+	depends on OF && HAVE_CLK
+	select INPUT_MATRIXKMAP
+	default ARCH_BCM_CYGNUS
+	help
+	  Say Y here if you want to use Broadcom keypad.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called bcm-keypad.
+
 endif
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 470767884bd8..a648f6c6bbfa 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_KEYBOARD_ADP5589)		+= adp5589-keys.o
 obj-$(CONFIG_KEYBOARD_AMIGA)		+= amikbd.o
 obj-$(CONFIG_KEYBOARD_ATARI)		+= atakbd.o
 obj-$(CONFIG_KEYBOARD_ATKBD)		+= atkbd.o
+obj-$(CONFIG_KEYBOARD_BCM)		+= bcm-keypad.o
 obj-$(CONFIG_KEYBOARD_BFIN)		+= bf54x-keys.o
 obj-$(CONFIG_KEYBOARD_CAP11XX)		+= cap11xx.o
 obj-$(CONFIG_KEYBOARD_CLPS711X)		+= clps711x-keypad.o
diff --git a/drivers/input/keyboard/bcm-keypad.c b/drivers/input/keyboard/bcm-keypad.c
new file mode 100644
index 000000000000..86a8b723ae15
--- /dev/null
+++ b/drivers/input/keyboard/bcm-keypad.c
@@ -0,0 +1,458 @@
+/*
+ * Copyright (C) 2014 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/gfp.h>
+#include <linux/io.h>
+#include <linux/input.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+
+#define DEFAULT_CLK_HZ			31250
+#define MAX_ROWS			8
+#define MAX_COLS			8
+
+/* Register/field definitions */
+#define KPCR_OFFSET			0x00000080
+#define KPCR_MODE			0x00000002
+#define KPCR_MODE_SHIFT			1
+#define KPCR_MODE_MASK			1
+#define KPCR_ENABLE			0x00000001
+#define KPCR_STATUSFILTERENABLE		0x00008000
+#define KPCR_STATUSFILTERTYPE_SHIFT	12
+#define KPCR_COLFILTERENABLE		0x00000800
+#define KPCR_COLFILTERTYPE_SHIFT	8
+#define KPCR_ROWWIDTH_SHIFT		20
+#define KPCR_COLUMNWIDTH_SHIFT		16
+
+#define KPIOR_OFFSET			0x00000084
+#define KPIOR_ROWOCONTRL_SHIFT		24
+#define KPIOR_ROWOCONTRL_MASK		0xFF000000
+#define KPIOR_COLUMNOCONTRL_SHIFT	16
+#define KPIOR_COLUMNOCONTRL_MASK	0x00FF0000
+#define KPIOR_COLUMN_IO_DATA_SHIFT	0
+
+#define KPEMR0_OFFSET			0x00000090
+#define KPEMR1_OFFSET			0x00000094
+#define KPEMR2_OFFSET			0x00000098
+#define KPEMR3_OFFSET			0x0000009C
+#define KPEMR_EDGETYPE_BOTH		3
+
+#define KPSSR0_OFFSET			0x000000A0
+#define KPSSR1_OFFSET			0x000000A4
+#define KPSSRN_OFFSET(reg_n)		(KPSSR0_OFFSET + 4 * (reg_n))
+#define KPIMR0_OFFSET			0x000000B0
+#define KPIMR1_OFFSET			0x000000B4
+#define KPICR0_OFFSET			0x000000B8
+#define KPICR1_OFFSET			0x000000BC
+#define KPICRN_OFFSET(reg_n)		(KPICR0_OFFSET + 4 * (reg_n))
+#define KPISR0_OFFSET			0x000000C0
+#define KPISR1_OFFSET			0x000000C4
+
+#define KPCR_STATUSFILTERTYPE_MAX	7
+#define KPCR_COLFILTERTYPE_MAX		7
+
+/* Macros to determine the row/column from a bit that is set in SSR0/1. */
+#define BIT_TO_ROW_SSRN(bit_nr, reg_n)	(((bit_nr) >> 3) + 4 * (reg_n))
+#define BIT_TO_COL(bit_nr)		((bit_nr) % 8)
+
+/* Structure representing various run-time entities */
+struct bcm_kp {
+	void __iomem *base;
+	int irq;
+	struct clk *clk;
+	struct input_dev *input_dev;
+	unsigned long last_state[2];
+	unsigned int n_rows;
+	unsigned int n_cols;
+	u32 kpcr;
+	u32 kpior;
+	u32 kpemr;
+	u32 imr0_val;
+	u32 imr1_val;
+};
+
+/*
+ * Returns the keycode from the input device keymap given the row and
+ * column.
