[PATCH v3 00/11] add mcf54415 DAC driver

[PATCH v3 00/11] add mcf54415 DAC driver

[Angelo Dureghello]

This patchset adds a minimalistic DAC driver for the NXP mcf54415/6/7/8
ibuiltin DACs.

Currently the driver enables the raw write only. Feature as dma, sync, or
format are not supoprted for this version.

Additional options suppoerted by the DAC module will be added to the driver
later on, as needed.

The same patchset prepares the m68k/coldfire architecture to support
the driver.

Below soem basic tests done on stmark2 mcf54415-based board, voltage check
on DAC0 and DAC1:

~ # cd /sys/bus/iio/devices/iio:device0/
/sys/bus/iio/devices/iio:device0 # ls
name               out_voltage_scale  uevent
out_voltage_raw    subsystem
/sys/bus/iio/devices/iio:device0 # cat name
mcf54415
/sys/bus/iio/devices/iio:device0 # echo 4095 > out_voltage_raw 
/sys/bus/iio/devices/iio:device0 # echo 2048 > out_voltage_raw 
/sys/bus/iio/devices/iio:device0 # echo 4096 > out_voltage_raw 
sh: write error: Invalid argument
/sys/bus/iio/devices/iio:device0 # cat out_voltage_raw 
2048
/sys/bus/iio/devices/iio:device0 # 

Same behavior for /sys/bus/iio/devices/iio:device1.

Generated a sine wave by shell script, sine shape is good.

is actually in progress:

Note: this patchset depends on mew mcf_read/mcf_write implementation that
Link: https://lore.kernel.org/linux-m68k/209d0653-6386-4b64-9e15-e358f84453ab@app.fastmail.com/T/#t
Link: https://lore.kernel.org/linux-m68k/20260506142644.3234270-2-gerg@kernel.org/
---
Changes in v3:
- keeping changelog in each single patch, where any
- Link to v2: https://patch.msgid.link/20260513-wip-stmark2-dac-v2-0-fcdae50cf51a@baylibre.com

Changes in v2:
- keeping changelog in each single patch, where any
- Link to v1: https://patch.msgid.link/20260504-wip-stmark2-dac-v1-0-874c36a4910d@baylibre.com

To: Greg Ungerer <gerg@linux-m68k.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
To: Steven King <sfking@fdwdc.com>
To: Arnd Bergmann <arnd@arndb.de>
To: Maxime Coquelin <mcoquelin.stm32@gmail.com>
To: Alexandre Torgue <alexandre.torgue@foss.st.com>
To: Jonathan Cameron <jic23@kernel.org>
To: David Lechner <dlechner@baylibre.com>
To: Nuno Sá <nuno.sa@analog.com>
To: Andy Shevchenko <andy@kernel.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-iio@vger.kernel.org

---
Angelo Dureghello (11):
      m68k: mcf5441x: fix clocks numbering
      m68k: mcf5441x: add clock for DAC channel 1
      m68k: mcf5441x: initialize DAC clocks by iio DAC driver name
      m68k: defconfig: update stmark2 defconfig
      m68k: add DAC modules base addresses
      m68k: mcf5441x: add CCM registers
      m68k: mcf5441x: add CCR MISCCR2 bitfields
      m68k: stmark2: use ioport.h macros for resources
      m68k: stmark2: add mcf5441x DAC platform devices
      m68k: stmark2: enable DACs outputs
      iio: dac: add mcf54415 DAC

 arch/m68k/coldfire/m5441x.c         |  21 ++--
 arch/m68k/coldfire/stmark2.c        |  47 +++++---
 arch/m68k/configs/stmark2_defconfig |   2 +
 arch/m68k/include/asm/m5441xsim.h   |  42 ++++++++
 drivers/iio/dac/Kconfig             |  11 ++
 drivers/iio/dac/Makefile            |   1 +
 drivers/iio/dac/mcf54415_dac.c      | 207 ++++++++++++++++++++++++++++++++++++
 7 files changed, 307 insertions(+), 24 deletions(-)
---
base-commit: 9edf4183f0d32146b708220d56ee2d35905ba516
change-id: 20260430-wip-stmark2-dac-7060f49dd94f

Best regards,
--  
Angelo Dureghello <adureghello@baylibre.com>

[PATCH v3 01/11] m68k: mcf5441x: fix clocks numbering

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Fix clocks numbering, set correct values for eport and DAC,
as per RM Rev 5, 05/2018, table 9.5.

Fixes: bea8bcb12da09 ("m68knommu: Add support for the Coldfire m5441x.")
Fixes: 007f84ede6e3e ("m68k: coldfire: remove private clk_get/clk_put")
Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
 arch/m68k/coldfire/m5441x.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/m68k/coldfire/m5441x.c b/arch/m68k/coldfire/m5441x.c
index 6ce730098ff6..613b0275d9d8 100644
--- a/arch/m68k/coldfire/m5441x.c
+++ b/arch/m68k/coldfire/m5441x.c
@@ -41,9 +41,9 @@ DEFINE_CLK(0, "mcfpit.0", 32, MCF_BUSCLK);
 DEFINE_CLK(0, "mcfpit.1", 33, MCF_BUSCLK);
 DEFINE_CLK(0, "mcfpit.2", 34, MCF_BUSCLK);
 DEFINE_CLK(0, "mcfpit.3", 35, MCF_BUSCLK);
-DEFINE_CLK(0, "mcfeport.0", 37, MCF_CLK);
-DEFINE_CLK(0, "mcfadc.0", 38, MCF_CLK);
-DEFINE_CLK(0, "mcfdac.0", 39, MCF_CLK);
+DEFINE_CLK(0, "mcfeport.0", 36, MCF_CLK);
+DEFINE_CLK(0, "mcfadc.0", 37, MCF_CLK);
+DEFINE_CLK(0, "mcfdac.0", 38, MCF_CLK);
 DEFINE_CLK(0, "mcfrtc.0", 42, MCF_CLK);
 DEFINE_CLK(0, "mcfsim.0", 43, MCF_CLK);
 DEFINE_CLK(0, "mcfusb-otg.0", 44, MCF_CLK);
@@ -103,9 +103,9 @@ static struct clk_lookup m5411x_clk_lookup[] = {
 	CLKDEV_INIT("mcfpit.1", NULL, &__clk_0_33),
 	CLKDEV_INIT("mcfpit.2", NULL, &__clk_0_34),
 	CLKDEV_INIT("mcfpit.3", NULL, &__clk_0_35),
-	CLKDEV_INIT("mcfeport.0", NULL, &__clk_0_37),
-	CLKDEV_INIT("mcfadc.0", NULL, &__clk_0_38),
-	CLKDEV_INIT("mcfdac.0", NULL, &__clk_0_39),
+	CLKDEV_INIT("mcfeport.0", NULL, &__clk_0_36),
+	CLKDEV_INIT("mcfadc.0", NULL, &__clk_0_37),
+	CLKDEV_INIT("mcfdac.0", NULL, &__clk_0_38),
 	CLKDEV_INIT("mcfrtc.0", NULL, &__clk_0_42),
 	CLKDEV_INIT("mcfsim.0", NULL, &__clk_0_43),
 	CLKDEV_INIT("mcfusb-otg.0", NULL, &__clk_0_44),
@@ -156,7 +156,7 @@ static struct clk * const enable_clks[] __initconst = {
 	&__clk_0_27, /* uart3 */
 
