[PATCH v2] gpio-syscon: do not report bogus error

From: Etienne Buira
Date: Fri Apr 19 2024 - 08:35:30 EST


Do not issue "can't read the data register offset!" when gpio,syscon-dev
is not set albeit unneeded. gpio-syscon is used with rk3328 chip, but
this iomem region is documented in
Documentation/devicetree/bindings/gpio/rockchip,rk3328-grf-gpio.yaml and
does not require gpio,syscon-dev setting.

It has been suggested to automatically detect if node has a valid
parent, but that would defeat the purpose of error message, for example
arch/arm/boot/dts/ti/keystone/keystone-k2g.dtsi could then be used
without gpio,syscon-dev, and lead to funny results without error
message.

It has been tried to mandate use of gpio,syscon-dev, but that raised
objection.

So while this patch may be kludgy, it looks the less bad to address
the spurious dev_err call.

v2:
- changed flag name

Signed-off-by: Etienne Buira <etienne.buira@xxxxxxx>
---
drivers/gpio/gpio-syscon.c | 35 ++++++++++++++++++++---------------
1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/drivers/gpio/gpio-syscon.c b/drivers/gpio/gpio-syscon.c
index 6e1a2581e6ae..4f103ce26019 100644
--- a/drivers/gpio/gpio-syscon.c
+++ b/drivers/gpio/gpio-syscon.c
@@ -13,9 +13,10 @@
#include <linux/regmap.h>
#include <linux/mfd/syscon.h>

-#define GPIO_SYSCON_FEAT_IN BIT(0)
-#define GPIO_SYSCON_FEAT_OUT BIT(1)
-#define GPIO_SYSCON_FEAT_DIR BIT(2)
+#define GPIO_SYSCON_FEAT_IN BIT(0)
+#define GPIO_SYSCON_FEAT_OUT BIT(1)
+#define GPIO_SYSCON_FEAT_DIR BIT(2)
+#define GPIO_SYSCON_FEAT_USE_PARENT BIT(3)

/* SYSCON driver is designed to use 32-bit wide registers */
#define SYSCON_REG_SIZE (4)
@@ -27,7 +28,9 @@
* @flags: Set of GPIO_SYSCON_FEAT_ flags:
* GPIO_SYSCON_FEAT_IN: GPIOs supports input,
* GPIO_SYSCON_FEAT_OUT: GPIOs supports output,
- * GPIO_SYSCON_FEAT_DIR: GPIOs supports switch direction.
+ * GPIO_SYSCON_FEAT_DIR: GPIOs supports switch direction,
+ * GPIO_SYSCON_FEAT_USE_PARENT: gpio,syscon-dev do not
+ * have to be set, parent regspace will be used.
* @bit_count: Number of bits used as GPIOs.
* @dat_bit_offset: Offset (in bits) to the first GPIO bit.
* @dir_bit_offset: Optional offset (in bits) to the first bit to switch
@@ -149,7 +152,7 @@ static void rockchip_gpio_set(struct gpio_chip *chip, unsigned int offset,

static const struct syscon_gpio_data rockchip_rk3328_gpio_mute = {
/* RK3328 GPIO_MUTE is an output only pin at GRF_SOC_CON10[1] */
- .flags = GPIO_SYSCON_FEAT_OUT,
+ .flags = GPIO_SYSCON_FEAT_OUT | GPIO_SYSCON_FEAT_USE_PARENT,
.bit_count = 1,
.dat_bit_offset = 0x0428 * 8 + 1,
.set = rockchip_gpio_set,
@@ -221,19 +224,21 @@ static int syscon_gpio_probe(struct platform_device *pdev)
if (IS_ERR(priv->syscon))
return PTR_ERR(priv->syscon);

- ret = of_property_read_u32_index(np, "gpio,syscon-dev", 1,
- &priv->dreg_offset);
- if (ret)
- dev_err(dev, "can't read the data register offset!\n");
+ if (!(priv->data->flags & GPIO_SYSCON_FEAT_USE_PARENT)) {
+ ret = of_property_read_u32_index(np, "gpio,syscon-dev", 1,
+ &priv->dreg_offset);
+ if (ret)
+ dev_err(dev, "can't read the data register offset!\n");

- priv->dreg_offset <<= 3;
+ priv->dreg_offset <<= 3;

- ret = of_property_read_u32_index(np, "gpio,syscon-dev", 2,
- &priv->dir_reg_offset);
- if (ret)
- dev_dbg(dev, "can't read the dir register offset!\n");
+ ret = of_property_read_u32_index(np, "gpio,syscon-dev", 2,
+ &priv->dir_reg_offset);
+ if (ret)
+ dev_dbg(dev, "can't read the dir register offset!\n");

- priv->dir_reg_offset <<= 3;
+ priv->dir_reg_offset <<= 3;
+ }

priv->chip.parent = dev;
priv->chip.owner = THIS_MODULE;

base-commit: 4cece764965020c22cff7665b18a012006359095
--
2.43.0