[PATCH v4 3/5] i2c: tegra: Add HS mode support
From: Kartik Rajput <hidden>
Date: 2025-08-18 09:25:04
Also in:
linux-i2c, linux-tegra, lkml
Subsystem:
i2c subsystem, i2c subsystem host drivers, tegra i2c driver, the rest · Maintainers:
Andi Shyti, Laxman Dewangan, Linus Torvalds
From: Akhil R <akhilrajeev@nvidia.com> Add support for HS (High Speed) mode transfers, which is supported by Tegra194 onwards. Signed-off-by: Akhil R <akhilrajeev@nvidia.com> Signed-off-by: Kartik Rajput <redacted> --- v2 -> v3: * Document tlow_hs_mode and thigh_hs_mode. v1 -> v2: * Document has_hs_mode_support. * Add a check to set the frequency to fastmode+ if the device does not support HS mode but the requested frequency is more than fastmode+. --- drivers/i2c/busses/i2c-tegra.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 0c428cba4df3..6e322dba42b1 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
@@ -198,6 +199,8 @@ enum msg_end_type { * @thigh_std_mode: High period of the clock in standard mode. * @tlow_fast_fastplus_mode: Low period of the clock in fast/fast-plus modes. * @thigh_fast_fastplus_mode: High period of the clock in fast/fast-plus modes. + * @tlow_hs_mode: Low period of the clock in HS mode. + * @thigh_hs_mode: High period of the clock in HS mode. * @setup_hold_time_std_mode: Setup and hold time for start and stop conditions * in standard mode. * @setup_hold_time_fast_fast_plus_mode: Setup and hold time for start and stop
@@ -206,6 +209,7 @@ enum msg_end_type { * in HS mode. * @has_interface_timing_reg: Has interface timing register to program the tuned * timing settings. + * @has_hs_mode_support: Has support for high speed (HS) mode transfers. */ struct tegra_i2c_hw_feature { bool has_continue_xfer_support;
@@ -226,10 +230,13 @@ 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; }; /**
@@ -717,6 +724,20 @@ 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); + } else if (t->bus_freq_hz > I2C_MAX_FAST_MODE_PLUS_FREQ) { + t->bus_freq_hz = I2C_MAX_FAST_MODE_PLUS_FREQ; + } + clk_multiplier = (tlow + thigh + 2) * (non_hs_mode + 1); err = clk_set_rate(i2c_dev->div_clk,
@@ -1214,6 +1235,9 @@ 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
@@ -1648,10 +1672,13 @@ 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[] = {
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2.43.0