Input: add support for LM8333 keypads

This driver adds support for the keypad part of the LM8333 and is
prepared for possible GPIO/PWM drivers. Note that this is not a MFD
because you cannot disable the keypad functionality which, thus,
has to be handled by the core anyhow.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 236 insertions, 0 deletions

diff --git a/drivers/input/keyboard/lm8333.c b/drivers/input/keyboard/lm8333.c
new file mode 100644
index 000000000000..9a8c4a6cf5c6
--- /dev/null
+++ b/drivers/input/keyboard/lm8333.c
@@ -0,0 +1,236 @@
+/*
+ * LM8333 keypad driver
+ * Copyright (C) 2012 Wolfram Sang, Pengutronix <w.sang@pengutronix.de>
+ *
+ * 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; either version 2 of the License.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/irq.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/input/lm8333.h>
+
+#define LM8333_FIFO_READ                0x20
+#define LM8333_DEBOUNCE                 0x22
+#define LM8333_READ_INT                 0xD0
+#define LM8333_ACTIVE                   0xE4
+#define LM8333_READ_ERROR               0xF0
+
+#define LM8333_KEYPAD_IRQ               (1 << 0)
+#define LM8333_ERROR_IRQ                (1 << 3)
+
+#define LM8333_ERROR_KEYOVR             0x04
+#define LM8333_ERROR_FIFOOVR            0x40
+
+#define LM8333_FIFO_TRANSFER_SIZE       16
+
+#define LM8333_ROW_SHIFT        4
+#define LM8333_NUM_ROWS         8
+
+
+struct lm8333 {
+        struct i2c_client *client;
+        struct input_dev *input;
+        unsigned short keycodes[LM8333_NUM_ROWS << LM8333_ROW_SHIFT];
+};
+
+/* The accessors try twice because the first access may be needed for wakeup */
+#define LM8333_READ_RETRIES 2
+
+int lm8333_read8(struct lm8333 *lm8333, u8 cmd)
+{
+        int retries = 0, ret;
+
+        do {
+                ret = i2c_smbus_read_byte_data(lm8333->client, cmd);
+        } while (ret < 0 && retries++ < LM8333_READ_RETRIES);
+
+        return ret;
+}
+
+int lm8333_write8(struct lm8333 *lm8333, u8 cmd, u8 val)
+{
+        int retries = 0, ret;
+
+        do {
+                ret = i2c_smbus_write_byte_data(lm8333->client, cmd, val);
+        } while (ret < 0 && retries++ < LM8333_READ_RETRIES);
+
+        return ret;
+}
+
+int lm8333_read_block(struct lm8333 *lm8333, u8 cmd, u8 len, u8 *buf)
+{
+        int retries = 0, ret;
+
+        do {
+                ret = i2c_smbus_read_i2c_block_data(lm8333->client,
+                                                    cmd, len, buf);
+        } while (ret < 0 && retries++ < LM8333_READ_RETRIES);
+
+        return ret;
+}
+
+static void lm8333_key_handler(struct lm8333 *lm8333)
+{
+        struct input_dev *input = lm8333->input;
+        u8 keys[LM8333_FIFO_TRANSFER_SIZE];
+        u8 code, pressed;
+        int i, ret;
+
+        ret = lm8333_read_block(lm8333, LM8333_FIFO_READ,
+                                LM8333_FIFO_TRANSFER_SIZE, keys);
+        if (ret != LM8333_FIFO_TRANSFER_SIZE) {
+                dev_err(&lm8333->client->dev,
+                        "Error %d while reading FIFO\n", ret);
+                return;
+        }
+
+        for (i = 0; keys[i] && i < LM8333_FIFO_TRANSFER_SIZE; i++) {
+                pressed = keys[i] & 0x80;
+                code = keys[i] & 0x7f;
+
+                input_event(input, EV_MSC, MSC_SCAN, code);
+                input_report_key(input, lm8333->keycodes[code], pressed);
+        }
+
+        input_sync(input);
+}
+
+static irqreturn_t lm8333_irq_thread(int irq, void *data)
+{
+        struct lm8333 *lm8333 = data;
+        u8 status = lm8333_read8(lm8333, LM8333_READ_INT);
+
+        if (!status)
+                return IRQ_NONE;
+
+        if (status & LM8333_ERROR_IRQ) {
+                u8 err = lm8333_read8(lm8333, LM8333_READ_ERROR);
+
+                if (err & (LM8333_ERROR_KEYOVR | LM8333_ERROR_FIFOOVR)) {
