Input: add TI-Nspire keypad support

This is a driver for the keypads found on the TI-Nspire series calculators.

Signed-off-by: Daniel Tang <dt.tangr@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

3 files changed, 296 insertions, 0 deletions

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index ac0500667000..37c366623fc0 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -418,6 +418,16 @@ config KEYBOARD_NOMADIK
           To compile this driver as a module, choose M here: the
           module will be called nmk-ske-keypad.
 
+config KEYBOARD_NSPIRE
+        tristate "TI-NSPIRE built-in keyboard"
+        depends on ARCH_NSPIRE && OF
+        select INPUT_MATRIXKMAP
+        help
+          Say Y here if you want to use the built-in keypad on TI-NSPIRE.
+
+          To compile this driver as a module, choose M here: the
+          module will be called nspire-keypad.
+
 config KEYBOARD_TEGRA
         tristate "NVIDIA Tegra internal matrix keyboard controller support"
         depends on ARCH_TEGRA && OF
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 49b16453d00e..89d997b05452 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_KEYBOARD_MCS)		+= mcs_touchkey.o
 obj-$(CONFIG_KEYBOARD_MPR121)           += mpr121_touchkey.o
 obj-$(CONFIG_KEYBOARD_NEWTON)           += newtonkbd.o
 obj-$(CONFIG_KEYBOARD_NOMADIK)          += nomadik-ske-keypad.o
+obj-$(CONFIG_KEYBOARD_NSPIRE)           += nspire-keypad.o
 obj-$(CONFIG_KEYBOARD_OMAP)             += omap-keypad.o
 obj-$(CONFIG_KEYBOARD_OMAP4)            += omap4-keypad.o
 obj-$(CONFIG_KEYBOARD_OPENCORES)        += opencores-kbd.o
diff --git a/drivers/input/keyboard/nspire-keypad.c b/drivers/input/keyboard/nspire-keypad.c
new file mode 100644
index 000000000000..1b0d04c68d45
--- /dev/null
+++ b/drivers/input/keyboard/nspire-keypad.c
@@ -0,0 +1,285 @@
+/*
+ *  Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/input/matrix_keypad.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#define KEYPAD_SCAN_MODE        0x00
+#define KEYPAD_CNTL             0x04
+#define KEYPAD_INT              0x08
+#define KEYPAD_INTMSK           0x0C
+
+#define KEYPAD_DATA             0x10
+#define KEYPAD_GPIO             0x30
+
+#define KEYPAD_UNKNOWN_INT      0x40
+#define KEYPAD_UNKNOWN_INT_STS  0x44
+
+#define KEYPAD_BITMASK_COLS     11
+#define KEYPAD_BITMASK_ROWS     8
+
+struct nspire_keypad {
+        void __iomem *reg_base;
+        u32 int_mask;
+
+        struct input_dev *input;
+        struct clk *clk;
+
+        struct matrix_keymap_data *keymap;
+        int row_shift;
+
+        /* Maximum delay estimated assuming 33MHz APB */
+        u32 scan_interval;      /* In microseconds (~2000us max) */
+        u32 row_delay;          /* In microseconds (~500us max) */
+
+        u16 state[KEYPAD_BITMASK_ROWS];
+
+        bool active_low;
+};
+
+static irqreturn_t nspire_keypad_irq(int irq, void *dev_id)
+{
+        struct nspire_keypad *keypad = dev_id;
+        struct input_dev *input = keypad->input;
+        unsigned short *keymap = input->keycode;
+        unsigned int code;
+        int row, col;
+        u32 int_sts;
+        u16 state[8];
+        u16 bits, changed;
+
+        int_sts = readl(keypad->reg_base + KEYPAD_INT) & keypad->int_mask;
+        if (!int_sts)
+                return IRQ_NONE;
+
+        memcpy_fromio(state, keypad->reg_base + KEYPAD_DATA, sizeof(state));
+
+        for (row = 0; row < KEYPAD_BITMASK_ROWS; row++) {
+                bits = state[row];
+                if (keypad->active_low)
+                        bits = ~bits;
+
+                changed = bits ^ keypad->state[row];
+                if (!changed)
+                        continue;
+
+                keypad->state[row] = bits;
+
+                for (col = 0; col < KEYPAD_BITMASK_COLS; col++) {
+                        if (!(changed & (1U << col)))
+                                continue;
+
+                        code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
+                        input_event(input, EV_MSC, MSC_SCAN, code);
+                        input_report_key(input, keymap[code],
+                                         bits & (1U << col));
+                }
+        }
+
+        input_sync(input);
+
+        writel(0x3, keypad->reg_base + KEYPAD_INT);
+
+        return IRQ_HANDLED;
+}
+
+static int nspire_keypad_chip_init(struct nspire_keypad *keypad)
+{
+        unsigned long val = 0, cycles_per_us, delay_cycles, row_delay_cycles;
+
+        cycles_per_us = (clk_get_rate(keypad->clk) / 1000000);
+        if (cycles_per_us == 0)
+                cycles_per_us = 1;
+
+        delay_cycles = cycles_per_us * keypad->scan_interval;
+        WARN_ON(delay_cycles >= (1 << 16)); /* Overflow */
+        delay_cycles &= 0xffff;
+
+        row_delay_cycles = cycles_per_us * keypad->row_delay;
+        WARN_ON(row_delay_cycles >= (1 << 14)); /* Overflow */
+        row_delay_cycles &= 0x3fff;
+
+        val |= 3 << 0; /* Set scan mode to 3 (continuous scan) */
+        val |= row_delay_cycles << 2; /* Delay between scanning each row */
+        val |= delay_cycles << 16; /* Delay between scans */
+        writel(val, keypad->reg_base + KEYPAD_SCAN_MODE);
+
+        val = (KEYPAD_BITMASK_ROWS & 0xff) | (KEYPAD_BITMASK_COLS & 0xff)<<8;
+        writel(val, keypad->reg_base + KEYPAD_CNTL);
