/**
* cbus_send_data - sends @len amount of data over the bus
* @host: the host we're using
* @data: the data to send
* @len: size of the transfer
* @input: whether to set data pin as input after sending
*/
static int cbus_send_data(struct cbus_host *host, unsigned data, unsigned len,
unsigned input)
{
int ret = 0;
int i;
for (i = len; i > 0; i--) {
ret = cbus_send_bit(host, data & (1 << (i - 1)),
input && (i == 1));
if (ret < 0)
goto out;
}
out:
return ret;
}
static int cbus_transfer(struct cbus_host *host, int dev, int reg, int data)
{
int i;
int is_read = 0;
unsigned long flags;
u32 base;
#ifdef CONFIG_ARCH_OMAP1
base = OMAP1_IO_ADDRESS(OMAP1_MPUIO_BASE);
#else
base = 0;
#endif
if (data < 0)
is_read = 1;
/* We don't want interrupts disturbing our transfer */
spin_lock_irqsave(&host->lock, flags);
/* Reset state and start of transfer, SEL stays down during transfer */
cbus_set_gpio_dataout(base, host->sel_gpio, 0);
/* Set the DAT pin to output */
cbus_output(base, host->dat_gpio, 1);
/* Send the device address */
for (i = 3; i > 0; i--)
cbus_send_bit(host, base, dev & (1 << (i - 1)), 0);
/* Send the rw flag */
cbus_send_bit(host, base, is_read, 0);
/* Send the register address */
for (i = 5; i > 0; i--) {
int set_to_input = 0;
if (is_read && i == 1)
set_to_input = 1;
cbus_send_bit(host, base, reg & (1 << (i - 1)), set_to_input);
}
if (!is_read) {
for (i = 16; i > 0; i--)
cbus_send_bit(host, base, data & (1 << (i - 1)), 0);
} else {
cbus_set_gpio_dataout(base, host->clk_gpio, 1);
data = 0;
for (i = 16; i > 0; i--) {
u8 bit = cbus_receive_bit(host, base);
if (bit)
data |= 1 << (i - 1);
}
}
/* Indicate end of transfer, SEL goes up until next transfer */
cbus_set_gpio_dataout(base, host->sel_gpio, 1);
cbus_set_gpio_dataout(base, host->clk_gpio, 1);
cbus_set_gpio_dataout(base, host->clk_gpio, 0);
spin_unlock_irqrestore(&host->lock, flags);
return is_read ? data : 0;
}
/**
* cbus_transfer - transfers data over the bus
* @host: the host we're using
* @rw: read/write flag
* @dev: device address
* @reg: register address
* @data: if @rw == 0 data to send otherwise 0
*/
static int cbus_transfer(struct cbus_host *host, unsigned rw, unsigned dev,
unsigned reg, unsigned data)
{
unsigned long flags;
int input = 0;
int ret = 0;
/* We don't want interrupts disturbing our transfer */
spin_lock_irqsave(&host->lock, flags);
/* Reset state and start of transfer, SEL stays down during transfer */
gpio_set_value(host->sel_gpio, 0);
/* Set the DAT pin to output */
gpio_direction_output(host->dat_gpio, 1);
/* Send the device address */
ret = cbus_send_data(host, dev, 3, 0);
if (ret < 0) {
dev_dbg(host->dev, "failed sending device addr\n");
goto out;
}
/* Send the rw flag */
ret = cbus_send_bit(host, rw, 0);
if (ret < 0) {
dev_dbg(host->dev, "failed sending read/write flag\n");
goto out;
}
/* Send the register address */
if (rw)
input = true;
ret = cbus_send_data(host, reg, 5, input);
if (ret < 0) {
dev_dbg(host->dev, "failed sending register addr\n");
goto out;
}
if (!rw) {
ret = cbus_send_data(host, data, 16, 0);
if (ret < 0) {
dev_dbg(host->dev, "failed sending data\n");
goto out;
}
} else {
gpio_set_value(host->clk_gpio, 1);
ret = cbus_receive_data(host, 16);
if (ret < 0) {
dev_dbg(host->dev, "failed receiving data\n");
goto out;
}
}
/* Indicate end of transfer, SEL goes up until next transfer */
gpio_set_value(host->sel_gpio, 1);
gpio_set_value(host->clk_gpio, 1);
gpio_set_value(host->clk_gpio, 0);
out:
spin_unlock_irqrestore(&host->lock, flags);
return ret;
}
