Add initial version of the Broadcom touchscreen driver.

Reviewed-by: Ray Jui <r...@broadcom.com>
Reviewed-by: Scott Branden <sbran...@broadcom.com>
Tested-by: Scott Branden <sbran...@broadcom.com>
Signed-off-by: Jonathan Richardson <jonat...@broadcom.com>
---
 drivers/input/touchscreen/Kconfig         |   11 +
 drivers/input/touchscreen/Makefile        |    1 +
 drivers/input/touchscreen/bcm_iproc_tsc.c |  559 +++++++++++++++++++++++++++++
 3 files changed, 571 insertions(+)
 create mode 100644 drivers/input/touchscreen/bcm_iproc_tsc.c

diff --git a/drivers/input/touchscreen/Kconfig 
b/drivers/input/touchscreen/Kconfig
index e1d8003..77ff531 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -310,6 +310,17 @@ config TOUCHSCREEN_ILI210X
          To compile this driver as a module, choose M here: the
          module will be called ili210x.
 
+config TOUCHSCREEN_IPROC
+       tristate "IPROC touch panel driver support"
+       help
+         Say Y here if you want to add support for the IPROC touch
+         controller to your system.
+
+         If unsure, say N.
+
+         To compile this driver as a module, choose M here: the
+         module will be called iproc-ts.
+
 config TOUCHSCREEN_S3C2410
        tristate "Samsung S3C2410/generic touchscreen input driver"
        depends on ARCH_S3C24XX || SAMSUNG_DEV_TS
diff --git a/drivers/input/touchscreen/Makefile 
b/drivers/input/touchscreen/Makefile
index 090e61c..f7e6de9 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_TOUCHSCREEN_FUJITSU)     += fujitsu_ts.o
 obj-$(CONFIG_TOUCHSCREEN_ILI210X)      += ili210x.o
 obj-$(CONFIG_TOUCHSCREEN_INEXIO)       += inexio.o
 obj-$(CONFIG_TOUCHSCREEN_INTEL_MID)    += intel-mid-touch.o
+obj-$(CONFIG_TOUCHSCREEN_IPROC)                += bcm_iproc_tsc.o
 obj-$(CONFIG_TOUCHSCREEN_LPC32XX)      += lpc32xx_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MAX11801)     += max11801_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MC13783)      += mc13783_ts.o
diff --git a/drivers/input/touchscreen/bcm_iproc_tsc.c 
b/drivers/input/touchscreen/bcm_iproc_tsc.c
new file mode 100644
index 0000000..6f0fa71
--- /dev/null
+++ b/drivers/input/touchscreen/bcm_iproc_tsc.c
@@ -0,0 +1,559 @@
+/*
+* Copyright (C) 2014 Broadcom Corporation
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License as
+* published by the Free Software Foundation version 2.
+*
+* This program is distributed "as is" WITHOUT ANY WARRANTY of any
+* kind, whether express or implied; without even the implied warranty
+* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU General Public License for more details.
