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staging: fbtft: Rectify GPIO handling 

The infamous commit c440eee1a7 ("Staging: staging: fbtft: Switch to
the GPIO descriptor interface") broke GPIO handling completely.
It has already four commits to rectify and it seems not enough.
In order to fix the mess here we:

  1) Set default to "inactive" for all requested pins

  2) Fix CS#, RD#, and WR# pins polarity since it's active low
     and GPIO descriptor interface takes it into consideration
     from the Device Tree or ACPI

  3) Consolidate chip activation (CS# assertion) under default
     ->reset() callback

To summarize the expectations about polarity for GPIOs:

   RD#			Low
   WR#			Low
   CS#			Low
   RESET#		Low
   DC or RS		High
   RW			High
   Data	0 .. 15		High

See also Adafruit learning course [1] for the example of the schematics.

While at it, drop unneeded NULL checks, since GPIO API is tolerant to that.

[1]: https://learn.adafruit.com/adafruit-2-8-and-3-2-color-tft-touchscreen-breakout-v2/downloads

Fixes: 92e3e88488 ("Staging: fbtft: Fix GPIO handling")
Fixes: b918d1c270 ("Staging: fbtft: Fix reset assertion when using gpio descriptor")
Fixes: dbc4f989c8 ("Staging: fbtft: Fix probing of gpio descriptor")
Fixes: c440eee1a7 ("Staging: fbtft: Switch to the gpio descriptor interface")
Cc: Jan Sebastian Götte <linux@jaseg.net>
Cc: Nishad Kamdar <nishadkamdar@gmail.com>
Reviewed-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210503172114.27891-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andy Shevchenko 2021-05-03 20:21:10 +03:00 committed by Greg Kroah-Hartman
parent 0d59ca5a7e
commit ec03c21043
17 changed files with 25 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/staging/fbtft/fb_agm1264k-fl.c
View File

@ -84,9 +84,9 @@ static void reset(struct fbtft_par *par)
dev_dbg(par->info->device, "%s()\n", __func__);
gpiod_set_value(par->gpio.reset, 0);
udelay(20);
gpiod_set_value(par->gpio.reset, 1);
udelay(20);
gpiod_set_value(par->gpio.reset, 0);
mdelay(120);
}
@ -194,12 +194,12 @@ static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
/* select chip */
if (*buf) {
/* cs1 */
gpiod_set_value(par->CS0, 1);
gpiod_set_value(par->CS1, 0);
} else {
/* cs0 */
gpiod_set_value(par->CS0, 0);
gpiod_set_value(par->CS1, 1);
} else {
/* cs0 */
gpiod_set_value(par->CS0, 1);
gpiod_set_value(par->CS1, 0);
}
gpiod_set_value(par->RS, 0); /* RS->0 (command mode) */
@ -397,8 +397,8 @@ static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
}
kfree(convert_buf);
gpiod_set_value(par->CS0, 1);
gpiod_set_value(par->CS1, 1);
gpiod_set_value(par->CS0, 0);
gpiod_set_value(par->CS1, 0);
return ret;
}
@ -419,10 +419,10 @@ static int write(struct fbtft_par *par, void *buf, size_t len)
for (i = 0; i < 8; ++i)
gpiod_set_value(par->gpio.db[i], data & (1 << i));
/* set E */
gpiod_set_value(par->EPIN, 1);
gpiod_set_value(par->EPIN, 0);
udelay(5);
/* unset E - write */
gpiod_set_value(par->EPIN, 0);
gpiod_set_value(par->EPIN, 1);
udelay(1);
}

4
drivers/staging/fbtft/fb_bd663474.c
View File

@ -12,7 +12,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include "fbtft.h"
@ -24,9 +23,6 @@
static int init_display(struct fbtft_par *par)
{
if (par->gpio.cs)
gpiod_set_value(par->gpio.cs, 0); /* Activate chip */
par->fbtftops.reset(par);
/* Initialization sequence from Lib_UTFT */