 	&__clk_0_33, /* pit.1 */
-	&__clk_0_37, /* eport */
+	&__clk_0_36, /* eport */
 	&__clk_0_48, /* pll */
 	&__clk_0_51, /* esdhc */
 
@@ -174,8 +174,8 @@ static struct clk * const disable_clks[] __initconst = {
 	&__clk_0_32, /* pit.0 */
 	&__clk_0_34, /* pit.2 */
 	&__clk_0_35, /* pit.3 */
-	&__clk_0_38, /* adc */
-	&__clk_0_39, /* dac */
+	&__clk_0_37, /* adc */
+	&__clk_0_38, /* dac.0 */
 	&__clk_0_44, /* usb otg */
 	&__clk_0_45, /* usb host */
 	&__clk_0_47, /* ssi.0 */

-- 
2.54.0

[PATCH v3 02/11] m68k: mcf5441x: add clock for DAC channel 1

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Add missing clock for mcf5441x DAC channel 1.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
 arch/m68k/coldfire/m5441x.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/m68k/coldfire/m5441x.c b/arch/m68k/coldfire/m5441x.c
index 613b0275d9d8..5b5e09ecf487 100644
--- a/arch/m68k/coldfire/m5441x.c
+++ b/arch/m68k/coldfire/m5441x.c
@@ -44,6 +44,7 @@ DEFINE_CLK(0, "mcfpit.3", 35, MCF_BUSCLK);
 DEFINE_CLK(0, "mcfeport.0", 36, MCF_CLK);
 DEFINE_CLK(0, "mcfadc.0", 37, MCF_CLK);
 DEFINE_CLK(0, "mcfdac.0", 38, MCF_CLK);
+DEFINE_CLK(0, "mcfdac.1", 39, MCF_CLK);
 DEFINE_CLK(0, "mcfrtc.0", 42, MCF_CLK);
 DEFINE_CLK(0, "mcfsim.0", 43, MCF_CLK);
 DEFINE_CLK(0, "mcfusb-otg.0", 44, MCF_CLK);
@@ -106,6 +107,7 @@ static struct clk_lookup m5411x_clk_lookup[] = {
 	CLKDEV_INIT("mcfeport.0", NULL, &__clk_0_36),
 	CLKDEV_INIT("mcfadc.0", NULL, &__clk_0_37),
 	CLKDEV_INIT("mcfdac.0", NULL, &__clk_0_38),
+	CLKDEV_INIT("mcfdac.1", NULL, &__clk_0_39),
 	CLKDEV_INIT("mcfrtc.0", NULL, &__clk_0_42),
 	CLKDEV_INIT("mcfsim.0", NULL, &__clk_0_43),
 	CLKDEV_INIT("mcfusb-otg.0", NULL, &__clk_0_44),
@@ -176,6 +178,7 @@ static struct clk * const disable_clks[] __initconst = {
 	&__clk_0_35, /* pit.3 */
 	&__clk_0_37, /* adc */
 	&__clk_0_38, /* dac.0 */
+	&__clk_0_39, /* dac.1 */
 	&__clk_0_44, /* usb otg */
 	&__clk_0_45, /* usb host */
 	&__clk_0_47, /* ssi.0 */

-- 
2.54.0

[PATCH v3 03/11] m68k: mcf5441x: initialize DAC clocks by iio DAC driver name

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Later in this patchset, the mcf54415 DAC driver is added.
Considering some other different ColdFire cpu DACs exists, the DAC driver
is named as "mcf54415_dac", related to the mcf5441x family SoCs with
DACs (mcf54415/6/7/8).

So updating DAC CLKDEDV_INIT with proper driver name.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
Changes in v2:
- none
Changes in v3
- roll back clock names as they was originally
---
 arch/m68k/coldfire/m5441x.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/m68k/coldfire/m5441x.c b/arch/m68k/coldfire/m5441x.c
index 5b5e09ecf487..b02ca2eb55a4 100644
--- a/arch/m68k/coldfire/m5441x.c
+++ b/arch/m68k/coldfire/m5441x.c
@@ -106,8 +106,8 @@ static struct clk_lookup m5411x_clk_lookup[] = {
 	CLKDEV_INIT("mcfpit.3", NULL, &__clk_0_35),
 	CLKDEV_INIT("mcfeport.0", NULL, &__clk_0_36),
 	CLKDEV_INIT("mcfadc.0", NULL, &__clk_0_37),
-	CLKDEV_INIT("mcfdac.0", NULL, &__clk_0_38),
-	CLKDEV_INIT("mcfdac.1", NULL, &__clk_0_39),
+	CLKDEV_INIT("mcf54415_dac.0", NULL, &__clk_0_38),
+	CLKDEV_INIT("mcf54415_dac.1", NULL, &__clk_0_39),
 	CLKDEV_INIT("mcfrtc.0", NULL, &__clk_0_42),
 	CLKDEV_INIT("mcfsim.0", NULL, &__clk_0_43),
 	CLKDEV_INIT("mcfusb-otg.0", NULL, &__clk_0_44),

-- 
2.54.0

Re: [PATCH v3 03/11] m68k: mcf5441x: initialize DAC clocks by iio DAC driver name

[Greg Ungerer]

