[PATCH v8 0/5] Introducing an attribute to select the time setting

@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/module.h>

@@ -49,6 +50,8 @@
 #define I2C_RD_TRANAC_VALUE		0x0001
 #define I2C_SCL_MIS_COMP_VALUE		0x0000
 #define I2C_CHN_CLR_FLAG		0x0000
+#define I2C_RELIABILITY		0x0010
+#define I2C_DMAACK_ENABLE		0x0008
 
 #define I2C_DMA_CON_TX			0x0000
 #define I2C_DMA_CON_RX			0x0001

@@ -851,6 +854,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
 	u16 restart_flag = 0;
 	u16 dma_sync = 0;
 	u32 reg_4g_mode;
+	u32 reg_dma_reset;
 	u8 *dma_rd_buf = NULL;
 	u8 *dma_wr_buf = NULL;
 	dma_addr_t rpaddr = 0;

@@ -864,6 +868,28 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
 
 	reinit_completion(&i2c->msg_complete);
 
+	if (i2c->dev_comp->apdma_sync &&
+	    i2c->op != I2C_MASTER_WRRD && num > 1) {
+		mtk_i2c_writew(i2c, 0x00, OFFSET_DEBUGCTRL);
+		writel(I2C_DMA_HANDSHAKE_RST | I2C_DMA_WARM_RST,
+		       i2c->pdmabase + OFFSET_RST);
+
+		ret = readw_poll_timeout(i2c->pdmabase + OFFSET_RST,
+					 reg_dma_reset,
+					 !(reg_dma_reset & I2C_DMA_WARM_RST),
+					 0, 100);
+		if (ret) {
+			dev_err(i2c->dev, "DMA warm reset timeout\n");
+			return -ETIMEDOUT;
+		}
+
+		writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST);
+		mtk_i2c_writew(i2c, I2C_HANDSHAKE_RST, OFFSET_SOFTRESET);
+		mtk_i2c_writew(i2c, I2C_CHN_CLR_FLAG, OFFSET_SOFTRESET);
+		mtk_i2c_writew(i2c, I2C_RELIABILITY | I2C_DMAACK_ENABLE,
+			       OFFSET_DEBUGCTRL);
+	}
+
 	control_reg = mtk_i2c_readw(i2c, OFFSET_CONTROL) &
 			~(I2C_CONTROL_DIR_CHANGE | I2C_CONTROL_RS);
 	if ((i2c->speed_hz > I2C_MAX_FAST_MODE_PLUS_FREQ) || (left_num >= 1))

@@ -130,6 +130,7 @@ enum I2C_REGS_OFFSET {
 	OFFSET_HS,
 	OFFSET_SOFTRESET,
 	OFFSET_DCM_EN,
+	OFFSET_MULTI_DMA,
 	OFFSET_PATH_DIR,
 	OFFSET_DEBUGSTAT,
 	OFFSET_DEBUGCTRL,

@@ -197,6 +198,7 @@ static const u16 mt_i2c_regs_v2[] = {
 	[OFFSET_TRANSFER_LEN_AUX] = 0x44,
 	[OFFSET_CLOCK_DIV] = 0x48,
 	[OFFSET_SOFTRESET] = 0x50,
+	[OFFSET_MULTI_DMA] = 0x8c,
 	[OFFSET_SCL_MIS_COMP_POINT] = 0x90,
 	[OFFSET_DEBUGSTAT] = 0xe4,
 	[OFFSET_DEBUGCTRL] = 0xe8,

@@ -845,6 +847,57 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
 	return 0;
 }
 