4
drivers/staging/fbtft/fb_ili9163.c
View File

@ -11,7 +11,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include <video/mipi_display.h>
@ -77,9 +76,6 @@ static int init_display(struct fbtft_par *par)
{
par->fbtftops.reset(par);
if (par->gpio.cs)
gpiod_set_value(par->gpio.cs, 0); /* Activate chip */
write_reg(par, MIPI_DCS_SOFT_RESET); /* software reset */
mdelay(500);
write_reg(par, MIPI_DCS_EXIT_SLEEP_MODE); /* exit sleep */

1
drivers/staging/fbtft/fb_ili9320.c
View File

@ -8,7 +8,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/spi/spi.h>
#include <linux/delay.h>

4
drivers/staging/fbtft/fb_ili9325.c
View File

@ -10,7 +10,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include "fbtft.h"
@ -85,9 +84,6 @@ static int init_display(struct fbtft_par *par)
{
par->fbtftops.reset(par);
if (par->gpio.cs)
gpiod_set_value(par->gpio.cs, 0); /* Activate chip */
bt &= 0x07;
vc &= 0x07;
vrh &= 0x0f;

1
drivers/staging/fbtft/fb_ili9340.c
View File

@ -8,7 +8,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include <video/mipi_display.h>

4
drivers/staging/fbtft/fb_s6d1121.c
View File

@ -12,7 +12,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include "fbtft.h"
@ -29,9 +28,6 @@ static int init_display(struct fbtft_par *par)
{
par->fbtftops.reset(par);
if (par->gpio.cs)
gpiod_set_value(par->gpio.cs, 0); /* Activate chip */
/* Initialization sequence from Lib_UTFT */
write_reg(par, 0x0011, 0x2004);

1
drivers/staging/fbtft/fb_sh1106.c
View File

@ -9,7 +9,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include "fbtft.h"

4
drivers/staging/fbtft/fb_ssd1289.c
View File

@ -10,7 +10,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include "fbtft.h"
@ -28,9 +27,6 @@ static int init_display(struct fbtft_par *par)
{
par->fbtftops.reset(par);
if (par->gpio.cs)
gpiod_set_value(par->gpio.cs, 0); /* Activate chip */
write_reg(par, 0x00, 0x0001);
write_reg(par, 0x03, 0xA8A4);
write_reg(par, 0x0C, 0x0000);

2
drivers/staging/fbtft/fb_ssd1325.c
View File

@ -35,8 +35,6 @@ static int init_display(struct fbtft_par *par)
{
par->fbtftops.reset(par);
gpiod_set_value(par->gpio.cs, 0);
write_reg(par, 0xb3);
write_reg(par, 0xf0);
write_reg(par, 0xae);

6
drivers/staging/fbtft/fb_ssd1331.c
View File

@ -81,8 +81,7 @@ static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
va_start(args, len);
*buf = (u8)va_arg(args, unsigned int);
if (par->gpio.dc)
gpiod_set_value(par->gpio.dc, 0);
gpiod_set_value(par->gpio.dc, 0);
ret = par->fbtftops.write(par, par->buf, sizeof(u8));
if (ret < 0) {
va_end(args);
@ -104,8 +103,7 @@ static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
return;
}
}
if (par->gpio.dc)
gpiod_set_value(par->gpio.dc, 1);
gpiod_set_value(par->gpio.dc, 1);
va_end(args);
}

1
drivers/staging/fbtft/fb_ssd1351.c
View File

@ -2,7 +2,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/spi/spi.h>
#include <linux/delay.h>

4
drivers/staging/fbtft/fb_upd161704.c
View File

@ -12,7 +12,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include "fbtft.h"
@ -26,9 +25,6 @@ static int init_display(struct fbtft_par *par)
{
par->fbtftops.reset(par);
if (par->gpio.cs)
gpiod_set_value(par->gpio.cs, 0); /* Activate chip */
/* Initialization sequence from Lib_UTFT */
/* register reset */

1
drivers/staging/fbtft/fb_watterott.c
View File

@ -8,7 +8,6 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include "fbtft.h"

3
drivers/staging/fbtft/fbtft-bus.c
View File

@ -135,8 +135,7 @@ int fbtft_write_vmem16_bus8(struct fbtft_par *par, size_t offset, size_t len)
remain = len / 2;
vmem16 = (u16 *)(par->info->screen_buffer + offset);
if (par->gpio.dc)
gpiod_set_value(par->gpio.dc, 1);
gpiod_set_value(par->gpio.dc, 1);
/* non buffered write */
if (!par->txbuf.buf)

