linux-kernel - [PATCH v6 2/8] mfd: simple-mfd-i2c: specify max

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Message-ID: <20250627142309.1444135-3-elder@riscstar.com>
Date: Fri, 27 Jun 2025 09:23:01 -0500
From: Alex Elder <elder@...cstar.com>
To: lee@...nel.org,
	lgirdwood@...il.com,
	broonie@...nel.org,
	alexandre.belloni@...tlin.com,
	robh@...nel.org,
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Cc: mat.jonczyk@...pl,
	dlan@...too.org,
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	palmer@...belt.com,
	aou@...s.berkeley.edu,
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Subject: [PATCH v6 2/8] mfd: simple-mfd-i2c: specify max_register

All devices supported by simple MFD use the same 8-bit register
8-bit value regmap configuration.  There is an option available
for a device to specify a custome configuration, but no existing
device uses it.

Lee Jones suggested modifying the simple MFD implementation to
remove the generality of the full regmap configuration and add a
max_register value to the simple_mfd_data structure.  This can
be used in the regmap configuration to limit the valid register
addresses if desired.  It's simpler, and covers all existing and
anticipated device types.

Signed-off-by: Alex Elder <elder@...cstar.com>
Suggested-by: Lee Jones <lee@...nel.org>
---
v6: - New patch, changing the simple MFD functionality

 drivers/mfd/simple-mfd-i2c.c | 18 ++++++------------
 drivers/mfd/simple-mfd-i2c.h |  2 +-
 2 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
index 22159913bea03..c1dc315d44dcf 100644
--- a/drivers/mfd/simple-mfd-i2c.c
+++ b/drivers/mfd/simple-mfd-i2c.c
@@ -24,27 +24,21 @@
 
 #include "simple-mfd-i2c.h"
 
-static const struct regmap_config regmap_config_8r_8v = {
-	.reg_bits = 8,
-	.val_bits = 8,
-};
-
 static int simple_mfd_i2c_probe(struct i2c_client *i2c)
 {
 	const struct simple_mfd_data *simple_mfd_data;
-	const struct regmap_config *regmap_config;
+	struct regmap_config regmap_config = { };
 	struct regmap *regmap;
 	int ret;
 
 	simple_mfd_data = device_get_match_data(&i2c->dev);
 
-	/* If no regmap_config is specified, use the default 8reg and 8val bits */
-	if (!simple_mfd_data || !simple_mfd_data->regmap_config)
-		regmap_config = &regmap_config_8r_8v;
-	else
-		regmap_config = simple_mfd_data->regmap_config;
+	regmap_config.reg_bits = 8;
+	regmap_config.val_bits = 8;
+	if (simple_mfd_data)
+		regmap_config.max_register = simple_mfd_data->max_register;
 
-	regmap = devm_regmap_init_i2c(i2c, regmap_config);
+	regmap = devm_regmap_init_i2c(i2c, &regmap_config);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
 
diff --git a/drivers/mfd/simple-mfd-i2c.h b/drivers/mfd/simple-mfd-i2c.h
index 7cb2bdd347d97..4121fe1bc1d70 100644
--- a/drivers/mfd/simple-mfd-i2c.h
+++ b/drivers/mfd/simple-mfd-i2c.h
@@ -24,9 +24,9 @@
 #include <linux/regmap.h>
 
 struct simple_mfd_data {
-	const struct regmap_config *regmap_config;
 	const struct mfd_cell *mfd_cell;
 	size_t mfd_cell_size;
+	unsigned int max_register;
 };
 
 #endif /* __MFD_SIMPLE_MFD_I2C_H */
-- 
2.45.2