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Subject[PATCH] i2c: tegra: add support for Tegra114 SoC
Date
NVIDIA's Tegra114 has following enhanced feature in i2c controller:
- Enable/disable control for per packet transfer complete interrupt.
Earlier SoCs could not disable this.
- Single clock source for standard/fast and HS mode clock speed.
The clock divisor for fast/standard mode is added into the i2c
controller to meet the HS and standard/fast mode of clock speed
from single source.

Add support for the above feature to make it functional on T114 SOCs.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
drivers/i2c/busses/i2c-tegra.c | 77 ++++++++++++++++++++++++++++++++-------
1 files changed, 63 insertions(+), 14 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 7b38877..2dadb96 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -71,6 +71,8 @@
#define I2C_INT_TX_FIFO_DATA_REQ (1<<1)
#define I2C_INT_RX_FIFO_DATA_REQ (1<<0)
#define I2C_CLK_DIVISOR 0x06c
+#define I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT 16
+#define I2C_CLK_MULTIPLIER_STD_FAST_MODE 8

#define DVC_CTRL_REG1 0x000
#define DVC_CTRL_REG1_INTR_EN (1<<10)
@@ -117,10 +119,23 @@ enum msg_end_type {
/**
* struct tegra_i2c_hw_feature : Different HW support on Tegra
* @has_continue_xfer_support: Continue transfer supports.
+ * @has_per_pkt_xfer_complete_irq: Has enable/disable capability for transfer
+ * complete interrupt per packet basis.
+ * @has_single_clk_source: The i2c controller has single clock source. Tegra30
+ * and earlier Socs has two clock sources i.e. div-clk and
+ * fast-clk.
+ * @clk_divisor_hs_mode: Clock divisor in HS mode.
+ * @clk_divisor_std_fast_mode: Clock divisor in standard/fast mode. It is
+ * applicable if there is no fast clock source i.e. single clock
+ * source.
*/

struct tegra_i2c_hw_feature {
bool has_continue_xfer_support;
+ bool has_per_pkt_xfer_complete_irq;
+ bool has_single_clk_source;
+ int clk_divisor_hs_mode;
+ int clk_divisor_std_fast_mode;
};

/**
@@ -366,11 +381,13 @@ static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
static inline int tegra_i2c_clock_enable(struct tegra_i2c_dev *i2c_dev)
{
int ret;
- ret = clk_prepare_enable(i2c_dev->fast_clk);
- if (ret < 0) {
- dev_err(i2c_dev->dev,
- "Enabling fast clk failed, err %d\n", ret);
- return ret;
+ if (!i2c_dev->hw->has_single_clk_source) {
+ ret = clk_prepare_enable(i2c_dev->fast_clk);
+ if (ret < 0) {
+ dev_err(i2c_dev->dev,
+ "Enabling fast clk failed, err %d\n", ret);
+ return ret;
+ }
}
ret = clk_prepare_enable(i2c_dev->div_clk);
if (ret < 0) {
@@ -384,13 +401,16 @@ static inline int tegra_i2c_clock_enable(struct tegra_i2c_dev *i2c_dev)
static inline void tegra_i2c_clock_disable(struct tegra_i2c_dev *i2c_dev)
{
clk_disable_unprepare(i2c_dev->div_clk);
- clk_disable_unprepare(i2c_dev->fast_clk);
+ if (!i2c_dev->hw->has_single_clk_source)
+ clk_disable_unprepare(i2c_dev->fast_clk);
}

static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
{
u32 val;
int err = 0;
+ int clk_multiplier = I2C_CLK_MULTIPLIER_STD_FAST_MODE;
+ u32 clk_divisor;

tegra_i2c_clock_enable(i2c_dev);