Hi Angelo,

On 23/5/26 07:20, Angelo Dureghello wrote:
> From: Angelo Dureghello <adureghello@baylibre.com>
> 
> Later in this patchset, the mcf54415 DAC driver is added.
> Considering some other different ColdFire cpu DACs exists, the DAC driver
> is named as "mcf54415_dac", related to the mcf5441x family SoCs with
> DACs (mcf54415/6/7/8).
> 
> So updating DAC CLKDEDV_INIT with proper driver name.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> ---
> Changes in v2:
> - none
> Changes in v3
> - roll back clock names as they was originally
> ---
>   arch/m68k/coldfire/m5441x.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/m68k/coldfire/m5441x.c b/arch/m68k/coldfire/m5441x.c
> index 5b5e09ecf487..b02ca2eb55a4 100644
> --- a/arch/m68k/coldfire/m5441x.c
> +++ b/arch/m68k/coldfire/m5441x.c
> @@ -106,8 +106,8 @@ static struct clk_lookup m5411x_clk_lookup[] = {
>   	CLKDEV_INIT("mcfpit.3", NULL, &__clk_0_35),
>   	CLKDEV_INIT("mcfeport.0", NULL, &__clk_0_36),
>   	CLKDEV_INIT("mcfadc.0", NULL, &__clk_0_37),
> -	CLKDEV_INIT("mcfdac.0", NULL, &__clk_0_38),
> -	CLKDEV_INIT("mcfdac.1", NULL, &__clk_0_39),
> +	CLKDEV_INIT("mcf54415_dac.0", NULL, &__clk_0_38),
> +	CLKDEV_INIT("mcf54415_dac.1", NULL, &__clk_0_39),

I thought after the last discussion on this that we would not change these
clock names?

Regards
Greg



>   	CLKDEV_INIT("mcfrtc.0", NULL, &__clk_0_42),
>   	CLKDEV_INIT("mcfsim.0", NULL, &__clk_0_43),
>   	CLKDEV_INIT("mcfusb-otg.0", NULL, &__clk_0_44),
> 

Re: [PATCH v3 03/11] m68k: mcf5441x: initialize DAC clocks by iio DAC driver name

[Angelo Dureghello]

Hi Greg,

On Sun, May 31, 2026 at 11:15:43PM +1000, Greg Ungerer wrote:
> Hi Angelo,
>
> On 23/5/26 07:20, Angelo Dureghello wrote:
> > From: Angelo Dureghello <adureghello@baylibre.com>
> >
> > Later in this patchset, the mcf54415 DAC driver is added.
> > Considering some other different ColdFire cpu DACs exists, the DAC driver
> > is named as "mcf54415_dac", related to the mcf5441x family SoCs with
> > DACs (mcf54415/6/7/8).
> >
> > So updating DAC CLKDEDV_INIT with proper driver name.
> >
> > Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> > ---
> > Changes in v2:
> > - none
> > Changes in v3
> > - roll back clock names as they was originally
> > ---
> >   arch/m68k/coldfire/m5441x.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/m68k/coldfire/m5441x.c b/arch/m68k/coldfire/m5441x.c
> > index 5b5e09ecf487..b02ca2eb55a4 100644
> > --- a/arch/m68k/coldfire/m5441x.c
> > +++ b/arch/m68k/coldfire/m5441x.c
> > @@ -106,8 +106,8 @@ static struct clk_lookup m5411x_clk_lookup[] = {
> >   	CLKDEV_INIT("mcfpit.3", NULL, &__clk_0_35),
> >   	CLKDEV_INIT("mcfeport.0", NULL, &__clk_0_36),
> >   	CLKDEV_INIT("mcfadc.0", NULL, &__clk_0_37),
> > -	CLKDEV_INIT("mcfdac.0", NULL, &__clk_0_38),
> > -	CLKDEV_INIT("mcfdac.1", NULL, &__clk_0_39),
> > +	CLKDEV_INIT("mcf54415_dac.0", NULL, &__clk_0_38),
> > +	CLKDEV_INIT("mcf54415_dac.1", NULL, &__clk_0_39),
>
> I thought after the last discussion on this that we would not change these
> clock names?
>

sorry, seems i seen this comment just after sending v4.

As a change i rolled back original names in DEFINE_CLK as they was, "mcfdac".
While i cannot change these names above, from tests i did they must match with
the driver name or driver does not find the clock from his code.

Or am i missing something ?

> Regards
> Greg
>

Regards,
angelo

>
>
> >   	CLKDEV_INIT("mcfrtc.0", NULL, &__clk_0_42),
> >   	CLKDEV_INIT("mcfsim.0", NULL, &__clk_0_43),
> >   	CLKDEV_INIT("mcfusb-otg.0", NULL, &__clk_0_44),
> >
>

[PATCH v3 04/11] m68k: defconfig: update stmark2 defconfig

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Update stmark2 defconfig enabling MCF5441X DACs.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
 arch/m68k/configs/stmark2_defconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/m68k/configs/stmark2_defconfig b/arch/m68k/configs/stmark2_defconfig
index b3fb95f73a95..3941113bc60b 100644
--- a/arch/m68k/configs/stmark2_defconfig
+++ b/arch/m68k/configs/stmark2_defconfig
@@ -76,6 +76,8 @@ CONFIG_DMADEVICES=y
 CONFIG_MCF_EDMA=y
 # CONFIG_VIRTIO_MENU is not set
 # CONFIG_VHOST_MENU is not set
+CONFIG_IIO=y
+CONFIG_MCF54415_DAC=y
 CONFIG_EXT2_FS=y
 CONFIG_EXT2_FS_XATTR=y
 CONFIG_EXT2_FS_POSIX_ACL=y

-- 
2.54.0

[PATCH v3 05/11] m68k: add DAC modules base addresses

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Add DAC controller 0 and 1 base addresses.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
 arch/m68k/include/asm/m5441xsim.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/m68k/include/asm/m5441xsim.h b/arch/m68k/include/asm/m5441xsim.h
index f48cf63bd782..f5acc962bb95 100644
--- a/arch/m68k/include/asm/m5441xsim.h
+++ b/arch/m68k/include/asm/m5441xsim.h
@@ -191,6 +191,11 @@
 #define MCFEPORT_EPPAR		0xfc090000
 #define MCFEPORT_EPIER		0xfc090003
 #define MCFEPORT_EPFR		0xfc090006
+/*
+ * DAC Modules.
+ */
+#define MCFDAC_BASE0		0xfc098000
+#define MCFDAC_BASE1		0xfc09c000
 /*
  *  RTC Module.
  */