+static void i2c_dump_register(struct mtk_i2c *i2c)
+{
+	dev_dbg(i2c->dev, "SLAVE_ADDR: 0x%x, INTR_MASK: 0x%x\n",
+		mtk_i2c_readw(i2c, OFFSET_SLAVE_ADDR),
+		mtk_i2c_readw(i2c, OFFSET_INTR_MASK));
+	dev_dbg(i2c->dev, "INTR_STAT: 0x%x, CONTROL: 0x%x\n",
+		mtk_i2c_readw(i2c, OFFSET_INTR_STAT),
+		mtk_i2c_readw(i2c, OFFSET_CONTROL));
+	dev_dbg(i2c->dev, "TRANSFER_LEN: 0x%x, TRANSAC_LEN: 0x%x\n",
+		mtk_i2c_readw(i2c, OFFSET_TRANSFER_LEN),
+		mtk_i2c_readw(i2c, OFFSET_TRANSAC_LEN));
+	dev_dbg(i2c->dev, "DELAY_LEN: 0x%x, HTIMING: 0x%x\n",
+		mtk_i2c_readw(i2c, OFFSET_DELAY_LEN),
+		mtk_i2c_readw(i2c, OFFSET_TIMING));
+	dev_dbg(i2c->dev, "START: 0x%x, EXT_CONF: 0x%x\n",
+		mtk_i2c_readw(i2c, OFFSET_START),
+		mtk_i2c_readw(i2c, OFFSET_EXT_CONF));
+	dev_dbg(i2c->dev, "HS: 0x%x, IO_CONFIG: 0x%x\n",
+		mtk_i2c_readw(i2c, OFFSET_HS),
+		mtk_i2c_readw(i2c, OFFSET_IO_CONFIG));
+	dev_dbg(i2c->dev, "DCM_EN: 0x%x, TRANSFER_LEN_AUX: 0x%x\n",
+		mtk_i2c_readw(i2c, OFFSET_DCM_EN),
+		mtk_i2c_readw(i2c, OFFSET_TRANSFER_LEN_AUX));
+	dev_dbg(i2c->dev, "CLOCK_DIV: 0x%x, FIFO_STAT: 0x%x\n",
+		mtk_i2c_readw(i2c, OFFSET_CLOCK_DIV),
+		mtk_i2c_readw(i2c, OFFSET_FIFO_STAT));
+	dev_dbg(i2c->dev, "DEBUGCTRL : 0x%x, DEBUGSTAT: 0x%x\n",
+		mtk_i2c_readw(i2c, OFFSET_DEBUGCTRL),
+		mtk_i2c_readw(i2c, OFFSET_DEBUGSTAT));
+	if (i2c->dev_comp->regs == mt_i2c_regs_v2) {
+		dev_dbg(i2c->dev, "LTIMING: 0x%x, MULTI_DMA: 0x%x\n",
+			mtk_i2c_readw(i2c, OFFSET_LTIMING),
+			mtk_i2c_readw(i2c, OFFSET_MULTI_DMA));
+	}
+	dev_dbg(i2c->dev, "\nDMA_INT_FLAG: 0x%x, DMA_INT_EN: 0x%x\n",
+		readl(i2c->pdmabase + OFFSET_INT_FLAG),
+		readl(i2c->pdmabase + OFFSET_INT_EN));
+	dev_dbg(i2c->dev, "DMA_EN: 0x%x, DMA_CON: 0x%x\n",
+		readl(i2c->pdmabase + OFFSET_EN),
+		readl(i2c->pdmabase + OFFSET_CON));
+	dev_dbg(i2c->dev, "DMA_TX_MEM_ADDR: 0x%x, DMA_RX_MEM_ADDR: 0x%x\n",
+		readl(i2c->pdmabase + OFFSET_TX_MEM_ADDR),
+		readl(i2c->pdmabase + OFFSET_RX_MEM_ADDR));
+	dev_dbg(i2c->dev, "DMA_TX_LEN: 0x%x, DMA_RX_LEN: 0x%x\n",
+		readl(i2c->pdmabase + OFFSET_TX_LEN),
+		readl(i2c->pdmabase + OFFSET_RX_LEN));
+	dev_dbg(i2c->dev, "DMA_TX_4G_MODE: 0x%x, DMA_RX_4G_MODE: 0x%x",
+		readl(i2c->pdmabase + OFFSET_TX_4G_MODE),
+		readl(i2c->pdmabase + OFFSET_RX_4G_MODE));
+}
+
 static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
 			       int num, int left_num)
 {

@@ -1075,6 +1128,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
 
 	if (ret == 0) {
 		dev_dbg(i2c->dev, "addr: %x, transfer timeout\n", msgs->addr);
+		i2c_dump_register(i2c);
 		mtk_i2c_init_hw(i2c);
 		return -ETIMEDOUT;
 	}

@@ -34,6 +34,8 @@ Optional properties:
     Only mt6589 and mt8135 support this feature.
   - mediatek,use-push-pull: IO config use push-pull mode.
   - vbus-supply: phandle to the regulator that provides power to SCL/SDA.
+  - mediatek,use-default-timing: use default timing calculation, no timing
+    adjustment.
 
 Example:
 

@@ -65,6 +65,7 @@
 #define I2C_DMA_HARD_RST		0x0002
 #define I2C_DMA_HANDSHAKE_RST		0x0004
 
+#define I2C_DEFAULT_CLK_DIV		5
 #define MAX_SAMPLE_CNT_DIV		8
 #define MAX_STEP_CNT_DIV		64
 #define MAX_CLOCK_DIV			256

@@ -249,6 +250,7 @@ struct mtk_i2c {
 	struct clk *clk_arb;		/* Arbitrator clock for i2c */
 	bool have_pmic;			/* can use i2c pins from PMIC */
 	bool use_push_pull;		/* IO config push-pull mode */
+	bool use_default_timing;	/* no timing adjust mode */
 
 	u16 irq_stat;			/* interrupt status */
 	unsigned int clk_src_div;

