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Subject[PATCH v3 09/10] gpio-exar/8250-exar: Make set of exported GPIOs configurable
Date
On the SIMATIC, IOT2040 only a single pin is exportable as GPIO, the
rest is required to operate the UART. To allow modeling this case,
expand the platform device data structure to specify a (consecutive) pin
subset for exporting by the gpio-exar driver.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
drivers/gpio/gpio-exar.c | 29 ++++++++++++++++++++---------
drivers/tty/serial/8250/8250_exar.c | 14 +++++++++++---
2 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/drivers/gpio/gpio-exar.c b/drivers/gpio/gpio-exar.c
index d13bf20b8639..8970f50e681e 100644
--- a/drivers/gpio/gpio-exar.c
+++ b/drivers/gpio/gpio-exar.c
@@ -31,6 +31,7 @@ struct exar_gpio_chip {
int index;
void __iomem *regs;
char name[20];
+ unsigned int first_pin;
};

static void exar_update(struct gpio_chip *chip, unsigned int reg, int val,
@@ -51,9 +52,10 @@ static void exar_update(struct gpio_chip *chip, unsigned int reg, int val,
static int exar_set_direction(struct gpio_chip *chip, int direction,
unsigned int offset)
{
- unsigned int addr = offset / 8 ?
+ struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
+ unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
- unsigned int bit = offset % 8;
+ unsigned int bit = (offset + exar_gpio->first_pin) % 8;

exar_update(chip, addr, direction, bit);
return 0;
@@ -73,18 +75,20 @@ static int exar_get(struct gpio_chip *chip, unsigned int reg)

static int exar_get_direction(struct gpio_chip *chip, unsigned int offset)
{
- unsigned int addr = offset / 8 ?
+ struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
+ unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
- unsigned int bit = offset % 8;
+ unsigned int bit = (offset + exar_gpio->first_pin) % 8;

return !!(exar_get(chip, addr) & BIT(bit));
}

static int exar_get_value(struct gpio_chip *chip, unsigned int offset)
{
- unsigned int addr = offset / 8 ?
+ struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
+ unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
- unsigned int bit = offset % 8;
+ unsigned int bit = (offset + exar_gpio->first_pin) % 8;

return !!(exar_get(chip, addr) & BIT(bit));
}
@@ -92,9 +96,10 @@ static int exar_get_value(struct gpio_chip *chip, unsigned int offset)
static void exar_set_value(struct gpio_chip *chip, unsigned int offset,
int value)
{
- unsigned int addr = offset / 8 ?
+ struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
+ unsigned int addr = (offset + exar_gpio->first_pin) / 8 ?
EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
- unsigned int bit = offset % 8;
+ unsigned int bit = (offset + exar_gpio->first_pin) % 8;

exar_update(chip, addr, value, bit);
}
@@ -115,6 +120,7 @@ static int gpio_exar_probe(struct platform_device *pdev)
{
struct pci_dev *pcidev = to_pci_dev(pdev->dev.parent);
struct exar_gpio_chip *exar_gpio;
+ u32 first_pin, npins;
void __iomem *p;
int index, ret;

@@ -126,6 +132,10 @@ static int gpio_exar_probe(struct platform_device *pdev)
if (!p)
return -ENOMEM;

+ if (device_property_read_u32(&pdev->dev, "first_pin", &first_pin) < 0 ||
+ device_property_read_u32(&pdev->dev, "npins", &npins) < 0)
+ return -EINVAL;
+
exar_gpio = devm_kzalloc(&pdev->dev, sizeof(*exar_gpio), GFP_KERNEL);
if (!exar_gpio)
return -ENOMEM;
@@ -143,9 +153,10 @@ static int gpio_exar_probe(struct platform_device *pdev)
exar_gpio->gpio_chip.get = exar_get_value;
exar_gpio->gpio_chip.set = exar_set_value;
exar_gpio->gpio_chip.base = -1;
- exar_gpio->gpio_chip.ngpio = 16;
+ exar_gpio->gpio_chip.ngpio = npins;
exar_gpio->regs = p;
exar_gpio->index = index;
+ exar_gpio->first_pin = first_pin;

ret = devm_gpiochip_add_data(&pdev->dev,
&exar_gpio->gpio_chip, exar_gpio);
diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index ee4b142f3ed0..42e7c5149c07 100644
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c
@@ -14,6 +14,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
+#include <linux/property.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/slab.h>
@@ -196,8 +197,14 @@ static void setup_gpio(struct pci_dev *pcidev, u8 __iomem *p)
}

static void *
-xr17v35x_register_gpio(struct pci_dev *pcidev)
+xr17v35x_register_gpio(struct pci_dev *pcidev, unsigned int first_pin,
+ unsigned int npins)
{
+ struct property_entry properties[] = {
+ PROPERTY_ENTRY_U32("first_pin", first_pin),
+ PROPERTY_ENTRY_U32("npins", npins),
+ { }
+ };
struct platform_device *pdev;

pdev = platform_device_alloc("gpio_exar", PLATFORM_DEVID_AUTO);
@@ -207,7 +214,8 @@ xr17v35x_register_gpio(struct pci_dev *pcidev)
pdev->dev.parent = &pcidev->dev;
ACPI_COMPANION_SET(&pdev->dev, ACPI_COMPANION(&pcidev->dev));

- if (platform_device_add(pdev) < 0) {
+ if (platform_device_add_properties(pdev, properties) < 0 ||
+ platform_device_add(pdev) < 0) {
platform_device_put(pdev);
return NULL;
}
@@ -250,7 +258,7 @@ pci_xr17v35x_setup(struct exar8250 *priv, struct pci_dev *pcidev,

if (pcidev->vendor == PCI_VENDOR_ID_EXAR)
port->port.private_data =
- xr17v35x_register_gpio(pcidev);
+ xr17v35x_register_gpio(pcidev, 0, 16);
}

return 0;
--
2.12.0
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