[PATCH v3 0/3] nvmem: upstream snvs_lpgpr driver

[PATCH v3 0/3] nvmem: upstream snvs_lpgpr driver

[Oleksij Rempel]

changes v3:
 - remove regmap and offset properties.

changes v2:
 - correct typos: Registe, parrent...

Oleksij Rempel (3):
  nvmem: dt: document SNVS LPGPR binding
  nvmem: add snvs_lpgpr driver
  ARM: dts: imx6qdl.dtsi: add "fsl,imx6q-snvs-lpgpr" node

 .../devicetree/bindings/nvmem/snvs-lpgpr.txt       |  19 +++
 arch/arm/boot/dts/imx6qdl.dtsi                     |   4 +
 drivers/nvmem/Kconfig                              |  13 ++
 drivers/nvmem/Makefile                             |   2 +
 drivers/nvmem/snvs_lpgpr.c                         | 143 +++++++++++++++++++++
 5 files changed, 181 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/nvmem/snvs-lpgpr.txt
 create mode 100644 drivers/nvmem/snvs_lpgpr.c

-- 
2.11.0

[PATCH v3 1/3] nvmem: dt: document SNVS LPGPR binding

[Oleksij Rempel]

Documentation bindings for the Low Power General Purpose Register
available on i.MX6 SoCs in the Secure Non-Volatile Storage.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 .../devicetree/bindings/nvmem/snvs-lpgpr.txt          | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/nvmem/snvs-lpgpr.txt

diff --git a/Documentation/devicetree/bindings/nvmem/snvs-lpgpr.txt b/Documentation/devicetree/bindings/nvmem/snvs-lpgpr.txt
new file mode 100644
index 000000000000..21910fb3159f
--- /dev/null
+++ b/Documentation/devicetree/bindings/nvmem/snvs-lpgpr.txt
@@ -0,0 +1,19 @@
+Device tree bindings for Low Power General Purpose Register found in i.MX6Q/D
+Secure Non-Volatile Storage.
+
+This DT node should be represented as a sub-node of a "syscon",
+"simple-mfd" node.
+
+Required properties:
+- compatible: should be:
+	"fsl,imx6q-snvs-lpgpr" for Freescale i.MX6Q/D/DL/S
+
+Example:
+snvs: snvs@020cc000 {
+	compatible = "fsl,sec-v4.0-mon", "syscon", "simple-mfd";
+	reg = <0x020cc000 0x4000>;
+
+	snvs_lpgpr: snvs-lpgpr {
+		compatible = "fsl,imx6q-snvs-lpgpr";
+	};
+};
-- 
2.11.0

[PATCH v3 2/3] nvmem: add snvs_lpgpr driver

[Oleksij Rempel]

This is a driver for Low Power General Purpose Register (LPGPR)
available on i.MX6 SoCs in Secure Non-Volatile Storage (SNVS)
of this chip.

It is a 32-bit read/write register located in the low power domain.
Since LPGPR is located in the battery-backed power domain, LPGPR can
be used by any application for retaining data during an SoC power-down
mode.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/nvmem/Kconfig      |  13 +++++
 drivers/nvmem/Makefile     |   2 +
 drivers/nvmem/snvs_lpgpr.c | 143 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 158 insertions(+)
 create mode 100644 drivers/nvmem/snvs_lpgpr.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 101ced4c84be..00537b91cc22 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -144,4 +144,17 @@ config MESON_EFUSE
 	  This driver can also be built as a module. If so, the module
 	  will be called nvmem_meson_efuse.
 