-- 
2.54.0

[PATCH v3 06/11] m68k: mcf5441x: add CCM registers

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Add CCM module register offsets.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
 arch/m68k/include/asm/m5441xsim.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/m68k/include/asm/m5441xsim.h b/arch/m68k/include/asm/m5441xsim.h
index f5acc962bb95..9ce2cbb05316 100644
--- a/arch/m68k/include/asm/m5441xsim.h
+++ b/arch/m68k/include/asm/m5441xsim.h
@@ -125,6 +125,26 @@
 #define MCFPM_PPMHR1		0xfc040038
 #define MCFPM_PPMLR1		0xfc04003c
 #define MCFPM_LPCR		0xec090007
+
+/*
+ * Chip Configuration Module (CCM).
+ */
+#define MCF_CCM_CCR		0xec090004
+#define MCF_CCM_RCON		0xec090008
+#define MCF_CCM_CIR		0xec09000a
+#define MCF_CCM_MISCCR		0xec09000e
+#define MCF_CCM_CDRH		0xec090010
+#define MCF_CCM_CDRL		0xec090012
+#define MCF_CCM_UOCSR		0xec090014
+#define MCF_CCM_UHCSR		0xec090016
+#define MCF_CCM_MISCCR3		0xec090018
+#define MCF_CCM_MISCCR2		0xec09001a
+#define MCF_CCM_ADCTSR		0xec09001c
+#define MCF_CCM_DACTSR		0xec09001e
+#define MCF_CCM_SBFSR		0xec090020
+#define MCF_CCM_SBFCR		0xec090022
+#define MCF_CCM_FNACR		0xec090024
+
 /*
  *  UART module.
  */

-- 
2.54.0

[PATCH v3 07/11] m68k: mcf5441x: add CCR MISCCR2 bitfields

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Add CCR MISCCR2 register bitfields.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
Changes in v2:
- add "iwyu" include for BIT and GENMASK
- fix MCF_CCM_MISCCR2_PLL_MODE bitfield
---
 arch/m68k/include/asm/m5441xsim.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/m68k/include/asm/m5441xsim.h b/arch/m68k/include/asm/m5441xsim.h
index 9ce2cbb05316..ea01c7753b7b 100644
--- a/arch/m68k/include/asm/m5441xsim.h
+++ b/arch/m68k/include/asm/m5441xsim.h
@@ -8,6 +8,8 @@
 #ifndef m5441xsim_h
 #define m5441xsim_h
 
+#include <linux/bits.h>
+
 #define CPU_NAME		"COLDFIRE(m5441x)"
 #define CPU_INSTR_PER_JIFFY	2
 #define MCF_BUSCLK		(MCF_CLK / 2)
@@ -145,6 +147,21 @@
 #define MCF_CCM_SBFCR		0xec090022
 #define MCF_CCM_FNACR		0xec090024
 
+/* Bit definitions and macros for MCF_CCM_MISCCR2 */
+#define MCF_CCM_MISCCR2_ULPI		BIT(0)
+#define MCF_CCM_MISCCR2_FB_HALF		BIT(1)
+#define MCF_CCM_MISCCR2_ADC3_EN		BIT(2)
+#define MCF_CCM_MISCCR2_ADC7_EN		BIT(3)
+#define MCF_CCM_MISCCR2_ADC_EN		BIT(4)
+#define MCF_CCM_MISCCR2_DAC0_SEL	BIT(5)
+#define MCF_CCM_MISCCR2_DAC1_SEL	BIT(6)
+#define MCF_CCM_MISCCR2_DCC_BYP		BIT(7)
+#define MCF_CCM_MISCCR2_PLL_MODE	GENMASK(10, 8)
+#define MCF_CCM_MISCCR2_SWT_SCR		BIT(12)
+#define MCF_CCM_MISCCR2_RGPIO_HALF	BIT(13)
+#define MCF_CCM_MISCCR2_DDR2_CLK	BIT(14)
+#define MCF_CCM_MISCCR2_EXTCLK_BYP	BIT(15)
+
 /*
  *  UART module.
  */

-- 
2.54.0

[PATCH v3 08/11] m68k: stmark2: use ioport.h macros for resources

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Change resource declaration using DEFINE_RES_*() macros.
DEFINE_DMA_RES() is for a single dma channel, not a range, so used twice.

Also, some drivers assume IRQ resources are from index 1, so just to stay
uniform, moved IRQ resource at index 1.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
Changes in v2:
- none
Changes in v3:
- moved this patch (cleanup) before adding new resources
- moved IRQ resource to index pos 1
---
 arch/m68k/coldfire/stmark2.c | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/arch/m68k/coldfire/stmark2.c b/arch/m68k/coldfire/stmark2.c
index 9263b77bd09a..536252ccb87e 100644
--- a/arch/m68k/coldfire/stmark2.c
+++ b/arch/m68k/coldfire/stmark2.c
@@ -62,21 +62,10 @@ static struct fsl_dspi_platform_data dspi_spi0_info = {
 };
 
 static struct resource dspi_spi0_resource[] = {
-	[0] = {
-		.start = MCFDSPI_BASE0,
-		.end   = MCFDSPI_BASE0 + 0xFF,
-		.flags = IORESOURCE_MEM,
-		},
-	[1] = {
-		.start = 12,
-		.end   = 13,
-		.flags = IORESOURCE_DMA,
-	},
-	[2] = {
-		.start = MCF_IRQ_DSPI0,
-		.end   = MCF_IRQ_DSPI0,
-		.flags = IORESOURCE_IRQ,
-	},
+	DEFINE_RES_MEM(MCFDSPI_BASE0, 0x100),
+	DEFINE_RES_IRQ(MCF_IRQ_DSPI0),
+	DEFINE_RES_DMA(12),
+	DEFINE_RES_DMA(13),
 };
 
 static u64 stmark2_dspi_mask = DMA_BIT_MASK(32);

-- 
2.54.0

[PATCH v3 09/11] m68k: stmark2: add mcf5441x DAC platform devices

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Add mcf5441x DAC platform devices.

Reviewed-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
Changes in v2:
- fix copy-paste error on naming
- use DEFINE_RES()
Changes in v3:
- simplified DACs as single resource entries in place of an array
---
 arch/m68k/coldfire/stmark2.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/m68k/coldfire/stmark2.c b/arch/m68k/coldfire/stmark2.c
index 536252ccb87e..d3be4b2953fd 100644
--- a/arch/m68k/coldfire/stmark2.c
+++ b/arch/m68k/coldfire/stmark2.c
@@ -8,6 +8,7 @@
  * for more details.
  */
 
+#include <linux/ioport.h>
 #include <linux/platform_device.h>
 #include <linux/mtd/partitions.h>
 #include <linux/spi/spi.h>
@@ -83,8 +84,28 @@ static struct platform_device dspi_spi0_device = {
 	},
 };
 
+static struct resource dac0_resource = DEFINE_RES_MEM(MCFDAC_BASE0, 0x100);
+
+static struct platform_device dac0_device = {
+	.name = "mcf54415_dac",
+	.id = 0,
+	.num_resources = 1,
+	.resource = &dac0_resource,
+};
+
+static struct resource dac1_resource = DEFINE_RES_MEM(MCFDAC_BASE1, 0x100);
+
+static struct platform_device dac1_device = {
+	.name = "mcf54415_dac",
+	.id = 1,
+	.num_resources = 1,
+	.resource = &dac1_resource,
+};
+
 static struct platform_device *stmark2_devices[] __initdata = {
 	&dspi_spi0_device,
+	&dac0_device,
+	&dac1_device,
 };
 
 /*

-- 
2.54.0

[PATCH v3 10/11] m68k: stmark2: enable DACs outputs

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Enabled DAC0 and DAC1 outpus disabling shared ADC inputs on ADC3 and ADC7.

