[PATCH v2] debugfs: allow to use regmap for print regs

Li Chen
2023-01-11T07:22:52Z

From: Li Chen <lchen@ambarella.com>

Currently, debugfs_regset32 only contains void __iomem *base,
and it is not friendly to regmap user.

Let's add regmap to debugfs_regset32, and add debugfs_print_regmap_reg32
to allow debugfs_regset32_show handle regmap.

Signed-off-by: Li Chen <lchen@ambarella.com>
---
Changelog:

v1 -> v2:

Suggested by Greg, provide a new function for regmap instead of trying to overload old function.
---
fs/debugfs/file.c | 46 ++++++++++++++++++++++++++++++++++++++++-
include/linux/debugfs.h | 10 +++++++++
2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index b54f470e0d03..f204b27f757f 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -1137,14 +1137,58 @@ void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
}
EXPORT_SYMBOL_GPL(debugfs_print_regs32);

+/**
+ * debugfs_print_regmap_regs32 - use seq_print to describe a set of registers
+ * @s: the seq_file structure being used to generate output
+ * @regs: an array if struct debugfs_reg32 structures
+ * @nregs: the length of the above array
+ * @regmap: regmap to be used in reading the registers
+ * @prefix: a string to be prefixed to every output line
+ *
+ * This function outputs a text block describing the current values of
+ * some 32-bit hardware registers. It is meant to be used within debugfs
+ * files based on seq_file that need to show registers, intermixed with other
+ * information. The prefix argument may be used to specify a leading string,
+ * because some peripherals have several blocks of identical registers,
+ * for example configuration of dma channels
+ */
+void debugfs_print_regmap_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
+ int nregs, struct regmap *regmap, char *prefix)
+{
+ int i;
+ u32 val;
+
+ for (i = 0; i < nregs; i++, regs++) {
+ if (prefix)
+ seq_printf(s, "%s", prefix);
+ regmap_read(regmap, regs->offset, &val);
+ seq_printf(s, "%s = 0x%08x\n", regs->name, val);
+ if (seq_has_overflowed(s))
+ break;
+ }
+}
+EXPORT_SYMBOL_GPL(debugfs_print_regmap_regs32);
+
static int debugfs_regset32_show(struct seq_file *s, void *data)
{
struct debugfs_regset32 *regset = s->private;
+ void __iomem *base = regset->base;
+ struct regmap *regmap = regset->regmap;
+
+ if ((regmap && base) || (!regmap && !base)) {
+ seq_puts(
+ s,
+ "You should provide one and only one between base and regmap!\n");
+ return -EINVAL;
+ }

if (regset->dev)
pm_runtime_get_sync(regset->dev);

- debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
+ if (base)
+ debugfs_print_regs32(s, regset->regs, regset->nregs, base, "");
+ if (regmap)
+ debugfs_print_regmap_regs32(s, regset->regs, regset->nregs, regmap, "");

if (regset->dev)
pm_runtime_put(regset->dev);
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index ea2d919fd9c7..04bc2bb70b79 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -17,6 +17,7 @@

#include <linux/types.h>
#include <linux/compiler.h>
+#include <linux/regmap.h>

struct device;
struct file_operations;
@@ -35,6 +36,7 @@ struct debugfs_regset32 {
const struct debugfs_reg32 *regs;
int nregs;
void __iomem *base;
+ struct regmap *regmap;
struct device *dev; /* Optional device for Runtime PM */
};

@@ -152,6 +154,9 @@ void debugfs_create_regset32(const char *name, umode_t mode,
void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
int nregs, void __iomem *base, char *prefix);

+void debugfs_print_regmap_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
+ int nregs, struct regmap *regmap, char *prefix);
+
void debugfs_create_u32_array(const char *name, umode_t mode,
struct dentry *parent,
struct debugfs_u32_array *array);
@@ -338,6 +343,11 @@ static inline void debugfs_print_regs32(struct seq_file *s, const struct debugfs
{
}

+static inline void debugfs_print_regmap_regs32(struct seq_file *s,
+ const struct debugfs_reg32 *regs,
+ int nregs, struct regmap *regmap,
+ char *prefix);
+
static inline bool debugfs_initialized(void)
{
return false;
--
2.34.1