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");