Reviewed-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
Changes in v2:
- using mcf_read16/mcf_write16
- remove unuseful comment
---
 arch/m68k/coldfire/stmark2.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/m68k/coldfire/stmark2.c b/arch/m68k/coldfire/stmark2.c
index d3be4b2953fd..8aa9286e85d2 100644
--- a/arch/m68k/coldfire/stmark2.c
+++ b/arch/m68k/coldfire/stmark2.c
@@ -113,6 +113,8 @@ static struct platform_device *stmark2_devices[] __initdata = {
  */
 static int __init init_stmark2(void)
 {
+	u16 val;
+
 	/* DSPI0, all pins as DSPI, and using CS1 */
 	mcf_write8(0x80, MCFGPIO_PAR_DSPIOWL);
 	mcf_write8(0xfc, MCFGPIO_PAR_DSPIOWH);
@@ -125,6 +127,11 @@ static int __init init_stmark2(void)
 	/* CAN pads */
 	mcf_write8(0x50, MCFGPIO_PAR_CANI2C);
 
+	val = mcf_read16(MCF_CCM_MISCCR2);
+	val &= ~(MCF_CCM_MISCCR2_ADC3_EN | MCF_CCM_MISCCR2_ADC7_EN);
+	val |= MCF_CCM_MISCCR2_DAC0_SEL | MCF_CCM_MISCCR2_DAC1_SEL;
+	mcf_write16(val, MCF_CCM_MISCCR2);
+
 	platform_add_devices(stmark2_devices, ARRAY_SIZE(stmark2_devices));
 
 	spi_register_board_info(stmark2_board_info,

-- 
2.54.0

[PATCH v3 11/11] iio: dac: add mcf54415 DAC

[Angelo Dureghello]

From: Angelo Dureghello <adureghello@baylibre.com>

Add basic version of mcf54415 DAC driver. DAC is embedded in the cpu and
DAC configuration registers are mapped in the internal IO address space.

The DAC accepts a 12-bit digital signal and creates a monotonic 12-bit
analog output varying from DAC_VREFL to DAC_VREFH. The DAC module
consists of a conversion unit, an output amplifier, and the associated
digital control blocks. Default register values for DAC_VREFL and DAC_VREFH
are respectively 0 and 0xfff, left untouched in this initial version.

This initial version of the driver is minimalistic, "output raw" only, to
be extended in the future. DMA and external sync are disabled, default mode
is high speed, default format is right-justified 12bit on 16bit word.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
---
Changes in v2:
- remove tests from commit message, moved to patch 0
- remove additional blank lines
- remove dead code and unused definitions
- use regmap
- add limit check on raw write
- non functional style fixes
- add COMPILE_TEST to Kconfig
Changes in v3:
- add comments where needed
- code style changes
- remove unneeded variables
- use regmap_set_bits where possible
- remove macro not needed to define a single channel
- set up regmap to big_endian accesses for next patches that will come,
  that will adjust ColdFire readx/writex as standard LE (links in 0/x).
- add return value check on regmap calls
- sashiko: remove unneeded .io_port from regmap init.
- sashiko: add select REGMAP_MMIO in Kconfig
---
 drivers/iio/dac/Kconfig        |  11 +++
 drivers/iio/dac/Makefile       |   1 +
 drivers/iio/dac/mcf54415_dac.c | 207 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 219 insertions(+)

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index cd4870b65415..b1a578076188 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -516,6 +516,17 @@ config MAX5821
 	  Say yes here to build support for Maxim MAX5821
 	  10 bits DAC.
 