+config NVMEM_SNVS_LPGPR
+	tristate "Support for Low Power General Purpose Register"
+	depends on HAS_IOMEM
+	depends on OF
+	select REGMAP_MMIO
+	select MFD_SYSCON
+	help
+	  This is a driver for Low Power General Purpose Register (LPGPR) available on
+	  i.MX6 SoCs in Secure Non-Volatile Storage (SNVS) of this chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called nvmem-snvs-lpgpr.
+
 endif
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 173140658693..4c589184acee 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -30,3 +30,5 @@ obj-$(CONFIG_NVMEM_VF610_OCOTP)	+= nvmem-vf610-ocotp.o
 nvmem-vf610-ocotp-y		:= vf610-ocotp.o
 obj-$(CONFIG_MESON_EFUSE)	+= nvmem_meson_efuse.o
 nvmem_meson_efuse-y		:= meson-efuse.o
+obj-$(CONFIG_NVMEM_SNVS_LPGPR)	+= nvmem_snvs_lpgpr.o
+nvmem_snvs_lpgpr-y		:= snvs_lpgpr.o
diff --git a/drivers/nvmem/snvs_lpgpr.c b/drivers/nvmem/snvs_lpgpr.c
new file mode 100644
index 000000000000..c90a8e8a161f
--- /dev/null
+++ b/drivers/nvmem/snvs_lpgpr.c
@@ -0,0 +1,143 @@
+/*
+ * Copyright (c) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
+ * Copyright (c) 2017 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+struct snvs_lpgpr_priv {
+	struct device_d		*dev;
+	struct regmap		*regmap;
+	int			offset;
+	struct nvmem_config	cfg;
+};
+
+struct snvs_lpgpr_cfg {
+	int offset;
+};
+
+static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx6q = {
+	.offset = 0x68,
+};
+
+static int snvs_lpgpr_write(void *context, unsigned int offset, void *_val,
+			    size_t bytes)
+{
+	struct snvs_lpgpr_priv *priv = context;
+	const u32 *val = _val;
+	int i = 0, words = bytes / 4;
+
+	while (words--)
+		regmap_write(priv->regmap, priv->offset + offset + (i++ * 4),
+			     *val++);
+
+	return 0;
+}
+
+static int snvs_lpgpr_read(void *context, unsigned int offset, void *_val,
+			   size_t bytes)
+{
+	struct snvs_lpgpr_priv *priv = context;
+	u32 *val = _val;
+	int i = 0, words = bytes / 4;
+
+	while (words--)
+		regmap_read(priv->regmap, priv->offset + offset + (i++ * 4),
+			    val++);
+
+	return 0;
+}
+
+static int snvs_lpgpr_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	struct device_node *syscon_node;
+	struct snvs_lpgpr_priv *priv;
+	struct nvmem_config *cfg;
+	struct nvmem_device *nvmem;
+	const struct snvs_lpgpr_cfg *dcfg;
+	int err;
+
+	if (!node)
+		return -ENOENT;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	dcfg = of_device_get_match_data(dev);
+	if (!dcfg)
+		return -EINVAL;
+
+	syscon_node = of_get_parent(node);
+	if (!syscon_node)
+		return -ENODEV;
+
+	priv->regmap = syscon_node_to_regmap(syscon_node);
+	of_node_put(syscon_node);
+	if (IS_ERR(priv->regmap))
+		return PTR_ERR(priv->regmap);
+
+	priv->offset = dcfg->offset;
+
+	cfg = &priv->cfg;
+	cfg->priv = priv;
+	cfg->name = dev_name(dev);
+	cfg->dev = dev;
+	cfg->stride = 4,
+	cfg->word_size = 4,
+	cfg->size = 4,
+	cfg->owner = THIS_MODULE,
+	cfg->reg_read  = snvs_lpgpr_read,
+	cfg->reg_write = snvs_lpgpr_write,
+
+	nvmem = nvmem_register(cfg);
+	if (IS_ERR(nvmem))
+		return PTR_ERR(nvmem);
+
+	platform_set_drvdata(pdev, nvmem);
+
+	return 0;
+}
+
+static int snvs_lpgpr_remove(struct platform_device *pdev)
+{
+	struct nvmem_device *nvmem = platform_get_drvdata(pdev);
+
+	return nvmem_unregister(nvmem);
+}
+
+static const struct of_device_id snvs_lpgpr_dt_ids[] = {
+	{ .compatible = "fsl,imx6q-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx6q },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, snvs_lpgpr_dt_ids);
+
+static struct platform_driver snvs_lpgpr_driver = {
+	.probe	= snvs_lpgpr_probe,
+	.remove	= snvs_lpgpr_remove,
+	.driver = {
+		.name	= "snvs_lpgpr",
+		.of_match_table = snvs_lpgpr_dt_ids,
+	},
+};
+module_platform_driver(snvs_lpgpr_driver);
+
+MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
+MODULE_DESCRIPTION("Low Power General Purpose Register in i.MX6 Secure Non-Volatile Storage");
+MODULE_LICENSE("GPL");
-- 
2.11.0

