On 17. 04. 25 3:27 odp., Andrew Lunn wrote:
Anyway, I have a different idea... completely abstract mailboxes from the
caller. The mailbox content can be large and the caller is barely interested
in all registers from the mailbox but this could be resolved this way:
The proposed API e.g for Ref mailbox:
int zl3073x_mb_ref_read(struct zl3073x_dev *zldev, u8 index,
struct zl3073x_mb_ref *mb);
int zl3073x_mb_ref_write(struct zl3073x_dev *zldev, u8 index,
struct zl3073x_mb_ref *mb);
struct zl3073x_mb_ref {
u32 flags;
u16 freq_base;
u16 freq_mult;
u16 ratio_m;
u16 ratio_n;
u8 config;
u64 phase_offset_compensation;
u8 sync_ctrl;
u32 esync_div;
}
#define ZL3073X_MB_REF_FREQ_BASE BIT(0)
#define ZL3073X_MB_REF_FREQ_MULT BIT(1)
#define ZL3073X_MB_REF_RATIO_M BIT(2)
#define ZL3073X_MB_REF_RATIO_N BIT(3)
#define ZL3073X_MB_REF_CONFIG BIT(4)
#define ZL3073X_MB_REF_PHASE_OFFSET_COMPENSATION BIT(5)
#define ZL3073X_MB_REF_SYNC_CTRL BIT(6)
#define ZL3073X_MB_REF_ESYNC_DIV BIT(7)
Then a reader can read this way (read freq and ratio of 3rd ref):
{
struct zl3073x_mb_ref mb;
...
mb.flags = ZL3073X_MB_REF_FREQ_BASE |
ZL3073X_MB_REF_FREQ_MULT |
ZL3073X_MB_REF_RATIO_M |
ZL3073X_MB_REF_RATIO_N;
rc = zl3073x_mb_ref_read(zldev, 3, &mb);
if (rc)
return rc;
/* at this point mb fields requested via flags are filled */
}
A writer similarly (write config of 5th ref):
{
struct zl3073x_mb_ref mb;
...
mb.flags = ZL3073X_MB_REF_CONFIG;
mb.config = FIELD_PREP(SOME_MASK, SOME_VALUE);
rc = zl3073x_mb_ref_write(zldev, 5, &mb);
...
/* config of 5th ref was commited */
}
The advantages:
* no explicit locking required from the callers
* locking is done inside mailbox API
* each mailbox type can have different mutex so multiple calls for
different mailbox types (e.g ref & output) can be done in parallel
WDYT about this approach?
I would say this is actually your next layer on top of the basic
mailbox API. This makes it more friendly to your sub driver and puts
all the locking in one place where it can easily be reviewed.
One question would be, where does this code belong. Is it in the MFD,
or in the subdrivers? I guess it is in the subdrivers.
No, it should be part of MFD because it does not make sense to implement
API above in each sub-driver separately.
Sub-driver would use this MB ABI for MB access and
zl3073x_{read,write}_u{8,16,32,48} for non-MB registers.
Ivan
