u-boot/drivers/input/tegra-kbc.c

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/*
* (C) Copyright 2011
* NVIDIA Corporation <www.nvidia.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <fdtdec.h>
#include <input.h>
#include <keyboard.h>
#include <key_matrix.h>
#include <stdio_dev.h>
#include <tegra-kbc.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#include <asm/arch/funcmux.h>
#include <asm/arch-tegra/timer.h>
#include <linux/input.h>
DECLARE_GLOBAL_DATA_PTR;
enum {
KBC_MAX_GPIO = 24,
KBC_MAX_KPENT = 8, /* size of keypress entry queue */
};
#define KBC_FIFO_TH_CNT_SHIFT 14
#define KBC_DEBOUNCE_CNT_SHIFT 4
#define KBC_CONTROL_FIFO_CNT_INT_EN (1 << 3)
#define KBC_CONTROL_KBC_EN (1 << 0)
#define KBC_INT_FIFO_CNT_INT_STATUS (1 << 2)
#define KBC_KPENT_VALID (1 << 7)
#define KBC_ST_STATUS (1 << 3)
enum {
KBC_DEBOUNCE_COUNT = 2,
KBC_REPEAT_RATE_MS = 30,
KBC_REPEAT_DELAY_MS = 240,
KBC_CLOCK_KHZ = 32, /* Keyboard uses a 32KHz clock */
};
/* keyboard controller config and state */
struct tegra_kbd_priv {
struct input_config *input; /* The input layer */
struct key_matrix matrix; /* The key matrix layer */
struct kbc_tegra *kbc; /* tegra keyboard controller */
unsigned char inited; /* 1 if keyboard has been inited */
unsigned char first_scan; /* 1 if this is our first key scan */
/*
* After init we must wait a short time before polling the keyboard.
* This gives the tegra keyboard controller time to react after reset
* and lets us grab keys pressed during reset.
*/
unsigned int init_dly_ms; /* Delay before we can read keyboard */
unsigned int start_time_ms; /* Time that we inited (in ms) */
unsigned int last_poll_ms; /* Time we should last polled */
unsigned int next_repeat_ms; /* Next time we repeat a key */
};
/**
* reads the keyboard fifo for current keypresses
*
* @param priv Keyboard private data
* @param fifo Place to put fifo results
* @param max_keycodes Maximum number of key codes to put in the fifo
* @return number of items put into fifo
*/
static int tegra_kbc_find_keys(struct tegra_kbd_priv *priv, int *fifo,
int max_keycodes)
{
struct key_matrix_key keys[KBC_MAX_KPENT], *key;
u32 kp_ent = 0;
int i;
for (key = keys, i = 0; i < KBC_MAX_KPENT; i++, key++) {
/* Get next word */
if (!(i & 3))
kp_ent = readl(&priv->kbc->kp_ent[i / 4]);
key->valid = (kp_ent & KBC_KPENT_VALID) != 0;
key->row = (kp_ent >> 3) & 0xf;
key->col = kp_ent & 0x7;
/* Shift to get next entry */
kp_ent >>= 8;
}
return key_matrix_decode(&priv->matrix, keys, KBC_MAX_KPENT, fifo,
max_keycodes);
}
/**
* Process all the keypress sequences in fifo and send key codes
*
* The fifo contains zero or more keypress sets. Each set
* consists of from 1-8 keycodes, representing the keycodes which
* were simultaneously pressed during that scan.
*
* This function works through each set and generates ASCII characters
* for each. Not that one set may produce more than one ASCII characters -
* for example holding down 'd' and 'f' at the same time will generate
* two ASCII characters.
*
* Note: if fifo_cnt is 0, we will tell the input layer that no keys are
* pressed.