+config MCF54415_DAC
+	tristate "NXP MCF54415 DAC driver"
+	depends on M5441x || COMPILE_TEST
+	select REGMAP_MMIO
+	help
+	  Say yes here to build support for NXP MCF54415
+	  12bit DAC.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called mcf54415_dac.
+
 config MCP4725
 	tristate "MCP4725/6 DAC driver"
 	depends on I2C
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index 2a80bbf4e80a..1cb93e83d0eb 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_MAX517) += max517.o
 obj-$(CONFIG_MAX22007) += max22007.o
 obj-$(CONFIG_MAX5522) += max5522.o
 obj-$(CONFIG_MAX5821) += max5821.o
+obj-$(CONFIG_MCF54415_DAC) += mcf54415_dac.o
 obj-$(CONFIG_MCP4725) += mcp4725.o
 obj-$(CONFIG_MCP4728) += mcp4728.o
 obj-$(CONFIG_MCP47FEB02) += mcp47feb02.o
diff --git a/drivers/iio/dac/mcf54415_dac.c b/drivers/iio/dac/mcf54415_dac.c
new file mode 100644
index 000000000000..c8c87572d43d
--- /dev/null
+++ b/drivers/iio/dac/mcf54415_dac.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * NXP mcf54415 DAC driver
+ *
+ * Copyright 2026 BayLibre - adureghello@baylibre.com
+ */
+
+#include <linux/array_size.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/compiler_types.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <linux/iio/iio.h>
+
+#define MCF54415_DAC_CR			0x00
+#define MCF54415_DAC_CR_PDN		BIT(0)
+#define MCF54415_DAC_CR_HSLS		BIT(6)
+#define MCF54415_DAC_CR_WMLVL		GENMASK(9, 8)
+#define MCF54415_DAC_CR_FILT		BIT(12)
+
+#define MCF54415_DAC_DATA		0x02
+
+struct mcf54415_dac {
+	struct regmap *map;
+	struct clk *clk;
+};
+
+static const struct regmap_config mcf54415_dac_regmap_config = {
+	.reg_bits = 16,
+	.reg_stride = 2,
+	.val_bits = 16,
+	.max_register = 0x0c, /* DACX_FILTCNT,  R.M. Table 30-2 */
+	.val_format_endian = REGMAP_ENDIAN_BIG,
+	.reg_format_endian = REGMAP_ENDIAN_BIG,
+};
+
+static int mcf54415_dac_init(struct mcf54415_dac *info)
+{
+	int ret;
+
+	/* Keeping defaults and enable DAC (bit 0 set to 0) */
+	ret = regmap_write(info->map, MCF54415_DAC_CR, MCF54415_DAC_CR_FILT |
+			   FIELD_PREP(MCF54415_DAC_CR_WMLVL, 1));
+	if (ret)
+		return ret;
+
+	/* DAC is ready after 12us, from RM table 40-3  */
+	fsleep(12);
+
+	return 0;
+}
+
+static void mcf54415_dac_exit(void *data)
+{
+	struct mcf54415_dac *info = data;
+
+	regmap_set_bits(info->map, MCF54415_DAC_CR, MCF54415_DAC_CR_PDN);
+}
+
+static const struct iio_chan_spec mcf54415_dac_iio_channel = {
+	.type = IIO_VOLTAGE,
+	.output = 1,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+};
+
+static int mcf54415_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int *val, int *val2, long mask)
+{
+	struct mcf54415_dac *info = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = regmap_read(info->map, MCF54415_DAC_DATA, val);
+		if (ret)
+			return -EIO;
+		*val &= 0xfff;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		/* Reference voltage as per ColdFire datasheet is 3.3V */
+		*val = 3300 /* mV */;
+		*val2 = 12;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mcf54415_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int val, int val2, long mask)
+{
+	struct mcf54415_dac *info = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		/* Check based on RM 30.3.2 (DACn_DATA) reg. resolution */
+		if (val < 0 || val > 4095)
+			return -EINVAL;
+		return regmap_write(info->map, MCF54415_DAC_DATA, val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info mcf54415_dac_iio_info = {
+	.read_raw = &mcf54415_read_raw,
+	.write_raw = &mcf54415_write_raw,
+};
+
+static int mcf54415_dac_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct iio_dev *indio_dev;
+	struct mcf54415_dac *info;
+	void __iomem *regs;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*info));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	info = iio_priv(indio_dev);
+
+	regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(regs))
+		return dev_err_probe(dev, PTR_ERR(regs),
+				     "failed to get io regs\n");
+
+	info->map = devm_regmap_init_mmio(dev, regs,
+					  &mcf54415_dac_regmap_config);
+	if (IS_ERR(info->map))
+		return PTR_ERR(info->map);
+
+	info->clk = devm_clk_get_enabled(dev, "dac");
+	if (IS_ERR(info->clk))
+		return dev_err_probe(dev, PTR_ERR(info->clk),
+				     "failed getting clock\n");
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	indio_dev->name = "mcf54415";
+	indio_dev->info = &mcf54415_dac_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = &mcf54415_dac_iio_channel;
+	indio_dev->num_channels = 1;
+
+	ret = mcf54415_dac_init(info);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, mcf54415_dac_exit, info);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static int mcf54415_dac_suspend(struct device *dev)
+{
+	struct mcf54415_dac *info = iio_priv(dev_get_drvdata(dev));
+
+	mcf54415_dac_exit(info);
+	clk_disable_unprepare(info->clk);
+
+	return 0;
+}
+
+static int mcf54415_dac_resume(struct device *dev)
+{
+	struct mcf54415_dac *info = iio_priv(dev_get_drvdata(dev));
+	int ret;
+
+	ret = clk_prepare_enable(info->clk);
+	if (ret)
+		return ret;
+
+	mcf54415_dac_init(info);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(mcf54415_dac_pm_ops,
+				mcf54415_dac_suspend, mcf54415_dac_resume);
+
+static struct platform_driver mcf54415_dac_driver = {
+	.probe = mcf54415_dac_probe,
+	.driver = {
+		.name = "mcf54415_dac",
+		.pm = pm_sleep_ptr(&mcf54415_dac_pm_ops),
+	},
+};
+module_platform_driver(mcf54415_dac_driver);
+
+MODULE_AUTHOR("Angelo Dureghello <angelo@kernel-space.org>");
+MODULE_DESCRIPTION("NXP MCF54415 DAC driver");
+MODULE_LICENSE("GPL");

-- 
2.54.0

Re: [PATCH v3 11/11] iio: dac: add mcf54415 DAC

[Jonathan Cameron]

On Fri, 22 May 2026 23:20:39 +0200
Angelo Dureghello <adureghello@baylibre.com> wrote:

> From: Angelo Dureghello <adureghello@baylibre.com>
> 
> Add basic version of mcf54415 DAC driver. DAC is embedded in the cpu and
> DAC configuration registers are mapped in the internal IO address space.
> 
> The DAC accepts a 12-bit digital signal and creates a monotonic 12-bit
> analog output varying from DAC_VREFL to DAC_VREFH. The DAC module
> consists of a conversion unit, an output amplifier, and the associated
> digital control blocks. Default register values for DAC_VREFL and DAC_VREFH
> are respectively 0 and 0xfff, left untouched in this initial version.
> 
> This initial version of the driver is minimalistic, "output raw" only, to
> be extended in the future. DMA and external sync are disabled, default mode
> is high speed, default format is right-justified 12bit on 16bit word.
> 
> Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
https://sashiko.dev/#/patchset/20260522-wip-stmark2-dac-v3-0-16be0ad35a67%40baylibre.com

Given there were only a couple of comments I've included them below alongside
my review.  All minor stuff.

Thanks,

Jonathan

> ---
> Changes in v2:
> - remove tests from commit message, moved to patch 0
> - remove additional blank lines
> - remove dead code and unused definitions
> - use regmap
> - add limit check on raw write
> - non functional style fixes
> - add COMPILE_TEST to Kconfig
> Changes in v3:
> - add comments where needed
> - code style changes
> - remove unneeded variables
> - use regmap_set_bits where possible
> - remove macro not needed to define a single channel
> - set up regmap to big_endian accesses for next patches that will come,
>   that will adjust ColdFire readx/writex as standard LE (links in 0/x).
> - add return value check on regmap calls
> - sashiko: remove unneeded .io_port from regmap init.
> - sashiko: add select REGMAP_MMIO in Kconfig

Looks like you missed or disagreed with the previous sashiko comment on v2 about
type passed to regmap_read()

> ---
>  drivers/iio/dac/Kconfig        |  11 +++
>  drivers/iio/dac/Makefile       |   1 +
>  drivers/iio/dac/mcf54415_dac.c | 207 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 219 insertions(+)
> 
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index cd4870b65415..b1a578076188 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -516,6 +516,17 @@ config MAX5821
>  	  Say yes here to build support for Maxim MAX5821
>  	  10 bits DAC.
>  
> +config MCF54415_DAC
> +	tristate "NXP MCF54415 DAC driver"
> +	depends on M5441x || COMPILE_TEST
> +	select REGMAP_MMIO
> +	help
> +	  Say yes here to build support for NXP MCF54415
> +	  12bit DAC.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called mcf54415_dac.
> +

> diff --git a/drivers/iio/dac/mcf54415_dac.c b/drivers/iio/dac/mcf54415_dac.c
> new file mode 100644
> index 000000000000..c8c87572d43d
> --- /dev/null
> +++ b/drivers/iio/dac/mcf54415_dac.c
> @@ -0,0 +1,207 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * NXP mcf54415 DAC driver
> + *
> + * Copyright 2026 BayLibre - adureghello@baylibre.com
> + */
> +
> +#include <linux/array_size.h>
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/clk.h>
> +#include <linux/compiler_types.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>

not seeing any use of this. I guess it 'evolved' away.
Anyhow, please sanity check these all one more time for v4.

> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#include <linux/iio/iio.h>
> +
> +#define MCF54415_DAC_CR			0x00
> +#define MCF54415_DAC_CR_PDN		BIT(0)
> +#define MCF54415_DAC_CR_HSLS		BIT(6)
> +#define MCF54415_DAC_CR_WMLVL		GENMASK(9, 8)
> +#define MCF54415_DAC_CR_FILT		BIT(12)
> +
> +#define MCF54415_DAC_DATA		0x02
> +
> +struct mcf54415_dac {
> +	struct regmap *map;
> +	struct clk *clk;
> +};
> +
> +static const struct regmap_config mcf54415_dac_regmap_config = {
> +	.reg_bits = 16,
> +	.reg_stride = 2,
> +	.val_bits = 16,
> +	.max_register = 0x0c, /* DACX_FILTCNT,  R.M. Table 30-2 */
> +	.val_format_endian = REGMAP_ENDIAN_BIG,
> +	.reg_format_endian = REGMAP_ENDIAN_BIG,
> +};
> +
> +static int mcf54415_dac_init(struct mcf54415_dac *info)
> +{
> +	int ret;
> +
> +	/* Keeping defaults and enable DAC (bit 0 set to 0) */
> +	ret = regmap_write(info->map, MCF54415_DAC_CR, MCF54415_DAC_CR_FILT |
> +			   FIELD_PREP(MCF54415_DAC_CR_WMLVL, 1));

Perhaps use a local variable. It is a tiny bit too easy to miss that
parameter being split over two lines.

	u16 val = MCF54415_DAC_CR_FILT | FIELD_PREP(MCF54415_DAC_CR_WMLVL, 1);

would avoid that.

Alternatively perhaps just reflowing as:
	ret = regmap_write(info->map, MCF54415_DAC_CR,
			   MCF54415_DAC_CR_FILT |
			   FIELD_PREP(MCF54415_DAC_CR_WMLVL, 1));

avoids that reading issue (I read it wrong ;)



> +	if (ret)
> +		return ret;
> +
> +	/* DAC is ready after 12us, from RM table 40-3  */
> +	fsleep(12);
> +
> +	return 0;
> +}

> +
> +static int mcf54415_read_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int *val, int *val2, long mask)
> +{
> +	struct mcf54415_dac *info = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		ret = regmap_read(info->map, MCF54415_DAC_DATA, val);

Sashiko pointed out that regmap_read() expects a u32* so this should use
a local variable for the read.

> +		if (ret)
> +			return -EIO;

Another one sashiko got. Why is this eating the possibly more useful error
code from regmap_read()?

> +		*val &= 0xfff;
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		/* Reference voltage as per ColdFire datasheet is 3.3V */
> +		*val = 3300 /* mV */;
> +		*val2 = 12;
> +		return IIO_VAL_FRACTIONAL_LOG2;
> +	default:
> +		return -EINVAL;
> +	}
> +}

> +static int mcf54415_dac_resume(struct device *dev)
> +{
> +	struct mcf54415_dac *info = iio_priv(dev_get_drvdata(dev));
> +	int ret;
> +
> +	ret = clk_prepare_enable(info->clk);
> +	if (ret)
> +		return ret;
> +
> +	mcf54415_dac_init(info);
If this fails should we report it?  I think you'd at least want
some print to help with debug. (Sashiko got this)

> +
> +	return 0;
> +}

Re: [PATCH v3 11/11] iio: dac: add mcf54415 DAC

[Angelo Dureghello]

Hi Jonathan,

On Tue, May 26, 2026 at 02:30:50PM +0100, Jonathan Cameron wrote:
> On Fri, 22 May 2026 23:20:39 +0200
> Angelo Dureghello <adureghello@baylibre.com> wrote:
>
> > From: Angelo Dureghello <adureghello@baylibre.com>
> >
> > Add basic version of mcf54415 DAC driver. DAC is embedded in the cpu and
> > DAC configuration registers are mapped in the internal IO address space.
> >
> > The DAC accepts a 12-bit digital signal and creates a monotonic 12-bit
> > analog output varying from DAC_VREFL to DAC_VREFH. The DAC module
> > consists of a conversion unit, an output amplifier, and the associated
> > digital control blocks. Default register values for DAC_VREFL and DAC_VREFH
> > are respectively 0 and 0xfff, left untouched in this initial version.
> >
> > This initial version of the driver is minimalistic, "output raw" only, to
> > be extended in the future. DMA and external sync are disabled, default mode
> > is high speed, default format is right-justified 12bit on 16bit word.
> >
> > Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> https://sashiko.dev/#/patchset/20260522-wip-stmark2-dac-v3-0-16be0ad35a67%40baylibre.com
>
> Given there were only a couple of comments I've included them below alongside
> my review.  All minor stuff.
>
> Thanks,
>
> Jonathan
>
> > ---
> > Changes in v2:
> > - remove tests from commit message, moved to patch 0
> > - remove additional blank lines
> > - remove dead code and unused definitions
> > - use regmap
> > - add limit check on raw write
> > - non functional style fixes
> > - add COMPILE_TEST to Kconfig
> > Changes in v3:
> > - add comments where needed
> > - code style changes
> > - remove unneeded variables
> > - use regmap_set_bits where possible
> > - remove macro not needed to define a single channel
> > - set up regmap to big_endian accesses for next patches that will come,
> >   that will adjust ColdFire readx/writex as standard LE (links in 0/x).
> > - add return value check on regmap calls
> > - sashiko: remove unneeded .io_port from regmap init.
> > - sashiko: add select REGMAP_MMIO in Kconfig
>
> Looks like you missed or disagreed with the previous sashiko comment on v2 about
> type passed to regmap_read()
>