+                        u8 dummy[LM8333_FIFO_TRANSFER_SIZE];
+
+                        lm8333_read_block(lm8333, LM8333_FIFO_READ,
+                                        LM8333_FIFO_TRANSFER_SIZE, dummy);
+                }
+                dev_err(&lm8333->client->dev, "Got error %02x\n", err);
+        }
+
+        if (status & LM8333_KEYPAD_IRQ)
+                lm8333_key_handler(lm8333);
+
+        return IRQ_HANDLED;
+}
+
+static int __devinit lm8333_probe(struct i2c_client *client,
+                                  const struct i2c_device_id *id)
+{
+        const struct lm8333_platform_data *pdata = client->dev.platform_data;
+        struct lm8333 *lm8333;
+        struct input_dev *input;
+        int err, active_time;
+
+        if (!pdata)
+                return -EINVAL;
+
+        active_time = pdata->active_time ?: 500;
+        if (active_time / 3 <= pdata->debounce_time / 3) {
+                dev_err(&client->dev, "Active time not big enough!\n");
+                return -EINVAL;
+        }
+
+        lm8333 = kzalloc(sizeof(*lm8333), GFP_KERNEL);
+        input = input_allocate_device();
+        if (!lm8333 || !input) {
+                err = -ENOMEM;
+                goto free_mem;
+        }
+
+        lm8333->client = client;
+        lm8333->input = input;
+
+        input->name = client->name;
+        input->dev.parent = &client->dev;
+        input->id.bustype = BUS_I2C;
+
+        input->keycode = lm8333->keycodes;
+        input->keycodesize = sizeof(lm8333->keycodes[0]);
+        input->keycodemax = ARRAY_SIZE(lm8333->keycodes);
+        input->evbit[0] = BIT_MASK(EV_KEY);
+        input_set_capability(input, EV_MSC, MSC_SCAN);
+
+        matrix_keypad_build_keymap(pdata->matrix_data, LM8333_ROW_SHIFT,
+                        input->keycode, input->keybit);
+
+        if (pdata->debounce_time) {
+                err = lm8333_write8(lm8333, LM8333_DEBOUNCE,
+                                    pdata->debounce_time / 3);
+                if (err)
+                        dev_warn(&client->dev, "Unable to set debounce time\n");
+        }
+
+        if (pdata->active_time) {
+                err = lm8333_write8(lm8333, LM8333_ACTIVE,
+                                    pdata->active_time / 3);
+                if (err)
+                        dev_warn(&client->dev, "Unable to set active time\n");
+        }
+
+        err = request_threaded_irq(client->irq, NULL, lm8333_irq_thread,
+                                   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+                                   "lm8333", lm8333);
+        if (err)
+                goto free_mem;
+
+        err = input_register_device(input);
+        if (err)
+                goto free_irq;
+
+        i2c_set_clientdata(client, lm8333);
+        return 0;
+
+ free_irq:
+        free_irq(client->irq, lm8333);
+ free_mem:
+        input_free_device(input);
+        kfree(lm8333);
+        return err;
+}
+
+static int __devexit lm8333_remove(struct i2c_client *client)
+{
+        struct lm8333 *lm8333 = i2c_get_clientdata(client);
+
+        free_irq(client->irq, lm8333);
+        input_unregister_device(lm8333->input);
+        kfree(lm8333);
+
+        return 0;
+}
+
+static const struct i2c_device_id lm8333_id[] = {
+        { "lm8333", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, lm8333_id);
+
+static struct i2c_driver lm8333_driver = {
+        .driver = {
+                .name           = "lm8333",
+                .owner          = THIS_MODULE,
+        },
+        .probe          = lm8333_probe,
+        .remove         = __devexit_p(lm8333_remove),
+        .id_table       = lm8333_id,
+};
+module_i2c_driver(lm8333_driver);
+
+MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
+MODULE_DESCRIPTION("LM8333 keyboard driver");
+MODULE_LICENSE("GPL v2");