gpio: mpc8xxx: latch GPIOs state on module load when configured as output
v2 cover gpio: mpc8xxx: latch GPIOs state on module load when configured as output
From: Michal Smulski <[email protected]>
Changes between v1 and v2:
* moved comments closer to the added code for clarity.
Michal Smulski (1):
gpio: mpc8xxx: latch GPIOs state on module load when configured as
output
drivers/gpio/gpio-mpc8xxx.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
Signature · 1 line
2.34.1
PATCH v2 1/1 gpio: mpc8xxx: latch GPIOs state on module load when configured as output
From: Michal Smulski <[email protected]>
Qoriq and related devices allow reading out state of GPIO set as output. However, currently on driver's init, all outputs are configured as driven low. So, any changes to GPIO confiuration will drive all pins (configured as output) as output-low.
This patch latches state of output GPIOs before any GPIO configuration takes place. This preserves any output settings done prior to loading the driver (for example, by u-boot).
--- drivers/gpio/gpio-mpc8xxx.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
drivers/gpio/gpio-mpc8xxx.c +5 -1
@@ -375,8 +375,12 @@ static int mpc8xxx_probe(struct platform_device *pdev)if (of_device_is_compatible (np,"fsl,qoriq-gpio" ) ||of_device_is_compatible (np,"fsl,ls1028a-gpio" ) ||of_device_is_compatible (np,"fsl,ls1088a-gpio" ) || -is_acpi_node (fwnode)) +is_acpi_node (fwnode)) { gc->write_reg (mpc8xxx_gc->regs +GPIO_IBE ,0xffffffff ); +/* Also, latch state of GPIOs configured as output by bootloader. */ + gc->bgpio_data = gc->read_reg (mpc8xxx_gc->regs +GPIO_DAT ) & + gc->read_reg (mpc8xxx_gc->regs +GPIO_DIR ); + } ret =devm_gpiochip_add_data (&pdev->dev, gc, mpc8xxx_gc);if (ret) {
Signature · 1 line
2.34.1
Bartosz Golaszewski
AppliedQuoted 35 lines · On Fri, Jun 2, 2023 at 1:02 AM <[email protected]> wrote:
From: Michal Smulski <[email protected]>
Qoriq and related devices allow reading out state of GPIO set as output. However, currently on driver's init, all outputs are configured as driven low. So, any changes to GPIO confiuration will drive all pins (configured as output) as output-low.
This patch latches state of output GPIOs before any GPIO configuration takes place. This preserves any output settings done prior to loading the driver (for example, by u-boot).Signed-off-by Michal Smulski <[email protected]>--- drivers/gpio/gpio-mpc8xxx.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)drivers/gpio/gpio-mpc8xxx.c +5
-2@@ -375,8 +375,12 @@ static int mpc8xxx_probe(struct platform_device *pdev)if (of_device_is_compatible (np,"fsl,qoriq-gpio" ) ||of_device_is_compatible (np,"fsl,ls1028a-gpio" ) ||of_device_is_compatible (np,"fsl,ls1088a-gpio" ) || -is_acpi_node (fwnode)) +is_acpi_node (fwnode)) { gc->write_reg (mpc8xxx_gc->regs +GPIO_IBE ,0xffffffff ); +/* Also, latch state of GPIOs configured as output by bootloader. */ + gc->bgpio_data = gc->read_reg (mpc8xxx_gc->regs +GPIO_DAT ) & + gc->read_reg (mpc8xxx_gc->regs +GPIO_DIR ); + } ret =devm_gpiochip_add_data (&pdev->dev, gc, mpc8xxx_gc);if (ret) { --
Quoted 2 lines
2.34.1
Applied, thanks!
Bart