+*/
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/keyboard.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <asm/irq.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/serio.h>
+
+#define IPROC_TS_NAME "iproc-ts"
+
+#define PEN_DOWN_STATUS     1
+#define PEN_UP_STATUS       0
+
+#define X_MIN               0
+#define Y_MIN               0
+#define X_MAX               0xFFF
+#define Y_MAX               0xFFF
+
+/* Value given by controller for invalid coordinate. */
+#define INVALID_COORD       0xFFFFFFFF
+
+/* Register offsets */
+#define REGCTL1             0x00
+#define REGCTL2             0x04
+#define INTERRUPT_THRES     0x08
+#define INTERRUPT_MASK      0x0c
+
+#define INTERRUPT_STATUS    0x10
+#define CONTROLLER_STATUS   0x14
+#define FIFO_DATA           0x18
+#define FIFO_DATA_X_Y_MASK  0xFFFF
+#define ANALOG_CONTROL      0x1c
+
+#define AUX_DATA            0x20
+#define DEBOUNCE_CNTR_STAT  0x24
+#define SCAN_CNTR_STAT      0x28
+#define REM_CNTR_STAT       0x2c
+
+#define SETTLING_TIMER_STAT 0x30
+#define SPARE_REG           0x34
+#define SOFT_BYPASS_CONTROL 0x38
+#define SOFT_BYPASS_DATA    0x3c
+
+
+/* Bit values for INTERRUPT_MASK and INTERRUPT_STATUS regs */
+#define TS_PEN_INTR_MASK        (1<<0)
+#define TS_FIFO_INTR_MASK       (1<<2)
+
+/* Bit values for CONTROLLER_STATUS reg1 */
+#define TS_PEN_DOWN             (1<<0)
+
+/* Shift values for control reg1 */
+#define SCANNING_PERIOD_SHIFT   24
+#define DEBOUNCE_TIMEOUT_SHIFT  16
+#define SETTLING_TIMEOUT_SHIFT  8
+#define TOUCH_TIMEOUT_SHIFT     0
+
+/* Shift values for coordinates from fifo */
+#define X_COORD_SHIFT  0
+#define Y_COORD_SHIFT  16
+
+/* Bit values for REGCTL2 */
+#define TS_CONTROLLER_EN_BIT    (1 << 16)
+#define TS_CONTROLLER_AVGDATA_SHIFT 8
+#define TS_CONTROLLER_AVGDATA_MASK (0x7 << TS_CONTROLLER_AVGDATA_SHIFT)
+#define TS_CONTROLLER_PWR_LDO   (1<<5)
+#define TS_CONTROLLER_PWR_ADC   (1<<4)
+#define TS_CONTROLLER_PWR_BGP   (1<<3)
+#define TS_CONTROLLER_PWR_TS    (1<<2)
+#define TS_WIRE_MODE_BIT        (1<<1)
+
+/*
+ * Touch screen mount angles w.r.t LCD panel left side top corner
+ * TS (x_min,y_min) placed at LCD (x_min,y_min) rotation angle is 0
+ * TS (x_min,y_max) placed at LCD (x_min,y_min) rotation angle is 90
+ * TS (x_max,y_max) placed at LCD (x_min,y_min) rotation angle is 180
+ * TS (x_max,y_min) placed at LCD (x_min,y_min) rotation angle is 270
+ */
+enum ts_rotation_angles {
+       TS_ROTATION_0,
+       TS_ROTATION_90,
+       TS_ROTATION_180,
+       TS_ROTATION_270,
+};
+
+struct tsc_param {
+       /* Each step is 1024 us.  Valid 1-256 */
+       u32 scanning_period;
+
+       /*  Each step is 512 us.  Valid 0-255 */
+       u32 debounce_timeout;
+
+       /*
+        * The settling duration (in ms) is the amount of time the tsc
+        * waits to allow the voltage to settle after turning on the
+        * drivers in detection mode. Valid values: 0-11
+        *   0 =  0.008 ms
+        *   1 =  0.01 ms
+        *   2 =  0.02 ms
+        *   3 =  0.04 ms
+        *   4 =  0.08 ms
+        *   5 =  0.16 ms
+        *   6 =  0.32 ms
+        *   7 =  0.64 ms
+        *   8 =  1.28 ms
+        *   9 =  2.56 ms
+        *   10 = 5.12 ms
+        *   11 = 10.24 ms
+        */
+       u32 settling_timeout;
+
+       /* touch timeout in sample counts */
+       u32 touch_timeout;
+
+       /*
+        * Number of data samples which are averaged before a final data point
+        * is placed into the FIFO
+        */
+       u32 average_data;
+
+       /* FIFO threshold */
+       u32 fifo_threshold;
+};
+
+struct iproc_ts_priv {
+       struct platform_device *pdev;
+       struct input_dev *idev;
+
+       void __iomem *regs;
+       struct clk *tsc_clk;
+
+       int  pen_status;
+       int  ts_rotation;
+       struct tsc_param cfg_params;
+};
+
+/*
+ * Set default values the same as hardware reset values
+ * except for fifo_threshold with is set to 1.
