On Fri, Feb 15, 2013 at 11:11:50AM +0100, Christian Ruppert wrote: > 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); AFAIK, DW_IC_SDA_HOLD minimum value is 1 so you could just do: if (dev->sda_hold_time) dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD); Also should this be configurable for standard and fast modes both? Something like sm_sda_hold_time and fm_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 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; I do not understand why you need a separate platform data at all? Can't you do it in a same way than the ACPI code? And this probably doesn't apply to the i2c/next branch because we added the ACPI enumeration there. > + } > > /* 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; Please check Wolfram's i2c/next. This is set already there. > + > + 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/ -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
