linux-kernel - [PATCH 2/2] i2c: designware: allow fine tuning tuning waveform from device tree

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Date: Thu,  1 Feb 2024 04:46:23 +0000
From: Aahil Awatramani <aahila@...gle.com>
To: Aahil Awatramani <aahila@...gle.com>, David Dillow <dillow@...gle.com>, 
	Wolfram Sang <wsa+renesas@...g-engineering.com>, Andi Shyti <andi.shyti@...nel.org>, 
	Rob Herring <robh+dt@...nel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>, 
	Jarkko Nikula <jarkko.nikula@...ux.intel.com>, 
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
	Mika Westerberg <mika.westerberg@...ux.intel.com>, Jan Dabros <jsd@...ihalf.com>, 
	linux-i2c@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] i2c: designware: allow fine tuning tuning waveform from
 device tree

The Synopsys i2c driver allows a user to override the parameters
controlling the waveform using ACPI; this is useful for fine tuning when
needed to make spec compliance. Extend this support to the device tree to
allow non-ACPI platforms the same capabilities.

Signed-off-by: Aahil Awatramani <aahila@...gle.com>
---
 drivers/i2c/busses/i2c-designware-platdrv.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 855b698e99c0..09c464874fdb 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -132,6 +132,17 @@ static int mscc_twi_set_sda_hold_time(struct dw_i2c_dev *dev)
 	return 0;
 }
 
+static void i2c_parse_cnt(struct device *dev, char *prop_name, u16 *cnt)
+{
+	u32 tmp_cnt;
+	int ret;
+
+	ret = device_property_read_u32(dev, prop_name, &tmp_cnt);
+	if (ret)
+		return;
+	*cnt = tmp_cnt;
+}
+
 static int dw_i2c_of_configure(struct platform_device *pdev)
 {
 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
@@ -146,6 +157,15 @@ static int dw_i2c_of_configure(struct platform_device *pdev)
 		break;
 	}
 
+	i2c_parse_cnt(&pdev->dev, "i2c-scl-ss-hcnt", &dev->ss_hcnt);
+	i2c_parse_cnt(&pdev->dev, "i2c-scl-ss-lcnt", &dev->ss_lcnt);
+	i2c_parse_cnt(&pdev->dev, "i2c-scl-fs-hcnt", &dev->fs_hcnt);
+	i2c_parse_cnt(&pdev->dev, "i2c-scl-fs-lcnt", &dev->fs_lcnt);
+	i2c_parse_cnt(&pdev->dev, "i2c-scl-fp-hcnt", &dev->fp_hcnt);
+	i2c_parse_cnt(&pdev->dev, "i2c-scl-fp-lcnt", &dev->fp_lcnt);
+	i2c_parse_cnt(&pdev->dev, "i2c-scl-hs-hcnt", &dev->hs_hcnt);
+	i2c_parse_cnt(&pdev->dev, "i2c-scl-hs-lcnt", &dev->hs_lcnt);
+
 	return 0;
 }
 
-- 
2.43.0.429.g432eaa2c6b-goog