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Message-Id: <1371808422-27742-1-git-send-email-christian.ruppert@abilis.com>
Date: Fri, 21 Jun 2013 11:53:42 +0200
From: Christian Ruppert <christian.ruppert@...lis.com>
To: Wolfram Sang <wsa@...-dreams.de>
Cc: Rob Herring <robherring2@...il.com>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
linux-i2c@...r.kernel.org,
"Ben Dooks (embedded platforms)" <ben-linux@...ff.org>,
Grant Likely <grant.likely@...retlab.ca>,
Rob Landley <rob@...dley.net>,
devicetree-discuss@...ts.ozlabs.org, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org,
Vineet Gupta <Vineet.Gupta1@...opsys.com>,
Pierrick Hascoet <pierrick.hascoet@...lis.com>,
Christian Ruppert <christian.ruppert@...lis.com>
Subject: [PATCH v9] i2c-designware: make SDA hold time configurable
This patch makes the SDA hold time configurable through device tree.
Signed-off-by: Christian Ruppert <christian.ruppert@...lis.com>
Signed-off-by: Pierrick Hascoet <pierrick.hascoet@...lis.com>
---
.../devicetree/bindings/i2c/i2c-designware.txt | 14 ++++++++++++++
arch/arc/boot/dts/abilis_tb100_dvk.dts | 10 +++++-----
arch/arc/boot/dts/abilis_tb101_dvk.dts | 10 +++++-----
drivers/i2c/busses/i2c-designware-core.c | 13 +++++++++++++
drivers/i2c/busses/i2c-designware-core.h | 1 +
drivers/i2c/busses/i2c-designware-platdrv.c | 10 ++++++++++
6 files changed, 48 insertions(+), 10 deletions(-)
diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
index e42a2ee..3266cc7 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
@@ -10,6 +10,9 @@ Recommended properties :
- clock-frequency : desired I2C bus clock frequency in Hz.
+Optional properties :
+ - i2c-sda-hold-time-ns : should contain the SDA hold time in nanoseconds.
+
Example :
i2c@...00 {
@@ -20,3 +23,14 @@ Example :
interrupts = <11>;
clock-frequency = <400000>;
};
+
+ i2c@...0000 {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ compatible = "snps,designware-i2c";
+ reg = <0x1120000 0x1000>;
+ interrupt-parent = <&ictl>;
+ interrupts = <12 1>;
+ clock-frequency = <400000>;
+ i2c-sda-hold-time-ns = <300>;
+ };
diff --git a/arch/arc/boot/dts/abilis_tb100_dvk.dts b/arch/arc/boot/dts/abilis_tb100_dvk.dts
index 0fa0d4a..ebc313a 100644
--- a/arch/arc/boot/dts/abilis_tb100_dvk.dts
+++ b/arch/arc/boot/dts/abilis_tb100_dvk.dts
@@ -45,19 +45,19 @@
};
i2c0: i2c@...20000 {
- sda-hold-time = <432>;
+ i2c-sda-hold-time-ns = <432>;
};
i2c1: i2c@...21000 {
- sda-hold-time = <432>;
+ i2c-sda-hold-time-ns = <432>;
};
i2c2: i2c@...22000 {
- sda-hold-time = <432>;
+ i2c-sda-hold-time-ns = <432>;
};
i2c3: i2c@...23000 {
- sda-hold-time = <432>;
+ i2c-sda-hold-time-ns = <432>;
};
i2c4: i2c@...24000 {
- sda-hold-time = <432>;
+ i2c-sda-hold-time-ns = <432>;
};
leds {
diff --git a/arch/arc/boot/dts/abilis_tb101_dvk.dts b/arch/arc/boot/dts/abilis_tb101_dvk.dts
index a4d80ce..b204657 100644
--- a/arch/arc/boot/dts/abilis_tb101_dvk.dts
+++ b/arch/arc/boot/dts/abilis_tb101_dvk.dts
@@ -45,19 +45,19 @@
};
i2c0: i2c@...20000 {
- sda-hold-time = <432>;
+ i2c-sda-hold-time-ns = <432>;
};
i2c1: i2c@...21000 {
- sda-hold-time = <432>;
+ i2c-sda-hold-time-ns = <432>;
};
i2c2: i2c@...22000 {
- sda-hold-time = <432>;
+ i2c-sda-hold-time-ns = <432>;
};
i2c3: i2c@...23000 {
- sda-hold-time = <432>;
+ i2c-sda-hold-time-ns = <432>;
};
i2c4: i2c@...24000 {
- sda-hold-time = <432>;
+ i2c-sda-hold-time-ns = <432>;
};
leds {
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index c41ca63..66119e2 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -67,9 +67,12 @@
#define DW_IC_STATUS 0x70
#define DW_IC_TXFLR 0x74
#define DW_IC_RXFLR 0x78
+#define DW_IC_SDA_HOLD 0x7c
#define DW_IC_TX_ABRT_SOURCE 0x80
#define DW_IC_ENABLE_STATUS 0x9c
#define DW_IC_COMP_PARAM_1 0xf4
+#define DW_IC_COMP_VERSION 0xf8
+#define DW_IC_SDA_HOLD_MIN_VERS 0x3131312A
#define DW_IC_COMP_TYPE 0xfc
#define DW_IC_COMP_TYPE_VALUE 0x44570140
@@ -332,6 +335,16 @@ 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);
+ /* Configure SDA Hold Time if required */
+ reg = dw_readl(dev, DW_IC_COMP_VERSION);
+ if (dev->sda_hold_time) {
+ if (reg >= DW_IC_SDA_HOLD_MIN_VERS)
+ dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);
+ else
+ dev_warn(dev->dev,
+ "Hardware too old to adjust SDA hold time.");
+ }
+
/* Configure Tx/Rx FIFO threshold levels */
dw_writel(dev, dev->tx_fifo_depth - 1, DW_IC_TX_TL);
dw_writel(dev, 0, DW_IC_RX_TL);
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index e761ad1..912aa22 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -90,6 +90,7 @@ struct dw_i2c_dev {
unsigned int tx_fifo_depth;
unsigned int rx_fifo_depth;
int rx_outstanding;
+ u32 sda_hold_time;
};
#define ACCESS_SWAP 0x00000001
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 35b70a1..8b9d3f1 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -34,6 +34,7 @@
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/interrupt.h>
+#include <linux/of.h>
#include <linux/of_i2c.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
@@ -121,6 +122,15 @@ static int dw_i2c_probe(struct platform_device *pdev)
return PTR_ERR(dev->clk);
clk_prepare_enable(dev->clk);
+ if (pdev->dev.of_node) {
+ u32 ht = 0;
+ u32 ic_clk = dev->get_clk_rate_khz(dev);
+
+ of_property_read_u32(pdev->dev.of_node,
+ "i2c-sda-hold-time-ns", &ht);
+ dev->sda_hold_time = ((u64)ic_clk * ht + 500000) / 1000000;
+ }
+
dev->functionality =
I2C_FUNC_I2C |
I2C_FUNC_10BIT_ADDR |
--
1.7.1
--
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