@@ -531,7 +533,11 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c)
 	else
 		ext_conf_val = I2C_FS_START_CON;
 
-	if (i2c->dev_comp->timing_adjust) {
+	if (i2c->use_default_timing) {
+		if (i2c->dev_comp->timing_adjust)
+			mtk_i2c_writew(i2c, I2C_DEFAULT_CLK_DIV - 1,
+				       OFFSET_CLOCK_DIV);
+	} else if (i2c->dev_comp->timing_adjust) {
 		ext_conf_val = i2c->ac_timing.ext;
 		mtk_i2c_writew(i2c, i2c->ac_timing.inter_clk_div,
 			       OFFSET_CLOCK_DIV);

@@ -614,7 +620,7 @@ static int mtk_i2c_check_ac_timing(struct mtk_i2c *i2c,
 	unsigned int sample_ns = div_u64(1000000000ULL * (sample_cnt + 1),
 					 clk_src);
 
-	if (!i2c->dev_comp->timing_adjust)
+	if (i2c->use_default_timing || !i2c->dev_comp->timing_adjust)
 		return 0;
 
 	if (i2c->dev_comp->ltiming_adjust)

@@ -774,7 +780,65 @@ static int mtk_i2c_calculate_speed(struct mtk_i2c *i2c, unsigned int clk_src,
 	return 0;
 }
 
-static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
+static int mtk_i2c_set_speed_default_timing(struct mtk_i2c *i2c,
+					    unsigned int parent_clk)
+{
+	unsigned int clk_src;
+	unsigned int step_cnt;
+	unsigned int sample_cnt;
+	unsigned int l_step_cnt;
+	unsigned int l_sample_cnt;
+	unsigned int target_speed;
+	int ret;
+
+	if (i2c->dev_comp->timing_adjust)
+		i2c->clk_src_div *= I2C_DEFAULT_CLK_DIV;
+
+	clk_src = parent_clk / i2c->clk_src_div;
+	target_speed = i2c->speed_hz;
+
+	if (target_speed > I2C_MAX_FAST_MODE_PLUS_FREQ) {
+		/* Set master code speed register */
+		ret = mtk_i2c_calculate_speed(i2c, clk_src,
+					      I2C_MAX_FAST_MODE_FREQ,
+					      &l_step_cnt, &l_sample_cnt);
+		if (ret < 0)
+			return ret;
+
+		i2c->timing_reg = (l_sample_cnt << 8) | l_step_cnt;
+
+		/* Set the high speed mode register */
+		ret = mtk_i2c_calculate_speed(i2c, clk_src, target_speed,
+					      &step_cnt, &sample_cnt);
+		if (ret < 0)
+			return ret;
+
+		i2c->high_speed_reg = I2C_TIME_DEFAULT_VALUE |
+			(sample_cnt << 12) | (step_cnt << 8);
+
+		if (i2c->dev_comp->ltiming_adjust)
+			i2c->ltiming_reg = (l_sample_cnt << 6) | l_step_cnt |
+					   (sample_cnt << 12) | (step_cnt << 9);
+	} else {
+		ret = mtk_i2c_calculate_speed(i2c, clk_src, target_speed,
+					      &step_cnt, &sample_cnt);
+		if (ret < 0)
+			return ret;
+
+		i2c->timing_reg = (sample_cnt << 8) | step_cnt;
+
+		/* Disable the high speed transaction */
+		i2c->high_speed_reg = I2C_TIME_CLR_VALUE;
+
+		if (i2c->dev_comp->ltiming_adjust)
+			i2c->ltiming_reg = (sample_cnt << 6) | step_cnt;
+	}
+
+	return 0;
+}
+
+static int mtk_i2c_set_speed_adjust_timing(struct mtk_i2c *i2c,
+					   unsigned int parent_clk)
 {
 	unsigned int clk_src;
 	unsigned int step_cnt;

@@ -1271,6 +1335,8 @@ static int mtk_i2c_parse_dt(struct device_node *np, struct mtk_i2c *i2c)
 	i2c->have_pmic = of_property_read_bool(np, "mediatek,have-pmic");
 	i2c->use_push_pull =
 		of_property_read_bool(np, "mediatek,use-push-pull");
+	i2c->use_default_timing =
+		of_property_read_bool(np, "mediatek,use-default-timing");
 
 	i2c_parse_fw_timings(i2c->dev, &i2c->timing_info, true);
 

@@ -1357,7 +1423,10 @@ static int mtk_i2c_probe(struct platform_device *pdev)
 
 	strlcpy(i2c->adap.name, I2C_DRV_NAME, sizeof(i2c->adap.name));
 