[PATCH v3 3/3] ARM: dts: imx6qdl.dtsi: add "fsl,imx6q-snvs-lpgpr" node

[Oleksij Rempel]

This node is for Low Power General Purpose Register which can
be used as Non-Volatile Storage.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 arch/arm/boot/dts/imx6qdl.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi
index e426faa9c243..94e992558238 100644
--- a/arch/arm/boot/dts/imx6qdl.dtsi
+++ b/arch/arm/boot/dts/imx6qdl.dtsi
@@ -769,6 +769,10 @@
 					mask = <0x60>;
 					status = "disabled";
 				};
+
+				snvs_lpgpr: snvs-lpgpr {
+					compatible = "fsl,imx6q-snvs-lpgpr";
+				};
 			};
 
 			epit1: epit@020d0000 { /* EPIT1 */
-- 
2.11.0

Re: [PATCH v3 2/3] nvmem: add snvs_lpgpr driver

[Srinivas Kandagatla]

On 07/06/17 07:41, Oleksij Rempel wrote:
> This is a driver for Low Power General Purpose Register (LPGPR)
> available on i.MX6 SoCs in Secure Non-Volatile Storage (SNVS)
> of this chip.
>
> It is a 32-bit read/write register located in the low power domain.
> Since LPGPR is located in the battery-backed power domain, LPGPR can
> be used by any application for retaining data during an SoC power-down
> mode.
>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
>  drivers/nvmem/Kconfig      |  13 +++++
>  drivers/nvmem/Makefile     |   2 +
>  drivers/nvmem/snvs_lpgpr.c | 143 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 158 insertions(+)
>  create mode 100644 drivers/nvmem/snvs_lpgpr.c

Minor comments...


>
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index 101ced4c84be..00537b91cc22 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -144,4 +144,17 @@ config MESON_EFUSE
>  	  This driver can also be built as a module. If so, the module
>  	  will be called nvmem_meson_efuse.
>
> +config NVMEM_SNVS_LPGPR
> +	tristate "Support for Low Power General Purpose Register"

<--
> +	depends on HAS_IOMEM
> +	depends on OF
> +	select REGMAP_MMIO
-->
Not sure why we need this selects here, if you are accessing regmap via 
syscon.

Consider adding COMPILE_TEST so that driver gets good test coverage.

> +	select MFD_SYSCON
> +	help
> +	  This is a driver for Low Power General Purpose Register (LPGPR) available on
> +	  i.MX6 SoCs in Secure Non-Volatile Storage (SNVS) of this chip.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called nvmem-snvs-lpgpr.
> +
>  endif
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index 173140658693..4c589184acee 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -30,3 +30,5 @@ obj-$(CONFIG_NVMEM_VF610_OCOTP)	+= nvmem-vf610-ocotp.o
>  nvmem-vf610-ocotp-y		:= vf610-ocotp.o
>  obj-$(CONFIG_MESON_EFUSE)	+= nvmem_meson_efuse.o
>  nvmem_meson_efuse-y		:= meson-efuse.o
> +obj-$(CONFIG_NVMEM_SNVS_LPGPR)	+= nvmem_snvs_lpgpr.o
> +nvmem_snvs_lpgpr-y		:= snvs_lpgpr.o
> diff --git a/drivers/nvmem/snvs_lpgpr.c b/drivers/nvmem/snvs_lpgpr.c
> new file mode 100644
> index 000000000000..c90a8e8a161f
> --- /dev/null
> +++ b/drivers/nvmem/snvs_lpgpr.c
> @@ -0,0 +1,143 @@
> +/*
> + * Copyright (c) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
> + * Copyright (c) 2017 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2
> + * as published by the Free Software Foundation.
> + */
> +
> +#include <linux/clk.h>

??

