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* [PATCH v2 1/1] mfd: simple-mfd-i2c: Add support for registering devices via MFD cells
@ 2021-08-05  8:56 Lee Jones
  2021-08-05 10:01 ` Michael Walle
  2021-08-06  8:19 ` Alistair Francis
  0 siblings, 2 replies; 5+ messages in thread
From: Lee Jones @ 2021-08-05  8:56 UTC (permalink / raw)
  To: lee.jones
  Cc: linux-arm-kernel, linux-kernel, Michael Walle, Mark Brown,
	Alistair Francis

More devices are cropping up requiring only Regmap initialisation and
child registration functionality.  We currently only support that if
all required devices are represented by their own Device Tree nodes
complete with compatible strings.

However, not everyone is happy with adding empty nodes that provide no
additional device information into the Device Tree.

Rather than have a plethora of mostly empty, function-less drivers in
MFD, we'll support those simple cases in here instead via MFD cells.

Cc: Michael Walle <michael@walle.cc>
Cc: Mark Brown <broonie@kernel.org>
Cc: Alistair Francis <alistair23@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
v2:
 - Check for empty of_device_id .data entry 

 drivers/mfd/simple-mfd-i2c.c | 41 +++++++++++++++++++++++++++++-------
 drivers/mfd/simple-mfd-i2c.h | 32 ++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 8 deletions(-)
 create mode 100644 drivers/mfd/simple-mfd-i2c.h

diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
index 87f684cff9a17..583e8c7924af0 100644
--- a/drivers/mfd/simple-mfd-i2c.c
+++ b/drivers/mfd/simple-mfd-i2c.c
@@ -2,39 +2,64 @@
 /*
  * Simple MFD - I2C
  *
+ * Author(s):
+ * 	Michael Walle <michael@walle.cc>
+ * 	Lee Jones <lee.jones@linaro.org>
+ *
  * This driver creates a single register map with the intention for it to be
  * shared by all sub-devices.  Children can use their parent's device structure
  * (dev.parent) in order to reference it.
  *
  * Once the register map has been successfully initialised, any sub-devices
- * represented by child nodes in Device Tree will be subsequently registered.
+ * represented by child nodes in Device Tree or via the MFD cells in this file
+ * will be subsequently registered.
  */
 
 #include <linux/i2c.h>
 #include <linux/kernel.h>
+#include <linux/mfd/core.h>
 #include <linux/module.h>
 #include <linux/of_platform.h>
 #include <linux/regmap.h>
 
-static const struct regmap_config simple_regmap_config = {
+#include "simple-mfd-i2c.h"
+
+static const struct regmap_config regmap_config_8r_8v = {
 	.reg_bits = 8,
 	.val_bits = 8,
 };
 
 static int simple_mfd_i2c_probe(struct i2c_client *i2c)
 {
-	const struct regmap_config *config;
+	const struct simple_mfd_data *simple_mfd_data;
+	const struct regmap_config *regmap_config;
 	struct regmap *regmap;
+	int ret;
+
+	simple_mfd_data = device_get_match_data(&i2c->dev);
 
-	config = device_get_match_data(&i2c->dev);
-	if (!config)
-		config = &simple_regmap_config;
+	/* If no regmap_config is specified, use the default 8reg and 8val bits */
+	if (!simple_mfd_data || !simple_mfd_data->regmap_config)
+		regmap_config = &regmap_config_8r_8v;
+	else
+		regmap_config = simple_mfd_data->regmap_config;
 
-	regmap = devm_regmap_init_i2c(i2c, config);
+	regmap = devm_regmap_init_i2c(i2c, regmap_config);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
 
