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

Kartik Rajput
2025-01-08T11:06:48Z

From: Akhil R <akhilrajeev@nvidia.com>

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

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Signed-off-by: Kartik Rajput <kkartik@nvidia.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