Sahiko asks if regmap_read produces a compiler watning.
I don't see any,

> > ---
> >  drivers/iio/dac/Kconfig        |  11 +++
> >  drivers/iio/dac/Makefile       |   1 +
> >  drivers/iio/dac/mcf54415_dac.c | 207 +++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 219 insertions(+)
> >
> > diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> > index cd4870b65415..b1a578076188 100644
> > --- a/drivers/iio/dac/Kconfig
> > +++ b/drivers/iio/dac/Kconfig
> > @@ -516,6 +516,17 @@ config MAX5821
> >  	  Say yes here to build support for Maxim MAX5821
> >  	  10 bits DAC.
> >
> > +config MCF54415_DAC
> > +	tristate "NXP MCF54415 DAC driver"
> > +	depends on M5441x || COMPILE_TEST
> > +	select REGMAP_MMIO
> > +	help
> > +	  Say yes here to build support for NXP MCF54415
> > +	  12bit DAC.
> > +
> > +	  To compile this driver as a module, choose M here: the module
> > +	  will be called mcf54415_dac.
> > +
>
> > diff --git a/drivers/iio/dac/mcf54415_dac.c b/drivers/iio/dac/mcf54415_dac.c
> > new file mode 100644
> > index 000000000000..c8c87572d43d
> > --- /dev/null
> > +++ b/drivers/iio/dac/mcf54415_dac.c
> > @@ -0,0 +1,207 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * NXP mcf54415 DAC driver
> > + *
> > + * Copyright 2026 BayLibre - adureghello@baylibre.com
> > + */
> > +
> > +#include <linux/array_size.h>
> > +#include <linux/bitfield.h>
> > +#include <linux/bits.h>
> > +#include <linux/clk.h>
> > +#include <linux/compiler_types.h>
> > +#include <linux/delay.h>
> > +#include <linux/err.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
>
> not seeing any use of this. I guess it 'evolved' away.
> Anyhow, please sanity check these all one more time for v4.
>

thanks,
removed it and also linux/array_size.h that's unused now.

> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +
> > +#include <linux/iio/iio.h>
> > +
> > +#define MCF54415_DAC_CR			0x00
> > +#define MCF54415_DAC_CR_PDN		BIT(0)
> > +#define MCF54415_DAC_CR_HSLS		BIT(6)
> > +#define MCF54415_DAC_CR_WMLVL		GENMASK(9, 8)
> > +#define MCF54415_DAC_CR_FILT		BIT(12)
> > +
> > +#define MCF54415_DAC_DATA		0x02
> > +
> > +struct mcf54415_dac {
> > +	struct regmap *map;
> > +	struct clk *clk;
> > +};
> > +
> > +static const struct regmap_config mcf54415_dac_regmap_config = {
> > +	.reg_bits = 16,
> > +	.reg_stride = 2,
> > +	.val_bits = 16,
> > +	.max_register = 0x0c, /* DACX_FILTCNT,  R.M. Table 30-2 */
> > +	.val_format_endian = REGMAP_ENDIAN_BIG,
> > +	.reg_format_endian = REGMAP_ENDIAN_BIG,
> > +};
> > +
> > +static int mcf54415_dac_init(struct mcf54415_dac *info)
> > +{
> > +	int ret;
> > +
> > +	/* Keeping defaults and enable DAC (bit 0 set to 0) */
> > +	ret = regmap_write(info->map, MCF54415_DAC_CR, MCF54415_DAC_CR_FILT |
> > +			   FIELD_PREP(MCF54415_DAC_CR_WMLVL, 1));
>
> Perhaps use a local variable. It is a tiny bit too easy to miss that
> parameter being split over two lines.
>
> 	u16 val = MCF54415_DAC_CR_FILT | FIELD_PREP(MCF54415_DAC_CR_WMLVL, 1);
>
> would avoid that.

ack, done.

>
> Alternatively perhaps just reflowing as:
> 	ret = regmap_write(info->map, MCF54415_DAC_CR,
> 			   MCF54415_DAC_CR_FILT |
> 			   FIELD_PREP(MCF54415_DAC_CR_WMLVL, 1));
>
> avoids that reading issue (I read it wrong ;)
>
>
>
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* DAC is ready after 12us, from RM table 40-3  */
> > +	fsleep(12);
> > +
> > +	return 0;
> > +}
>
> > +
> > +static int mcf54415_read_raw(struct iio_dev *indio_dev,
> > +			     struct iio_chan_spec const *chan,
> > +			     int *val, int *val2, long mask)
> > +{
> > +	struct mcf54415_dac *info = iio_priv(indio_dev);
> > +	int ret;
> > +
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_RAW:
> > +		ret = regmap_read(info->map, MCF54415_DAC_DATA, val);
>
> Sashiko pointed out that regmap_read() expects a u32* so this should use
> a local variable for the read.
>

Sashiko asked if this is causing a warning. I don't see any.
Register read is a 16bit reg, and the valid 12bits are masked just after
to ensure returned value is always correct.

So can stay as is, or to make sashiko happy i can do something as:

	struct mcf54415_dac *info = iio_priv(indio_dev);
	int ret;
	u32 reg;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = regmap_read(info->map, MCF54415_DAC_DATA, &reg);
		if (ret)
			return -EIO;
		*val = reg & 0xfff;
		return IIO_VAL_INT;

> > +		if (ret)
> > +			return -EIO;
>
> Another one sashiko got. Why is this eating the possibly more useful error
> code from regmap_read()?
>

fixed with return ret

> > +		*val &= 0xfff;
> > +		return IIO_VAL_INT;
> > +	case IIO_CHAN_INFO_SCALE:
> > +		/* Reference voltage as per ColdFire datasheet is 3.3V */
> > +		*val = 3300 /* mV */;
> > +		*val2 = 12;
> > +		return IIO_VAL_FRACTIONAL_LOG2;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +}
>
> > +static int mcf54415_dac_resume(struct device *dev)
> > +{
> > +	struct mcf54415_dac *info = iio_priv(dev_get_drvdata(dev));
> > +	int ret;
> > +
> > +	ret = clk_prepare_enable(info->clk);
> > +	if (ret)
> > +		return ret;
> > +
> > +	mcf54415_dac_init(info);
> If this fails should we report it?  I think you'd at least want
> some print to help with debug. (Sashiko got this)
>

Ok, so doing


	ret = mcf54415_dac_init(info);

	if (ret) {
		dev_err(dev, "could not resume device\n");
		return ret;
	}



> > +
> > +	return 0;
> > +}
>
>

Regards,
angelo