-	return devm_of_platform_populate(&i2c->dev);
+	/* If no MFD cells are spedified, use register the DT child nodes instead */
+	if (!simple_mfd_data || !simple_mfd_data->mfd_cell)
+		return devm_of_platform_populate(&i2c->dev);
+
+	ret = devm_mfd_add_devices(&i2c->dev, PLATFORM_DEVID_AUTO,
+				   simple_mfd_data->mfd_cell,
+				   simple_mfd_data->mfd_cell_size,
+				   NULL, 0, NULL);
+	if (!ret)
+		dev_err(&i2c->dev, "Failed to add child devices\n");
+
+	return ret;
 }
 
 static const struct of_device_id simple_mfd_i2c_of_match[] = {
diff --git a/drivers/mfd/simple-mfd-i2c.h b/drivers/mfd/simple-mfd-i2c.h
new file mode 100644
index 0000000000000..7cb2bdd347d97
--- /dev/null
+++ b/drivers/mfd/simple-mfd-i2c.h
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Simple MFD - I2C
+ *
+ * Author: Lee Jones <lee.jones@linaro.org>
+ *
+ * This driver creates a single register map with the intention for it to be
+ * shared by all sub-devices.  Children can use their parent's device structure
+ * (dev.parent) in order to reference it.
+ *
+ * This driver creates a single register map with the intention for it to be
+ * shared by all sub-devices.  Children can use their parent's device structure
+ * (dev.parent) in order to reference it.
+ *
+ * Once the register map has been successfully initialised, any sub-devices
+ * represented by child nodes in Device Tree or via the MFD cells in the
+ * associated C file will be subsequently registered.
+ */
+
+#ifndef __MFD_SIMPLE_MFD_I2C_H
+#define __MFD_SIMPLE_MFD_I2C_H
+
+#include <linux/mfd/core.h>
+#include <linux/regmap.h>
+
+struct simple_mfd_data {
+	const struct regmap_config *regmap_config;
+	const struct mfd_cell *mfd_cell;
+	size_t mfd_cell_size;
+};
+
+#endif /* __MFD_SIMPLE_MFD_I2C_H */
-- 
2.32.0.605.g8dce9f2422-goog


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2 1/1] mfd: simple-mfd-i2c: Add support for registering devices via MFD cells
  2021-08-05  8:56 [PATCH v2 1/1] mfd: simple-mfd-i2c: Add support for registering devices via MFD cells Lee Jones
@ 2021-08-05 10:01 ` Michael Walle
  2021-08-05 11:03   ` Lee Jones
  2021-08-06  8:19 ` Alistair Francis
  1 sibling, 1 reply; 5+ messages in thread
From: Michael Walle @ 2021-08-05 10:01 UTC (permalink / raw)
  To: Lee Jones; +Cc: linux-arm-kernel, linux-kernel, Mark Brown, Alistair Francis

Am 2021-08-05 10:56, schrieb Lee Jones:
> More devices are cropping up requiring only Regmap initialisation and
> child registration functionality.  We currently only support that if
> all required devices are represented by their own Device Tree nodes
> complete with compatible strings.
> 
> However, not everyone is happy with adding empty nodes that provide no
> additional device information into the Device Tree.
> 
> Rather than have a plethora of mostly empty, function-less drivers in
> MFD, we'll support those simple cases in here instead via MFD cells.
> 
> Cc: Michael Walle <michael@walle.cc>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Alistair Francis <alistair23@gmail.com>
> Signed-off-by: Lee Jones <lee.jones@linaro.org>

Tested-by: Michael Walle <michael@walle.cc>

-michael

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2 1/1] mfd: simple-mfd-i2c: Add support for registering devices via MFD cells
  2021-08-05 10:01 ` Michael Walle
@ 2021-08-05 11:03   ` Lee Jones
  0 siblings, 0 replies; 5+ messages in thread
From: Lee Jones @ 2021-08-05 11:03 UTC (permalink / raw)
  To: Michael Walle
  Cc: linux-arm-kernel, linux-kernel, Mark Brown, Alistair Francis

On Thu, 05 Aug 2021, Michael Walle wrote:

> Am 2021-08-05 10:56, schrieb Lee Jones:
> > More devices are cropping up requiring only Regmap initialisation and
> > child registration functionality.  We currently only support that if
> > all required devices are represented by their own Device Tree nodes
> > complete with compatible strings.
> > 
> > However, not everyone is happy with adding empty nodes that provide no
> > additional device information into the Device Tree.
> > 
> > Rather than have a plethora of mostly empty, function-less drivers in
> > MFD, we'll support those simple cases in here instead via MFD cells.
> > 
> > Cc: Michael Walle <michael@walle.cc>
> > Cc: Mark Brown <broonie@kernel.org>
> > Cc: Alistair Francis <alistair23@gmail.com>
> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> 
> Tested-by: Michael Walle <michael@walle.cc>

