[PATCH] mtd: rawnand: pl353: make sure optimal timings are applied

[Andrea Scian]

Dear Miquel,

> -----Original Message-----
> From: Miquel Raynal <miquel.raynal at bootlin.com>
> Sent: lunedì 16 marzo 2026 09:47
> [snip] 
> Andrea, this might be the reason why your NAND chip misbehaves after a
> set_feature. Would you mind testing it?

Thanks for pointing me to this patch.
I got a similar one in my tree (sorry for not publishing it before, but ECC was a bigger problem ;-) ), that applies new timing like on Olivier patch but only when they change


commit 35ba37433ebef77ab1f0e47e79e69bbc0d21cf90
Author: Andrea Scian <andrea.scian at dave.eu>
Date:   Mon Jan 12 17:49:37 2026 +0100

    mtd: rawnand: pl353: update timings on changes
    
    It's not enough to wait for selecting another chip to
    update the timings, because this also happens without
    changing CS (e.g. when switching between different SDR modes)

diff --git a/drivers/mtd/nand/raw/pl35x-nand-controller.c b/drivers/mtd/nand/raw/pl35x-nand-controller.c
index 74cc37e7b7da..72463638148d 100644
--- a/drivers/mtd/nand/raw/pl35x-nand-controller.c
+++ b/drivers/mtd/nand/raw/pl35x-nand-controller.c
@@ -790,6 +790,7 @@ static int pl35x_nfc_setup_interface(struct nand_chip *chip, int cs,
 	const struct nand_sdr_timings *sdr;
 	unsigned int period_ns, val;
 	struct clk *mclk;
+	u32 new_timings;
 
 	sdr = nand_get_sdr_timings(conf);
 	if (IS_ERR(sdr))
@@ -857,13 +858,18 @@ static int pl35x_nfc_setup_interface(struct nand_chip *chip, int cs,
 	if (cs == NAND_DATA_IFACE_CHECK_ONLY)
 		return 0;
 
-	plnand->timings = PL35X_SMC_NAND_TRC_CYCLES(tmgs.t_rc) |
+	new_timings =  PL35X_SMC_NAND_TRC_CYCLES(tmgs.t_rc) |
 			  PL35X_SMC_NAND_TWC_CYCLES(tmgs.t_wc) |
 			  PL35X_SMC_NAND_TREA_CYCLES(tmgs.t_rea) |
 			  PL35X_SMC_NAND_TWP_CYCLES(tmgs.t_wp) |
 			  PL35X_SMC_NAND_TCLR_CYCLES(tmgs.t_clr) |
 			  PL35X_SMC_NAND_TAR_CYCLES(tmgs.t_ar) |
 			  PL35X_SMC_NAND_TRR_CYCLES(tmgs.t_rr);
+	if (plnand->timings != new_timings) {
+		plnand->timings = new_timings;
+		writel(plnand->timings, nfc->conf_regs + PL35X_SMC_CYCLES);
+		pl35x_smc_update_regs(nfc);
+	}
 
 	dev_info(nfc->dev,
 		 "NAND timings: tRC=%u, tWC=%u, tREA=%u, tWP=%u, tCLR=%u, tAR=%u, tRR=%u (in cycles) (reg 0x%08x)\n",


This works on my setup (NAND now run a lot faster) but it doesn't solve the set_feature problem.
However, let me try this again with a cleaner setup

Kind Regards,

Andrea Scian