linux-kernel - [PATCH 2/3] i2c: k1: add reset support

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Message-Id: <20251230150653.42097-2-jyc0019@gmail.com>
Date: Tue, 30 Dec 2025 23:06:52 +0800
From: Encrow Thorne <jyc0019@...il.com>
To: jyc0019@...il.com
Cc: alex@...ti.fr,
	andi.shyti@...nel.org,
	aou@...s.berkeley.edu,
	conor+dt@...nel.org,
	devicetree@...r.kernel.org,
	dlan@...too.org,
	guodong@...cstar.com,
	krzk+dt@...nel.org,
	linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-riscv@...ts.infradead.org,
	p.zabel@...gutronix.de,
	palmer@...belt.com,
	pjw@...nel.org,
	robh@...nel.org,
	spacemit@...ts.linux.dev,
	troy.mitchell@...ux.spacemit.com,
	troymitchell988@...il.com
Subject: [PATCH 2/3] i2c: k1: add reset support

The K1 I2C controller provides a reset line that needs to be deasserted
before the controller can be accessed.

Add reset support to the driver to ensure the controller starts in the
required state.

Reviewed-by: Troy Mitchell <troy.mitchell@...ux.spacemit.com>
Signed-off-by: Encrow Thorne <jyc0019@...il.com>
---
 drivers/i2c/busses/i2c-k1.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
index d42c03ef5db5..23661c7ddb67 100644
--- a/drivers/i2c/busses/i2c-k1.c
+++ b/drivers/i2c/busses/i2c-k1.c
@@ -10,6 +10,7 @@
  #include <linux/module.h>
  #include <linux/of_address.h>
  #include <linux/platform_device.h>
+ #include <linux/reset.h>
 
 /* spacemit i2c registers */
 #define SPACEMIT_ICR		 0x0		/* Control register */
@@ -534,6 +535,7 @@ static int spacemit_i2c_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct device_node *of_node = pdev->dev.of_node;
 	struct spacemit_i2c_dev *i2c;
+	struct reset_control *rst;
 	int ret;
 
 	i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
@@ -578,6 +580,11 @@ static int spacemit_i2c_probe(struct platform_device *pdev)
 	if (IS_ERR(clk))
 		return dev_err_probe(dev, PTR_ERR(clk), "failed to enable bus clock");
 
+	rst = devm_reset_control_get_optional_exclusive_deasserted(dev, NULL);
+	if (IS_ERR(rst))
+		return dev_err_probe(dev, PTR_ERR(rst),
+				     "failed to acquire deasserted reset\n");
+
 	spacemit_i2c_reset(i2c);
 
 	i2c_set_adapdata(&i2c->adapt, i2c);
-- 
2.25.1