Good man.  Thank you Michael.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2 1/1] mfd: simple-mfd-i2c: Add support for registering devices via MFD cells
  2021-08-05  8:56 [PATCH v2 1/1] mfd: simple-mfd-i2c: Add support for registering devices via MFD cells Lee Jones
  2021-08-05 10:01 ` Michael Walle
@ 2021-08-06  8:19 ` Alistair Francis
  2021-08-06 11:41   ` Lee Jones
  1 sibling, 1 reply; 5+ messages in thread
From: Alistair Francis @ 2021-08-06  8:19 UTC (permalink / raw)
  To: Lee Jones
  Cc: linux-arm-kernel, Linux Kernel Mailing List, Michael Walle, Mark Brown

On Thu, Aug 5, 2021 at 6:56 PM Lee Jones <lee.jones@linaro.org> wrote:
>
> More devices are cropping up requiring only Regmap initialisation and
> child registration functionality.  We currently only support that if
> all required devices are represented by their own Device Tree nodes
> complete with compatible strings.
>
> However, not everyone is happy with adding empty nodes that provide no
> additional device information into the Device Tree.
>
> Rather than have a plethora of mostly empty, function-less drivers in
> MFD, we'll support those simple cases in here instead via MFD cells.
>
> Cc: Michael Walle <michael@walle.cc>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Alistair Francis <alistair23@gmail.com>
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
> v2:
>  - Check for empty of_device_id .data entry
>
>  drivers/mfd/simple-mfd-i2c.c | 41 +++++++++++++++++++++++++++++-------
>  drivers/mfd/simple-mfd-i2c.h | 32 ++++++++++++++++++++++++++++
>  2 files changed, 65 insertions(+), 8 deletions(-)
>  create mode 100644 drivers/mfd/simple-mfd-i2c.h
>
> diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
> index 87f684cff9a17..583e8c7924af0 100644
> --- a/drivers/mfd/simple-mfd-i2c.c
> +++ b/drivers/mfd/simple-mfd-i2c.c
> @@ -2,39 +2,64 @@
>  /*
>   * Simple MFD - I2C
>   *
> + * Author(s):
> + *     Michael Walle <michael@walle.cc>
> + *     Lee Jones <lee.jones@linaro.org>
> + *
>   * This driver creates a single register map with the intention for it to be
>   * shared by all sub-devices.  Children can use their parent's device structure
>   * (dev.parent) in order to reference it.
>   *
>   * Once the register map has been successfully initialised, any sub-devices
> - * represented by child nodes in Device Tree will be subsequently registered.
> + * represented by child nodes in Device Tree or via the MFD cells in this file
> + * will be subsequently registered.
>   */
>
>  #include <linux/i2c.h>
>  #include <linux/kernel.h>
> +#include <linux/mfd/core.h>
>  #include <linux/module.h>
>  #include <linux/of_platform.h>
>  #include <linux/regmap.h>
>
> -static const struct regmap_config simple_regmap_config = {
> +#include "simple-mfd-i2c.h"
> +
> +static const struct regmap_config regmap_config_8r_8v = {
>         .reg_bits = 8,
>         .val_bits = 8,
>  };
>
>  static int simple_mfd_i2c_probe(struct i2c_client *i2c)
>  {
> -       const struct regmap_config *config;
> +       const struct simple_mfd_data *simple_mfd_data;
> +       const struct regmap_config *regmap_config;
>         struct regmap *regmap;
> +       int ret;
> +
> +       simple_mfd_data = device_get_match_data(&i2c->dev);
>
> -       config = device_get_match_data(&i2c->dev);
> -       if (!config)
> -               config = &simple_regmap_config;
> +       /* If no regmap_config is specified, use the default 8reg and 8val bits */
> +       if (!simple_mfd_data || !simple_mfd_data->regmap_config)
> +               regmap_config = &regmap_config_8r_8v;
> +       else
> +               regmap_config = simple_mfd_data->regmap_config;
>
> -       regmap = devm_regmap_init_i2c(i2c, config);
> +       regmap = devm_regmap_init_i2c(i2c, regmap_config);
>         if (IS_ERR(regmap))
>                 return PTR_ERR(regmap);
>
> -       return devm_of_platform_populate(&i2c->dev);
> +       /* If no MFD cells are spedified, use register the DT child nodes instead */
> +       if (!simple_mfd_data || !simple_mfd_data->mfd_cell)
> +               return devm_of_platform_populate(&i2c->dev);
> +
> +       ret = devm_mfd_add_devices(&i2c->dev, PLATFORM_DEVID_AUTO,
> +                                  simple_mfd_data->mfd_cell,
> +                                  simple_mfd_data->mfd_cell_size,
> +                                  NULL, 0, NULL);
> +       if (!ret)