+ */
+static int bcm_kp_get_keycode(struct bcm_kp *kp, int row, int col)
+{
+	unsigned int row_shift = get_count_order(kp->n_cols);
+	unsigned short *keymap = kp->input_dev->keycode;
+
+	return keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
+}
+
+static void bcm_kp_report_keys(struct bcm_kp *kp, int reg_num, int pull_mode)
+{
+	unsigned long state, change;
+	int bit_nr;
+	int key_press;
+	int row, col;
+	unsigned int keycode;
+
+	/* Clear interrupts */
+	writel(0xFFFFFFFF, kp->base + KPICRN_OFFSET(reg_num));
+
+	state = readl(kp->base + KPSSRN_OFFSET(reg_num));
+	change = kp->last_state[reg_num] ^ state;
+	kp->last_state[reg_num] = state;
+
+	for_each_set_bit(bit_nr, &change, BITS_PER_LONG) {
+		key_press = state & BIT(bit_nr);
+		/* The meaning of SSR register depends on pull mode. */
+		key_press = pull_mode ? !key_press : key_press;
+		row = BIT_TO_ROW_SSRN(bit_nr, reg_num);
+		col = BIT_TO_COL(bit_nr);
+		keycode = bcm_kp_get_keycode(kp, row, col);
+		input_report_key(kp->input_dev, keycode, key_press);
+	}
+}
+
+static irqreturn_t bcm_kp_isr_thread(int irq, void *dev_id)
+{
+	struct bcm_kp *kp = dev_id;
+	int pull_mode = (kp->kpcr >> KPCR_MODE_SHIFT) & KPCR_MODE_MASK;
+	int reg_num;
+
+	for (reg_num = 0; reg_num <= 1; reg_num++)
+		bcm_kp_report_keys(kp, reg_num, pull_mode);
+
+	input_sync(kp->input_dev);
+
+	return IRQ_HANDLED;
+}
+
+static int bcm_kp_start(struct bcm_kp *kp)
+{
+	int error;
+
+	if (kp->clk) {
+		error = clk_prepare_enable(kp->clk);
+		if (error)
+			return error;
+	}
+
+	writel(kp->kpior, kp->base + KPIOR_OFFSET);
+
+	writel(kp->imr0_val, kp->base + KPIMR0_OFFSET);
+	writel(kp->imr1_val, kp->base + KPIMR1_OFFSET);
+
+	writel(kp->kpemr, kp->base + KPEMR0_OFFSET);
+	writel(kp->kpemr, kp->base + KPEMR1_OFFSET);
+	writel(kp->kpemr, kp->base + KPEMR2_OFFSET);
+	writel(kp->kpemr, kp->base + KPEMR3_OFFSET);
+
+	writel(0xFFFFFFFF, kp->base + KPICR0_OFFSET);
+	writel(0xFFFFFFFF, kp->base + KPICR1_OFFSET);
+
+	kp->last_state[0] = readl(kp->base + KPSSR0_OFFSET);
+	kp->last_state[0] = readl(kp->base + KPSSR1_OFFSET);
+
+	writel(kp->kpcr | KPCR_ENABLE, kp->base + KPCR_OFFSET);
+
+	return 0;
+}
+
+static void bcm_kp_stop(const struct bcm_kp *kp)
+{
+	u32 val;
+
+	val = readl(kp->base + KPCR_OFFSET);
+	val &= ~KPCR_ENABLE;
+	writel(0, kp->base + KPCR_OFFSET);
+	writel(0, kp->base + KPIMR0_OFFSET);
+	writel(0, kp->base + KPIMR1_OFFSET);
+	writel(0xFFFFFFFF, kp->base + KPICR0_OFFSET);
+	writel(0xFFFFFFFF, kp->base + KPICR1_OFFSET);
+
+	if (kp->clk)
+		clk_disable_unprepare(kp->clk);
+}
+
+static int bcm_kp_open(struct input_dev *dev)
+{
+	struct bcm_kp *kp = input_get_drvdata(dev);
