Re: [PATCH v1 1/2] spi: npcm-pspi: add full duplex support

From: Mark Brown
Date: Mon Jul 25 2022 - 08:15:22 EST


On Sun, Jul 24, 2022 at 12:35:37PM +0300, Tomer Maimon wrote:
> On Thu, 21 Jul 2022 at 16:46, Mark Brown <broonie@xxxxxxxxxx> wrote:
> > On Thu, Jul 21, 2022 at 01:15:55PM +0300, Tomer Maimon wrote:

> > > This patch adds full duplex support for NPCM PSPI driver by storing all
> > > rx-data when the Rx-buffer is defined also for TX-buffer handling.

> > This doesn't seem to entirely correspond to what the patch does, nor to
> > what the driver currently does? I can't see any dummy read code in the
> > current driver.

> In the current handler file, in the handler function.
> static irqreturn_t npcm_pspi_handler(int irq, void *dev_id)

> - if (priv->tx_buf) {
> - if (stat & NPCM_PSPI_STAT_RBF) {
> - ioread8(NPCM_PSPI_DATA + priv->base);

> the read above doing a dummy read

That's reading a single byte, not an entire buffer, and from a quick
glance looks more like an ack. Though perhaps you just end up with a
lot of interrupts and do that anyway.

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