*
* @param priv Keyboard private data
* @param fifo_cnt Number of entries in the keyboard fifo
*/
static void process_fifo(struct tegra_kbd_priv *priv, int fifo_cnt)
{
int fifo[KBC_MAX_KPENT];
int cnt = 0;
/* Always call input_send_keycodes() at least once */
do {
if (fifo_cnt)
cnt = tegra_kbc_find_keys(priv, fifo, KBC_MAX_KPENT);
input_send_keycodes(priv->input, fifo, cnt);
} while (--fifo_cnt > 0);
}
/**
* Check the keyboard controller and emit ASCII characters for any keys that
* are pressed.
*
* @param priv Keyboard private data
*/
static void check_for_keys(struct tegra_kbd_priv *priv)
{
int fifo_cnt;
if (!priv->first_scan &&
get_timer(priv->last_poll_ms) < KBC_REPEAT_RATE_MS)
return;
priv->last_poll_ms = get_timer(0);
priv->first_scan = 0;
/*
* Once we get here we know the keyboard has been scanned. So if there
* scan waiting for us, we know that nothing is held down.
*/
fifo_cnt = (readl(&priv->kbc->interrupt) >> 4) & 0xf;
process_fifo(priv, fifo_cnt);
}
/**
* In order to detect keys pressed on boot, wait for the hardware to
* complete scanning the keys. This includes time to transition from
* Wkup mode to Continous polling mode and the repoll time. We can
* deduct the time that's already elapsed.
*
* @param priv Keyboard private data
*/
static void kbd_wait_for_fifo_init(struct tegra_kbd_priv *priv)
{
if (!priv->inited) {
unsigned long elapsed_time;
long delay_ms;
elapsed_time = get_timer(priv->start_time_ms);
delay_ms = priv->init_dly_ms - elapsed_time;
if (delay_ms > 0) {
udelay(delay_ms * 1000);
debug("%s: delay %ldms\n", __func__, delay_ms);
}
priv->inited = 1;
}
}
/**
* Check the tegra keyboard, and send any keys that are pressed.
*
* This is called by input_tstc() and input_getc() when they need more
* characters
*
* @param input Input configuration
* @return 1, to indicate that we have something to look at
*/
static int tegra_kbc_check(struct input_config *input)
{
struct tegra_kbd_priv *priv = dev_get_priv(input->dev);
kbd_wait_for_fifo_init(priv);
check_for_keys(priv);
return 1;
}
/* configures keyboard GPIO registers to use the rows and columns */
static void config_kbc_gpio(struct tegra_kbd_priv *priv, struct kbc_tegra *kbc)
{
int i;
for (i = 0; i < KBC_MAX_GPIO; i++) {
u32 row_cfg, col_cfg;
u32 r_shift = 5 * (i % 6);
u32 c_shift = 4 * (i % 8);
u32 r_mask = 0x1f << r_shift;
u32 c_mask = 0xf << c_shift;
u32 r_offs = i / 6;
u32 c_offs = i / 8;
row_cfg = readl(&kbc->row_cfg[r_offs]);
col_cfg = readl(&kbc->col_cfg[c_offs]);
row_cfg &= ~r_mask;
col_cfg &= ~c_mask;
if (i < priv->matrix.num_rows) {
row_cfg |= ((i << 1) | 1) << r_shift;
} else {
col_cfg |= (((i - priv->matrix.num_rows) << 1) | 1)
<< c_shift;
}
writel(row_cfg, &kbc->row_cfg[r_offs]);
writel(col_cfg, &kbc->col_cfg[c_offs]);
}
}
/**
* Start up the keyboard device
*/
static void tegra_kbc_open(struct tegra_kbd_priv *priv)
{
struct kbc_tegra *kbc = priv->kbc;
unsigned int scan_period;
u32 val;
/*
* We will scan at twice the keyboard repeat rate, so that there is
* always a scan ready when we check it in check_for_keys().
*/
scan_period = KBC_REPEAT_RATE_MS / 2;
writel(scan_period * KBC_CLOCK_KHZ, &kbc->rpt_dly);
writel(scan_period * KBC_CLOCK_KHZ, &kbc->init_dly);
/*
* Before reading from the keyboard we must wait for the init_dly
* plus the rpt_delay, plus 2ms for the row scan time.
*/
priv->init_dly_ms = scan_period * 2 + 2;
val = KBC_DEBOUNCE_COUNT << KBC_DEBOUNCE_CNT_SHIFT;
val |= 1 << KBC_FIFO_TH_CNT_SHIFT; /* fifo interrupt threshold */
val |= KBC_CONTROL_KBC_EN; /* enable */
writel(val, &kbc->control);
priv->start_time_ms = get_timer(0);
priv->last_poll_ms = get_timer(0);
priv->next_repeat_ms = priv->last_poll_ms;
priv->first_scan = 1;
}
static int tegra_kbd_start(struct udevice *dev)
{
struct tegra_kbd_priv *priv = dev_get_priv(dev);
/* Set up pin mux and enable the clock */
funcmux_select(PERIPH_ID_KBC, FUNCMUX_DEFAULT);
clock_enable(PERIPH_ID_KBC);
config_kbc_gpio(priv, priv->kbc);
tegra_kbc_open(priv);
debug("%s: Tegra keyboard ready\n", __func__);
return 0;
}
/**
* Set up the tegra keyboard. This is called by the stdio device handler
*
* We want to do this init when the keyboard is actually used rather than
* at start-up, since keyboard input may not currently be selected.
*
* Once the keyboard starts there will be a period during which we must
* wait for the keyboard to init. We do this only when a key is first
* read - see kbd_wait_for_fifo_init().
*
* @return 0 if ok, -ve on error
*/
static int tegra_kbd_probe(struct udevice *dev)
{
struct tegra_kbd_priv *priv = dev_get_priv(dev);
struct keyboard_priv *uc_priv = dev_get_uclass_priv(dev);
struct stdio_dev *sdev = &uc_priv->sdev;
struct input_config *input = &uc_priv->input;
int node = dev_of_offset(dev);
int ret;
priv->kbc = (struct kbc_tegra *)dev_get_addr(dev);
if ((fdt_addr_t)priv->kbc == FDT_ADDR_T_NONE) {
debug("%s: No keyboard register found\n", __func__);
return -EINVAL;
}
input_set_delays(input, KBC_REPEAT_DELAY_MS, KBC_REPEAT_RATE_MS);
/* Decode the keyboard matrix information (16 rows, 8 columns) */
ret = key_matrix_init(&priv->matrix, 16, 8, 1);
if (ret) {
debug("%s: Could not init key matrix: %d\n", __func__, ret);
return ret;
}
ret = key_matrix_decode_fdt(&priv->matrix, gd->fdt_blob, node);
if (ret) {
debug("%s: Could not decode key matrix from fdt: %d\n",
__func__, ret);
return ret;
}
input_add_tables(input, false);
if (priv->matrix.fn_keycode) {
ret = input_add_table(input, KEY_FN, -1,
priv->matrix.fn_keycode,
priv->matrix.key_count);
if (ret) {
debug("%s: input_add_table() failed\n", __func__);
return ret;
}
}
/* Register the device. init_tegra_keyboard() will be called soon */
priv->input = input;
input->dev = dev;
input->read_keys = tegra_kbc_check;
strcpy(sdev->name, "tegra-kbc");
ret = input_stdio_register(sdev);
if (ret) {
debug("%s: input_stdio_register() failed\n", __func__);
return ret;
}
return 0;
}
static const struct keyboard_ops tegra_kbd_ops = {
.start = tegra_kbd_start,
};
static const struct udevice_id tegra_kbd_ids[] = {
{ .compatible = "nvidia,tegra20-kbc" },
{ }
};
U_BOOT_DRIVER(tegra_kbd) = {
.name = "tegra_kbd",
.id = UCLASS_KEYBOARD,
.of_match = tegra_kbd_ids,
.probe = tegra_kbd_probe,
.ops = &tegra_kbd_ops,
.priv_auto_alloc_size = sizeof(struct tegra_kbd_priv),
};