+
+        /* Enable interrupts */
+        keypad->int_mask = 1 << 1;
+        writel(keypad->int_mask, keypad->reg_base + 0xc);
+
+        /* Disable GPIO interrupts to prevent hanging on touchpad */
+        /* Possibly used to detect touchpad events */
+        writel(0, keypad->reg_base + KEYPAD_UNKNOWN_INT);
+        /* Acknowledge existing interrupts */
+        writel(~0, keypad->reg_base + KEYPAD_UNKNOWN_INT_STS);
+
+        return 0;
+}
+
+static int nspire_keypad_open(struct input_dev *input)
+{
+        struct nspire_keypad *keypad = input_get_drvdata(input);
+        int error;
+
+        error = clk_prepare_enable(keypad->clk);
+        if (error)
+                return error;
+
+        error = nspire_keypad_chip_init(keypad);
+        if (error)
+                return error;
+
+        return 0;
+}
+
+static void nspire_keypad_close(struct input_dev *input)
+{
+        struct nspire_keypad *keypad = input_get_drvdata(input);
+
+        clk_disable_unprepare(keypad->clk);
+}
+
+static int nspire_keypad_probe(struct platform_device *pdev)
+{
+        const struct device_node *of_node = pdev->dev.of_node;
+        struct nspire_keypad *keypad;
+        struct input_dev *input;
+        struct resource *res;
+        int irq;
+        int error;
+
+        irq = platform_get_irq(pdev, 0);
+        if (irq < 0) {
+                dev_err(&pdev->dev, "failed to get keypad irq\n");
+                return -EINVAL;
+        }
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res) {
+                dev_err(&pdev->dev, "missing platform resources\n");
+                return -EINVAL;
+        }
+
+        keypad = devm_kzalloc(&pdev->dev, sizeof(struct nspire_keypad),
+                              GFP_KERNEL);
+        if (!keypad) {
+                dev_err(&pdev->dev, "failed to allocate keypad memory\n");
+                return -ENOMEM;
+        }
+
+        keypad->row_shift = get_count_order(KEYPAD_BITMASK_COLS);
+
+        error = of_property_read_u32(of_node, "scan-interval",
+                                     &keypad->scan_interval);
+        if (error) {
+                dev_err(&pdev->dev, "failed to get scan-interval\n");
+                return error;
+        }
+
+        error = of_property_read_u32(of_node, "row-delay",
+                                     &keypad->row_delay);
+        if (error) {
+                dev_err(&pdev->dev, "failed to get row-delay\n");
+                return error;
+        }
+
+        keypad->active_low = of_property_read_bool(of_node, "active-low");
+
+        keypad->clk = devm_clk_get(&pdev->dev, NULL);
+        if (IS_ERR(keypad->clk)) {
+                dev_err(&pdev->dev, "unable to get clock\n");
+                return PTR_ERR(keypad->clk);
+        }
+
+        keypad->reg_base = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(keypad->reg_base)) {
+                dev_err(&pdev->dev, "failed to remap I/O memory\n");
+                return PTR_ERR(keypad->reg_base);
+        }
+
+        keypad->input = input = devm_input_allocate_device(&pdev->dev);
+        if (!input) {
+                dev_err(&pdev->dev, "failed to allocate input device\n");
+                return -ENOMEM;
+        }
+
+        input_set_drvdata(input, keypad);
+
+        input->id.bustype = BUS_HOST;
+        input->name = "nspire-keypad";
+        input->open = nspire_keypad_open;
+        input->close = nspire_keypad_close;
+
+        __set_bit(EV_KEY, input->evbit);
+        __set_bit(EV_REP, input->evbit);
+        input_set_capability(input, EV_MSC, MSC_SCAN);
+
+        error = matrix_keypad_build_keymap(NULL, NULL,
+                                           KEYPAD_BITMASK_ROWS,
+                                           KEYPAD_BITMASK_COLS,
+                                           NULL, input);
+        if (error) {
+                dev_err(&pdev->dev, "building keymap failed\n");
+                return error;
+        }
+
+        error = devm_request_irq(&pdev->dev, irq, nspire_keypad_irq, 0,
+                                 "nspire_keypad", keypad);
+        if (error) {
+                dev_err(&pdev->dev, "allocate irq %d failed\n", irq);
+                return error;
+        }
+
+        error = input_register_device(input);
+        if (error) {
+                dev_err(&pdev->dev,
+                        "unable to register input device: %d\n", error);
+                return error;
+        }
+
+        platform_set_drvdata(pdev, keypad);
+
+        dev_dbg(&pdev->dev,
+                "TI-NSPIRE keypad at %pR (scan_interval=%uus, row_delay=%uus%s)\n",
+                res, keypad->row_delay, keypad->scan_interval,
+                keypad->active_low ? ", active_low" : "");
+
+        return 0;
+}
+
+static const struct of_device_id nspire_keypad_dt_match[] = {
+        { .compatible = "ti,nspire-keypad" },
+        { },
+};
+MODULE_DEVICE_TABLE(of, nspire_keypad_dt_match);
+
+static struct platform_driver nspire_keypad_driver = {
+        .driver = {
+                .name = "nspire-keypad",
+                .owner = THIS_MODULE,
+                .of_match_table = of_match_ptr(nspire_keypad_dt_match),
+        },
+        .probe = nspire_keypad_probe,
+};
+
+module_platform_driver(nspire_keypad_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("TI-NSPIRE Keypad Driver");