[PATCH] i2c-designware: Interrupt sharing and SDA hold time
From: Christian Ruppert
Date: Fri Feb 15 2013 - 06:07:22 EST
This patch implements interrupt sharing and SDA hold time configuration in
the designware i2c driver. Both functions are enabled through platform data
or device tree. Tested with Linux-3.8rc4 (Synopsys ARC port, see
https://github.com/foss-for-synopsys-dwc-arc-processors/linux/commits/arc-3.8-baseline).
Signed-off-by: Christian Ruppert <christian.ruppert@xxxxxxxxxx>
Signed-off-by: Pierrick Hascoet <pierrick.hascoet@xxxxxxxxxx>
---
.../devicetree/bindings/i2c/i2c-designware.txt | 18 ++++++++++
drivers/i2c/busses/i2c-designware-core.c | 6 +++
drivers/i2c/busses/i2c-designware-core.h | 2 +
drivers/i2c/busses/i2c-designware-platdrv.c | 34 +++++++++++++++++++-
include/linux/i2c/i2c-designware.h | 13 +++++++
5 files changed, 72 insertions(+), 1 deletions(-)
create mode 100644 include/linux/i2c/i2c-designware.h
diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
index e42a2ee..474386b 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
@@ -10,6 +10,12 @@ Recommended properties :
- clock-frequency : desired I2C bus clock frequency in Hz.
+Optional properties :
+ - interrupts-shared : If this property is present, the interrupt line is
+ considered shared with other devices.
+ - sda-hold-time : If this property is present, the register SDA_HOLD will
+ be initialised with its value.
+
Example :
i2c@f0000 {
@@ -20,3 +26,15 @@ Example :
interrupts = <11>;
clock-frequency = <400000>;
};
+
+ i2c@1120000 {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ compatible = "snps,designware-i2c";
+ reg = <0x1120000 0x1000>;
+ interrupt-parent = <&ictl>;
+ interrupts = <12 1>;
+ interrupts-shared;
+ clock-frequency = <400000>;
+ sda-hold-time = <0x64>;
+ };
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index cbba7db..36ba0b5 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -34,6 +34,7 @@
#include <linux/io.h>
#include <linux/pm_runtime.h>
#include <linux/delay.h>
+#include <linux/i2c/i2c-designware.h>
#include "i2c-designware-core.h"
/*
@@ -66,6 +67,7 @@
#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_COMP_PARAM_1 0xf4
#define DW_IC_COMP_TYPE 0xfc
@@ -309,6 +311,10 @@ 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 */
+ if (dev->pdat_flags & I2C_DW_PDAT_FLAGS_SET_HOLDTIME)
+ dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);
+
/* 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 9c1840e..ef20477 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -88,6 +88,8 @@ struct dw_i2c_dev {
u32 master_cfg;
unsigned int tx_fifo_depth;
unsigned int rx_fifo_depth;
+ u32 sda_hold_time;
+ unsigned int pdat_flags;
};
#define ACCESS_SWAP 0x00000001
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 343357a..2ad2da3 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -34,11 +34,13 @@
#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>
#include <linux/io.h>
#include <linux/slab.h>
+#include <linux/i2c/i2c-designware.h>
#include "i2c-designware-core.h"
static struct i2c_algorithm i2c_dw_algo = {
@@ -56,6 +58,28 @@ static int dw_i2c_probe(struct platform_device *pdev)
struct i2c_adapter *adap;
struct resource *mem, *ioarea;
int irq, r;
+ unsigned long irqf;
+ struct i2c_designware_platform_data *pdat = pdev->dev.platform_data;
+
+ if ((!pdat) && pdev->dev.of_node) {
+ struct device_node *node = pdev->dev.of_node;
+
+ pdat = kmalloc(sizeof(struct i2c_designware_platform_data),
+ GFP_KERNEL);
+ if (!pdat)
+ return -ENOMEM;
+
+ pdat->flags = 0;
+
+ if (of_get_property(node, "interrupts-shared", NULL))
+ pdat->flags |= I2C_DW_PDAT_FLAGS_SHARE_IRQ;
+
+ if (!of_property_read_u32(node, "sda-hold-time",
+ &pdat->sda_hold_time))
+ pdat->flags |= I2C_DW_PDAT_FLAGS_SET_HOLDTIME;
+
+ pdev->dev.platform_data = pdat;
+ }
/* NOTE: driver uses the static register mapping */
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -120,12 +144,20 @@ static int dw_i2c_probe(struct platform_device *pdev)
dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1;
dev->rx_fifo_depth = ((param1 >> 8) & 0xff) + 1;
}
+ dev->sda_hold_time = pdat->sda_hold_time;
+ dev->pdat_flags = pdat->flags;
+
r = i2c_dw_init(dev);
if (r)
goto err_iounmap;
i2c_dw_disable_int(dev);
- r = request_irq(dev->irq, i2c_dw_isr, IRQF_DISABLED, pdev->name, dev);
+
+ irqf = IRQF_DISABLED;
+ if (dev->pdat_flags & I2C_DW_PDAT_FLAGS_SHARE_IRQ)
+ irqf |= IRQF_SHARED;
+
+ r = request_irq(dev->irq, i2c_dw_isr, irqf, pdev->name, dev);
if (r) {
dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
goto err_iounmap;
diff --git a/include/linux/i2c/i2c-designware.h b/include/linux/i2c/i2c-designware.h
new file mode 100644
index 0000000..ea8192a
--- /dev/null
+++ b/include/linux/i2c/i2c-designware.h
@@ -0,0 +1,13 @@
+#ifndef __I2C_DESIGNWARE_H__
+#define __I2C_DESIGNWARE_H__
+
+#include <linux/platform_device.h>
+
+struct i2c_designware_platform_data {
+ unsigned int flags;
+#define I2C_DW_PDAT_FLAGS_SHARE_IRQ (1L<<0)
+#define I2C_DW_PDAT_FLAGS_SET_HOLDTIME (1L<<1)
+ u32 sda_hold_time;
+};
+
+#endif /* __I2C_DESIGNWARE_H__ */
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/