Re: [PATCH v9] staging: fbtft: add tearing signal detect

From: Geert Uytterhoeven
Date: Wed Jan 27 2021 - 08:48:05 EST


Hi Carlis,

On Wed, Jan 27, 2021 at 2:03 PM Carlis <zhangxuezhi3@xxxxxxxxx> wrote:
> From: zhangxuezhi <zhangxuezhi1@xxxxxxxxxx>
>
> For st7789v ic,add tearing signal detect to avoid screen tearing
>
> Signed-off-by: zhangxuezhi <zhangxuezhi1@xxxxxxxxxx>
> ---
> v9: change pr_* to dev_*

Thanks for the update!

> --- a/drivers/staging/fbtft/fb_st7789v.c
> +++ b/drivers/staging/fbtft/fb_st7789v.c
> @@ -9,9 +9,12 @@
> #include <linux/delay.h>
> #include <linux/init.h>
> #include <linux/kernel.h>
> +#include <linux/mutex.h>
> +#include <linux/interrupt.h>
> +#include <linux/completion.h>
> #include <linux/module.h>
> #include <video/mipi_display.h>
> -
> +#include <linux/gpio/consumer.h>
> #include "fbtft.h"
>
> #define DRVNAME "fb_st7789v"
> @@ -66,6 +69,32 @@ enum st7789v_command {
> #define MADCTL_MX BIT(6) /* bitmask for column address order */
> #define MADCTL_MY BIT(7) /* bitmask for page address order */
>
> +#define SPI_PANEL_TE_TIMEOUT 400
> +static struct mutex te_mutex;/*mutex for tearing line*/
> +static struct completion spi_panel_te;
> +
> +static irqreturn_t spi_panel_te_handler(int irq, void *data)
> +{
> + complete(&spi_panel_te);
> + return IRQ_HANDLED;
> +}
> +
> +static void set_spi_panel_te_irq_status(struct fbtft_par *par, bool enable)
> +{
> + static int te_irq_count;
> +
> + 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 +111,33 @@ 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 (IS_ERR(par->gpio.te)) {
> + rc = PTR_ERR(par->gpio.te);
> + dev_err(par->info->device, "Failed to request te gpio: %d\n", rc);

This also prints an error in case of -EPROBE_DEFER.
dev_err_probe()?

> + return rc;
> + }
> + 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) {
> + dev_err(par->info->device, "TE request_irq failed.\n");
> + devm_gpiod_put(dev, par->gpio.te);

No need to call devm_gpiod_put() here, as it's managed automatically.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds