* [PATCH] Add tsc2007 based touchscreen driver.
@ 2008-12-02 13:39 Kwangwoo Lee
2008-12-03 11:21 ` Trilok Soni
0 siblings, 1 reply; 9+ messages in thread
From: Kwangwoo Lee @ 2008-12-02 13:39 UTC (permalink / raw)
To: dmitry.torokhov; +Cc: linux-kernel
Hello,
I'm newbie and I tested this driver on my ARM9 based SoC - MV86XX.
But the platform codes are not submitted yet.
The example of platform specific codes are followed:
/* TSC2007 Touchscreen */
#ifdef CONFIG_LCD_CT024TN02
/* GPIO13:GINT3 = PENIRQ */
#define TS_PENIRQ_GPIO GPIO13
#define TS_CHAINED_GPIO 3
#else
/* GPIO5:GINT1 = PENIRQ */
#define TS_PENIRQ_GPIO GPIO5
#define TS_CHAINED_GPIO 1
#endif
static int mv_get_pendown_state(void)
{
int val = 0;
mv_gpio_set_direction(TS_PENIRQ_GPIO, 0);
mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_GPIO);
val = mv_gpio_get_value(TS_PENIRQ_GPIO);
mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_INT);
val = val ? 0 : 1;
return val;
}
static void mv_clear_penirq(void)
{
mv_gpio_int_clear(TS_CHAINED_GPIO);
}
static int mv_init_ts(void)
{
mv_gpio_set_direction(TS_PENIRQ_GPIO, 0); /* input */
mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_INT);
mv_gpio_int_mode(TS_CHAINED_GPIO, GPIO_INT_FALLING_EDGE);
mv_gpio_int_clear(TS_CHAINED_GPIO);
mv_gpio_int_unmask(TS_CHAINED_GPIO);
return 0;
}
static void mv_exit_ts(void)
{
mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_GPIO);
mv_gpio_int_mask(TS_CHAINED_GPIO);
}
struct tsc2007_platform_data mv_tsc2007_data = {
.model = 2007,
.x_plate_ohms = 180,
.get_pendown_state = mv_get_pendown_state,
.clear_penirq = mv_clear_penirq,
.init_platform_hw = mv_init_ts,
.exit_platform_hw = mv_exit_ts,
};
/* I2C clients */
static struct i2c_board_info __initdata mv_i2c_clients[] = {
[0] = {
I2C_BOARD_INFO("tsc2007", 0x90),
.type = "tsc2007",
.platform_data = &mv_tsc2007_data,
.irq = IRQ_GPIO,
},
};
i2c_register_board_info() should be used.
Signed-off-by: Kwangwoo Lee <kwangwoo.lee@gmail.com>
---
drivers/input/touchscreen/Kconfig | 9 +
drivers/input/touchscreen/Makefile | 1 +
drivers/input/touchscreen/tsc2007.c | 398 +++++++++++++++++++++++++++++++++++
include/linux/i2c/tsc2007.h | 17 ++
4 files changed, 425 insertions(+), 0 deletions(-)
create mode 100644 drivers/input/touchscreen/tsc2007.c
create mode 100644 include/linux/i2c/tsc2007.h
diff --git a/drivers/input/touchscreen/Kconfig
b/drivers/input/touchscreen/Kconfig
index 3d1ab8f..78abdfb 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -376,4 +376,13 @@ config TOUCHSCREEN_TOUCHIT213
To compile this driver as a module, choose M here: the
module will be called touchit213.
+config TOUCHSCREEN_TSC2007
+ tristate "TSC2007 based touchscreens"
+ depends on I2C
+ help
+ Say Y here if you have a TSC2007 based touchscreens.
+
+ To compile this driver as a module, choose M here: the
+ module will be called tsc2007.
+
endif
diff --git a/drivers/input/touchscreen/Makefile
b/drivers/input/touchscreen/Makefile
index 15cf290..824999c 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -31,3 +31,4 @@ wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9705) += wm9705.o
wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9712) += wm9712.o
wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9713) += wm9713.o
obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE) += mainstone-wm97xx.o
+obj-$(CONFIG_TOUCHSCREEN_TSC2007) += tsc2007.o
diff --git a/drivers/input/touchscreen/tsc2007.c
b/drivers/input/touchscreen/tsc2007.c
new file mode 100644
index 0000000..85fb520
--- /dev/null
+++ b/drivers/input/touchscreen/tsc2007.c
@@ -0,0 +1,398 @@
+/*
+ * drivers/input/touchscreen/tsc2007.c
+ *
+ * Copyright (c) 2008 MtekVision Co., Ltd.
+ * Kwangwoo Lee <kwlee@mtekvision.com>
+ *
+ * Using code from:
+ * - ads7846.c
+ * Copyright (c) 2005 David Brownell
+ * Copyright (c) 2006 Nokia Corporation
+ * - corgi_ts.c
+ * Copyright (C) 2004-2005 Richard Purdie
+ * - omap_ts.[hc], ads7846.h, ts_osk.c
+ * Copyright (C) 2002 MontaVista Software
+ * Copyright (C) 2004 Texas Instruments
+ * Copyright (C) 2005 Dirk Behme
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/hwmon.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/i2c/tsc2007.h>
+#include <linux/io.h>
+
+#include <asm/irq.h>
+
+#define TS_POLL_DELAY (10 * 1000) /* ns delay before the first sample */
+#define TS_POLL_PERIOD (5 * 1000) /* ns delay between samples */
+
+#define TSC2007_MEASURE_TEMP0 (0x0 << 4)
+#define TSC2007_MEASURE_AUX (0x2 << 4)
+#define TSC2007_MEASURE_TEMP1 (0x4 << 4)
+#define TSC2007_ACTIVATE_XN (0x8 << 4)
+#define TSC2007_ACTIVATE_YN (0x9 << 4)
+#define TSC2007_ACTIVATE_YP_XN (0xa << 4)
+#define TSC2007_SETUP (0xb << 4)
+#define TSC2007_MEASURE_X (0xc << 4)
+#define TSC2007_MEASURE_Y (0xd << 4)
+#define TSC2007_MEASURE_Z1 (0xe << 4)
+#define TSC2007_MEASURE_Z2 (0xf << 4)
+
+#define TSC2007_POWER_OFF_IRQ_EN (0x0 << 2)
+#define TSC2007_ADC_ON_IRQ_DIS0 (0x1 << 2)
+#define TSC2007_ADC_OFF_IRQ_EN (0x2 << 2)
+#define TSC2007_ADC_ON_IRQ_DIS1 (0x3 << 2)
+
+#define TSC2007_12BIT (0x0 << 1)
+#define TSC2007_8BIT (0x1 << 1)
+
+#define MAX_12BIT ((1 << 12) - 1)
+
+#define ADC_ON_12BIT (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
+
+#define READ_Y (ADC_ON_12BIT | TSC2007_MEASURE_Y)
+#define READ_Z1 (ADC_ON_12BIT | TSC2007_MEASURE_Z1)
+#define READ_Z2 (ADC_ON_12BIT | TSC2007_MEASURE_Z2)
+#define READ_X (ADC_ON_12BIT | TSC2007_MEASURE_X)
+#define PWRDOWN (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
+
+struct ts_event {
+ u16 x;
+ u16 y;
+ u16 z1, z2;
+};
+
+struct tsc2007 {
+ struct input_dev *input;
+ char phys[32];
+ struct hrtimer timer;
+ struct ts_event tc;
+
+ struct i2c_client *client;
+
+ spinlock_t lock;
+
+ u16 model;
+ u16 x_plate_ohms;
+
+ unsigned pendown;
+ int irq;
+
+ int (*get_pendown_state)(void);
+ void (*clear_penirq)(void);
+};
+
+static int tsc2007_xfer(void *tsc, unsigned char cmd)
+{
+ struct tsc2007 *ts = tsc;
+ struct i2c_client *client = ts->client;
+
+ unsigned char rbuf[2];
+ unsigned short val;
+ int result;
+
+ result = i2c_master_send(client, &cmd, 1);
+ if (result != 1) {
+ dev_err(&client->dev, "send failed, cmd 0x%x\n", cmd);
+ goto cmd_fail;
+ }
+
+ result = i2c_master_recv(client, rbuf, 2);
+ if (result != 2) {
+ dev_err(&client->dev, "recv failed, cmd 0x%x\n", cmd);
+ goto cmd_fail;
+ }
+
+ rbuf[1] = (rbuf[1] >> 4) | ((rbuf[0] & 0x0f) << 4);
+ rbuf[0] = rbuf[0] >> 4;
+
+ val = *((unsigned short *) rbuf);
+ val = be16_to_cpu(val);
+
+ dev_dbg(&client->dev, "cmd [0x%x], rbuf [0x%x, 0x%x] => val [%u]\n",
+ cmd, rbuf[0], rbuf[1], val);
+
+ return (int) val;
+
+cmd_fail:
+ return -EIO;
+}
+
+static void tsc2007_send_event(void *tsc)
+{
+ struct tsc2007 *ts = tsc;
+ u32 Rt;
+ u16 x, y, z1, z2;
+
+ x = ts->tc.x;
+ y = ts->tc.y;
+ z1 = ts->tc.z1;
+ z2 = ts->tc.z2;
+
+ /* range filtering */
+ if (x == MAX_12BIT)
+ x = 0;
+
+ if (likely(x && z1)) {
+ /* compute touch pressure resistance using equation #1 */
+ Rt = z2;
+ Rt -= z1;
+ Rt *= x;
+ Rt *= ts->x_plate_ohms;
+ Rt /= z1;
+ Rt = (Rt + 2047) >> 12;
+ } else
+ Rt = 0;
+
+ /* Sample found inconsistent by debouncing or pressure is beyond
+ * the maximum. Don't report it to user space, repeat at least
+ * once more the measurement
+ */
+ if (Rt > MAX_12BIT) {
+ dev_dbg(&ts->client->dev, "ignored pressure %d\n", Rt);
+
+ hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
+ HRTIMER_MODE_REL);
+ return;
+ }
+
+ /* NOTE: We can't rely on the pressure to determine the pen down
+ * state, even this controller has a pressure sensor. The pressure
+ * value can fluctuate for quite a while after lifting the pen and
+ * in some cases may not even settle at the expected value.
+ *
+ * The only safe way to check for the pen up condition is in the
+ * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
+ */
+ if (Rt) {
+ struct input_dev *input = ts->input;
+
+ if (!ts->pendown) {
+ dev_dbg(&ts->client->dev, "DOWN\n");
+
+ input_report_key(input, BTN_TOUCH, 1);
+ ts->pendown = 1;
+ }
+
+ input_report_abs(input, ABS_X, x);
+ input_report_abs(input, ABS_Y, y);
+ input_report_abs(input, ABS_PRESSURE, Rt);
+
+ input_sync(input);
+
+ dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
+ x, y, Rt);
+ }
+
+ hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
+ HRTIMER_MODE_REL);
+}
+
+static int tsc2007_read_values(struct tsc2007 *tsc)
+{
+ struct tsc2007 *ts = tsc;
+
+ /* y- still on; turn on only y+ (and ADC) */
+ ts->tc.y = tsc2007_xfer(ts, READ_Y);
+
+ /* turn y- off, x+ on, then leave in lowpower */
+ ts->tc.x = tsc2007_xfer(ts, READ_X);
+
+ /* turn y+ off, x- on; we'll use formula #1 */
+ ts->tc.z1 = tsc2007_xfer(ts, READ_Z1);
+ ts->tc.z2 = tsc2007_xfer(ts, READ_Z2);
+
+ /* power down */
+ tsc2007_xfer(ts, PWRDOWN);
+ return 0;
+}
+
+static enum hrtimer_restart tsc2007_timer(struct hrtimer *handle)
+{
+ struct tsc2007 *ts = container_of(handle, struct tsc2007, timer);
+
+ spin_lock_irq(&ts->lock);
+
+ if (unlikely(!ts->get_pendown_state() && ts->pendown)) {
+ struct input_dev *input = ts->input;
+
+ dev_dbg(&ts->client->dev, "UP\n");
+
+ input_report_key(input, BTN_TOUCH, 0);
+ input_report_abs(input, ABS_PRESSURE, 0);
+ input_sync(input);
+
+ ts->pendown = 0;
+ enable_irq(ts->irq);
+ } else {
+ /* pen is still down, continue with the measurement */
+ dev_dbg(&ts->client->dev, "pen is still down\n");
+
+ tsc2007_read_values(ts);
+ tsc2007_send_event(ts);
+ }
+
+ spin_unlock_irq(&ts->lock);
+ return HRTIMER_NORESTART;
+}
+
+static irqreturn_t tsc2007_irq(int irq, void *handle)
+{
+ struct tsc2007 *ts = handle;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ts->lock, flags);
+ if (likely(ts->get_pendown_state())) {
+ disable_irq(ts->irq);
+ hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
+ HRTIMER_MODE_REL);
+ }
+
+ if (ts->clear_penirq)
+ ts->clear_penirq();
+
+ spin_unlock_irqrestore(&ts->lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+static int tsc2007_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+ struct tsc2007 *ts;
+ struct tsc2007_platform_data *pdata;
+ struct input_dev *input_dev;
+ int err;
+
+ pdata = client->dev.platform_data;
+ if (pdata == NULL) {
+ dev_err(&client->dev, "platform data is required!\n");
+ return -EINVAL;
+ }
+
+ if (!i2c_check_functionality(adapter,
+ I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+ return -EIO;
+
+ ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
+ input_dev = input_allocate_device();
+ if (!ts || !input_dev) {
+ err = -ENOMEM;
+ goto err_free_mem;
+ }
+
+ ts->client = client;
+ i2c_set_clientdata(client, ts);
+
+ ts->input = input_dev;
+
+ hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ ts->timer.function = tsc2007_timer;
+
+ spin_lock_init(&ts->lock);
+
+ ts->model = pdata->model;
+ ts->x_plate_ohms = pdata->x_plate_ohms;
+ ts->get_pendown_state = pdata->get_pendown_state;
+ ts->clear_penirq = pdata->clear_penirq;
+
+ pdata->init_platform_hw();
+
+ snprintf(ts->phys, sizeof(ts->phys), "%s/input0", client->dev.bus_id);
+
+ input_dev->name = "TSC2007 Touchscreen";
+ input_dev->phys = ts->phys;
+
+ input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+ input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+
+ input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
+ input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
+ input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
+
+ tsc2007_read_values(ts);
+
+ ts->irq = client->irq;
+ if (request_irq(ts->irq, tsc2007_irq, 0,
+ client->dev.driver->name, ts)) {
+ dev_err(&client->dev, "irq %d busy?\n", ts->irq);
+ err = -EBUSY;
+ goto err_free_mem;
+ }
+
+ err = input_register_device(input_dev);
+ if (err)
+ goto err_free_irq;
+
+ dev_info(&client->dev, "registered with irq (%d)\n", ts->irq);
+
+ return 0;
+
+ err_free_irq:
+ free_irq(ts->irq, ts);
+ err_free_mem:
+ input_free_device(input_dev);
+ kfree(ts);
+ return err;
+}
+
+static int tsc2007_remove(struct i2c_client *client)
+{
+ struct tsc2007 *ts = i2c_get_clientdata(client);
+ struct tsc2007_platform_data *pdata;
+
+ pdata = client->dev.platform_data;
+ pdata->exit_platform_hw();
+
+ input_unregister_device(ts->input);
+ free_irq(ts->irq, ts);
+ kfree(ts);
+
+ dev_info(&client->dev, "unregistered\n");
+ return 0;
+}
+
+static struct i2c_device_id tsc2007_idtable[] = {
+ { "tsc2007", 0 },
+ { }
+};
+
+MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
+
+static struct i2c_driver tsc2007_driver = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "tsc2007"
+ },
+ .id_table = tsc2007_idtable,
+ .probe = tsc2007_probe,
+ .remove = tsc2007_remove,
+};
+
+static int __init tsc2007_init(void)
+{
+ return i2c_add_driver(&tsc2007_driver);
+}
+
+static void __exit tsc2007_exit(void)
+{
+ i2c_del_driver(&tsc2007_driver);
+}
+
+module_init(tsc2007_init);
+module_exit(tsc2007_exit);
+
+MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
+MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/i2c/tsc2007.h b/include/linux/i2c/tsc2007.h
new file mode 100644
index 0000000..c6361fb
--- /dev/null
+++ b/include/linux/i2c/tsc2007.h
@@ -0,0 +1,17 @@
+#ifndef __LINUX_I2C_TSC2007_H
+#define __LINUX_I2C_TSC2007_H
+
+/* linux/i2c/tsc2007.h */
+
+struct tsc2007_platform_data {
+ u16 model; /* 2007. */
+ u16 x_plate_ohms;
+
+ int (*get_pendown_state)(void);
+ void (*clear_penirq)(void); /* If needed, clear 2nd level
+ interrupt source */
+ int (*init_platform_hw)(void);
+ void (*exit_platform_hw)(void);
+};
+
+#endif
--
1.5.6.5
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] Add tsc2007 based touchscreen driver.
2008-12-02 13:39 [PATCH] Add tsc2007 based touchscreen driver Kwangwoo Lee
@ 2008-12-03 11:21 ` Trilok Soni
2008-12-03 12:01 ` Felipe Balbi
` (2 more replies)
0 siblings, 3 replies; 9+ messages in thread
From: Trilok Soni @ 2008-12-03 11:21 UTC (permalink / raw)
To: Kwangwoo Lee
Cc: dmitry.torokhov, linux-kernel, David Brownell,
linux-omap@vger.kernel.org Mailing List
Hi Lee
Adding linux-omap mailing list. Sometime I am thinking that same chip
might have interface to be connected on another board/cpu through SPI
too, so in this case we will have two drivers doing the same thing and
difference is just a change of the bus interface.
We should do something v4l2_subdev framework right now going on on
v4l2 mailing list to abstract the sensor drivers from bus.
On Tue, Dec 2, 2008 at 7:09 PM, Kwangwoo Lee <kwangwoo.lee@gmail.com> wrote:
> Hello,
>
> I'm newbie and I tested this driver on my ARM9 based SoC - MV86XX.
> But the platform codes are not submitted yet.
>
> The example of platform specific codes are followed:
>
> /* TSC2007 Touchscreen */
> #ifdef CONFIG_LCD_CT024TN02
> /* GPIO13:GINT3 = PENIRQ */
> #define TS_PENIRQ_GPIO GPIO13
> #define TS_CHAINED_GPIO 3
> #else
> /* GPIO5:GINT1 = PENIRQ */
> #define TS_PENIRQ_GPIO GPIO5
> #define TS_CHAINED_GPIO 1
> #endif
>
> static int mv_get_pendown_state(void)
> {
> int val = 0;
>
> mv_gpio_set_direction(TS_PENIRQ_GPIO, 0);
> mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_GPIO);
>
> val = mv_gpio_get_value(TS_PENIRQ_GPIO);
> mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_INT);
>
> val = val ? 0 : 1;
> return val;
> }
>
> static void mv_clear_penirq(void)
> {
> mv_gpio_int_clear(TS_CHAINED_GPIO);
> }
>
> static int mv_init_ts(void)
> {
> mv_gpio_set_direction(TS_PENIRQ_GPIO, 0); /* input */
> mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_INT);
>
> mv_gpio_int_mode(TS_CHAINED_GPIO, GPIO_INT_FALLING_EDGE);
> mv_gpio_int_clear(TS_CHAINED_GPIO);
> mv_gpio_int_unmask(TS_CHAINED_GPIO);
> return 0;
> }
>
> static void mv_exit_ts(void)
> {
> mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_GPIO);
> mv_gpio_int_mask(TS_CHAINED_GPIO);
> }
>
> struct tsc2007_platform_data mv_tsc2007_data = {
> .model = 2007,
> .x_plate_ohms = 180,
> .get_pendown_state = mv_get_pendown_state,
> .clear_penirq = mv_clear_penirq,
> .init_platform_hw = mv_init_ts,
> .exit_platform_hw = mv_exit_ts,
> };
>
> /* I2C clients */
> static struct i2c_board_info __initdata mv_i2c_clients[] = {
> [0] = {
> I2C_BOARD_INFO("tsc2007", 0x90),
> .type = "tsc2007",
> .platform_data = &mv_tsc2007_data,
> .irq = IRQ_GPIO,
> },
> };
>
> i2c_register_board_info() should be used.
>
> Signed-off-by: Kwangwoo Lee <kwangwoo.lee@gmail.com>
> ---
> drivers/input/touchscreen/Kconfig | 9 +
> drivers/input/touchscreen/Makefile | 1 +
> drivers/input/touchscreen/tsc2007.c | 398 +++++++++++++++++++++++++++++++++++
> include/linux/i2c/tsc2007.h | 17 ++
> 4 files changed, 425 insertions(+), 0 deletions(-)
> create mode 100644 drivers/input/touchscreen/tsc2007.c
> create mode 100644 include/linux/i2c/tsc2007.h
>
> diff --git a/drivers/input/touchscreen/Kconfig
> b/drivers/input/touchscreen/Kconfig
> index 3d1ab8f..78abdfb 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -376,4 +376,13 @@ config TOUCHSCREEN_TOUCHIT213
> To compile this driver as a module, choose M here: the
> module will be called touchit213.
>
> +config TOUCHSCREEN_TSC2007
> + tristate "TSC2007 based touchscreens"
> + depends on I2C
> + help
> + Say Y here if you have a TSC2007 based touchscreens.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called tsc2007.
> +
> endif
> diff --git a/drivers/input/touchscreen/Makefile
> b/drivers/input/touchscreen/Makefile
> index 15cf290..824999c 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -31,3 +31,4 @@ wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9705) += wm9705.o
> wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9712) += wm9712.o
> wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9713) += wm9713.o
> obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE) += mainstone-wm97xx.o
> +obj-$(CONFIG_TOUCHSCREEN_TSC2007) += tsc2007.o
> diff --git a/drivers/input/touchscreen/tsc2007.c
> b/drivers/input/touchscreen/tsc2007.c
> new file mode 100644
> index 0000000..85fb520
> --- /dev/null
> +++ b/drivers/input/touchscreen/tsc2007.c
> @@ -0,0 +1,398 @@
> +/*
> + * drivers/input/touchscreen/tsc2007.c
> + *
> + * Copyright (c) 2008 MtekVision Co., Ltd.
> + * Kwangwoo Lee <kwlee@mtekvision.com>
> + *
> + * Using code from:
> + * - ads7846.c
> + * Copyright (c) 2005 David Brownell
> + * Copyright (c) 2006 Nokia Corporation
> + * - corgi_ts.c
> + * Copyright (C) 2004-2005 Richard Purdie
> + * - omap_ts.[hc], ads7846.h, ts_osk.c
> + * Copyright (C) 2002 MontaVista Software
> + * Copyright (C) 2004 Texas Instruments
> + * Copyright (C) 2005 Dirk Behme
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/hwmon.h>
> +#include <linux/init.h>
> +#include <linux/err.h>
> +#include <linux/delay.h>
> +#include <linux/input.h>
> +#include <linux/interrupt.h>
> +#include <linux/slab.h>
> +#include <linux/i2c.h>
> +#include <linux/i2c/tsc2007.h>
> +#include <linux/io.h>
> +
> +#include <asm/irq.h>
> +
> +#define TS_POLL_DELAY (10 * 1000) /* ns delay before the first sample */
> +#define TS_POLL_PERIOD (5 * 1000) /* ns delay between samples */
> +
> +#define TSC2007_MEASURE_TEMP0 (0x0 << 4)
> +#define TSC2007_MEASURE_AUX (0x2 << 4)
> +#define TSC2007_MEASURE_TEMP1 (0x4 << 4)
> +#define TSC2007_ACTIVATE_XN (0x8 << 4)
> +#define TSC2007_ACTIVATE_YN (0x9 << 4)
> +#define TSC2007_ACTIVATE_YP_XN (0xa << 4)
> +#define TSC2007_SETUP (0xb << 4)
> +#define TSC2007_MEASURE_X (0xc << 4)
> +#define TSC2007_MEASURE_Y (0xd << 4)
> +#define TSC2007_MEASURE_Z1 (0xe << 4)
> +#define TSC2007_MEASURE_Z2 (0xf << 4)
> +
> +#define TSC2007_POWER_OFF_IRQ_EN (0x0 << 2)
> +#define TSC2007_ADC_ON_IRQ_DIS0 (0x1 << 2)
> +#define TSC2007_ADC_OFF_IRQ_EN (0x2 << 2)
> +#define TSC2007_ADC_ON_IRQ_DIS1 (0x3 << 2)
> +
> +#define TSC2007_12BIT (0x0 << 1)
> +#define TSC2007_8BIT (0x1 << 1)
> +
> +#define MAX_12BIT ((1 << 12) - 1)
> +
> +#define ADC_ON_12BIT (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
> +
> +#define READ_Y (ADC_ON_12BIT | TSC2007_MEASURE_Y)
> +#define READ_Z1 (ADC_ON_12BIT | TSC2007_MEASURE_Z1)
> +#define READ_Z2 (ADC_ON_12BIT | TSC2007_MEASURE_Z2)
> +#define READ_X (ADC_ON_12BIT | TSC2007_MEASURE_X)
> +#define PWRDOWN (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
> +
> +struct ts_event {
> + u16 x;
> + u16 y;
> + u16 z1, z2;
> +};
> +
> +struct tsc2007 {
> + struct input_dev *input;
> + char phys[32];
> + struct hrtimer timer;
> + struct ts_event tc;
> +
> + struct i2c_client *client;
> +
> + spinlock_t lock;
> +
> + u16 model;
> + u16 x_plate_ohms;
> +
> + unsigned pendown;
> + int irq;
> +
> + int (*get_pendown_state)(void);
> + void (*clear_penirq)(void);
> +};
> +
> +static int tsc2007_xfer(void *tsc, unsigned char cmd)
> +{
> + struct tsc2007 *ts = tsc;
> + struct i2c_client *client = ts->client;
> +
> + unsigned char rbuf[2];
> + unsigned short val;
> + int result;
> +
> + result = i2c_master_send(client, &cmd, 1);
> + if (result != 1) {
> + dev_err(&client->dev, "send failed, cmd 0x%x\n", cmd);
> + goto cmd_fail;
> + }
> +
> + result = i2c_master_recv(client, rbuf, 2);
> + if (result != 2) {
> + dev_err(&client->dev, "recv failed, cmd 0x%x\n", cmd);
> + goto cmd_fail;
> + }
> +
> + rbuf[1] = (rbuf[1] >> 4) | ((rbuf[0] & 0x0f) << 4);
> + rbuf[0] = rbuf[0] >> 4;
> +
> + val = *((unsigned short *) rbuf);
> + val = be16_to_cpu(val);
> +
> + dev_dbg(&client->dev, "cmd [0x%x], rbuf [0x%x, 0x%x] => val [%u]\n",
> + cmd, rbuf[0], rbuf[1], val);
> +
> + return (int) val;
> +
> +cmd_fail:
> + return -EIO;
> +}
> +
> +static void tsc2007_send_event(void *tsc)
> +{
> + struct tsc2007 *ts = tsc;
> + u32 Rt;
> + u16 x, y, z1, z2;
> +
> + x = ts->tc.x;
> + y = ts->tc.y;
> + z1 = ts->tc.z1;
> + z2 = ts->tc.z2;
> +
> + /* range filtering */
> + if (x == MAX_12BIT)
> + x = 0;
> +
> + if (likely(x && z1)) {
> + /* compute touch pressure resistance using equation #1 */
> + Rt = z2;
> + Rt -= z1;
> + Rt *= x;
> + Rt *= ts->x_plate_ohms;
> + Rt /= z1;
> + Rt = (Rt + 2047) >> 12;
> + } else
> + Rt = 0;
> +
> + /* Sample found inconsistent by debouncing or pressure is beyond
> + * the maximum. Don't report it to user space, repeat at least
> + * once more the measurement
> + */
> + if (Rt > MAX_12BIT) {
> + dev_dbg(&ts->client->dev, "ignored pressure %d\n", Rt);
> +
> + hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
> + HRTIMER_MODE_REL);
> + return;
> + }
> +
> + /* NOTE: We can't rely on the pressure to determine the pen down
> + * state, even this controller has a pressure sensor. The pressure
> + * value can fluctuate for quite a while after lifting the pen and
> + * in some cases may not even settle at the expected value.
