linux-kernel - [PATCH 1/5] i2c: tegra: Add HS mode support

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Message-ID: <20250108110620.86900-2-kkartik@nvidia.com>
Date: Wed, 8 Jan 2025 16:36:16 +0530
From: Kartik Rajput <kkartik@...dia.com>
To: <akhilrajeev@...dia.com>, <andi.shyti@...nel.org>, <robh@...nel.org>,
	<krzk+dt@...nel.org>, <conor+dt@...nel.org>, <thierry.reding@...il.com>,
	<jonathanh@...dia.com>, <ldewangan@...dia.com>, <digetx@...il.com>,
	<linux-i2c@...r.kernel.org>, <devicetree@...r.kernel.org>,
	<linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/5] i2c: tegra: Add HS mode support

From: Akhil R <akhilrajeev@...dia.com>

Add support for HS (High Speed) mode tranfers, which is supported by
Tegra194 onwards.

Signed-off-by: Akhil R <akhilrajeev@...dia.com>
Signed-off-by: Kartik Rajput <kkartik@...dia.com>
---
 drivers/i2c/busses/i2c-tegra.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 87976e99e6d0..7b97c6d347ee 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -91,6 +91,7 @@
 #define I2C_HEADER_IE_ENABLE			BIT(17)
 #define I2C_HEADER_REPEAT_START			BIT(16)
 #define I2C_HEADER_CONTINUE_XFER		BIT(15)
+#define I2C_HEADER_HS_MODE			BIT(22)
 #define I2C_HEADER_SLAVE_ADDR_SHIFT		1
 
 #define I2C_BUS_CLEAR_CNFG			0x084
@@ -220,10 +221,13 @@ struct tegra_i2c_hw_feature {
 	u32 thigh_std_mode;
 	u32 tlow_fast_fastplus_mode;
 	u32 thigh_fast_fastplus_mode;
+	u32 tlow_hs_mode;
+	u32 thigh_hs_mode;
 	u32 setup_hold_time_std_mode;
 	u32 setup_hold_time_fast_fast_plus_mode;
 	u32 setup_hold_time_hs_mode;
 	bool has_interface_timing_reg;
+	bool has_hs_mode_support;
 };
 
 /**
@@ -681,6 +685,18 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 	if (i2c_dev->hw->has_interface_timing_reg && tsu_thd)
 		i2c_writel(i2c_dev, tsu_thd, I2C_INTERFACE_TIMING_1);
 
+	/* Write HS mode registers. These will get used only for HS mode*/
+	if (i2c_dev->hw->has_hs_mode_support) {
+		tlow = i2c_dev->hw->tlow_hs_mode;
+		thigh = i2c_dev->hw->thigh_hs_mode;
+		tsu_thd = i2c_dev->hw->setup_hold_time_hs_mode;
+
+		val = FIELD_PREP(I2C_HS_INTERFACE_TIMING_THIGH, thigh) |
+			FIELD_PREP(I2C_HS_INTERFACE_TIMING_TLOW, tlow);
+		i2c_writel(i2c_dev, val, I2C_HS_INTERFACE_TIMING_0);
+		i2c_writel(i2c_dev, tsu_thd, I2C_HS_INTERFACE_TIMING_1);
+	}
+
 	clk_multiplier = (tlow + thigh + 2) * (non_hs_mode + 1);
 
 	err = clk_set_rate(i2c_dev->div_clk,
@@ -1178,6 +1194,9 @@ static void tegra_i2c_push_packet_header(struct tegra_i2c_dev *i2c_dev,
 	if (msg->flags & I2C_M_RD)
 		packet_header |= I2C_HEADER_READ;
 
+	if (i2c_dev->timings.bus_freq_hz > I2C_MAX_FAST_MODE_PLUS_FREQ)
+		packet_header |= I2C_HEADER_HS_MODE;
+
 	if (i2c_dev->dma_mode && !i2c_dev->msg_read)
 		*dma_buf++ = packet_header;
 	else
@@ -1618,10 +1637,13 @@ static const struct tegra_i2c_hw_feature tegra194_i2c_hw = {
 	.thigh_std_mode = 0x7,
 	.tlow_fast_fastplus_mode = 0x2,
 	.thigh_fast_fastplus_mode = 0x2,
+	.tlow_hs_mode = 0x8,
+	.thigh_hs_mode = 0x3,
 	.setup_hold_time_std_mode = 0x08080808,
 	.setup_hold_time_fast_fast_plus_mode = 0x02020202,
 	.setup_hold_time_hs_mode = 0x090909,
 	.has_interface_timing_reg = true,
+	.has_hs_mode_support = true,
 };
 
 static const struct of_device_id tegra_i2c_of_match[] = {
-- 
2.43.0