Re: [RFC PATCH v2 11/12] spi: cadence-quadspi: restrict PHY frequency to tuned operations

On 07/02/2026 at 00:57:04 +0530, Santhosh Kumar K [off-list ref] wrote:

On 05/02/26 23:17, Miquel Raynal wrote:

quoted

Hi Santhosh,

quoted

+	/*
+	 * PHY tuning allows high-frequency operation only for calibrated
+	 * commands. Uncalibrated operations use safe non-PHY frequency to
+	 * avoid timing violations.
+	 */
+	if (cqspi->ddata->execute_tuning && f_pdata->use_phy &&
+	    (cqspi_op_matches_tuned(op, &f_pdata->phy_read_op) ||
+	     cqspi_op_matches_tuned(op, &f_pdata->phy_write_op))) {
+		cqspi_configure(f_pdata, op->max_freq);
+	} else if (cqspi->ddata->execute_tuning) {
+		/* Use safe frequency for untuned operations */
+		cqspi_configure(f_pdata, f_pdata->non_phy_clk_rate);
+	} else {
+		/* No tuning support, always use requested frequency */
+		cqspi_configure(f_pdata, op->max_freq);
+	}

Shouldn't we handle this at the core level? We know what kind of
operation pattern we provided, so it is easy to set the correct
frequency in the operation structure.
Can you please make this happen? Perhaps you can return the operation
frequency once the calibration is successful (in the read and write op
templates maybe?) so this can be picked up by the core and used for the
following operations. This way the controller driver no longer needs to
check if the operation has been tuned or not, it can just look at the
frequency. When using the highest frequency, PHY tuning must be
used/enabled, otherwise not.

No, Miquel, this may not be correct. There can be cases where an
operation does not require tuning but still can run at maximum
frequency (166 MHz, for instance).

This is currently not the case. Currently you tune for one or two ops
(read/write) and you enable PHY tuning only on these. Do you plan on
adding such a feature? If not, I would not bother with this now.

In such scenarios, simply setting
op->max_freq to the maximum frequency value and deciding whether to
enable tuning based on an op->max_freq comparison would not be
sufficient.

If there are such cases, can they be listed? I am sorry but I fail to
see where this would not work. Any examples to share?

Thanks,
Miquèl