> + *
> + * The only safe way to check for the pen up condition is in the
> + * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
> + */
> + if (Rt) {
> + struct input_dev *input = ts->input;
> +
> + if (!ts->pendown) {
> + dev_dbg(&ts->client->dev, "DOWN\n");
> +
> + input_report_key(input, BTN_TOUCH, 1);
> + ts->pendown = 1;
> + }
> +
> + input_report_abs(input, ABS_X, x);
> + input_report_abs(input, ABS_Y, y);
> + input_report_abs(input, ABS_PRESSURE, Rt);
> +
> + input_sync(input);
> +
> + dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
> + x, y, Rt);
> + }
> +
> + hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
> + HRTIMER_MODE_REL);
> +}
> +
> +static int tsc2007_read_values(struct tsc2007 *tsc)
> +{
> + struct tsc2007 *ts = tsc;
> +
> + /* y- still on; turn on only y+ (and ADC) */
> + ts->tc.y = tsc2007_xfer(ts, READ_Y);
> +
> + /* turn y- off, x+ on, then leave in lowpower */
> + ts->tc.x = tsc2007_xfer(ts, READ_X);
> +
> + /* turn y+ off, x- on; we'll use formula #1 */
> + ts->tc.z1 = tsc2007_xfer(ts, READ_Z1);
> + ts->tc.z2 = tsc2007_xfer(ts, READ_Z2);
> +
> + /* power down */
> + tsc2007_xfer(ts, PWRDOWN);
> + return 0;
> +}
> +
> +static enum hrtimer_restart tsc2007_timer(struct hrtimer *handle)
> +{
> + struct tsc2007 *ts = container_of(handle, struct tsc2007, timer);
> +
> + spin_lock_irq(&ts->lock);
> +
> + if (unlikely(!ts->get_pendown_state() && ts->pendown)) {
> + struct input_dev *input = ts->input;
> +
> + dev_dbg(&ts->client->dev, "UP\n");
> +
> + input_report_key(input, BTN_TOUCH, 0);
> + input_report_abs(input, ABS_PRESSURE, 0);
> + input_sync(input);
> +
> + ts->pendown = 0;
> + enable_irq(ts->irq);
> + } else {
> + /* pen is still down, continue with the measurement */
> + dev_dbg(&ts->client->dev, "pen is still down\n");
> +
> + tsc2007_read_values(ts);
> + tsc2007_send_event(ts);
> + }
> +
> + spin_unlock_irq(&ts->lock);
> + return HRTIMER_NORESTART;
> +}
> +
> +static irqreturn_t tsc2007_irq(int irq, void *handle)
> +{
> + struct tsc2007 *ts = handle;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ts->lock, flags);
> + if (likely(ts->get_pendown_state())) {
> + disable_irq(ts->irq);
> + hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
> + HRTIMER_MODE_REL);
> + }
> +
> + if (ts->clear_penirq)
> + ts->clear_penirq();
> +
> + spin_unlock_irqrestore(&ts->lock, flags);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int tsc2007_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
> + struct tsc2007 *ts;
> + struct tsc2007_platform_data *pdata;
> + struct input_dev *input_dev;
> + int err;
> +
> + pdata = client->dev.platform_data;
> + if (pdata == NULL) {
> + dev_err(&client->dev, "platform data is required!\n");
> + return -EINVAL;
> + }
> +
> + if (!i2c_check_functionality(adapter,
> + I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
> + return -EIO;
> +
> + ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
> + input_dev = input_allocate_device();
> + if (!ts || !input_dev) {
> + err = -ENOMEM;
> + goto err_free_mem;
> + }
> +
> + ts->client = client;
> + i2c_set_clientdata(client, ts);
> +
> + ts->input = input_dev;
> +
> + hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> + ts->timer.function = tsc2007_timer;
> +
> + spin_lock_init(&ts->lock);
> +
> + ts->model = pdata->model;
> + ts->x_plate_ohms = pdata->x_plate_ohms;
> + ts->get_pendown_state = pdata->get_pendown_state;
> + ts->clear_penirq = pdata->clear_penirq;
> +
> + pdata->init_platform_hw();
> +
> + snprintf(ts->phys, sizeof(ts->phys), "%s/input0", client->dev.bus_id);
> +
> + input_dev->name = "TSC2007 Touchscreen";
> + input_dev->phys = ts->phys;
> +
> + input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
> + input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
> +
> + input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
> + input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
> + input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
> +
> + tsc2007_read_values(ts);
> +
> + ts->irq = client->irq;
> + if (request_irq(ts->irq, tsc2007_irq, 0,
> + client->dev.driver->name, ts)) {
> + dev_err(&client->dev, "irq %d busy?\n", ts->irq);
> + err = -EBUSY;
> + goto err_free_mem;
> + }
> +
> + err = input_register_device(input_dev);
> + if (err)
> + goto err_free_irq;
> +
> + dev_info(&client->dev, "registered with irq (%d)\n", ts->irq);
> +
> + return 0;
> +
> + err_free_irq:
> + free_irq(ts->irq, ts);
> + err_free_mem:
> + input_free_device(input_dev);
> + kfree(ts);
> + return err;
> +}
> +
> +static int tsc2007_remove(struct i2c_client *client)
> +{
> + struct tsc2007 *ts = i2c_get_clientdata(client);
> + struct tsc2007_platform_data *pdata;
> +
> + pdata = client->dev.platform_data;
> + pdata->exit_platform_hw();
> +
> + input_unregister_device(ts->input);
> + free_irq(ts->irq, ts);
> + kfree(ts);
> +
> + dev_info(&client->dev, "unregistered\n");
> + return 0;
> +}
> +
> +static struct i2c_device_id tsc2007_idtable[] = {
> + { "tsc2007", 0 },
> + { }
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
> +
> +static struct i2c_driver tsc2007_driver = {
> + .driver = {
> + .owner = THIS_MODULE,
> + .name = "tsc2007"
> + },
> + .id_table = tsc2007_idtable,
> + .probe = tsc2007_probe,
> + .remove = tsc2007_remove,
> +};
> +
> +static int __init tsc2007_init(void)
> +{
> + return i2c_add_driver(&tsc2007_driver);
> +}
> +
> +static void __exit tsc2007_exit(void)
> +{
> + i2c_del_driver(&tsc2007_driver);
> +}
> +
> +module_init(tsc2007_init);
> +module_exit(tsc2007_exit);
> +
> +MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
> +MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/i2c/tsc2007.h b/include/linux/i2c/tsc2007.h
> new file mode 100644
> index 0000000..c6361fb
> --- /dev/null
> +++ b/include/linux/i2c/tsc2007.h
> @@ -0,0 +1,17 @@
> +#ifndef __LINUX_I2C_TSC2007_H
> +#define __LINUX_I2C_TSC2007_H
> +
> +/* linux/i2c/tsc2007.h */
> +
> +struct tsc2007_platform_data {
> + u16 model; /* 2007. */
> + u16 x_plate_ohms;
> +
> + int (*get_pendown_state)(void);
> + void (*clear_penirq)(void); /* If needed, clear 2nd level
> + interrupt source */
> + int (*init_platform_hw)(void);
> + void (*exit_platform_hw)(void);
> +};
> +
> +#endif
> --
> 1.5.6.5
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
--
---Trilok Soni
http://triloksoni.wordpress.com
http://www.linkedin.com/in/triloksoni
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Add tsc2007 based touchscreen driver.
