RE: [PATCH] spi: spi-nxp-fspi: add per-SoC SDR/DTR clock rate limits for all supported SoCs

From: Bough Chen

Date: Mon Jul 27 2026 - 22:36:44 EST

> -----Original Message-----
> From: Frank Li (OSS) <frank.li@xxxxxxxxxxx>
> Sent: 2026年7月27日 23:00
> To: Bough Chen (OSS) <haibo.chen@xxxxxxxxxxx>
> Cc: Han Xu <han.xu@xxxxxxx>; Yogesh Gaur <yogeshgaur.83@xxxxxxxxx>;
> Mark Brown <broonie@xxxxxxxxxx>; linux-spi@xxxxxxxxxxxxxxx;
> imx@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Bough Chen
> <haibo.chen@xxxxxxx>
> Subject: Re: [PATCH] spi: spi-nxp-fspi: add per-SoC SDR/DTR clock rate limits
> for all supported SoCs
>
> On Mon, Jul 27, 2026 at 05:08:47PM +0800, haibo.chen@xxxxxxxxxxx
> wrote:
> > From: Haibo Chen <haibo.chen@xxxxxxx>
> >
> > The commit f43579ef3500 ("spi: spi-nxp-fspi: limit the clock rate for
> > different sample clock source selection") introduced a global 166MHz
> > cap for DTR mode (RXCLKSRC=3), based on the i.MX8MN datasheet timing
> > specification (Section 3.9.9, page 65).
> >
> > After reviewing the FlexSPI timing parameters in the datasheets for
> > all supported SoCs, the following corrections and additions are needed:
> >
> > 1. SDR mode (RXCLKSRC=0) limits vary per SoC:
> > - i.MX8MN/MM/MP/95: 66MHz (IMX8MNCEC §3.9.9, IMX8MMCEC
> §3.9.10,
> > IMX8MPCEC, IMX95CEC Rev.8
> §4.11.7)
> > - i.MX8QXP/QM/DXL/ULP: 60MHz (IMX8QXPCEC, IMX8QMCEC,
> IMX8DXLCEC,
> > IMX8ULPCEC §7.3.1 ND mode)
> > - LX2160A: 100MHz (LX2160ACEC FlexSPI timing
> parameters)
> >
> > 2. DTR mode (RXCLKSRC=3) limits vary per SoC:
> > - i.MX8MN/MM/MP/ULP: 166MHz
> > - i.MX8QXP/QM/DXL: 200MHz (same FlexSPI IP across this family)
> > - i.MX95: 200MHz (IMX95CEC §4.11.7.3.2.3 Table 106)
> > - LX2160A: DTR disabled (FSPI_QUIRK_DISABLE_DTR)
> >
> > - Add max_sdr_rate and max_dtr_rate field to nxp_fspi_devtype_data
> > - Use per-SoC max_sdr_rate in nxp_fspi_select_rx_sample_clk_source(),
> > falling back to 66MHz default when zero (preserves existing behavior
> > for any future SoC entries that omit the field)
> > - Use per-SoC max_ddr_rate in nxp_fspi_select_rx_sample_clk_source(),
> > falling back to 166MHz default when zero (preserves existing behavior
> > for any future SoC entries that omit the field)
> > - Add dedicated imx8mp_data (previously aliased to imx8mm_data) with
> > explicit frequency limits
> > - Update imx8qxp_data, imx8dxl_data with correct 60/200MHz limits
> > - Update imx8ulp_data with ND (Normal Drive, 1.0V) mode limits:
> > 60/166MHz
> > - Update lx2160a_data with correct SDR 100MHz limit
> > - Update imx95_data with correct 66/200MHz limits
>
> Update related platform data with correct speed limation according to
> datasheet.
>
> You already list frequency at above 1/2, needn't duplicate these informaiton
> again.
>
> > Note: i.MX8ULP limits are specified for Normal Drive (ND, 1.0V) mode
> > as this is the standard operating condition. Overdrive (OD, 1.05V)
> > allows up to 180MHz DTR but is not the default use case.
>
> Move this to comments.

Thanks for the suggestions, will update in V2.

