linux-kernel - [RFT PATCH v2 1/3] hwmon: (spd5118) Use regmap to implement paging

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Date: Tue, 18 Jun 2024 12:53:46 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: linux-hwmon@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	Wolfram Sang <wsa+renesas@...g-engineering.com>,
	René Rebe <rene@...ctcode.de>,
	Thomas Weißschuh <linux@...ssschuh.net>,
	Armin Wolf <W_Armin@....de>,
	Stephen Horvath <s.horvath@...look.com.au>,
	Paul Menzel <pmenzel@...gen.mpg.de>,
	Sasha Kozachuk <skozachuk@...gle.com>,
	John Hamrick <johnham@...gle.com>,
	Chris Sarra <chrissarra@...gle.com>,
	Guenter Roeck <linux@...ck-us.net>
Subject: [RFT PATCH v2 1/3] hwmon: (spd5118) Use regmap to implement paging

Using regmap for paging significantly improves caching since the regmap
cache no longer needs to be cleared after changing the page, so let's
use it.

Suggested-by: Armin Wolf <W_Armin@....de>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
v2: Added patch

 drivers/hwmon/spd5118.c | 47 ++++++++++++++++-------------------------
 1 file changed, 18 insertions(+), 29 deletions(-)

diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
index ac94a6779360..d405c5ef755d 100644
--- a/drivers/hwmon/spd5118.c
+++ b/drivers/hwmon/spd5118.c
@@ -382,45 +382,19 @@ static const struct hwmon_chip_info spd5118_chip_info = {
 
 /* nvmem */
 
-static int spd5118_nvmem_set_page(struct regmap *regmap, int page)
-{
-	unsigned int old_page;
-	int err;
-
-	err = regmap_read(regmap, SPD5118_REG_I2C_LEGACY_MODE, &old_page);
-	if (err)
-		return err;
-
-	if (page != (old_page & SPD5118_LEGACY_MODE_MASK)) {
-		/* Update page and explicitly select 1-byte addressing */
-		err = regmap_update_bits(regmap, SPD5118_REG_I2C_LEGACY_MODE,
-					 SPD5118_LEGACY_MODE_MASK, page);
-		if (err)
-			return err;
-
-		/* Selected new NVMEM page, drop cached data */
-		regcache_drop_region(regmap, SPD5118_EEPROM_BASE, 0xff);
-	}
-
-	return 0;
-}
-
 static ssize_t spd5118_nvmem_read_page(struct regmap *regmap, char *buf,
 				       unsigned int offset, size_t count)
 {
+	int addr = (offset >> SPD5118_PAGE_SHIFT) * 0x100 + SPD5118_EEPROM_BASE;
 	int err;
 
-	err = spd5118_nvmem_set_page(regmap, offset >> SPD5118_PAGE_SHIFT);
-	if (err)
-		return err;
-
 	offset &= SPD5118_PAGE_MASK;
 
 	/* Can't cross page boundaries */
 	if (offset + count > SPD5118_PAGE_SIZE)
 		count = SPD5118_PAGE_SIZE - offset;
 
-	err = regmap_bulk_read(regmap, SPD5118_EEPROM_BASE + offset, buf, count);
+	err = regmap_bulk_read(regmap, addr + offset, buf, count);
 	if (err)
 		return err;
 
@@ -515,13 +489,28 @@ static bool spd5118_volatile_reg(struct device *dev, unsigned int reg)
 	}
 }
 
+static const struct regmap_range_cfg spd5118_regmap_range_cfg[] = {
+	{
+	.selector_reg   = SPD5118_REG_I2C_LEGACY_MODE,
+	.selector_mask  = SPD5118_LEGACY_PAGE_MASK,
+	.selector_shift = 0,
+	.window_start   = 0,
+	.window_len     = 0x100,
+	.range_min      = 0,
+	.range_max      = 0x7ff,
+	},
+};
+
 static const struct regmap_config spd5118_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
-	.max_register = 0xff,
+	.max_register = 0x7ff,
 	.writeable_reg = spd5118_writeable_reg,
 	.volatile_reg = spd5118_volatile_reg,
 	.cache_type = REGCACHE_MAPLE,
+
+	.ranges = spd5118_regmap_range_cfg,
+	.num_ranges = ARRAY_SIZE(spd5118_regmap_range_cfg),
 };
 
 static int spd5118_probe(struct i2c_client *client)
-- 
2.39.2