+
+	return bcm_kp_start(kp);
+}
+
+static void bcm_kp_close(struct input_dev *dev)
+{
+	struct bcm_kp *kp = input_get_drvdata(dev);
+
+	bcm_kp_stop(kp);
+}
+
+static int bcm_kp_matrix_key_parse_dt(struct bcm_kp *kp)
+{
+	struct device *dev = kp->input_dev->dev.parent;
+	struct device_node *np = dev->of_node;
+	int error;
+	unsigned int dt_val;
+	unsigned int i;
+	unsigned int num_rows, col_mask, rows_set;
+
+	/* Initialize the KPCR Keypad Configuration Register */
+	kp->kpcr = KPCR_STATUSFILTERENABLE | KPCR_COLFILTERENABLE;
+
+	error = matrix_keypad_parse_of_params(dev, &kp->n_rows, &kp->n_cols);
+	if (error) {
+		dev_err(dev, "failed to parse kp params\n");
+		return error;
+	}
+
+	/* Set row width for the ASIC block. */
+	kp->kpcr |= (kp->n_rows - 1) << KPCR_ROWWIDTH_SHIFT;
+
+	/* Set column width for the ASIC block. */
+	kp->kpcr |= (kp->n_cols - 1) << KPCR_COLUMNWIDTH_SHIFT;
+
+	/* Configure the IMR registers */
+
+	/*
+	 * IMR registers contain interrupt enable bits for 8x8 matrix
+	 * IMR0 register format: <row3> <row2> <row1> <row0>
+	 * IMR1 register format: <row7> <row6> <row5> <row4>
+	 */
+	col_mask = (1 << (kp->n_cols)) - 1;
+	num_rows = kp->n_rows;
+
+	/* Set column bits in rows 0 to 3 in IMR0 */
+	kp->imr0_val = col_mask;
+
+	rows_set = 1;
+	while (--num_rows && rows_set++ < 4)
+		kp->imr0_val |= kp->imr0_val << MAX_COLS;
+
+	/* Set column bits in rows 4 to 7 in IMR1 */
+	kp->imr1_val = 0;
+	if (num_rows) {
+		kp->imr1_val = col_mask;
+		while (--num_rows)
+			kp->imr1_val |= kp->imr1_val << MAX_COLS;
+	}
+
+	/* Initialize the KPEMR Keypress Edge Mode Registers */
+	/* Trigger on both edges */
+	kp->kpemr = 0;
+	for (i = 0; i <= 30; i += 2)
+		kp->kpemr |= (KPEMR_EDGETYPE_BOTH << i);
+
+	/*
+	 * Obtain the Status filter debounce value and verify against the
+	 * possible values specified in the DT binding.
+	 */
+	of_property_read_u32(np, "status-debounce-filter-period", &dt_val);
+
+	if (dt_val > KPCR_STATUSFILTERTYPE_MAX) {
+		dev_err(dev, "Invalid Status filter debounce value %d\n",
+			dt_val);
+		return -EINVAL;
+	}
+
+	kp->kpcr |= dt_val << KPCR_STATUSFILTERTYPE_SHIFT;
+
+	/*
+	 * Obtain the Column filter debounce value and verify against the
+	 * possible values specified in the DT binding.
+	 */
+	of_property_read_u32(np, "col-debounce-filter-period", &dt_val);
+
+	if (dt_val > KPCR_COLFILTERTYPE_MAX) {
+		dev_err(dev, "Invalid Column filter debounce value %d\n",
+			dt_val);
+		return -EINVAL;
+	}
+
+	kp->kpcr |= dt_val << KPCR_COLFILTERTYPE_SHIFT;
+
+	/*
+	 * Determine between the row and column,
+	 * which should be configured as output.
