Re: [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