Shouldn't this be `if (ret)` instead?

With that changed this works for me as well:

Reviewed-by: Alistair Francis <alistair@alistair23.me>
Tested-by: Alistair Francis <alistair@alistair23.me>

Alistair

> +               dev_err(&i2c->dev, "Failed to add child devices\n");
> +
> +       return ret;
>  }
>
>  static const struct of_device_id simple_mfd_i2c_of_match[] = {
> diff --git a/drivers/mfd/simple-mfd-i2c.h b/drivers/mfd/simple-mfd-i2c.h
> new file mode 100644
> index 0000000000000..7cb2bdd347d97
> --- /dev/null
> +++ b/drivers/mfd/simple-mfd-i2c.h
> @@ -0,0 +1,32 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Simple MFD - I2C
> + *
> + * Author: Lee Jones <lee.jones@linaro.org>
> + *
> + * This driver creates a single register map with the intention for it to be
> + * shared by all sub-devices.  Children can use their parent's device structure
> + * (dev.parent) in order to reference it.
> + *
> + * This driver creates a single register map with the intention for it to be
> + * shared by all sub-devices.  Children can use their parent's device structure
> + * (dev.parent) in order to reference it.
> + *
> + * Once the register map has been successfully initialised, any sub-devices
> + * represented by child nodes in Device Tree or via the MFD cells in the
> + * associated C file will be subsequently registered.
> + */
> +
> +#ifndef __MFD_SIMPLE_MFD_I2C_H
> +#define __MFD_SIMPLE_MFD_I2C_H
> +
> +#include <linux/mfd/core.h>
> +#include <linux/regmap.h>
> +
> +struct simple_mfd_data {
> +       const struct regmap_config *regmap_config;
> +       const struct mfd_cell *mfd_cell;
> +       size_t mfd_cell_size;
> +};
> +
> +#endif /* __MFD_SIMPLE_MFD_I2C_H */
> --
> 2.32.0.605.g8dce9f2422-goog
>

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2 1/1] mfd: simple-mfd-i2c: Add support for registering devices via MFD cells
  2021-08-06  8:19 ` Alistair Francis
@ 2021-08-06 11:41   ` Lee Jones
  0 siblings, 0 replies; 5+ messages in thread
From: Lee Jones @ 2021-08-06 11:41 UTC (permalink / raw)
  To: Alistair Francis
  Cc: linux-arm-kernel, Linux Kernel Mailing List, Michael Walle, Mark Brown

On Fri, 06 Aug 2021, Alistair Francis wrote:

