Hi Andy,

On Tue, Jun 14, 2022 at 4:10 AM Andy Shevchenko
[off-list ref] wrote:

On Mon, Jun 13, 2022 at 9:57 PM Brad Larson [off-list ref] wrote:
...

quoted

+/*
+ * Elba SoC does not use ssi, pin override is used for cs 0,1 and
+ * gpios for cs 2,3 as defined in the device tree.
+ *
+ * cs:  |       1               0
+ * bit: |---3-------2-------1-------0
+ *      |  cs1   cs1_ovr   cs0   cs0_ovr
+ */

quoted

+#define ELBA_SPICS_SHIFT(cs)           (2 * (cs))

Useless.It takes much more than simply multiplying each time in two
macros. Also see below.

quoted

+#define ELBA_SPICS_MASK(cs)            (0x3 << ELBA_SPICS_SHIFT(cs))

(GENMASK(1, 0) << ((cs) << 1))

Or ((cs) * 2) to show that it takes 2 bits and not two times of CS',

quoted

+#define ELBA_SPICS_SET(cs, val)        \
+                       ((((val) << 1) | 0x1) << ELBA_SPICS_SHIFT(cs))

BIT(0)

So the main point is to use GENMASK() and BIT() the rest is up to you.

I think you're recommending this approach which I'll change to

static void dw_spi_elba_override_cs(struct dw_spi_elba *dwselba, int
cs, int enable)
{
        regmap_update_bits(dwselba->syscon, ELBA_SPICS_REG,
                           (GENMASK(1, 0) << ((cs) << 1)),
                           ((enable) << 1 | BIT(0)) << ((cs) << 1));
}

Regards,
Brad

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