Extract musicpal.c I2C bitbanging code and make it gpio aware
Signed-off-by: Benoit Canet <benoit.canet@gmail.com> Signed-off-by: Andrzej Zaborowski <balrogg@gmail.com>
This commit is contained in:
Andrzej Zaborowski
parent
343ec8e485
commit
3ead03bd0a
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@ -272,7 +272,7 @@ obj-arm-y += omap2.o omap_dss.o soc_dma.o
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obj-arm-y += omap_sx1.o palm.o tsc210x.o
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obj-arm-y += nseries.o blizzard.o onenand.o vga.o cbus.o tusb6010.o usb-musb.o
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obj-arm-y += mst_fpga.o mainstone.o
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obj-arm-y += musicpal.o pflash_cfi02.o
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obj-arm-y += musicpal.o pflash_cfi02.o bitbang_i2c.o
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obj-arm-y += framebuffer.o
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obj-arm-y += syborg.o syborg_fb.o syborg_interrupt.o syborg_keyboard.o
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obj-arm-y += syborg_serial.o syborg_timer.o syborg_pointer.o syborg_rtc.o
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@ -0,0 +1,179 @@
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/*
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* Bit-Bang i2c emulation extracted from
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* Marvell MV88W8618 / Freecom MusicPal emulation.
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*
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* Copyright (c) 2008 Jan Kiszka
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*
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* This code is licenced under the GNU GPL v2.
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*/
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#include "hw.h"
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#include "i2c.h"
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#include "sysbus.h"
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typedef enum bitbang_i2c_state {
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STOPPED = 0,
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INITIALIZING,
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SENDING_BIT7,
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SENDING_BIT6,
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SENDING_BIT5,
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SENDING_BIT4,
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SENDING_BIT3,
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SENDING_BIT2,
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SENDING_BIT1,
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SENDING_BIT0,
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WAITING_FOR_ACK,
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RECEIVING_BIT7,
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RECEIVING_BIT6,
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RECEIVING_BIT5,
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RECEIVING_BIT4,
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RECEIVING_BIT3,
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RECEIVING_BIT2,
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RECEIVING_BIT1,
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RECEIVING_BIT0,
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SENDING_ACK
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} bitbang_i2c_state;
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typedef struct bitbang_i2c_interface {
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SysBusDevice busdev;
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i2c_bus *bus;
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bitbang_i2c_state state;
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int last_data;
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int last_clock;
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uint8_t buffer;
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int current_addr;
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qemu_irq out;
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} bitbang_i2c_interface;
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static void bitbang_i2c_enter_stop(bitbang_i2c_interface *i2c)
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{
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if (i2c->current_addr >= 0)
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i2c_end_transfer(i2c->bus);
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i2c->current_addr = -1;
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i2c->state = STOPPED;
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}
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static void bitbang_i2c_gpio_set(void *opaque, int irq, int level)
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{
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bitbang_i2c_interface *i2c = opaque;
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int data;
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int clock;
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int data_goes_up;
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int data_goes_down;
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int clock_goes_up;
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int clock_goes_down;
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/* get pins states */
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data = i2c->last_data;
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clock = i2c->last_clock;
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if (irq == 0)
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data = level;
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if (irq == 1)
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clock = level;
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/* compute pins changes */
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data_goes_up = data == 1 && i2c->last_data == 0;
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data_goes_down = data == 0 && i2c->last_data == 1;
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clock_goes_up = clock == 1 && i2c->last_clock == 0;
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clock_goes_down = clock == 0 && i2c->last_clock == 1;
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if (data_goes_up == 0 && data_goes_down == 0 &&
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clock_goes_up == 0 && clock_goes_down == 0)
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return;
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if (!i2c)
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return;
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if ((RECEIVING_BIT7 > i2c->state && i2c->state > RECEIVING_BIT0)
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|| i2c->state == WAITING_FOR_ACK)
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qemu_set_irq(i2c->out, 0);
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switch (i2c->state) {
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case STOPPED:
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if (data_goes_down && clock == 1)
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i2c->state = INITIALIZING;
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break;
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case INITIALIZING:
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if (clock_goes_down && data == 0)
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i2c->state = SENDING_BIT7;
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else
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bitbang_i2c_enter_stop(i2c);
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break;
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case SENDING_BIT7 ... SENDING_BIT0:
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if (clock_goes_down) {
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i2c->buffer = (i2c->buffer << 1) | data;
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/* will end up in WAITING_FOR_ACK */
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i2c->state++;
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} else if (data_goes_up && clock == 1)
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bitbang_i2c_enter_stop(i2c);
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break;
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case WAITING_FOR_ACK:
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if (clock_goes_down) {
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if (i2c->current_addr < 0) {
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i2c->current_addr = i2c->buffer;
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i2c_start_transfer(i2c->bus, (i2c->current_addr & 0xfe) / 2,
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i2c->buffer & 1);
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} else
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i2c_send(i2c->bus, i2c->buffer);
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if (i2c->current_addr & 1) {
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i2c->state = RECEIVING_BIT7;
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i2c->buffer = i2c_recv(i2c->bus);
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} else
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i2c->state = SENDING_BIT7;
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} else if (data_goes_up && clock == 1)
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bitbang_i2c_enter_stop(i2c);
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break;
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case RECEIVING_BIT7 ... RECEIVING_BIT0:
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qemu_set_irq(i2c->out, i2c->buffer >> 7);
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if (clock_goes_down) {
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/* will end up in SENDING_ACK */
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i2c->state++;
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i2c->buffer <<= 1;
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} else if (data_goes_up && clock == 1)
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bitbang_i2c_enter_stop(i2c);
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break;
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case SENDING_ACK:
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if (clock_goes_down) {
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i2c->state = RECEIVING_BIT7;
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if (data == 0)
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i2c->buffer = i2c_recv(i2c->bus);
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else
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i2c_nack(i2c->bus);
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} else if (data_goes_up && clock == 1)
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bitbang_i2c_enter_stop(i2c);
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break;
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}
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i2c->last_data = data;
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i2c->last_clock = clock;
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}
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static void bitbang_i2c_init(SysBusDevice *dev)
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{
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bitbang_i2c_interface *s = FROM_SYSBUS(bitbang_i2c_interface, dev);
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i2c_bus *bus;
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sysbus_init_mmio(dev, 0x0, 0);
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bus = i2c_init_bus(&dev->qdev, "i2c");
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s->bus = bus;
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s->last_data = 1;
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s->last_clock = 1;
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qdev_init_gpio_in(&dev->qdev, bitbang_i2c_gpio_set, 2);
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qdev_init_gpio_out(&dev->qdev, &s->out, 1);
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}
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static void bitbang_i2c_register(void)
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{
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sysbus_register_dev("bitbang_i2c",
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sizeof(bitbang_i2c_interface), bitbang_i2c_init);
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}
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device_init(bitbang_i2c_register)
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