Hi Geert,
A few notes.
> On Jun 1, 2016, at 22:50 , Geert Uytterhoeven <geert+rene...@glider.be> wrote:
>
> Add DT fixup code to add a reset-controller node for the r8a7791 RST
> module if it's not yet present.
>
> This allows the R-Car Gen2 clock driver to use the RST driver to obtain
> the value of the mode pins, instead of reading from a hardcoded address
> in rcar_gen2_read_mode_pins(), while providing backward compatibility
> with old DTBs.
>
> Signed-off-by: Geert Uytterhoeven <geert+rene...@glider.be>
> ---
> ---
> drivers/soc/renesas/Makefile | 4 +
> drivers/soc/renesas/renesas-dt-fixup.c | 159 +++++++++++++++++++++++++++++++++
> 2 files changed, 163 insertions(+)
> create mode 100644 drivers/soc/renesas/renesas-dt-fixup.c
>
> diff --git a/drivers/soc/renesas/Makefile b/drivers/soc/renesas/Makefile
> index 0d732ff893dd8fba..e5f4454821ca6f63 100644
> --- a/drivers/soc/renesas/Makefile
> +++ b/drivers/soc/renesas/Makefile
> @@ -1,3 +1,7 @@
> +# FIXME Depend on new Kconfig symbol CONFIG_ARCH_RENESAS_LEGACY
> +# FIXME Needs OF_DYNAMIC
> +obj-$(CONFIG_ARCH_RENESAS) += renesas-dt-fixup.o
> +
> obj-$(CONFIG_ARCH_RCAR_GEN1) += rcar-rst.o
> obj-$(CONFIG_ARCH_RCAR_GEN2) += rcar-rst.o
> obj-$(CONFIG_ARCH_R8A7795) += rcar-rst.o
> diff --git a/drivers/soc/renesas/renesas-dt-fixup.c
> b/drivers/soc/renesas/renesas-dt-fixup.c
> new file mode 100644
> index 0000000000000000..83c9ca6b44f8136c
> --- /dev/null
> +++ b/drivers/soc/renesas/renesas-dt-fixup.c
> @@ -0,0 +1,159 @@
> +/*
> + * Renesas DT Fixup Code
> + *
> + * Provide backwards compatibility with old DTBs by updating the DT
> + *
> + * Copyright (C) 2016 Glider bvba
> + *
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License. See the file "COPYING" in the main directory of this archive
> + * for more details.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/of.h>
> +#include <linux/slab.h>
> +
> +#define RST_BASE 0xe6160000
> +#define RST_SIZE 0x0100 /* R-Car Gen2 */
> +
> +static struct property rst_compatible = {
> + .name = "compatible",
> +};
> +
> +static __be32 rst_reg_values[4] = {
> + cpu_to_be32(0),
> + cpu_to_be32(RST_BASE),
> + cpu_to_be32(0),
> + cpu_to_be32(RST_SIZE),
> +};
> +
> +static struct property rst_name = {
> + .name = "name",
> + .length = sizeof("reset-controller"),
> + .value = "reset-controller",
> +};
> +
> +static struct property rst_reg = {
> + .name = "reg",
> + .length = sizeof(rst_reg_values),
> + .value = rst_reg_values,
> +};
> +
> +static int __init add_rst(struct device_node *parent, const char *path,
> + char *compatible)
> +{
> + struct property *prop[] = { &rst_compatible, &rst_name, &rst_reg };
> + struct device_node *np;
> + char *full_name;
> + unsigned int i;
> + int error;
> +
> + pr_debug("Adding RST node %s\n", compatible);
> + np = kzalloc(sizeof(*np), GFP_KERNEL);
> + if (!np)
> + return -ENOMEM;
> +
> + np->name = kasprintf(GFP_KERNEL, "%s@%x", (char *)rst_name.value,
> + RST_BASE);
> + full_name = kasprintf(GFP_KERNEL, "%s/%s", path, np->name);
> + np->full_name = full_name;
> + np->parent = parent;
> +
> + of_node_set_flag(np, OF_DYNAMIC);
> + of_node_init(np);
> +
> + error = of_attach_node(np);
> + if (error) {
> + pr_err("%s: of_attach_node() %s failed %d\n", __func__,
> + np->name, error);
> + kfree(np);
> + return error;
> + }
> +
> + rst_compatible.value = compatible;
> + rst_compatible.length = strlen(rst_compatible.value) + 1;
> +
> + for (i = 0; i < ARRAY_SIZE(prop); i++) {
> + error = of_add_property(np, prop[i]);
> + if (error)
> + pr_err("%s: of_add_property() %s/%s failed %d\n",
> + __func__, np->name, prop[i]->name, error);
> + }
> +
> + return 0;
> +}
> +
Using changesets (especially with the new changeset helpers would make this
so much simpler. Or you could compile in a DTBO that performs the changes
although you will have to tweak it since it appears you’re not using fixed
names and properties all the way.
> +static int __init add_sysc(struct device_node *parent, const char *path,
> + char *compatible)
> +{
> + pr_debug("NOT YET adding SYSC node %s\n", compatible);
> + return 0;
> +}
> +
> +static const struct of_device_id renesas_matches[] __initconst = {
> + { .compatible = "renesas,r8a7791", },
> + { /* sentinel */ }
> +};
> +
> +static int __init renesas_dt_fixup(void)
> +{
> + const struct of_device_id *match;
> + struct device_node *np, *parent;
> + const char *parent_path;
> + char *compatible;
> +
> + np = of_find_node_by_path("/");
> + if (!np)
> + return -ENODEV;
> +
> + for (match = renesas_matches; match->compatible[0]; match++)
> + if (of_device_is_compatible(np, match->compatible))
> + break;
> + of_node_put(np);
> +
> + if (!match->compatible[0])
> + return -ENODEV;
> +
> + /* Find the main SoC bus node */
> + np = of_find_compatible_node(NULL, NULL, "arm,gic-400");
> + if (!np) {
> + pr_warn("%s: Cannot find %s\n", __func__, "arm,gic-400");
> + return -ENODEV;
> + }
> +
> + parent = of_get_parent(np);
> + of_node_put(np);
> + if (!parent) {
> + pr_warn("%s: Cannot find GIC parent\n", __func__);
> + return -ENODEV;
> + }
> +
> + parent_path = parent->full_name;
> + /* Prevent double leading slash */
> + if (!parent_path[1])
> + parent_path++;
> +
> + compatible = kasprintf(GFP_KERNEL, "%s-rst", match->compatible);
> + if (of_find_compatible_node(NULL, NULL, compatible)) {
> + pr_debug("%s: RST node %s present\n", __func__, compatible);
> + kfree(compatible);
> + } else {
> + add_rst(parent, parent_path, compatible);
> + }
> +
> + compatible = kasprintf(GFP_KERNEL, "%s-sysc", match->compatible);
> + if (of_find_compatible_node(NULL, NULL, compatible)) {
> + pr_debug("%s: SYSC node %s present\n", __func__, compatible);
> + kfree(compatible);
> + } else {
> + add_sysc(parent, parent_path, compatible);
> + }
> +
> + of_node_put(parent);
> + return 0;
> +}
> +early_initcall(renesas_dt_fixup);
> --
> 1.9.1
>
Regards
— Pantelis