2008-12-03 11:21 ` Trilok Soni
@ 2008-12-03 12:01 ` Felipe Balbi
2008-12-04 5:07 ` Kwangwoo Lee
2008-12-03 20:18 ` David Brownell
2008-12-04 4:37 ` Kwangwoo Lee
2 siblings, 1 reply; 9+ messages in thread
From: Felipe Balbi @ 2008-12-03 12:01 UTC (permalink / raw)
To: ext Trilok Soni
Cc: Kwangwoo Lee, dmitry.torokhov, linux-kernel, David Brownell,
linux-omap@vger.kernel.org Mailing List
On Wed, Dec 03, 2008 at 04:51:12PM +0530, ext Trilok Soni wrote:
> Hi Lee
>
> Adding linux-omap mailing list. Sometime I am thinking that same chip
> might have interface to be connected on another board/cpu through SPI
> too, so in this case we will have two drivers doing the same thing and
> difference is just a change of the bus interface.
>
> We should do something v4l2_subdev framework right now going on on
> v4l2 mailing list to abstract the sensor drivers from bus.
I've seen spi only for tsc2005.
> > /* TSC2007 Touchscreen */
> > #ifdef CONFIG_LCD_CT024TN02
> > /* GPIO13:GINT3 = PENIRQ */
> > #define TS_PENIRQ_GPIO GPIO13
> > #define TS_CHAINED_GPIO 3
> > #else
> > /* GPIO5:GINT1 = PENIRQ */
> > #define TS_PENIRQ_GPIO GPIO5
> > #define TS_CHAINED_GPIO 1
> > #endif
this should be using the platform_data.
> > static int mv_get_pendown_state(void)
> > {
> > int val = 0;
> >
> > mv_gpio_set_direction(TS_PENIRQ_GPIO, 0);
> > mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_GPIO);
should be using gpiolib
> > val = mv_gpio_get_value(TS_PENIRQ_GPIO);
> > mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_INT);
> >
> > val = val ? 0 : 1;
> > return val;
> > }
> >
> > static void mv_clear_penirq(void)
> > {
> > mv_gpio_int_clear(TS_CHAINED_GPIO);
> > }
> >
> > static int mv_init_ts(void)
> > {
> > mv_gpio_set_direction(TS_PENIRQ_GPIO, 0); /* input */
> > mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_INT);
> >
> > mv_gpio_int_mode(TS_CHAINED_GPIO, GPIO_INT_FALLING_EDGE);
> > mv_gpio_int_clear(TS_CHAINED_GPIO);
> > mv_gpio_int_unmask(TS_CHAINED_GPIO);
> > return 0;
> > }
> >
> > static void mv_exit_ts(void)
> > {
> > mv_gpio_mux_ctrl(TS_PENIRQ_GPIO, GPIO_PIN_MODE_GPIO);
> > mv_gpio_int_mask(TS_CHAINED_GPIO);
> > }
> >
> > struct tsc2007_platform_data mv_tsc2007_data = {
should be static.
> > .model = 2007,
> > .x_plate_ohms = 180,
> > .get_pendown_state = mv_get_pendown_state,
> > .clear_penirq = mv_clear_penirq,
> > .init_platform_hw = mv_init_ts,
> > .exit_platform_hw = mv_exit_ts,
> > };
> >
> > /* I2C clients */
> > static struct i2c_board_info __initdata mv_i2c_clients[] = {
> > [0] = {
> > I2C_BOARD_INFO("tsc2007", 0x90),
> > .type = "tsc2007",
> > .platform_data = &mv_tsc2007_data,
> > .irq = IRQ_GPIO,
> > },
> > };
> >
> > i2c_register_board_info() should be used.
> >
> > Signed-off-by: Kwangwoo Lee <kwangwoo.lee@gmail.com>
> > ---
> > drivers/input/touchscreen/Kconfig | 9 +
> > drivers/input/touchscreen/Makefile | 1 +
> > drivers/input/touchscreen/tsc2007.c | 398 +++++++++++++++++++++++++++++++++++
> > include/linux/i2c/tsc2007.h | 17 ++
> > 4 files changed, 425 insertions(+), 0 deletions(-)
> > create mode 100644 drivers/input/touchscreen/tsc2007.c
> > create mode 100644 include/linux/i2c/tsc2007.h
> >
> > diff --git a/drivers/input/touchscreen/Kconfig
> > b/drivers/input/touchscreen/Kconfig
> > index 3d1ab8f..78abdfb 100644
> > --- a/drivers/input/touchscreen/Kconfig
> > +++ b/drivers/input/touchscreen/Kconfig
> > @@ -376,4 +376,13 @@ config TOUCHSCREEN_TOUCHIT213
> > To compile this driver as a module, choose M here: the
> > module will be called touchit213.
> >
> > +config TOUCHSCREEN_TSC2007
> > + tristate "TSC2007 based touchscreens"
> > + depends on I2C
> > + help
> > + Say Y here if you have a TSC2007 based touchscreens.