Regards
Haibo Chen
>
> Frank
> >
> > Fixes: f43579ef3500 ("spi: spi-nxp-fspi: limit the clock rate for
> > different sample clock source selection")
> > Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
> > ---
> > drivers/spi/spi-nxp-fspi.c | 81
> > ++++++++++++++++++++++++++++++++++++++++++++--
> > 1 file changed, 78 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/spi/spi-nxp-fspi.c b/drivers/spi/spi-nxp-fspi.c
> > index
> >
> d94a2a7b98d44db217ba96a8ce7df23e37a08ba4..1159f5fc8a3a69eb464f32
> fd92e2
> > 83e84ebd67ab 100644
> > --- a/drivers/spi/spi-nxp-fspi.c
> > +++ b/drivers/spi/spi-nxp-fspi.c
> > @@ -340,6 +340,18 @@ struct nxp_fspi_devtype_data {
> > unsigned int quirks;
> > unsigned int lut_num;
> > bool little_endian;
> > + /*
> > + * The max clock rate (Hz) that FlexSPI can output to the device
> > + * in SDR mode (RXCLKSRC=0). Defaults to 66MHz if zero.
> > + * Some SoCs (e.g. LX2160A) support up to 100MHz in SDR mode.
> > + */
> > + unsigned long max_sdr_rate;
> > + /*
> > + * The max clock rate (Hz) that FlexSPI can output to the device
> > + * in DTR mode (RXCLKSRC=3). Defaults to 166MHz if zero.
> > + * Some SoCs (e.g. i.MX95, i.MX8QM, i.MX8DXL) support up to
> 200MHz.
> > + */
> > + unsigned long max_dtr_rate;
> > };
> >
> > static struct nxp_fspi_devtype_data lx2160a_data = { @@ -349,6
> > +361,10 @@ static struct nxp_fspi_devtype_data lx2160a_data = {
> > .quirks = FSPI_QUIRK_DISABLE_DTR,
> > .lut_num = 32,
> > .little_endian = true, /* little-endian */
> > + /*
> > + * LX2160ACEC: SDR RXCLKSRC=0 max 100MHz, DTR disabled via quirk.
> > + */
> > + .max_sdr_rate = 100000000,
> > };
> >
> > static struct nxp_fspi_devtype_data imx8mm_data = { @@ -358,6 +374,21
> > @@ static struct nxp_fspi_devtype_data imx8mm_data = {
> > .quirks = 0,
> > .lut_num = 32,
> > .little_endian = true, /* little-endian */
> > + /* IMX8MMCEC §3.9.10: SDR RXCLKSRC=0 max 66MHz, DDR
> RXCLKSRC=3 max 166MHz */
> > + .max_sdr_rate = 66000000,
> > + .max_dtr_rate = 166000000,
> > +};
> > +
> > +static struct nxp_fspi_devtype_data imx8mp_data = {
> > + .rxfifo = SZ_512, /* (64 * 64 bits) */
> > + .txfifo = SZ_1K, /* (128 * 64 bits) */
> > + .ahb_buf_size = SZ_2K, /* (256 * 64 bits) */
> > + .quirks = 0,
> > + .lut_num = 32,
> > + .little_endian = true, /* little-endian */
> > + /* IMX8MPCEC: SDR RXCLKSRC=0 max 66MHz, DDR RXCLKSRC=3 max
> 166MHz */
> > + .max_sdr_rate = 66000000,
> > + .max_dtr_rate = 166000000,
> > };
> >
> > static struct nxp_fspi_devtype_data imx8qxp_data = { @@ -367,6
> > +398,12 @@ static struct nxp_fspi_devtype_data imx8qxp_data = {
> > .quirks = 0,
> > .lut_num = 32,
> > .little_endian = true, /* little-endian */
> > + /*
> > + * IMX8QXPCEC: SDR RXCLKSRC=0 max 60MHz, DDR RXCLKSRC=3 max
> 200MHz.
> > + * i.MX8QM and i.MX8DXL share the same FlexSPI IP and limits.
> > + */
> > + .max_sdr_rate = 60000000,
> > + .max_dtr_rate = 200000000,
> > };
> >
> > static struct nxp_fspi_devtype_data imx8dxl_data = { @@ -376,6
> > +413,12 @@ static struct nxp_fspi_devtype_data imx8dxl_data = {
> > .quirks = FSPI_QUIRK_USE_IP_ONLY,
