1 files changed, 31 insertions, 13 deletions

diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index e8ac9a7bf0b3..c8cbe5b1aeb1 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -22,7 +22,7 @@
 #include <linux/regmap.h>
 #include <linux/reset.h>
 
-#define DEFAULT_SYMBOL_NAMESPACE	I2C_DW
+#define DEFAULT_SYMBOL_NAMESPACE	"I2C_DW"
 
 #include "i2c-designware-core.h"
 
@@ -71,7 +71,6 @@ static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 					ic_clk,
 					4000,	/* tHD;STA = tHIGH = 4.0 us */
 					sda_falling_time,
-					0,	/* 0: DW default, 1: Ideal */
 					0);	/* No offset */
 		dev->ss_lcnt =
 			i2c_dw_scl_lcnt(dev,
@@ -105,7 +104,6 @@ static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 						ic_clk,
 						260,	/* tHIGH = 260 ns */
 						sda_falling_time,
-						0,	/* DW default */
 						0);	/* No offset */
 			dev->fs_lcnt =
 				i2c_dw_scl_lcnt(dev,
@@ -129,7 +127,6 @@ static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 					ic_clk,
 					600,	/* tHD;STA = tHIGH = 0.6 us */
 					sda_falling_time,
-					0,	/* 0: DW default, 1: Ideal */
 					0);	/* No offset */
 		dev->fs_lcnt =
 			i2c_dw_scl_lcnt(dev,
@@ -154,20 +151,38 @@ static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 			dev->hs_hcnt = 0;
 			dev->hs_lcnt = 0;
 		} else if (!dev->hs_hcnt || !dev->hs_lcnt) {
+			u32 t_high, t_low;
+
+			/*
+			 * The legal values stated in the databook for bus
+			 * capacitance are only 100pF and 400pF.
+			 * If dev->bus_capacitance_pF is greater than or equals
+			 * to 400, t_high and t_low are assumed to be
+			 * appropriate values for 400pF, otherwise 100pF.
+			 */
+			if (dev->bus_capacitance_pF >= 400) {
+				/* assume bus capacitance is 400pF */
+				t_high = dev->clk_freq_optimized ? 160 : 120;
+				t_low = 320;
+			} else {
+				/* assume bus capacitance is 100pF */
+				t_high = 60;
+				t_low = dev->clk_freq_optimized ? 120 : 160;
+			}
+
 			ic_clk = i2c_dw_clk_rate(dev);
 			dev->hs_hcnt =
 				i2c_dw_scl_hcnt(dev,
 						DW_IC_HS_SCL_HCNT,
 						ic_clk,
-						160,	/* tHIGH = 160 ns */
+						t_high,
 						sda_falling_time,
-						0,	/* DW default */
 						0);	/* No offset */
 			dev->hs_lcnt =
 				i2c_dw_scl_lcnt(dev,
 						DW_IC_HS_SCL_LCNT,
 						ic_clk,
-						320,	/* tLOW = 320 ns */
+						t_low,
 						scl_falling_time,
 						0);	/* No offset */
 		}
@@ -184,12 +199,14 @@ static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 }
 
 /**
- * i2c_dw_init_master() - Initialize the designware I2C master hardware
+ * i2c_dw_init_master() - Initialize the DesignWare I2C master hardware
  * @dev: device private data
  *
  * This functions configures and enables the I2C master.
  * This function is called during I2C init function, and in case of timeout at
  * run time.
+ *
+ * Return: 0 on success, or negative errno otherwise.
  */
 static int i2c_dw_init_master(struct dw_i2c_dev *dev)
 {
@@ -357,7 +374,7 @@ static int amd_i2c_dw_xfer_quirk(struct i2c_adapter *adap, struct i2c_msg *msgs,
 		/*
 		 * Initiate the i2c read/write transaction of buffer length,
 		 * and poll for bus busy status. For the last message transfer,
-		 * update the command with stopbit enable.
+		 * update the command with stop bit enable.
 		 */
 		for (msg_itr_lmt = buf_len; msg_itr_lmt > 0; msg_itr_lmt--) {
 			if (msg_wrt_idx == num_msgs - 1 && msg_itr_lmt == 1)
@@ -402,7 +419,7 @@ static int amd_i2c_dw_xfer_quirk(struct i2c_adapter *adap, struct i2c_msg *msgs,
 
 /*
  * Initiate (and continue) low level master read/write transaction.
- * This function is only called from i2c_dw_isr, and pumping i2c_msg
+ * This function is only called from i2c_dw_isr(), and pumping i2c_msg
  * messages into the tx buffer.  Even if the size of i2c_msg data is
  * longer than the size of the tx buffer, it handles everything.
  */
@@ -440,7 +457,8 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
 			buf = msgs[dev->msg_write_idx].buf;
 			buf_len = msgs[dev->msg_write_idx].len;
 
-			/* If both IC_EMPTYFIFO_HOLD_MASTER_EN and
+			/*
+			 * If both IC_EMPTYFIFO_HOLD_MASTER_EN and
 			 * IC_RESTART_EN are set, we must manually
 			 * set restart bit between messages.
 			 */
@@ -971,7 +989,7 @@ static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
 	rinfo->unprepare_recovery = i2c_dw_unprepare_recovery;
 	adap->bus_recovery_info = rinfo;
 
-	dev_info(dev->dev, "running with gpio recovery mode! scl%s",
+	dev_info(dev->dev, "running with GPIO recovery mode! scl%s",
 		 rinfo->sda_gpiod ? ",sda" : "");
 
 	return 0;
@@ -1076,4 +1094,4 @@ EXPORT_SYMBOL_GPL(i2c_dw_probe_master);
 
 MODULE_DESCRIPTION("Synopsys DesignWare I2C bus master adapter");
 MODULE_LICENSE("GPL");
-MODULE_IMPORT_NS(I2C_DW_COMMON);
+MODULE_IMPORT_NS("I2C_DW_COMMON");