+ */
+static struct tsc_param default_config = {
+       .scanning_period  = 0x5,  /* 1 to 256 */
+       .debounce_timeout = 0x28, /* 0 to 255 */
+       .settling_timeout = 0x7,  /* 0 to 11 */
+       .touch_timeout    = 0xa,  /* 0 to 255 */
+       .average_data     = 5,    /* entry 5 = 32 pts */
+       .fifo_threshold   = 1,    /* 0 to 31 */
+};
+
+static void ts_reg_dump(struct iproc_ts_priv *priv)
+{
+       struct device *dev = &priv->pdev->dev;
+
+       dev_dbg(dev, "regCtl1             = 0x%08x\n",
+                               readl(priv->regs + REGCTL1));
+       dev_dbg(dev, "regCtl2             = 0x%08x\n",
+                               readl(priv->regs + REGCTL2));
+       dev_dbg(dev, "interrupt_Thres     = 0x%08x\n",
+                               readl(priv->regs + INTERRUPT_THRES));
+       dev_dbg(dev, "interrupt_Mask      = 0x%08x\n",
+                               readl(priv->regs + INTERRUPT_MASK));
+       dev_dbg(dev, "interrupt_Status    = 0x%08x\n",
+                               readl(priv->regs + INTERRUPT_STATUS));
+       dev_dbg(dev, "controller_Status   = 0x%08x\n",
+                               readl(priv->regs + CONTROLLER_STATUS));
+       dev_dbg(dev, "FIFO_Data           = 0x%08x\n",
+                               readl(priv->regs + FIFO_DATA));
+       dev_dbg(dev, "analog_Control      = 0x%08x\n",
+                               readl(priv->regs + ANALOG_CONTROL));
+       dev_dbg(dev, "aux_Data            = 0x%08x\n",
+                               readl(priv->regs + AUX_DATA));
+       dev_dbg(dev, "debounce_Cntr_Stat  = 0x%08x\n",
+                               readl(priv->regs + DEBOUNCE_CNTR_STAT));
+       dev_dbg(dev, "scan_Cntr_Stat      = 0x%08x\n",
+                               readl(priv->regs + SCAN_CNTR_STAT));
+       dev_dbg(dev, "rem_Cntr_Stat       = 0x%08x\n",
+                               readl(priv->regs + REM_CNTR_STAT));
+       dev_dbg(dev, "settling_Timer_Stat = 0x%08x\n",
+                               readl(priv->regs + SETTLING_TIMER_STAT));
+       dev_dbg(dev, "spare_Reg           = 0x%08x\n",
+                               readl(priv->regs + SPARE_REG));
+       dev_dbg(dev, "soft_Bypass_Control = 0x%08x\n",
+                               readl(priv->regs + SOFT_BYPASS_CONTROL));
+       dev_dbg(dev, "soft_Bypass_Data    = 0x%08x\n",
+                               readl(priv->regs + SOFT_BYPASS_DATA));
+}
+
+static irqreturn_t iproc_touchscreen_interrupt(int irq, void *data)
+{
+       struct platform_device *pdev = (struct platform_device *)data;
+       struct iproc_ts_priv *priv;
+       u32 intr_status = 0;
+       u32 raw_coordinate = 0;
+       u16 x = 0;
+       u16 y = 0;
+       int i;
+
+       priv = (struct iproc_ts_priv *)platform_get_drvdata(pdev);
+
+       intr_status = readl(priv->regs + INTERRUPT_STATUS);
+       intr_status &= (TS_PEN_INTR_MASK | TS_FIFO_INTR_MASK);
+       if (intr_status == 0)
+               return IRQ_NONE;
+
+       /* Clear all interrupt status bits, write-1-clear */
+       writel(intr_status, priv->regs + INTERRUPT_STATUS);
+
+       /* Pen up/down */
+       if (intr_status & TS_PEN_INTR_MASK) {
+               if (readl(priv->regs + CONTROLLER_STATUS) & TS_PEN_DOWN) {
+                       priv->pen_status = PEN_DOWN_STATUS;
+                       input_report_key(priv->idev, BTN_TOUCH,
+                               priv->pen_status);
+               } else {
+                       priv->pen_status = PEN_UP_STATUS;
+                       input_report_key(priv->idev, BTN_TOUCH,
+                               priv->pen_status);
+                       input_sync(priv->idev);
+               }
+
+               dev_dbg(&priv->pdev->dev,
+                       "pen up-down (%d)\n", priv->pen_status);
+       }
+
+       /* coordinates in FIFO exceed the theshold */
+       if (intr_status & TS_FIFO_INTR_MASK) {
+               for (i = 0; i < priv->cfg_params.fifo_threshold; i++) {
+                       raw_coordinate = readl(priv->regs + FIFO_DATA);
+                       if (raw_coordinate == INVALID_COORD)
+                               continue;
+
+                       /*
+                        * The x and y coordinate are 16 bits each
+                        * with the x in the lower 16 bits and y in the
+                        * upper 16 bits.