> > .lut_num = 32,
> > .little_endian = true, /* little-endian */
> > + /*
> > + * IMX8DXLCEC (i.MX 8XLite): SDR RXCLKSRC=0 max 60MHz,
> > + * DDR RXCLKSRC=3 max 200MHz.
> > + */
> > + .max_sdr_rate = 60000000,
> > + .max_dtr_rate = 200000000,
> > };
> >
> > static struct nxp_fspi_devtype_data imx8ulp_data = { @@ -385,6
> > +428,27 @@ static struct nxp_fspi_devtype_data imx8ulp_data = {
> > .quirks = 0,
> > .lut_num = 16,
> > .little_endian = true, /* little-endian */
> > + /*
> > + * IMX8ULPCEC §7.3.1, Normal Drive (ND, 1.0V) mode:
> > + * SDR RXCLKSRC=0 max 60MHz, DDR RXCLKSRC=3 max 166MHz.
> > + */
> > + .max_sdr_rate = 60000000,
> > + .max_dtr_rate = 166000000,
> > +};
> > +
> > +static struct nxp_fspi_devtype_data imx95_data = {
> > + .rxfifo = SZ_512, /* (64 * 64 bits) */
> > + .txfifo = SZ_1K, /* (128 * 64 bits) */
> > + .ahb_buf_size = SZ_2K, /* (256 * 64 bits) */
> > + .quirks = 0,
> > + .lut_num = 32,
> > + .little_endian = true, /* little-endian */
> > + /*
> > + * IMX95CEC Rev.8 §4.11.7: SDR RXCLKSRC=0 max 66MHz,
> > + * DDR RXCLKSRC=3 max 200MHz (Nominal/Overdrive mode).
> > + */
> > + .max_sdr_rate = 66000000,
> > + .max_dtr_rate = 200000000,
> > };
> >
> > struct nxp_fspi {
> > @@ -691,10 +755,20 @@ static void
> nxp_fspi_select_rx_sample_clk_source(struct nxp_fspi *f,
> > reg = fspi_readl(f, f->iobase + FSPI_MCR0);
> > if (op_is_dtr) {
> > reg |= FSPI_MCR0_RXCLKSRC(3);
> > - f->max_rate = 166000000;
> > + /*
> > + * Use the SoC-specific DTR max rate if provided, otherwise
> > + * fall back to 166MHz (limit from IMX8MN datasheet §3.9.9).
> > + */
> > + f->max_rate = f->devtype_data->max_dtr_rate ?
> > + f->devtype_data->max_dtr_rate : 166000000;
> > } else { /*select mode 0 */
> > reg &= ~FSPI_MCR0_RXCLKSRC(3);
> > - f->max_rate = 66000000;
> > + /*
> > + * Use the SoC-specific SDR max rate if provided, otherwise
> > + * fall back to 66MHz (limit from IMX8MN datasheet §3.9.9).
> > + */
> > + f->max_rate = f->devtype_data->max_sdr_rate ?
> > + f->devtype_data->max_sdr_rate : 66000000;
> > }
> > fspi_writel(f, reg, f->iobase + FSPI_MCR0); } @@ -1457,10 +1531,11
> > @@ static const struct dev_pm_ops nxp_fspi_pm_ops = { static const
> > struct of_device_id nxp_fspi_dt_ids[] = {
> > { .compatible = "nxp,lx2160a-fspi", .data = (void *)&lx2160a_data, },
> > { .compatible = "nxp,imx8mm-fspi", .data = (void *)&imx8mm_data, },
> > - { .compatible = "nxp,imx8mp-fspi", .data = (void *)&imx8mm_data, },
> > + { .compatible = "nxp,imx8mp-fspi", .data = (void *)&imx8mp_data, },
> > { .compatible = "nxp,imx8qxp-fspi", .data = (void *)&imx8qxp_data, },
> > { .compatible = "nxp,imx8dxl-fspi", .data = (void *)&imx8dxl_data, },
> > { .compatible = "nxp,imx8ulp-fspi", .data = (void *)&imx8ulp_data,
> > },
> > + { .compatible = "nxp,imx95-fspi", .data = (void *)&imx95_data, },
> > { /* sentinel */ }
> > };
> > MODULE_DEVICE_TABLE(of, nxp_fspi_dt_ids);
> >
> > ---
> > base-commit: c5e32e86ca02b003f86e095d379b38148999293d
> > change-id: 20260727-fspi-clock-adcae0c35283
> >
> > Best regards,
> > --
> > Haibo Chen <haibo.chen@xxxxxxx>
> >
> >