@@ -405,7 +425,15 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
(0x2 << I2C_CNFG_DEBOUNCE_CNT_SHIFT);
i2c_writel(i2c_dev, val, I2C_CNFG);
i2c_writel(i2c_dev, 0, I2C_INT_MASK);
- clk_set_rate(i2c_dev->div_clk, i2c_dev->bus_clk_rate * 8);
+
+ clk_multiplier *= (i2c_dev->hw->clk_divisor_std_fast_mode + 1);
+ clk_set_rate(i2c_dev->div_clk, i2c_dev->bus_clk_rate * clk_multiplier);
+
+ /* Make sure clock divisor programmed correctly */
+ clk_divisor = i2c_dev->hw->clk_divisor_hs_mode;
+ clk_divisor |= i2c_dev->hw->clk_divisor_std_fast_mode <<
+ I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT;
+ i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR);

if (!i2c_dev->is_dvc) {
u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG);
@@ -547,6 +575,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
tegra_i2c_fill_tx_fifo(i2c_dev);

int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
+ if (i2c_dev->hw->has_per_pkt_xfer_complete_irq)
+ int_mask |= I2C_INT_PACKET_XFER_COMPLETE;
if (msg->flags & I2C_M_RD)
int_mask |= I2C_INT_RX_FIFO_DATA_REQ;
else if (i2c_dev->msg_buf_remaining)
@@ -634,15 +664,32 @@ static const struct i2c_algorithm tegra_i2c_algo = {

static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {
.has_continue_xfer_support = false,
+ .has_per_pkt_xfer_complete_irq = false,
+ .has_single_clk_source = false,
+ .clk_divisor_hs_mode = 3,
+ .clk_divisor_std_fast_mode = 0,
};

static const struct tegra_i2c_hw_feature tegra30_i2c_hw = {
.has_continue_xfer_support = true,
+ .has_per_pkt_xfer_complete_irq = false,
+ .has_single_clk_source = false,
+ .clk_divisor_hs_mode = 3,
+ .clk_divisor_std_fast_mode = 0,
+};
+
+static const struct tegra_i2c_hw_feature tegra114_i2c_hw = {
+ .has_continue_xfer_support = true,
+ .has_per_pkt_xfer_complete_irq = true,
+ .has_single_clk_source = true,
+ .clk_divisor_hs_mode = 1,
+ .clk_divisor_std_fast_mode = 0x19,
};

#if defined(CONFIG_OF)
/* Match table for of_platform binding */
static const struct of_device_id tegra_i2c_of_match[] = {
+ { .compatible = "nvidia,tegra114-i2c", .data = &tegra114_i2c_hw, },
{ .compatible = "nvidia,tegra30-i2c", .data = &tegra30_i2c_hw, },
{ .compatible = "nvidia,tegra20-i2c", .data = &tegra20_i2c_hw, },
{ .compatible = "nvidia,tegra20-i2c-dvc", .data = &tegra20_i2c_hw, },
@@ -688,12 +735,6 @@ static int tegra_i2c_probe(struct platform_device *pdev)
return PTR_ERR(div_clk);
}

- fast_clk = devm_clk_get(&pdev->dev, "fast-clk");
- if (IS_ERR(fast_clk)) {
- dev_err(&pdev->dev, "missing bus clock");
- return PTR_ERR(fast_clk);
- }
-
i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
if (!i2c_dev) {
dev_err(&pdev->dev, "Could not allocate struct tegra_i2c_dev");
@@ -702,7 +743,6 @@ static int tegra_i2c_probe(struct platform_device *pdev)

i2c_dev->base = base;
i2c_dev->div_clk = div_clk;
- i2c_dev->fast_clk = fast_clk;
i2c_dev->adapter.algo = &tegra_i2c_algo;
i2c_dev->irq = irq;
i2c_dev->cont_id = pdev->id;
@@ -733,6 +773,15 @@ static int tegra_i2c_probe(struct platform_device *pdev)
}
init_completion(&i2c_dev->msg_complete);

+ if (!i2c_dev->hw->has_single_clk_source) {
+ fast_clk = devm_clk_get(&pdev->dev, "fast-clk");
+ if (IS_ERR(fast_clk)) {
+ dev_err(&pdev->dev, "missing fast clock");
+ return PTR_ERR(fast_clk);
+ }
+ i2c_dev->fast_clk = fast_clk;
+ }
+
platform_set_drvdata(pdev, i2c_dev);

ret = tegra_i2c_init(i2c_dev);
--
1.7.1.1


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