Hi Paul,

thanks for your patch!

On Thu, Nov 28, 2019 at 4:54 PM Paul Kocialkowski
[off-list ref] wrote:

The LogiCVC display hardware block comes with GPIO capabilities
that must be exposed separately from the main driver (as GPIOs) for
use with regulators and panels. A syscon is used to share the same
regmap across the two drivers.

Since the GPIO capabilities are pretty simple, add them to the syscon
GPIO driver.

Signed-off-by: Paul Kocialkowski <redacted>

(...)

+#define LOGICVC_CTRL_REG               0x40
+#define LOGICVC_CTRL_GPIO_SHIFT                11
+#define LOGICVC_CTRL_GPIO_BITS         5
+
+#define LOGICVC_POWER_CTRL_REG         0x78
+#define LOGICVC_POWER_CTRL_GPIO_SHIFT  0
+#define LOGICVC_POWER_CTRL_GPIO_BITS   4
+
+static void logicvc_gpio_offset(struct syscon_gpio_priv *priv,
+                               unsigned offset, unsigned int *reg,
+                               unsigned int *bit)
+{
+       if (offset >= LOGICVC_CTRL_GPIO_BITS) {
+               *reg = LOGICVC_POWER_CTRL_REG;
+
+               /* To the (virtual) power ctrl offset. */
+               offset -= LOGICVC_CTRL_GPIO_BITS;
+               /* To the actual bit offset in reg. */
+               offset += LOGICVC_POWER_CTRL_GPIO_SHIFT;
+       } else {
+               *reg = LOGICVC_CTRL_REG;
+
+               /* To the actual bit offset in reg. */
+               offset += LOGICVC_CTRL_GPIO_SHIFT;
+       }
+
+       *bit = BIT(offset);
+}

The gpio-syscon.c is for simple syscons where the lines
you want to affect are nicely ordered in the registers.
It is intended to be generic.

This is kind of shoehorning a special case into the generic
code.

Isn't it more appropriate to create a specific driver for this
hardware?

Special get/set quirks for any possible quirky offset is
certainly not the way to go, if this should be supported
we need generic properties in struct syscon_gpio_data
to indicate the valid bits and offsets.

Yours,
Linus Walleij