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SubjectRe: [PATCH] fbtft: add tearing signal detect
On Sun, Jan 24, 2021 at 11:35:37PM +0800, Carlis wrote:
> +static irqreturn_t spi_panel_te_handler(int irq, void *data)
> +{
> + complete(&spi_panel_te);
> + return IRQ_HANDLED;
> +}
> +
> +static void enable_spi_panel_te_irq(struct fbtft_par *par, bool enable)

It quite confused me that enable actually disables. I always feel like
it's clearer to write these as two separate functions.

> +{
> + static int te_irq_count;
> +
> + if (!par->gpio.te) {

This is always checked in the caller. And it's when it's NULL that
means it's deliberate so don't print a message.

> + pr_err("%s:%d,SPI panel TE GPIO not configured\n",
> + __func__, __LINE__);
> + return;
> + }
> +
> + mutex_lock(&te_mutex);
> +
> + if (enable) {
> + if (++te_irq_count == 1)
> + enable_irq(gpiod_to_irq(par->gpio.te));
> + } else {
> + if (--te_irq_count == 0)
> + disable_irq(gpiod_to_irq(par->gpio.te));
> + }
> + mutex_unlock(&te_mutex);
> +}
> +
> /**
> * init_display() - initialize the display controller
> *
> @@ -82,6 +117,28 @@ enum st7789v_command {
> */
> static int init_display(struct fbtft_par *par)
> {
> + int rc;
> + struct device *dev = par->info->device;
> +
> + par->gpio.te = devm_gpiod_get_index_optional(dev, "te", 0, GPIOD_IN);
> + if (par->gpio.te) {

devm_gpiod_get_index_optional() can return NULL or error pointers. If
it returns NULL then don't print an error message. NULL reports are
deliberate.

par->gpio.te = devm_gpiod_get_index_optional(dev, "te", 0, GPIOD_IN);
if (IS_ERR(par->gpio.te)) {
pr_err("%s:%d, TE gpio not specified\n", __func__, __LINE__);
return PTR_ERR(par->gpio.te);
}

if (par->gpio.te) {


> + init_completion(&spi_panel_te);
> + mutex_init(&te_mutex);
> + rc = devm_request_irq(dev,
> + gpiod_to_irq(par->gpio.te),
> + spi_panel_te_handler, IRQF_TRIGGER_RISING,
> + "TE_GPIO", par);
> + if (rc) {
> + pr_err("TE request_irq failed.\n");
> + par->gpio.te = NULL;
> + } else {
> + disable_irq_nosync(gpiod_to_irq(par->gpio.te));
> + pr_err("TE request_irq completion.\n");

Why is this printing an error message if devm_request_irq() succeeds?

> + }
> + } else {
> + pr_err("%s:%d, TE gpio not specified\n",
> + __func__, __LINE__);
> + }
> /* turn off sleep mode */
> write_reg(par, MIPI_DCS_EXIT_SLEEP_MODE);
> mdelay(120);
> @@ -137,6 +194,9 @@ static int init_display(struct fbtft_par *par)
> */
> write_reg(par, PWCTRL1, 0xA4, 0xA1);
>
> + /*Tearing Effect Line On*/
> + if (par->gpio.te)
> + write_reg(par, 0x35, 0x00);
> write_reg(par, MIPI_DCS_SET_DISPLAY_ON);
>
> if (HSD20_IPS)
> @@ -145,6 +205,76 @@ static int init_display(struct fbtft_par *par)
> return 0;
> }
>
> +/*****************************************************************************
> + *
> + * int (*write_vmem)(struct fbtft_par *par);
> + *
> + *****************************************************************************/
> +
> +/* 16 bit pixel over 8-bit databus */
> +int st7789v_write_vmem16_bus8(struct fbtft_par *par, size_t offset, size_t len)
> +{
> + u16 *vmem16;
> + __be16 *txbuf16 = par->txbuf.buf;
> + size_t remain;
> + size_t to_copy;
> + size_t tx_array_size;
> + int i;
> + int rc, ret = 0;

Delete one of these "rc" or "rec" variables.

> + size_t startbyte_size = 0;
> +
> + fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "st7789v ---%s(offset=%zu, len=%zu)\n",
> + __func__, offset, len);
> +
> + remain = len / 2;
> + vmem16 = (u16 *)(par->info->screen_buffer + offset);
> +
> + if (par->gpio.dc)
> + gpiod_set_value(par->gpio.dc, 1);
> +
> + /* non buffered write */
> + if (!par->txbuf.buf)
> + return par->fbtftops.write(par, vmem16, len);
> +
> + /* buffered write */
> + tx_array_size = par->txbuf.len / 2;
> +
> + if (par->startbyte) {
> + txbuf16 = par->txbuf.buf + 1;
> + tx_array_size -= 2;
> + *(u8 *)(par->txbuf.buf) = par->startbyte | 0x2;
> + startbyte_size = 1;
> + }
> +
> + while (remain) {
> + to_copy = min(tx_array_size, remain);
> + dev_dbg(par->info->device, " to_copy=%zu, remain=%zu\n",
> + to_copy, remain - to_copy);
> +
> + for (i = 0; i < to_copy; i++)
> + txbuf16[i] = cpu_to_be16(vmem16[i]);
> +
> + vmem16 = vmem16 + to_copy;
> + if (par->gpio.te) {
> + enable_spi_panel_te_irq(par, true);
> + reinit_completion(&spi_panel_te);
> + rc = wait_for_completion_timeout(&spi_panel_te,
> + msecs_to_jiffies(SPI_PANEL_TE_TIMEOUT));
> + if (rc == 0)
> + pr_err("wait panel TE time out\n");
> + }
> + ret = par->fbtftops.write(par, par->txbuf.buf,
> + startbyte_size + to_copy * 2);

Line break is whacky.

> + if (par->gpio.te)
> + enable_spi_panel_te_irq(par, false);
> + if (ret < 0)
> + return ret;
> + remain -= to_copy;
> + }
> +
> + return ret;

Shouldn't this be "return len;" or something?

> +}
> +
regards,
dan carpenter

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