original development tree for Linux kernel GTP module; now long in mainline.
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/*
* 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 + KEYPAD_INTMSK);
/* 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))
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");