linux-kernel - [PATCH 5/5] i2c: designware: Enable high speed mode

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Date:	Thu, 26 May 2016 16:01:12 +0800
From:	Weifeng Voon <weifeng.voon@...el.com>
To:	Wolfram Sang <wsa@...-dreams.de>,
	Jarkko Nikula <jarkko.nikula@...ux.intel.com>
Cc:	linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	jui.nee.tan@...el.com
Subject: [PATCH 5/5] i2c: designware: Enable high speed mode

This patch enabled high speed mode. High speed mode can be turn on by
setting the clk_freq to 3400000. High speed HCNT and LCNT are needed
as there is no default value provided.

Signed-off-by: Weifeng Voon <weifeng.voon@...el.com>
---
 drivers/i2c/busses/i2c-designware-core.c    | 26 +++++++++++++++++++++++++-
 drivers/i2c/busses/i2c-designware-core.h    |  2 ++
 drivers/i2c/busses/i2c-designware-platdrv.c | 16 +++++++++++-----
 3 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 25c78d2..5299b88 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -42,6 +42,8 @@
 #define DW_IC_SS_SCL_LCNT	0x18
 #define DW_IC_FS_SCL_HCNT	0x1c
 #define DW_IC_FS_SCL_LCNT	0x20
+#define DW_IC_HS_SCL_HCNT	0x24
+#define DW_IC_HS_SCL_LCNT	0x28
 #define DW_IC_INTR_STAT		0x2c
 #define DW_IC_INTR_MASK		0x30
 #define DW_IC_RAW_INTR_STAT	0x34
@@ -95,6 +97,9 @@
 
 #define DW_IC_TAR_10BITADDR_MASTER BIT(12)
 
+#define DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH	(BIT(2) | BIT(3))
+#define DW_IC_COMP_PARAM_1_SPEED_MODE_MASK	GENMASK(3, 2)
+
 /*
  * status codes
  */
@@ -293,7 +298,7 @@ static unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev)
 int i2c_dw_init(struct dw_i2c_dev *dev)
 {
 	u32 hcnt, lcnt;
-	u32 reg;
+	u32 reg, comp_param1;
 	u32 sda_falling_time, scl_falling_time;
 	int ret;
 
@@ -320,6 +325,8 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 		return -ENODEV;
 	}
 
+	comp_param1 = dw_readl(dev, DW_IC_COMP_PARAM_1);
+
 	/* Disable the adapter */
 	__i2c_dw_enable(dev, false);
 
@@ -369,6 +376,23 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 	dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
 	dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
 
+	if ((dev->master_cfg & DW_IC_CON_SPEED_MASK) ==
+		DW_IC_CON_SPEED_HIGH) {
+		if ((comp_param1 & DW_IC_COMP_PARAM_1_SPEED_MODE_MASK)
+			!= DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH) {
+			dev_err(dev->dev, "High Speed not supported!\n");
+			dev->master_cfg &= ~DW_IC_CON_SPEED_MASK;
+			dev->master_cfg |= DW_IC_CON_SPEED_FAST;
+		} else if (dev->hs_hcnt && dev->hs_lcnt) {
+			hcnt = dev->hs_hcnt;
+			lcnt = dev->hs_lcnt;
+			dw_writel(dev, hcnt, DW_IC_HS_SCL_HCNT);
+			dw_writel(dev, lcnt, DW_IC_HS_SCL_LCNT);
+			dev_dbg(dev->dev, "HighSpeed-mode HCNT:LCNT = %d:%d\n",
+				hcnt, lcnt);
+		}
+	}
+
 	/* Configure SDA Hold Time if required */
 	if (dev->sda_hold_time) {
 		reg = dw_readl(dev, DW_IC_COMP_VERSION);
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 1124240..d545011 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -26,6 +26,8 @@
 #define DW_IC_CON_MASTER		0x1
 #define DW_IC_CON_SPEED_STD		0x2
 #define DW_IC_CON_SPEED_FAST		0x4
+#define DW_IC_CON_SPEED_HIGH		0x6
+#define DW_IC_CON_SPEED_MASK		GENMASK(2, 1)
 #define DW_IC_CON_10BITADDR_MASTER	0x10
 #define DW_IC_CON_RESTART_EN		0x20
 #define DW_IC_CON_SLAVE_DISABLE		0x40
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index d45481e..cb846cb 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -197,12 +197,12 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 
 	/*
 	 * Only standard mode at 100kHz, fast mode at 400kHz,
-	 * and fast mode plus at 1MHz are supported.
+	 * fast mode plus at 1MHz and high speed mode at 3.4MHz are supported.
 	 */
 	if (dev->clk_freq != 100000 && dev->clk_freq != 400000
-	    && dev->clk_freq != 1000000) {
+	    && dev->clk_freq != 1000000 && dev->clk_freq != 3400000) {
 		dev_err(&pdev->dev,
-			"Only 100kHz, 400kHz and 1MHz are supported");
+			"Only 100kHz, 400kHz, 1MHz and 3.4MHz supported");
 		return -EINVAL;
 	}
 
@@ -221,10 +221,16 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 	dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
 			  DW_IC_CON_RESTART_EN;
 
-	if (dev->clk_freq == 100000)
+	switch (dev->clk_freq) {
+	case 100000:
 		dev->master_cfg |= DW_IC_CON_SPEED_STD;
-	else
+		break;
+	case 3400000:
+		dev->master_cfg |= DW_IC_CON_SPEED_HIGH;
+		break;
+	default:
 		dev->master_cfg |= DW_IC_CON_SPEED_FAST;
+	}
 
 	dev->clk = devm_clk_get(&pdev->dev, NULL);
 	if (!i2c_dw_plat_prepare_clk(dev, true)) {
-- 
1.9.1