On 5/18/23 16:22, Krzysztof Kozlowski wrote: [...]
+++ b/drivers/nvmem/nvmem-syscon.c @@ -0,0 +1,105 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2022 Marek Vasut <marex@xxxxxxx> + * + * Based on snvs_lpgpr.c . + */ + +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/nvmem-provider.h> +#include <linux/of_device.h> +#include <linux/regmap.h> + +struct nvmem_syscon_priv { + struct device_d *dev; + struct regmap *regmap; + struct nvmem_config cfg; + unsigned int off; +}; + +static int nvmem_syscon_write(void *context, unsigned int offset, void *val, + size_t bytes) +{ + struct nvmem_syscon_priv *priv = context; + + return regmap_bulk_write(priv->regmap, priv->off + offset, + val, bytes / 4); +} + +static int nvmem_syscon_read(void *context, unsigned int offset, void *val, + size_t bytes) +{ + struct nvmem_syscon_priv *priv = context; + + return regmap_bulk_read(priv->regmap, priv->off + offset, + val, bytes / 4); +} + +static int nvmem_syscon_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *node = dev->of_node; + struct device_node *syscon_node; + struct nvmem_syscon_priv *priv; + struct nvmem_device *nvmem; + struct nvmem_config *cfg; + int ret; + + if (!node) + return -ENOENT; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + ret = of_property_read_u32_index(node, "reg", 0, &priv->off); + if (ret) + return ret; + + ret = of_property_read_u32_index(node, "reg", 1, &priv->cfg.size); + if (ret) + return ret; + + syscon_node = of_get_parent(node);This does not look correct. You hard-code dependency that it must be a child of syscon node. This is weird requirement and not explained in the bindings. Why this cannot be then generic MMIO node? Why it has to be a child of syscon?
Because I already have a syscon node and I want to expose only a subset of it to userspace (bootcounter in my case) . See 1/3, I replied there, let's continue the discussion there.
I fixed the rest in prep for V3, sorry for the horrid delays in replies.