> +#include <linux/device.h>
> +#include <linux/io.h>

??

> +#include <linux/module.h>
> +#include <linux/nvmem-provider.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +
> +struct snvs_lpgpr_priv {
> +	struct device_d		*dev;
> +	struct regmap		*regmap;
> +	int			offset;
> +	struct nvmem_config	cfg;
> +};
> +
> +struct snvs_lpgpr_cfg {
> +	int offset;
> +};
> +
> +static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx6q = {
> +	.offset = 0x68,
> +};
> +
> +static int snvs_lpgpr_write(void *context, unsigned int offset, void *_val,
> +			    size_t bytes)
> +{
> +	struct snvs_lpgpr_priv *priv = context;
> +	const u32 *val = _val;
> +	int i = 0, words = bytes / 4;
> +
> +	while (words--)
> +		regmap_write(priv->regmap, priv->offset + offset + (i++ * 4),
> +			     *val++);
> +
> +	return 0;
> +}
> +
> +static int snvs_lpgpr_read(void *context, unsigned int offset, void *_val,
> +			   size_t bytes)
> +{
> +	struct snvs_lpgpr_priv *priv = context;
> +	u32 *val = _val;
> +	int i = 0, words = bytes / 4;
> +
> +	while (words--)
> +		regmap_read(priv->regmap, priv->offset + offset + (i++ * 4),
> +			    val++);
> +
> +	return 0;
> +}
> +
> +static int snvs_lpgpr_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *node = dev->of_node;
> +	struct device_node *syscon_node;
> +	struct snvs_lpgpr_priv *priv;
> +	struct nvmem_config *cfg;
> +	struct nvmem_device *nvmem;
> +	const struct snvs_lpgpr_cfg *dcfg;
> +	int err;
> +
> +	if (!node)
> +		return -ENOENT;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	dcfg = of_device_get_match_data(dev);
> +	if (!dcfg)
> +		return -EINVAL;
> +
> +	syscon_node = of_get_parent(node);
> +	if (!syscon_node)
> +		return -ENODEV;
> +
> +	priv->regmap = syscon_node_to_regmap(syscon_node);
> +	of_node_put(syscon_node);
> +	if (IS_ERR(priv->regmap))
> +		return PTR_ERR(priv->regmap);
> +
> +	priv->offset = dcfg->offset;
> +
> +	cfg = &priv->cfg;
> +	cfg->priv = priv;
> +	cfg->name = dev_name(dev);
> +	cfg->dev = dev;
> +	cfg->stride = 4,
> +	cfg->word_size = 4,
> +	cfg->size = 4,
> +	cfg->owner = THIS_MODULE,
> +	cfg->reg_read  = snvs_lpgpr_read,
> +	cfg->reg_write = snvs_lpgpr_write,
> +
> +	nvmem = nvmem_register(cfg);
> +	if (IS_ERR(nvmem))
> +		return PTR_ERR(nvmem);
> +
> +	platform_set_drvdata(pdev, nvmem);
> +
> +	return 0;
> +}
> +
> +static int snvs_lpgpr_remove(struct platform_device *pdev)
> +{
> +	struct nvmem_device *nvmem = platform_get_drvdata(pdev);
> +
> +	return nvmem_unregister(nvmem);
> +}
> +
> +static const struct of_device_id snvs_lpgpr_dt_ids[] = {
> +	{ .compatible = "fsl,imx6q-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx6q },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, snvs_lpgpr_dt_ids);
> +
> +static struct platform_driver snvs_lpgpr_driver = {
> +	.probe	= snvs_lpgpr_probe,
> +	.remove	= snvs_lpgpr_remove,
> +	.driver = {
> +		.name	= "snvs_lpgpr",
> +		.of_match_table = snvs_lpgpr_dt_ids,
> +	},
> +};
> +module_platform_driver(snvs_lpgpr_driver);
> +
> +MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
> +MODULE_DESCRIPTION("Low Power General Purpose Register in i.MX6 Secure Non-Volatile Storage");
> +MODULE_LICENSE("GPL");

GPLv2??

>