> On Thu, Aug 5, 2021 at 6:56 PM Lee Jones <lee.jones@linaro.org> wrote:
> >
> > More devices are cropping up requiring only Regmap initialisation and
> > child registration functionality.  We currently only support that if
> > all required devices are represented by their own Device Tree nodes
> > complete with compatible strings.
> >
> > However, not everyone is happy with adding empty nodes that provide no
> > additional device information into the Device Tree.
> >
> > Rather than have a plethora of mostly empty, function-less drivers in
> > MFD, we'll support those simple cases in here instead via MFD cells.
> >
> > Cc: Michael Walle <michael@walle.cc>
> > Cc: Mark Brown <broonie@kernel.org>
> > Cc: Alistair Francis <alistair23@gmail.com>
> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > ---
> > v2:
> >  - Check for empty of_device_id .data entry
> >
> >  drivers/mfd/simple-mfd-i2c.c | 41 +++++++++++++++++++++++++++++-------
> >  drivers/mfd/simple-mfd-i2c.h | 32 ++++++++++++++++++++++++++++
> >  2 files changed, 65 insertions(+), 8 deletions(-)
> >  create mode 100644 drivers/mfd/simple-mfd-i2c.h
> >
> > diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
> > index 87f684cff9a17..583e8c7924af0 100644
> > --- a/drivers/mfd/simple-mfd-i2c.c
> > +++ b/drivers/mfd/simple-mfd-i2c.c
> > @@ -2,39 +2,64 @@
> >  /*
> >   * Simple MFD - I2C
> >   *
> > + * Author(s):
> > + *     Michael Walle <michael@walle.cc>
> > + *     Lee Jones <lee.jones@linaro.org>
> > + *
> >   * This driver creates a single register map with the intention for it to be
> >   * shared by all sub-devices.  Children can use their parent's device structure
> >   * (dev.parent) in order to reference it.
> >   *
> >   * Once the register map has been successfully initialised, any sub-devices
> > - * represented by child nodes in Device Tree will be subsequently registered.
> > + * represented by child nodes in Device Tree or via the MFD cells in this file
> > + * will be subsequently registered.
> >   */
> >
> >  #include <linux/i2c.h>
> >  #include <linux/kernel.h>
> > +#include <linux/mfd/core.h>
> >  #include <linux/module.h>
> >  #include <linux/of_platform.h>
> >  #include <linux/regmap.h>
> >
> > -static const struct regmap_config simple_regmap_config = {
> > +#include "simple-mfd-i2c.h"
> > +
> > +static const struct regmap_config regmap_config_8r_8v = {
> >         .reg_bits = 8,
> >         .val_bits = 8,
> >  };
> >
> >  static int simple_mfd_i2c_probe(struct i2c_client *i2c)
> >  {
> > -       const struct regmap_config *config;
> > +       const struct simple_mfd_data *simple_mfd_data;
> > +       const struct regmap_config *regmap_config;
> >         struct regmap *regmap;
> > +       int ret;
> > +
> > +       simple_mfd_data = device_get_match_data(&i2c->dev);
> >
> > -       config = device_get_match_data(&i2c->dev);
> > -       if (!config)
> > -               config = &simple_regmap_config;
> > +       /* If no regmap_config is specified, use the default 8reg and 8val bits */
> > +       if (!simple_mfd_data || !simple_mfd_data->regmap_config)
> > +               regmap_config = &regmap_config_8r_8v;
> > +       else
> > +               regmap_config = simple_mfd_data->regmap_config;
> >
> > -       regmap = devm_regmap_init_i2c(i2c, config);
> > +       regmap = devm_regmap_init_i2c(i2c, regmap_config);
> >         if (IS_ERR(regmap))
> >                 return PTR_ERR(regmap);
> >
> > -       return devm_of_platform_populate(&i2c->dev);
> > +       /* If no MFD cells are spedified, use register the DT child nodes instead */
> > +       if (!simple_mfd_data || !simple_mfd_data->mfd_cell)
> > +               return devm_of_platform_populate(&i2c->dev);
> > +
> > +       ret = devm_mfd_add_devices(&i2c->dev, PLATFORM_DEVID_AUTO,
> > +                                  simple_mfd_data->mfd_cell,
> > +                                  simple_mfd_data->mfd_cell_size,
> > +                                  NULL, 0, NULL);
> > +       if (!ret)
> 
> Shouldn't this be `if (ret)` instead?
> 
> With that changed this works for me as well:

You're right.  Will fix.

> Reviewed-by: Alistair Francis <alistair@alistair23.me>
> Tested-by: Alistair Francis <alistair@alistair23.me>

Thanks.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-08-06 11:41 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-05  8:56 [PATCH v2 1/1] mfd: simple-mfd-i2c: Add support for registering devices via MFD cells Lee Jones
2021-08-05 10:01 ` Michael Walle
2021-08-05 11:03   ` Lee Jones
2021-08-06  8:19 ` Alistair Francis
2021-08-06 11:41   ` Lee Jones

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