13
drivers/staging/fbtft/fbtft-core.c
View File

@ -38,8 +38,7 @@ int fbtft_write_buf_dc(struct fbtft_par *par, void *buf, size_t len, int dc)
{
int ret;
if (par->gpio.dc)
gpiod_set_value(par->gpio.dc, dc);
gpiod_set_value(par->gpio.dc, dc);
ret = par->fbtftops.write(par, buf, len);
if (ret < 0)
@ -79,7 +78,7 @@ static int fbtft_request_one_gpio(struct fbtft_par *par,
int ret = 0;
*gpiop = devm_gpiod_get_index_optional(dev, name, index,
GPIOD_OUT_HIGH);
GPIOD_OUT_LOW);
if (IS_ERR(*gpiop)) {
ret = PTR_ERR(*gpiop);
dev_err(dev,
@ -226,11 +225,15 @@ static void fbtft_reset(struct fbtft_par *par)
{
if (!par->gpio.reset)
return;
fbtft_par_dbg(DEBUG_RESET, par, "%s()\n", __func__);
gpiod_set_value_cansleep(par->gpio.reset, 1);
usleep_range(20, 40);
gpiod_set_value_cansleep(par->gpio.reset, 0);
msleep(120);
gpiod_set_value_cansleep(par->gpio.cs, 1); /* Activate chip */
}
static void fbtft_update_display(struct fbtft_par *par, unsigned int start_line,
@ -922,8 +925,6 @@ static int fbtft_init_display_from_property(struct fbtft_par *par)
goto out_free;
par->fbtftops.reset(par);
if (par->gpio.cs)
gpiod_set_value(par->gpio.cs, 0); /* Activate chip */
index = -1;
val = values[++index];
@ -1018,8 +1019,6 @@ int fbtft_init_display(struct fbtft_par *par)
}
par->fbtftops.reset(par);
if (par->gpio.cs)
gpiod_set_value(par->gpio.cs, 0); /* Activate chip */
i = 0;
while (i < FBTFT_MAX_INIT_SEQUENCE) {

12
drivers/staging/fbtft/fbtft-io.c
View File

@ -142,12 +142,12 @@ int fbtft_write_gpio8_wr(struct fbtft_par *par, void *buf, size_t len)
data = *(u8 *)buf;
/* Start writing by pulling down /WR */
gpiod_set_value(par->gpio.wr, 0);
gpiod_set_value(par->gpio.wr, 1);
/* Set data */
#ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
if (data == prev_data) {
gpiod_set_value(par->gpio.wr, 0); /* used as delay */
gpiod_set_value(par->gpio.wr, 1); /* used as delay */
} else {
for (i = 0; i < 8; i++) {
if ((data & 1) != (prev_data & 1))
@ -165,7 +165,7 @@ int fbtft_write_gpio8_wr(struct fbtft_par *par, void *buf, size_t len)
#endif
/* Pullup /WR */
gpiod_set_value(par->gpio.wr, 1);
gpiod_set_value(par->gpio.wr, 0);
#ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
prev_data = *(u8 *)buf;
@ -192,12 +192,12 @@ int fbtft_write_gpio16_wr(struct fbtft_par *par, void *buf, size_t len)
data = *(u16 *)buf;
/* Start writing by pulling down /WR */
gpiod_set_value(par->gpio.wr, 0);
gpiod_set_value(par->gpio.wr, 1);
/* Set data */
#ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
if (data == prev_data) {
gpiod_set_value(par->gpio.wr, 0); /* used as delay */
gpiod_set_value(par->gpio.wr, 1); /* used as delay */
} else {
for (i = 0; i < 16; i++) {
if ((data & 1) != (prev_data & 1))
@ -215,7 +215,7 @@ int fbtft_write_gpio16_wr(struct fbtft_par *par, void *buf, size_t len)
#endif
/* Pullup /WR */
gpiod_set_value(par->gpio.wr, 1);
gpiod_set_value(par->gpio.wr, 0);
#ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
prev_data = *(u16 *)buf;