linux-kernel - [PATCH 2/2] pinctrl: cy8c95x0: Update cache modification

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Date: Wed, 26 Jun 2024 10:45:23 +0200
From: Patrick Rudolph <patrick.rudolph@...ements.com>
To: Patrick Rudolph <patrick.rudolph@...ements.com>,
	Linus Walleij <linus.walleij@...aro.org>
Cc: naresh.solanki@...ements.com,
	andy.shevchenko@...il.com,
	broonie@...nel.org,
	linux-gpio@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] pinctrl: cy8c95x0: Update cache modification

In the previous review cycle the regmap cache update code was
questioned since it seems and odd way of using regmap_update_bits().
Thus update the regmap cache modification code to better explain
what it does and why it's done. This is no functional change, but
it's improving code maintainability.

Signed-off-by: Patrick Rudolph <patrick.rudolph@...ements.com>
---
 drivers/pinctrl/pinctrl-cy8c95x0.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-cy8c95x0.c b/drivers/pinctrl/pinctrl-cy8c95x0.c
index 781949e0e09e..9a92707d2525 100644
--- a/drivers/pinctrl/pinctrl-cy8c95x0.c
+++ b/drivers/pinctrl/pinctrl-cy8c95x0.c
@@ -475,7 +475,7 @@ static inline int cy8c95x0_regmap_update_bits_base(struct cy8c95x0_pinctrl *chip
 						   bool *change, bool async,
 						   bool force)
 {
-	int ret, off, i, read_val;
+	int ret, off, i;
 
 	/* Caller should never modify PORTSEL directly */
 	if (reg == CY8C95X0_PORTSEL)
@@ -497,24 +497,20 @@ static inline int cy8c95x0_regmap_update_bits_base(struct cy8c95x0_pinctrl *chip
 	if (ret < 0)
 		return ret;
 
-	/* Update the cache when a WC bit is written */
+	/* Mimic what hardware does and update the cache when a WC bit is written.
+	 * Allows to mark the registers as non-volatile and reduces I/O cycles.
+	 */
 	if (cy8c95x0_wc_register(reg) && (mask & val)) {
+		/* Writing a 1 clears set bits in the other drive mode registers */
+		regcache_cache_only(chip->regmap, true);
 		for (i = CY8C95X0_DRV_PU; i <= CY8C95X0_DRV_HIZ; i++) {
 			if (i == reg)
 				continue;
-			off = CY8C95X0_MUX_REGMAP_TO_OFFSET(i, port);
-
-			ret = regmap_read(chip->regmap, off, &read_val);
-			if (ret < 0)
-				continue;
 
-			if (!(read_val & mask & val))
-				continue;
-
-			regcache_cache_only(chip->regmap, true);
-			regmap_update_bits(chip->regmap, off, mask & val, 0);
-			regcache_cache_only(chip->regmap, false);
+			off = CY8C95X0_MUX_REGMAP_TO_OFFSET(i, port);
+			regmap_clear_bits(chip->regmap, off, mask & val);
 		}
+		regcache_cache_only(chip->regmap, false);
 	}
 
 	return ret;
-- 
2.44.0