+                        */
+                       x = (raw_coordinate >> X_COORD_SHIFT) &
+                               FIFO_DATA_X_Y_MASK;
+                       y = (raw_coordinate >> Y_COORD_SHIFT) &
+                               FIFO_DATA_X_Y_MASK;
+
+                       /* We only want to retain the 12 msb of the 16 */
+                       x = (x >> 4) & 0x0FFF;
+                       y = (y >> 4) & 0x0FFF;
+
+                       /* adjust x y according to lcd tsc mount angle */
+                       if (priv->ts_rotation == TS_ROTATION_90) {
+                               y = Y_MAX - y;
+                       } else if (priv->ts_rotation == TS_ROTATION_180) {
+                               x = X_MAX - x;
+                               y = Y_MAX - y;
+                       } else if (priv->ts_rotation == TS_ROTATION_270) {
+                               x = X_MAX - x;
+                       }
+
+                       input_report_abs(priv->idev, ABS_X, x);
+                       input_report_abs(priv->idev, ABS_Y, y);
+                       input_sync(priv->idev);
+
+                       dev_dbg(&priv->pdev->dev, "xy (0x%x 0x%x)\n", x, y);
+               }
+       }
+
+       return IRQ_HANDLED;
+}
+
+static int iproc_ts_start(struct input_dev *idev)
+{
+       u32 val;
+       int ret;
+       struct iproc_ts_priv *priv;
+
+       priv = input_get_drvdata(idev);
+       if (priv == NULL)
+               return -ENODEV;
+
+       /* Enable clock */
+       ret = clk_prepare_enable(priv->tsc_clk);
+       if (ret) {
+               dev_err(&priv->pdev->dev, "%s clk_prepare_enable failed %d\n",
+                       __func__, ret);
+               return ret;
+       }
+
+       /*
+        * Interrupt is generated when:
+        *  FIFO reaches the int_th value, and pen event(up/down)
+        */
+       val = TS_PEN_INTR_MASK | TS_FIFO_INTR_MASK;
+       writel(val, priv->regs + INTERRUPT_MASK);
+
+       writel(priv->cfg_params.fifo_threshold, priv->regs + INTERRUPT_THRES);
+
+       /* Initialize control reg1 */
+       val = 0;
+       val |= (priv->cfg_params.scanning_period << SCANNING_PERIOD_SHIFT);
+       val |= (priv->cfg_params.debounce_timeout << DEBOUNCE_TIMEOUT_SHIFT);
+       val |= (priv->cfg_params.settling_timeout << SETTLING_TIMEOUT_SHIFT);
+       val |= (priv->cfg_params.touch_timeout << TOUCH_TIMEOUT_SHIFT);
+       writel(val, priv->regs + REGCTL1);
+
+       /* Try to clear all interrupt status */
+       val = readl(priv->regs + INTERRUPT_STATUS);
+       val |= (TS_FIFO_INTR_MASK | TS_PEN_INTR_MASK);
+       writel(val, priv->regs + INTERRUPT_STATUS);
+
+       /* Initialize control reg2 */
+       val = readl(priv->regs + REGCTL2);
+       val |= (TS_CONTROLLER_EN_BIT | TS_WIRE_MODE_BIT);
+
+       val &= ~(TS_CONTROLLER_AVGDATA_MASK);
+       val |= (priv->cfg_params.average_data << TS_CONTROLLER_AVGDATA_SHIFT);
+
+       val &= ~(TS_CONTROLLER_PWR_LDO |        /* PWR up LDO */
+                  TS_CONTROLLER_PWR_ADC |      /* PWR up ADC */
+                  TS_CONTROLLER_PWR_BGP |      /* PWR up BGP */
+                  TS_CONTROLLER_PWR_TS);       /* PWR up TS */
+
+       writel(val, priv->regs + REGCTL2);
+
+       ts_reg_dump(priv);
+
+       return 0;
+}
+
+static void iproc_ts_stop(struct input_dev *dev)
+{
