Hi Andy,

On Sun, Mar 7, 2021 at 11:21 AM Andy Shevchenko
[off-list ref] wrote:

On Thu, Mar 4, 2021 at 4:40 PM Brad Larson [off-list ref] wrote:

quoted

This GPIO driver is for the Pensando Elba SoC which
provides control of four chip selects on two SPI busses.

I will try to avoid repeating otheris in their reviews, but my comments below.

...

quoted

+config GPIO_ELBA_SPICS
+       bool "Pensando Elba SPI chip-select"

Can't it be a module? Why?

quoted

+       depends on ARCH_PENSANDO_ELBA_SOC
+       help
+         Say yes here to support the Pensndo Elba SoC SPI chip-select driver

Please give more explanation what it is and why users might need it,
and also tell users how the module will be named (if there is no
strong argument why it can't be a  module).

...

quoted

+#include <linux/of.h>

It's not used here, but you missed mod_devicetable.h.

Based on the feedback I realized this should not be a loadable module.
I should be using builtin_platform_driver(elba_spics_driver).
Currently I have this for gpio/Kconfig

config GPIO_ELBA_SPICS
        def_bool y
        depends on ARCH_PENSANDO_ELBA_SOC || COMPILE_TEST

quoted

+/*
+ * pin:             3            2        |       1            0
+ * bit:         7------6------5------4----|---3------2------1------0
+ *     cs1  cs1_ovr  cs0  cs0_ovr |  cs1  cs1_ovr  cs0  cs0_ovr
+ *                ssi1            |             ssi0
+ */
+#define SPICS_PIN_SHIFT(pin)   (2 * (pin))
+#define SPICS_MASK(pin)                (0x3 << SPICS_PIN_SHIFT(pin))

quoted

+#define SPICS_SET(pin, val)    ((((val) << 1) | 0x1) << SPICS_PIN_SHIFT(pin))

Isn't it easier to define as ((value) << (2 * (pin) + 1) | BIT(2 * (pin)))

Both are functionally correct.  I don't have a preference, do you want
this change?

quoted

+struct elba_spics_priv {
+       void __iomem *base;
+       spinlock_t lock;

quoted

+       struct gpio_chip chip;

If you put it as a first member a container_of() becomes a no-op. OTOH
dunno if there is any such container_of() use in the code.

There is no use of container_of() for this structure

quoted

+static int elba_spics_get_value(struct gpio_chip *chip, unsigned int pin)
+{
+       return -ENXIO;

Hmm... Is it really acceptable error code here?

No it's not, thanks.  Changed to -ENOTSUPP as gpio output direction
only is supported.

quoted

+static int elba_spics_direction_input(struct gpio_chip *chip, unsigned int pin)
+{
+       return -ENXIO;

Ditto.

Changed to ENOTSUPP

quoted

+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       p->base = devm_ioremap_resource(&pdev->dev, res);

p->base = devm_platform_ioremap_resource(pdev, 0);

Changed to single call to devm_platform_ioremap_resource(pdev, 0)

quoted

+       if (IS_ERR(p->base)) {

quoted

+               dev_err(&pdev->dev, "failed to remap I/O memory\n");

Duplicate noisy message.

Removed extra log message

quoted

+               return PTR_ERR(p->base);
+       }

quoted

+       ret = devm_gpiochip_add_data(&pdev->dev, &p->chip, p);
+       if (ret) {
+               dev_err(&pdev->dev, "unable to add gpio chip\n");

quoted

+               return ret;
+       }
+
+       dev_info(&pdev->dev, "elba spics registered\n");
+       return 0;

if (ret)
  dev_err(...);
return ret;

Yes, made this change and will include in v3 patchset

--- a/drivers/gpio/gpio-elba-spics.c
+++ b/drivers/gpio/gpio-elba-spics.c

@@ -91,13 +91,9 @@ static int elba_spics_probe(struct platform_device *pdev)
        ret = devm_gpiochip_add_data(&pdev->dev, &p->chip, p);
-       if (ret) {
+       if (ret)
                dev_err(&pdev->dev, "unable to add gpio chip\n");
-               return ret;
-       }
-
-       dev_info(&pdev->dev, "elba spics registered\n");
-       return 0;
+       return ret;

Regards,
Brad