linux-kernel - [PATCH v7 2/8] mfd: simple-mfd-i2c: specify max

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Message-ID: <20250702213658.545163-3-elder@riscstar.com>
Date: Wed,  2 Jul 2025 16:36:51 -0500
From: Alex Elder <elder@...cstar.com>
To: lee@...nel.org,
	lgirdwood@...il.com,
	broonie@...nel.org,
	alexandre.belloni@...tlin.com,
	robh@...nel.org,
	krzk+dt@...nel.org,
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Cc: mat.jonczyk@...pl,
	dlan@...too.org,
	paul.walmsley@...ive.com,
	palmer@...belt.com,
	aou@...s.berkeley.edu,
	alex@...ti.fr,
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	linux-rtc@...r.kernel.org,
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Subject: [PATCH v7 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 custom configuration, but no existing
device uses it.

Rather than specify a "full" regmap configuration to use this
option, Lee Jones suggested allowing just the max_register value
to be specified in the simple_mfd_data structure.

Signed-off-by: Alex Elder <elder@...cstar.com>
Suggested-by: Lee Jones <lee@...nel.org>
---
v2: - Allow max_register *and* regmap_config to be supplied

 drivers/mfd/simple-mfd-i2c.c | 15 ++++++++++++---
 drivers/mfd/simple-mfd-i2c.h |  1 +
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
index 22159913bea03..3f959f4f98261 100644
--- a/drivers/mfd/simple-mfd-i2c.c
+++ b/drivers/mfd/simple-mfd-i2c.c
@@ -33,16 +33,25 @@ 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 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)
+	if (simple_mfd_data) {
+		if (simple_mfd_data->regmap_config)
+			config = *simple_mfd_data->regmap_config;
+		else
+			config = regmap_config_8r_8v;
+
+		if (simple_mfd_data->max_register)
+			config.max_register = simple_mfd_data->max_register;
+		regmap_config = &config;
+	} else {
 		regmap_config = &regmap_config_8r_8v;
-	else
-		regmap_config = simple_mfd_data->regmap_config;
+	}
 
 	regmap = devm_regmap_init_i2c(i2c, regmap_config);
 	if (IS_ERR(regmap))
diff --git a/drivers/mfd/simple-mfd-i2c.h b/drivers/mfd/simple-mfd-i2c.h
index 7cb2bdd347d97..706b6f53155ff 100644
--- a/drivers/mfd/simple-mfd-i2c.h
+++ b/drivers/mfd/simple-mfd-i2c.h
@@ -27,6 +27,7 @@ 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