+	 */
+	if (of_property_read_bool(np, "row-output-enabled")) {
+		/*
+		* Set RowOContrl or ColumnOContrl in KPIOR
+		* to the number of pins to drive as outputs
+		*/
+		kp->kpior = ((1 << kp->n_rows) - 1) <<
+				KPIOR_ROWOCONTRL_SHIFT;
+	} else {
+		kp->kpior = ((1 << kp->n_cols) - 1) <<
+				KPIOR_COLUMNOCONTRL_SHIFT;
+	}
+
+	/*
+	 * Determine if the scan pull up needs to be enabled
+	 */
+	if (of_property_read_bool(np, "pull-up-enabled"))
+		kp->kpcr |= KPCR_MODE;
+
+	dev_dbg(dev, "n_rows=%d n_col=%d kpcr=%x kpior=%x kpemr=%x\n",
+		kp->n_rows, kp->n_cols,
+		kp->kpcr, kp->kpior, kp->kpemr);
+
+	return 0;
+}
+
+
+static int bcm_kp_probe(struct platform_device *pdev)
+{
+	struct bcm_kp *kp;
+	struct input_dev *input_dev;
+	struct resource *res;
+	int error;
+
+	kp = devm_kzalloc(&pdev->dev, sizeof(*kp), GFP_KERNEL);
+	if (!kp)
+		return -ENOMEM;
+
+	input_dev = devm_input_allocate_device(&pdev->dev);
+	if (!input_dev) {
+		dev_err(&pdev->dev, "failed to allocate the input device\n");
+		return -ENOMEM;
+	}
+
+	__set_bit(EV_KEY, input_dev->evbit);
+
+	/* Enable auto repeat feature of Linux input subsystem */
+	if (of_property_read_bool(pdev->dev.of_node, "autorepeat"))
+		__set_bit(EV_REP, input_dev->evbit);
+
+	input_dev->name = pdev->name;
+	input_dev->phys = "keypad/input0";
+	input_dev->dev.parent = &pdev->dev;
+	input_dev->open = bcm_kp_open;
+	input_dev->close = bcm_kp_close;
+
+	input_dev->id.bustype = BUS_HOST;
+	input_dev->id.vendor = 0x0001;
+	input_dev->id.product = 0x0001;
+	input_dev->id.version = 0x0100;
+
+	input_set_drvdata(input_dev, kp);
+
+	kp->input_dev = input_dev;
+
+	platform_set_drvdata(pdev, kp);
+
+	error = bcm_kp_matrix_key_parse_dt(kp);
+	if (error)
+		return error;
+
+	error = matrix_keypad_build_keymap(NULL, NULL,
+					   kp->n_rows, kp->n_cols,
+					   NULL, input_dev);
+	if (error) {
+		dev_err(&pdev->dev, "failed to build keymap\n");
+		return error;
+	}
+
+	/* Get the KEYPAD base address */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "Missing keypad base address resource\n");
+		return -ENODEV;
+	}
+
+	kp->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(kp->base))
+		return PTR_ERR(kp->base);
+
+	/* Enable clock */
+	kp->clk = devm_clk_get(&pdev->dev, "peri_clk");
+	if (IS_ERR(kp->clk)) {
+		error = PTR_ERR(kp->clk);
+		if (error != -ENOENT) {
+			if (error != -EPROBE_DEFER)
+				dev_err(&pdev->dev, "Failed to get clock\n");
+			return error;
+		}
+		dev_dbg(&pdev->dev,
+			"No clock specified. Assuming it's enabled\n");
+		kp->clk = NULL;
+	} else {
+		unsigned int desired_rate;
+		long actual_rate;
+
+		error = of_property_read_u32(pdev->dev.of_node,
+					     "clock-frequency", &desired_rate);
+		if (error < 0)
+			desired_rate = DEFAULT_CLK_HZ;
+
+		actual_rate = clk_round_rate(kp->clk, desired_rate);
+		if (actual_rate <= 0)
+			return -EINVAL;
+
+		error = clk_set_rate(kp->clk, actual_rate);
+		if (error)
+			return error;
+
+		error = clk_prepare_enable(kp->clk);
+		if (error)
+			return error;
+	}
+
+	/* Put the kp into a known sane state */
+	bcm_kp_stop(kp);
+
+	kp->irq = platform_get_irq(pdev, 0);
+	if (kp->irq < 0) {
+		dev_err(&pdev->dev, "no IRQ specified\n");
+		return -EINVAL;
+	}
+
+	error = devm_request_threaded_irq(&pdev->dev, kp->irq,
+					  NULL, bcm_kp_isr_thread,
+					  IRQF_ONESHOT, pdev->name, kp);
+	if (error) {
+		dev_err(&pdev->dev, "failed to request IRQ\n");
+		return error;
+	}
+
+	error = input_register_device(input_dev);
+	if (error) {
+		dev_err(&pdev->dev, "failed to register input device\n");
+		return error;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id bcm_kp_of_match[] = {
+	{ .compatible = "brcm,bcm-keypad" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, bcm_kp_of_match);
+
+static struct platform_driver bcm_kp_device_driver = {
+	.probe		= bcm_kp_probe,
+	.driver		= {
+		.name	= "bcm-keypad",
+		.of_match_table = of_match_ptr(bcm_kp_of_match),
+	}
+};
+
+module_platform_driver(bcm_kp_device_driver);
+
+MODULE_AUTHOR("Broadcom Corporation");
+MODULE_DESCRIPTION("BCM Keypad Driver");
+MODULE_LICENSE("GPL v2");