+       u32 val;
+       struct iproc_ts_priv *priv;
+
+       priv = input_get_drvdata(dev);
+       if (priv == NULL)
+               return;
+
+       writel(0, priv->regs + INTERRUPT_MASK); /* Disable all interrupts */
+
+       /* Only power down touch screen controller */
+       val = readl(priv->regs + REGCTL2);
+       val |= TS_CONTROLLER_PWR_TS;
+       writel(val, priv->regs + REGCTL2);
+
+       clk_disable(priv->tsc_clk);
+}
+
+static int get_tsc_config(struct device_node *np, struct iproc_ts_priv *priv)
+{
+       int ret;
+       u32 val;
+       struct device *dev = &priv->pdev->dev;
+
+       priv->cfg_params = default_config;
+
+       ret = of_property_read_u32(np, "scanning_period", &val);
+       if (ret >= 0) {
+               if ((1 <= val) && (val <= 256))
+                       priv->cfg_params.scanning_period = val;
+               else {
+                       dev_err(dev, "scanning_period must be [1-256]");
+                       return -EINVAL;
+               }
+       }
+
+       ret = of_property_read_u32(np, "debounce_timeout", &val);
+       if (ret >= 0) {
+               if ((0 <= val) && (val <= 255))
+                       priv->cfg_params.debounce_timeout = val;
+               else {
+                       dev_err(dev, "debounce_timeout must be [0-255]");
+                       return -EINVAL;
+               }
+       }
+
+       ret = of_property_read_u32(np, "settling_timeout", &val);
+       if (ret >= 0) {
+               if ((0 <= val) && (val <= 11))
+                       priv->cfg_params.settling_timeout = val;
+               else {
+                       dev_err(dev, "settling_timeout must be [0-11]");
+                       return -EINVAL;
+               }
+       }
+
+       ret = of_property_read_u32(np, "touch_timeout", &val);
+       if (ret >= 0) {
+               if ((0 <= val) && (val <= 255))
+                       priv->cfg_params.touch_timeout = val;
+               else {
+                       dev_err(dev, "touch_timeout must be [0-255]");
+                       return -EINVAL;
+               }
+       }
+
+       ret = of_property_read_u32(np, "average_data", &val);
+       if (ret >= 0) {
+               if ((0 <= val) && (val <= 7))
+                       priv->cfg_params.average_data = val;
+               else {
+                       dev_err(dev, "average_data must be [0-8]");
+                       return -EINVAL;
+               }
+       }
+
+       ret = of_property_read_u32(np, "fifo_threshold", &val);
+       if (ret >= 0) {
+               if ((0 <= val) && (val <= 31))
+                       priv->cfg_params.fifo_threshold = val;
+               else {
+                       dev_err(dev, "fifo_threshold must be [0-31]");
+                       return -EINVAL;
+               }
+       }
+       priv->ts_rotation = TS_ROTATION_0;
+       ret = of_property_read_u32(np, "ts-rotation", &val);
+       if (ret >= 0) {
+               priv->ts_rotation = val;
+               dev_dbg(dev, "ts rotation [%d] degrees\n",
+                       90 * priv->ts_rotation);
+       }
+
+       return 0;
+}
+
+static int iproc_ts_probe(struct platform_device *pdev)
+{
+       struct iproc_ts_priv *priv;
+       struct input_dev *idev;
+       struct resource *res;
+       int ret;
+       int irq;
+
