/**
* Driver write function
*
* This function uses a generic SPI write to send values to the Pmod device
* It takes a raw data array from the app in the buffer, copied it into
* device dispay buffer, and finally sends the buffer to the OLED using SPI
*/
static ssize_t gpio_pmodoled_write(struct file *fp, const char __user *buffer, size_t length, loff_t *offset)
{
ssize_t retval = 0;
struct gpio_pmodoled_device *dev;
unsigned int minor_id;
int cnt;
int status;
dev = fp->private_data;
minor_id = MINOR(dev->dev_id);
if(mutex_lock_interruptible(&dev->mutex)) {
retval = -ERESTARTSYS;
goto write_lock_err;
}
if (buffer == NULL) {
dev_err(&dev->spi->dev, "oled_write: ERROR: invalid buffer address: 0x%08x\n",
(unsigned int) buffer);
retval = -EINVAL;
goto quit_write;
}
if(length > DISPLAY_BUF_SZ) {
cnt = DISPLAY_BUF_SZ;
}
else {
cnt = length;
}
if(copy_from_user(dev->disp_buf, buffer, cnt)) {
dev_err(&dev->spi->dev, "oled_write: copy_from_user failed\n");
retval = -EFAULT;
goto quit_write;
}
else {
retval = cnt;
}
status = screen_buf_to_display(dev->disp_buf, dev);
if(status) {
dev_err(&dev->spi->dev, "oled_write: Error sending string to display\n");
retval = -EFAULT;
goto quit_write;
}
quit_write:
mutex_unlock(&dev->mutex);
write_lock_err:
return retval;
}
static int gpio_pmodoled_spi_remove(struct spi_device *spi)
{
int status;
struct gpio_pmodoled_device *dev;
uint8_t wr_buf[10];
dev = (struct gpio_pmodoled_device *) spi->dev.platform_data;
if (dev == NULL) {
dev_err(&spi->dev, "spi_remove: Error fetch gpio_pmodoled_device struct\n");
return -EINVAL;
}
#ifdef CONFIG_PMODS_DEBUG
printk(KERN_INFO SPI_DRIVER_NAME " [%s] spi_remove: Clearing Display\n", dev->name);
#endif
/* Clear Display */
memset(dev->disp_buf, 0, DISPLAY_BUF_SZ);
status = screen_buf_to_display(dev->disp_buf, dev);
/* Turn off display */
wr_buf[0] = OLED_DISPLAY_OFF;
status = spi_write(spi, wr_buf, 1);
if (status)
dev_err(&spi->dev, "oled_spi_remove: Error writing to SPI device\n");
/* Turn off VCC (VBAT) */
gpio_set_value(dev->iVBAT, 1);
msleep(100);
/* TUrn off VDD Power */
gpio_set_value(dev->iVDD, 1);
#ifdef CONFIG_PMODS_DEBUG
printk(KERN_INFO SPI_DRIVER_NAME " [%s] spi_remove: Free GPIOs\n", dev->name);
#endif
{
struct gpio gpio_pmodoled_ctrl[] = {
{dev->iVBAT, GPIOF_OUT_INIT_HIGH, "OLED VBat"},
{dev->iVDD, GPIOF_OUT_INIT_HIGH, "OLED VDD"},
{dev->iRES, GPIOF_OUT_INIT_HIGH, "OLED_RESET"},
{dev->iDC, GPIOF_OUT_INIT_HIGH, "OLED_D/C"},
};
gpio_free_array(gpio_pmodoled_ctrl, 4);
}
if (&dev->cdev) {
#ifdef CONFIG_PMODS_DEBUG
printk(KERN_INFO SPI_DRIVER_NAME " [%s] spi_remove: Destroy Char Device\n", dev->name);
#endif
device_destroy(gpio_pmodoled_class, dev->dev_id);
cdev_del(&dev->cdev);
}
cur_minor--;
printk(KERN_INFO SPI_DRIVER_NAME " [%s] spi_remove: Device Removed\n", dev->name);
return status;
}
/**
* SPI hardware probe. Sets correct SPI mode, attempts
* to obtain memory needed by the driver, and performs
* a simple initialization of the device.
*/
static int gpio_pmodoled_spi_probe(struct spi_device *spi)
{
int status = 0;
struct gpio_pmodoled_device *gpio_pmodoled_dev;
/* We rely on full duplex transfers, mostly to reduce
* per transfer overheads (by making few transfers).
*/
if (spi->master->flags & SPI_MASTER_HALF_DUPLEX) {
status = -EINVAL;
dev_err(&spi->dev, "SPI settings incorrect: %d\n", status);
goto spi_err;
}
/* We must use SPI_MODE_0 */
spi->mode = SPI_MODE_0;
spi->bits_per_word = 8;
status = spi_setup(spi);
if (status < 0) {
dev_err(&spi->dev, "needs SPI mode %02x, %d KHz; %d\n",
spi->mode, spi->max_speed_hz / 1000,
status);
goto spi_err;
}
/* Get gpio_pmodoled_device structure */
gpio_pmodoled_dev = (struct gpio_pmodoled_device *) spi->dev.platform_data;
if (gpio_pmodoled_dev == NULL) {
dev_err(&spi->dev, "Cannot get gpio_pmodoled_device.\n");
status = -EINVAL;
goto spi_platform_data_err;
}
printk(KERN_INFO SPI_DRIVER_NAME " [%s] SPI Probing\n", gpio_pmodoled_dev->name);
#ifdef CONFIG_PMODS_DEBUG
printk(KERN_INFO SPI_DRIVER_NAME " [%s] spi_probe: setup char device\n", gpio_pmodoled_dev->name);
#endif
/* Setup char driver */
status = gpio_pmodoled_setup_cdev(gpio_pmodoled_dev, &(gpio_pmodoled_dev->dev_id), spi);
if (status) {
dev_err(&spi->dev, "spi_probe: Error adding %s device: %d\n", SPI_DRIVER_NAME, status);
goto cdev_add_err;
}
/* Initialize Mutex */
mutex_init(&gpio_pmodoled_dev->mutex);
/**
* It is important to the OLED's longevity that the lines that
* control it's power are carefully controlled. This is a good
* time to ensure that the device is ot turned on until it is
* instructed to do so.
*/
#ifdef CONFIG_PMODS_DEBUG
printk(KERN_INFO SPI_DRIVER_NAME " [%s] spi_probe: initialize device\n", gpio_pmodoled_dev->name);
#endif
status = gpio_pmodoled_init_gpio(gpio_pmodoled_dev);
if (status) {
dev_err(&spi->dev, "spi_probe: Error initializing GPIO\n");
goto oled_init_error;
}
gpio_pmodoled_disp_init(gpio_pmodoled_dev);
memset(gpio_pmodoled_dev->disp_buf, 0x00, DISPLAY_BUF_SZ);
status = screen_buf_to_display(gpio_pmodoled_dev->disp_buf, gpio_pmodoled_dev);
if (status) {
dev_err(&spi->dev, "spi_probe: Error sending initial Display String\n");
goto oled_init_error;
}
return status;
oled_init_error:
if (&gpio_pmodoled_dev->cdev)
cdev_del(&gpio_pmodoled_dev->cdev);
cdev_add_err:
spi_platform_data_err:
spi_err:
return status;
}