Re: [PATCH v10] staging: fbtft: add tearing signal detect

carlis
2021-01-28T01:45:02Z

On Thu, 28 Jan 2021 00:32:22 +0200
Kari Argillander <kari.argillander@gmail.com> wrote:

> On Wed, Jan 27, 2021 at 09:42:52PM +0800, Carlis wrote:
> > For st7789v ic,when we need continuous full screen refresh, it is
> > best to wait for the TE signal arrive to avoid screen tearing
>
> > diff --git a/drivers/staging/fbtft/fb_st7789v.c
> > b/drivers/staging/fbtft/fb_st7789v.c index 3a280cc..cba08a8 100644
> > --- 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>
>
> Space after local headers. Also this should one up so all Linux
> headers are group together. You agreed?
>
OK,i will fix it in patch v12 tomorrow

> > #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 /* msecs */
> > +static struct mutex te_mutex;/* mutex for set te gpio irq status
> > */
>
> Space after ;
hi, i have fix it in the patch v11
>
> > +static struct completion spi_panel_te;
>
> What if multiple displays? Is this possible for user?
I will check it carefully again about this logic.
>
> > +
> > +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;
>
> Same here. Maybe you can think better way and then this code would
> also be cleaner.
>
> > +
> > + mutex_lock(&te_mutex);
>
> So locking should be done if we really do action and not just in case.
>
> > +
> > + 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);
> > + return rc;
> > + }
>
> You request with optinal and you still want to error out? We could
> just continue and not care about that error. User will be happier if
> device still works somehow.
You mean i just delete this dev_err print ?!
like this:
par->gpio.te = devm_gpiod_get_index_optional(dev, "te",
0,GPIOD_IN);
if (IS_ERR(par->gpio.te))
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) {
> > + dev_err(par->info->device, "TE request_irq
> > failed.\n");
> > + devm_gpiod_put(dev, par->gpio.te);
> > + return rc;
> > + }
> > +
> > + disable_irq_nosync(gpiod_to_irq(par->gpio.te));
> > + } else {
> > + dev_info(par->info->device, "%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 +193,9 @@ static int init_display(struct fbtft_par *par)
> > */
> > write_reg(par, PWCTRL1, 0xA4, 0xA1);
> >
> > + /*Tearing Effect Line On*/
>
> Spaces and why upcase everything?
i will fix it in patch v12 tomorrow
>
> > + if (par->gpio.te)
> > + write_reg(par, 0x35, 0x00);
> > write_reg(par, MIPI_DCS_SET_DISPLAY_ON);
> >
> > if (HSD20_IPS)
> > @@ -145,6 +204,76 @@ static int init_display(struct fbtft_par *par)
> > return 0;
> > }
> >
> > +/*****************************************************************************
> > + *
> > + * int (*write_vmem)(struct fbtft_par *par);
> > + *
> > +
> > *****************************************************************************/
> > +
>
> Why this kind of function comment? Please use same as another function
> comments in this file. They are atleast almoust like kernel-doc style.
i will fix it in patch v12 tomorrow
> > +/* 16 bit pixel over 8-bit databus */
> > +static 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 ret = 0;
> > + 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) {
>
> for (remain = len / 2; remain; remain -= to_copy) {
>
> or even use len = len / 2 if you wanna save variable.
>
> > + to_copy = min(tx_array_size, remain);
>
> Care must be taken that this will not be endless loop if another is
> 0. I will not check this further but hopefully you have.
>
> > + 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;
>
> += Or you can ++ vmem16 at the for loop but that is not so readable
> sometimes with pointers.
>
> > + if (par->gpio.te) {
> > + set_spi_panel_te_irq_status(par, true);
> > + reinit_completion(&spi_panel_te);
> > + ret =
> > wait_for_completion_timeout(&spi_panel_te,
> > +
> > msecs_to_jiffies(SPI_PANEL_TE_TIMEOUT));
> > + if (ret == 0)
>
> !ret
>
> > + dev_err(par->info->device, "wait
> > panel TE time out\n");
> > + }
> > + ret = par->fbtftops.write(par, par->txbuf.buf,
> > + startbyte_size + to_copy
> > * 2);
> > + if (par->gpio.te)
> > + set_spi_panel_te_irq_status(par, false);
> > + if (ret < 0)
> > + return ret;
> > + remain -= to_copy;
> > + }
> > +
> > + return ret;
>
> Do we want to return something over 0? If not then this can be return
> 0. And then you do not need to even init ret value at the beginning.
>
> Also wait little bit like Greg sayd before sending new version.
> Someone might nack about what I say or say something more.
>
hi, i copy fbtft_write_vmem16_bus8 from file fbtft_bus.c and modify it
,just add te wait logic, i will take more time to check this original
function.
> > +}
> > +
> > /**
> > * set_var() - apply LCD properties like rotation and BGR mode
> > *
> > @@ -259,6 +388,7 @@ static int blank(struct fbtft_par *par, bool on)
> > .gamma = HSD20_IPS_GAMMA,
> > .fbtftops = {
> > .init_display = init_display,
> > + .write_vmem = st7789v_write_vmem16_bus8,
> > .set_var = set_var,
> > .set_gamma = set_gamma,
> > .blank = blank,
> > diff --git a/drivers/staging/fbtft/fbtft.h
> > b/drivers/staging/fbtft/fbtft.h index 76f8c09..93bac05 100644
> > --- a/drivers/staging/fbtft/fbtft.h
> > +++ b/drivers/staging/fbtft/fbtft.h
> > @@ -212,6 +212,7 @@ struct fbtft_par {
> > struct gpio_desc *wr;
> > struct gpio_desc *latch;
> > struct gpio_desc *cs;
> > + struct gpio_desc *te;
> > struct gpio_desc *db[16];
> > struct gpio_desc *led[16];
> > struct gpio_desc *aux[16];
> > --
> > 1.9.1
> >