+       priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
+
+       /* touchscreen controller memory mapped regs */
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       priv->regs = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(priv->regs)) {
+               dev_err(&pdev->dev, "unable to map I/O memory\n");
+               return PTR_ERR(priv->regs);
+       }
+
+       priv->tsc_clk = devm_clk_get(&pdev->dev, "tsc_clk");
+       if (IS_ERR(priv->tsc_clk)) {
+               dev_err(&pdev->dev,
+                       "%s Failed getting clock tsc_clk\n", __func__);
+               return PTR_ERR(priv->tsc_clk);
+       }
+
+       ret = get_tsc_config(pdev->dev.of_node, priv);
+       if (ret != 0) {
+               dev_err(&pdev->dev, "%s get_tsc_config failed\n", __func__);
+               return ret;
+       }
+
+       idev = devm_input_allocate_device(&pdev->dev);
+       if (!idev) {
+               dev_err(&pdev->dev,
+                       "%s Allocate input device failed\n", __func__);
+               return -ENOMEM;
+       }
+
+       priv->idev = idev;
+       priv->pdev = pdev;
+
+       priv->pen_status = PEN_UP_STATUS;
+
+       /* Set input device info  */
+       idev->name = IPROC_TS_NAME;
+       idev->dev.parent = &pdev->dev;
+
+       idev->id.bustype = BUS_HOST;
+       idev->id.vendor = SERIO_UNKNOWN;
+       idev->id.product = 0;
+       idev->id.version = 0;
+
+       idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+       set_bit(BTN_TOUCH, idev->keybit);
+
+       input_set_abs_params(idev, ABS_X, X_MIN, X_MAX, 0, 0);
+       input_set_abs_params(idev, ABS_Y, Y_MIN, Y_MAX, 0, 0);
+
+       idev->open = iproc_ts_start;
+       idev->close = iproc_ts_stop;
+
+       input_set_drvdata(idev, priv);
+       platform_set_drvdata(pdev, priv);
+
+       /* get interrupt */
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0) {
+               dev_err(&pdev->dev, "%s platform_get_irq failed\n", __func__);
+               return irq;
+       }
+
+       ret = devm_request_irq(&pdev->dev, irq,
+               iproc_touchscreen_interrupt,
+               IRQF_SHARED, IPROC_TS_NAME, pdev);
+       if (ret)
+               return ret;
+
+       ret = input_register_device(priv->idev);
+       if (ret) {
+               dev_err(&pdev->dev,
+                       "%s register input device failed %d\n", __func__, ret);
+               return ret;
+       }
+
+       return 0;
+}
+
+static int iproc_ts_remove(struct platform_device *pdev)
+{
+       struct iproc_ts_priv *priv = platform_get_drvdata(pdev);
+
+       platform_set_drvdata(pdev, NULL);
+       input_unregister_device(priv->idev);
+
+       return 0;
+}
+
+static const struct of_device_id iproc_ts_of_match[] = {
+       {.compatible = "brcm,iproc-touchscreen", },
+       { },
+};
+MODULE_DEVICE_TABLE(of, iproc_ts_of_match);
+
+static struct platform_driver iproc_ts_driver = {
+       .probe = iproc_ts_probe,
+       .remove = iproc_ts_remove,
+       .driver = {
+               .name   = IPROC_TS_NAME,
+               .of_match_table = of_match_ptr(iproc_ts_of_match),
+       },
+};
+
+module_platform_driver(iproc_ts_driver);
+
+MODULE_DESCRIPTION("IPROC Touchscreen driver");
+MODULE_AUTHOR("Broadcom");
+MODULE_LICENSE("GPL v2");
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to