Sansa clip zip: use a state machine for scanning buttons to avoid busy-waits
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30871 a1c6a512-1295-4272-9138-f99709370657
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1 changed files with 55 additions and 41 deletions
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@ -27,6 +27,59 @@
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#include "kernel.h"
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#include "system-target.h"
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static int keyscan(void)
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{
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static int buttons = 0;
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static int row = 1;
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switch (row) {
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case 1:
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/* read row 1 */
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buttons &= ~(BUTTON_RIGHT | BUTTON_SELECT | BUTTON_UP);
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if (GPIOC_PIN(3)) {
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buttons |= BUTTON_RIGHT;
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}
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if (GPIOC_PIN(4)) {
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buttons |= BUTTON_SELECT;
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}
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if (GPIOC_PIN(5)) {
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buttons |= BUTTON_UP;
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}
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/* prepare row 2 */
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GPIOC_PIN(1) = 0;
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GPIOC_PIN(2) = (1 << 2);
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row = 2;
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break;
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case 2:
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/* read row 2 */
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buttons &= ~(BUTTON_HOME | BUTTON_DOWN | BUTTON_LEFT);
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if (GPIOC_PIN(3)) {
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buttons |= BUTTON_HOME;
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}
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if (GPIOC_PIN(4)) {
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buttons |= BUTTON_DOWN;
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}
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if (GPIOC_PIN(5)) {
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buttons |= BUTTON_LEFT;
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}
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/* prepare row 1 */
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GPIOC_PIN(1) = (1 << 1);
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GPIOC_PIN(2) = 0;
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row = 1;
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break;
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default:
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row = 1;
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break;
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}
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return buttons;
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}
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void button_init_device(void)
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{
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/* GPIO A6, A7 and D6 are direct button inputs */
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@ -39,15 +92,6 @@ void button_init_device(void)
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GPIOC_DIR &= ~((1 << 3) | (1 << 4) | (1 << 5));
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}
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/* TODO:
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Instead of using udelay to wait for buttons to settle, we could use a
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simple state machine to alternate between key matrix rows (like we do on
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the clip) and this way avoid burning cycles in the udelay.
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TODO:
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Figure out the real mappings from GPIOs to buttons.
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The current mapping is just an educated guess.
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*/
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int button_read_device(void)
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{
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int buttons = 0;
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@ -64,39 +108,9 @@ int button_read_device(void)
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if (GPIOA_PIN(7)) {
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buttons |= BUTTON_VOL_UP;
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}
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/* key matrix buttons, first row */
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GPIOC_PIN(1) = (1 << 1);
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GPIOC_PIN(2) = 0;
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udelay(500);
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if (GPIOC_PIN(3)) {
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buttons |= BUTTON_RIGHT;
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}
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if (GPIOC_PIN(4)) {
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buttons |= BUTTON_SELECT;
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}
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if (GPIOC_PIN(5)) {
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buttons |= BUTTON_UP;
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}
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/* key matrix buttons, second row */
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GPIOC_PIN(1) = 0;
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GPIOC_PIN(2) = (1 << 2);
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udelay(500);
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if (GPIOC_PIN(3)) {
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buttons |= BUTTON_HOME;
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}
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if (GPIOC_PIN(4)) {
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buttons |= BUTTON_DOWN;
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}
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if (GPIOC_PIN(5)) {
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buttons |= BUTTON_LEFT;
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}
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/* deselect scan rows */
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GPIOC_PIN(2) = 0;
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/* keyscan buttons */
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buttons |= keyscan();
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return buttons;
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}
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