-	ret = mtk_i2c_set_speed(i2c, clk_get_rate(clk));
+	if (i2c->use_default_timing)
+		ret = mtk_i2c_set_speed_default_timing(i2c, clk_get_rate(clk));
+	else
+		ret = mtk_i2c_set_speed_adjust_timing(i2c, clk_get_rate(clk));
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to set the speed.\n");
 		return -EINVAL;

@@ -68,11 +68,12 @@
 #define I2C_DEFAULT_CLK_DIV		5
 #define MAX_SAMPLE_CNT_DIV		8
 #define MAX_STEP_CNT_DIV		64
-#define MAX_CLOCK_DIV			256
+#define MAX_CLOCK_DIV_8BITS		256
+#define MAX_CLOCK_DIV_5BITS		32
 #define MAX_HS_STEP_CNT_DIV		8
-#define I2C_STANDARD_MODE_BUFFER	(1000 / 2)
-#define I2C_FAST_MODE_BUFFER		(300 / 2)
-#define I2C_FAST_MODE_PLUS_BUFFER	(20 / 2)
+#define I2C_STANDARD_MODE_BUFFER	(1000 / 3)
+#define I2C_FAST_MODE_BUFFER		(300 / 3)
+#define I2C_FAST_MODE_PLUS_BUFFER	(20 / 3)
 
 #define I2C_CONTROL_RS                  (0x1 << 1)
 #define I2C_CONTROL_DMA_EN              (0x1 << 2)

@@ -724,14 +725,26 @@ static int mtk_i2c_calculate_speed(struct mtk_i2c *i2c, unsigned int clk_src,
 	unsigned int best_mul;
 	unsigned int cnt_mul;
 	int ret = -EINVAL;
+	int clock_div_constraint = 0;
 
 	if (target_speed > I2C_MAX_HIGH_SPEED_MODE_FREQ)
 		target_speed = I2C_MAX_HIGH_SPEED_MODE_FREQ;
 
+	if (i2c->use_default_timing) {
+		clock_div_constraint = 0;
+	} else if (i2c->dev_comp->ltiming_adjust &&
+		   i2c->ac_timing.inter_clk_div > 1) {
+		clock_div_constraint = 1;
+	} else if (i2c->dev_comp->ltiming_adjust &&
+		   i2c->ac_timing.inter_clk_div == 0) {
+		clock_div_constraint = -1;
+	}
+
 	max_step_cnt = mtk_i2c_max_step_cnt(target_speed);
 	base_step_cnt = max_step_cnt;
 	/* Find the best combination */
-	opt_div = DIV_ROUND_UP(clk_src >> 1, target_speed);
+	opt_div = DIV_ROUND_UP(clk_src >> 1, target_speed) +
+		  clock_div_constraint;
 	best_mul = MAX_SAMPLE_CNT_DIV * max_step_cnt;
 
 	/* Search for the best pair (sample_cnt, step_cnt) with

@@ -766,7 +779,8 @@ static int mtk_i2c_calculate_speed(struct mtk_i2c *i2c, unsigned int clk_src,
 	sample_cnt = base_sample_cnt;
 	step_cnt = base_step_cnt;
 
-	if ((clk_src / (2 * sample_cnt * step_cnt)) > target_speed) {
+	if ((clk_src / (2 * (sample_cnt * step_cnt - clock_div_constraint))) >
+		 target_speed) {
 		/* In this case, hardware can't support such
 		 * low i2c_bus_freq
 		 */

@@ -853,13 +867,16 @@ static int mtk_i2c_set_speed_adjust_timing(struct mtk_i2c *i2c,
 	target_speed = i2c->speed_hz;
 	parent_clk /= i2c->clk_src_div;
 
-	if (i2c->dev_comp->timing_adjust)
-		max_clk_div = MAX_CLOCK_DIV;
+	if (i2c->dev_comp->timing_adjust && i2c->dev_comp->ltiming_adjust)
+		max_clk_div = MAX_CLOCK_DIV_5BITS;
+	else if (i2c->dev_comp->timing_adjust)
+		max_clk_div = MAX_CLOCK_DIV_8BITS;
 	else
 		max_clk_div = 1;
 
 	for (clk_div = 1; clk_div <= max_clk_div; clk_div++) {
 		clk_src = parent_clk / clk_div;
+		i2c->ac_timing.inter_clk_div = clk_div - 1;
 
 		if (target_speed > I2C_MAX_FAST_MODE_PLUS_FREQ) {
 			/* Set master code speed register */

@@ -906,8 +923,6 @@ static int mtk_i2c_set_speed_adjust_timing(struct mtk_i2c *i2c,
 		break;
 	}
 
-	i2c->ac_timing.inter_clk_div = clk_div - 1;
-
 	return 0;
 }