diff mbox series

[v13,net-next,1/9] mfd: ocelot: add helper to get regmap from a resource

Message ID 20220705204743.3224692-2-colin.foster@in-advantage.com (mailing list archive)
State New, archived
Headers show
Series add support for VSC7512 control over SPI | expand

Commit Message

Colin Foster July 5, 2022, 8:47 p.m. UTC 
Several ocelot-related modules are designed for MMIO / regmaps. As such,
they often use a combination of devm_platform_get_and_ioremap_resource and
devm_regmap_init_mmio.

Operating in an MFD might be different, in that it could be memory mapped,
or it could be SPI, I2C... In these cases a fallback to use IORESOURCE_REG
instead of IORESOURCE_MEM becomes necessary.

When this happens, there's redundant logic that needs to be implemented in
every driver. In order to avoid this redundancy, utilize a single function
that, if the MFD scenario is enabled, will perform this fallback logic.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
---
 MAINTAINERS                |  5 ++++
 include/linux/mfd/ocelot.h | 55 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)
 create mode 100644 include/linux/mfd/ocelot.h

Comments

Vladimir Oltean July 9, 2022, 6:56 p.m. UTC | #1 
On Tue, Jul 05, 2022 at 01:47:35PM -0700, Colin Foster wrote:
> Several ocelot-related modules are designed for MMIO / regmaps. As such,
> they often use a combination of devm_platform_get_and_ioremap_resource and
> devm_regmap_init_mmio.
> 
> Operating in an MFD might be different, in that it could be memory mapped,
> or it could be SPI, I2C... In these cases a fallback to use IORESOURCE_REG
> instead of IORESOURCE_MEM becomes necessary.
> 
> When this happens, there's redundant logic that needs to be implemented in
> every driver. In order to avoid this redundancy, utilize a single function
> that, if the MFD scenario is enabled, will perform this fallback logic.
> 
> Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
> ---

To me this looks good, I'll just add a few minor comments which I think
you don't necessarily need to address by resending, they're just things
I noticed.

Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>

>  MAINTAINERS                |  5 ++++
>  include/linux/mfd/ocelot.h | 55 ++++++++++++++++++++++++++++++++++++++
>  2 files changed, 60 insertions(+)
>  create mode 100644 include/linux/mfd/ocelot.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 28108e4fdb8f..f781caceeb38 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14467,6 +14467,11 @@ F:	net/dsa/tag_ocelot.c
>  F:	net/dsa/tag_ocelot_8021q.c
>  F:	tools/testing/selftests/drivers/net/ocelot/*
>  
> +OCELOT EXTERNAL SWITCH CONTROL
> +M:	Colin Foster <colin.foster@in-advantage.com>
> +S:	Supported
> +F:	include/linux/mfd/ocelot.h
> +
>  OCXL (Open Coherent Accelerator Processor Interface OpenCAPI) DRIVER
>  M:	Frederic Barrat <fbarrat@linux.ibm.com>
>  M:	Andrew Donnellan <ajd@linux.ibm.com>
> diff --git a/include/linux/mfd/ocelot.h b/include/linux/mfd/ocelot.h
> new file mode 100644
> index 000000000000..353b7c2ee445
> --- /dev/null
> +++ b/include/linux/mfd/ocelot.h
> @@ -0,0 +1,55 @@
> +/* SPDX-License-Identifier: GPL-2.0 OR MIT */
> +/* Copyright 2022 Innovative Advantage Inc. */

A header file should have ifdefs which should prevent double inclusion,
like

#ifndef _MFD_OCELOT_H
#define _MFD_OCELOT_H

...

#endif

> +
> +#include <linux/err.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/types.h>
> +
> +struct resource;

IMO if include/linux/platform_device.h doesn't provide "struct resource"
that's a problem for that header to solve, not for its users.

> +
> +static inline struct regmap *
> +ocelot_regmap_from_resource_optional(struct platform_device *pdev,
> +				     unsigned int index,
> +				     const struct regmap_config *config)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +	u32 __iomem *regs;

"regs" could be void *.

> +
> +	/*
> +	 * Don't use get_and_ioremap_resource here, since that will invoke
> +	 * prints of "invalid resource" which simply add confusion
> +	 */
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, index);
> +	if (res) {
> +		regs = devm_ioremap_resource(dev, res);
> +		if (IS_ERR(regs))
> +			return ERR_CAST(regs);
> +		return devm_regmap_init_mmio(dev, regs, config);
> +	}
> +
> +	/*
> +	 * Fall back to using REG and getting the resource from the parent
> +	 * device, which is possible in an MFD configuration
> +	 */
> +	if (dev->parent) {
> +		res = platform_get_resource(pdev, IORESOURCE_REG, index);
> +		if (!res)
> +			return NULL;
> +
> +		return dev_get_regmap(dev->parent, res->name);
> +	}
> +
> +	return NULL;
> +}
> +
> +static inline struct regmap *
> +ocelot_regmap_from_resource(struct platform_device *pdev, unsigned int index,
> +			    const struct regmap_config *config)
> +{
> +	struct regmap *map;
> +
> +	map = ocelot_regmap_from_resource_optional(pdev, index, config);
> +	return map ?: ERR_PTR(-ENOENT);
> +}
> -- 
> 2.25.1
>
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 28108e4fdb8f..f781caceeb38 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14467,6 +14467,11 @@  F:	net/dsa/tag_ocelot.c
 F:	net/dsa/tag_ocelot_8021q.c
 F:	tools/testing/selftests/drivers/net/ocelot/*
 
+OCELOT EXTERNAL SWITCH CONTROL
+M:	Colin Foster <colin.foster@in-advantage.com>
+S:	Supported
+F:	include/linux/mfd/ocelot.h
+
 OCXL (Open Coherent Accelerator Processor Interface OpenCAPI) DRIVER
 M:	Frederic Barrat <fbarrat@linux.ibm.com>
 M:	Andrew Donnellan <ajd@linux.ibm.com>
diff --git a/include/linux/mfd/ocelot.h b/include/linux/mfd/ocelot.h
new file mode 100644
index 000000000000..353b7c2ee445
--- /dev/null
+++ b/include/linux/mfd/ocelot.h
@@ -0,0 +1,55 @@ 
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+/* Copyright 2022 Innovative Advantage Inc. */
+
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+struct resource;
+
+static inline struct regmap *
+ocelot_regmap_from_resource_optional(struct platform_device *pdev,
+				     unsigned int index,
+				     const struct regmap_config *config)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	u32 __iomem *regs;
+
+	/*
+	 * Don't use get_and_ioremap_resource here, since that will invoke
+	 * prints of "invalid resource" which simply add confusion
+	 */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, index);
+	if (res) {
+		regs = devm_ioremap_resource(dev, res);
+		if (IS_ERR(regs))
+			return ERR_CAST(regs);
+		return devm_regmap_init_mmio(dev, regs, config);
+	}
+
+	/*
+	 * Fall back to using REG and getting the resource from the parent
+	 * device, which is possible in an MFD configuration
+	 */
+	if (dev->parent) {
+		res = platform_get_resource(pdev, IORESOURCE_REG, index);
+		if (!res)
+			return NULL;
+
+		return dev_get_regmap(dev->parent, res->name);
+	}
+
+	return NULL;
+}
+
+static inline struct regmap *
+ocelot_regmap_from_resource(struct platform_device *pdev, unsigned int index,
+			    const struct regmap_config *config)
+{
+	struct regmap *map;
+
+	map = ocelot_regmap_from_resource_optional(pdev, index, config);
+	return map ?: ERR_PTR(-ENOENT);
+}