linux-kernel - [PATCH 6/6] i3c: dw: Add quirk to address OD/PP timing issue on AMD platform

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Message-ID: <20241017150330.3035568-7-Shyam-sundar.S-k@amd.com>
Date: Thu, 17 Oct 2024 20:33:30 +0530
From: Shyam Sundar S K <Shyam-sundar.S-k@....com>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>, Jarkko Nikula
	<jarkko.nikula@...ux.intel.com>
CC: <Sanket.Goswami@....com>, <linux-i3c@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, Shyam Sundar S K <Shyam-sundar.S-k@....com>
Subject: [PATCH 6/6] i3c: dw: Add quirk to address OD/PP timing issue on AMD platform

The AMD Legacy I3C is having a problem with its IP, specifically with the
push-pull and open-drain pull-up registers. These registers need to be
manually programmed for every CCC submission to align with the duty cycle.
Therefore, add a quirk to address this issue.

Co-developed-by: Sanket Goswami <Sanket.Goswami@....com>
Signed-off-by: Sanket Goswami <Sanket.Goswami@....com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@....com>
---
 drivers/i3c/master/dw-i3c-master.c | 29 ++++++++++++++++++++++++++++-
 drivers/i3c/master/dw-i3c-master.h |  1 +
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index 8f452976dd7c..8500b0d0dcf3 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -220,6 +220,14 @@
 
 #define XFER_TIMEOUT (msecs_to_jiffies(1000))
 #define RPM_AUTOSUSPEND_TIMEOUT 1000 /* ms */
+
+/* Timing values to configure 12.5MHz frequency */
+#define AMD_I3C_OD_TIMING          0x4C007C
+#define AMD_I3C_PP_TIMING          0x8001A
+
+/* List of quirks */
+#define AMD_I3C_OD_PP_TIMING		BIT(1)
+
 struct dw_i3c_cmd {
 	u32 cmd_lo;
 	u32 cmd_hi;
@@ -795,6 +803,12 @@ static int dw_i3c_ccc_get(struct dw_i3c_master *master, struct i3c_ccc_cmd *ccc)
 	return ret;
 }
 
+static void amd_configure_od_pp_quirk(struct dw_i3c_master *master)
+{
+	master->i3c_od_timing = AMD_I3C_OD_TIMING;
+	master->i3c_pp_timing = AMD_I3C_PP_TIMING;
+}
+
 static int dw_i3c_master_send_ccc_cmd(struct i3c_master_controller *m,
 				      struct i3c_ccc_cmd *ccc)
 {
@@ -804,6 +818,13 @@ static int dw_i3c_master_send_ccc_cmd(struct i3c_master_controller *m,
 	if (ccc->id == I3C_CCC_ENTDAA)
 		return -EINVAL;
 
+	/* AMD platform specific OD and PP timings */
+	if (master->quirks & AMD_I3C_OD_PP_TIMING) {
+		amd_configure_od_pp_quirk(master);
+		writel(master->i3c_pp_timing, master->regs + SCL_I3C_PP_TIMING);
+		writel(master->i3c_od_timing, master->regs + SCL_I3C_OD_TIMING);
+	}
+
 	ret = pm_runtime_resume_and_get(master->dev);
 	if (ret < 0) {
 		dev_err(master->dev,
@@ -1608,6 +1629,8 @@ int dw_i3c_common_probe(struct dw_i3c_master *master,
 	if (!master->base.ahandle)
 		dev_err(&pdev->dev, "Failed to get acpi device handle\n");
 
+	master->quirks = (unsigned long)device_get_match_data(&pdev->dev);
+
 	INIT_WORK(&master->hj_work, dw_i3c_hj_work);
 	ret = i3c_master_register(&master->base, &pdev->dev,
 				  &dw_mipi_i3c_ops, false);
@@ -1681,6 +1704,10 @@ static void dw_i3c_master_restore_addrs(struct dw_i3c_master *master)
 
 static void dw_i3c_master_restore_timing_regs(struct dw_i3c_master *master)
 {
+	/* AMD platform specific OD and PP timings */
+	if (master->quirks & AMD_I3C_OD_PP_TIMING)
+		amd_configure_od_pp_quirk(master);
+
 	writel(master->i3c_pp_timing, master->regs + SCL_I3C_PP_TIMING);
 	writel(master->bus_free_timing, master->regs + BUS_FREE_TIMING);
 	writel(master->i3c_od_timing, master->regs + SCL_I3C_OD_TIMING);
@@ -1755,7 +1782,7 @@ static const struct of_device_id dw_i3c_master_of_match[] = {
 MODULE_DEVICE_TABLE(of, dw_i3c_master_of_match);
 
 static const struct acpi_device_id amd_i3c_device_match[] = {
-	{ "AMDI0015" },
+	{ "AMDI0015", AMD_I3C_OD_PP_TIMING },
 	{ }
 };
 MODULE_DEVICE_TABLE(acpi, amd_i3c_device_match);
diff --git a/drivers/i3c/master/dw-i3c-master.h b/drivers/i3c/master/dw-i3c-master.h
index 219ff815d3a7..c5cb695c16ab 100644
--- a/drivers/i3c/master/dw-i3c-master.h
+++ b/drivers/i3c/master/dw-i3c-master.h
@@ -50,6 +50,7 @@ struct dw_i3c_master {
 	u32 bus_free_timing;
 	u32 i2c_fm_timing;
 	u32 i2c_fmp_timing;
+	u32 quirks;
 	/*
 	 * Per-device hardware data, used to manage the device address table
 	 * (DAT)
-- 
2.34.1