> > +
> > + To compile this driver as a module, choose M here: the
> > + module will be called tsc2007.
> > +
> > endif
> > diff --git a/drivers/input/touchscreen/Makefile
> > b/drivers/input/touchscreen/Makefile
> > index 15cf290..824999c 100644
> > --- a/drivers/input/touchscreen/Makefile
> > +++ b/drivers/input/touchscreen/Makefile
> > @@ -31,3 +31,4 @@ wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9705) += wm9705.o
> > wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9712) += wm9712.o
> > wm97xx-ts-$(CONFIG_TOUCHSCREEN_WM9713) += wm9713.o
> > obj-$(CONFIG_TOUCHSCREEN_WM97XX_MAINSTONE) += mainstone-wm97xx.o
> > +obj-$(CONFIG_TOUCHSCREEN_TSC2007) += tsc2007.o
> > diff --git a/drivers/input/touchscreen/tsc2007.c
> > b/drivers/input/touchscreen/tsc2007.c
> > new file mode 100644
> > index 0000000..85fb520
> > --- /dev/null
> > +++ b/drivers/input/touchscreen/tsc2007.c
> > @@ -0,0 +1,398 @@
> > +/*
> > + * drivers/input/touchscreen/tsc2007.c
> > + *
> > + * Copyright (c) 2008 MtekVision Co., Ltd.
> > + * Kwangwoo Lee <kwlee@mtekvision.com>
> > + *
> > + * Using code from:
> > + * - ads7846.c
> > + * Copyright (c) 2005 David Brownell
> > + * Copyright (c) 2006 Nokia Corporation
> > + * - corgi_ts.c
> > + * Copyright (C) 2004-2005 Richard Purdie
> > + * - omap_ts.[hc], ads7846.h, ts_osk.c
> > + * Copyright (C) 2002 MontaVista Software
> > + * Copyright (C) 2004 Texas Instruments
> > + * Copyright (C) 2005 Dirk Behme
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/hwmon.h>
> > +#include <linux/init.h>
> > +#include <linux/err.h>
> > +#include <linux/delay.h>
> > +#include <linux/input.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/slab.h>
> > +#include <linux/i2c.h>
> > +#include <linux/i2c/tsc2007.h>
> > +#include <linux/io.h>
> > +
> > +#include <asm/irq.h>
> > +
> > +#define TS_POLL_DELAY (10 * 1000) /* ns delay before the first sample */
> > +#define TS_POLL_PERIOD (5 * 1000) /* ns delay between samples */
> > +
> > +#define TSC2007_MEASURE_TEMP0 (0x0 << 4)
> > +#define TSC2007_MEASURE_AUX (0x2 << 4)
> > +#define TSC2007_MEASURE_TEMP1 (0x4 << 4)
> > +#define TSC2007_ACTIVATE_XN (0x8 << 4)
> > +#define TSC2007_ACTIVATE_YN (0x9 << 4)
> > +#define TSC2007_ACTIVATE_YP_XN (0xa << 4)
> > +#define TSC2007_SETUP (0xb << 4)
> > +#define TSC2007_MEASURE_X (0xc << 4)
> > +#define TSC2007_MEASURE_Y (0xd << 4)
> > +#define TSC2007_MEASURE_Z1 (0xe << 4)
> > +#define TSC2007_MEASURE_Z2 (0xf << 4)
> > +
> > +#define TSC2007_POWER_OFF_IRQ_EN (0x0 << 2)
> > +#define TSC2007_ADC_ON_IRQ_DIS0 (0x1 << 2)
> > +#define TSC2007_ADC_OFF_IRQ_EN (0x2 << 2)
> > +#define TSC2007_ADC_ON_IRQ_DIS1 (0x3 << 2)
> > +
> > +#define TSC2007_12BIT (0x0 << 1)
> > +#define TSC2007_8BIT (0x1 << 1)
> > +
> > +#define MAX_12BIT ((1 << 12) - 1)
> > +
> > +#define ADC_ON_12BIT (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
> > +
> > +#define READ_Y (ADC_ON_12BIT | TSC2007_MEASURE_Y)
> > +#define READ_Z1 (ADC_ON_12BIT | TSC2007_MEASURE_Z1)
> > +#define READ_Z2 (ADC_ON_12BIT | TSC2007_MEASURE_Z2)
> > +#define READ_X (ADC_ON_12BIT | TSC2007_MEASURE_X)
> > +#define PWRDOWN (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
> > +
> > +struct ts_event {
> > + u16 x;
> > + u16 y;
> > + u16 z1, z2;
> > +};
> > +
> > +struct tsc2007 {
> > + struct input_dev *input;
> > + char phys[32];
> > + struct hrtimer timer;
> > + struct ts_event tc;
> > +
> > + struct i2c_client *client;
> > +
> > + spinlock_t lock;
> > +
> > + u16 model;
> > + u16 x_plate_ohms;
> > +
> > + unsigned pendown;
> > + int irq;
> > +
> > + int (*get_pendown_state)(void);
> > + void (*clear_penirq)(void);
> > +};
> > +
> > +static int tsc2007_xfer(void *tsc, unsigned char cmd)
> > +{
> > + struct tsc2007 *ts = tsc;
> > + struct i2c_client *client = ts->client;
> > +
> > + unsigned char rbuf[2];
> > + unsigned short val;
> > + int result;
> > +
> > + result = i2c_master_send(client, &cmd, 1);
> > + if (result != 1) {
> > + dev_err(&client->dev, "send failed, cmd 0x%x\n", cmd);
> > + goto cmd_fail;
> > + }
> > +
> > + result = i2c_master_recv(client, rbuf, 2);
> > + if (result != 2) {
> > + dev_err(&client->dev, "recv failed, cmd 0x%x\n", cmd);
> > + goto cmd_fail;
> > + }
> > +
> > + rbuf[1] = (rbuf[1] >> 4) | ((rbuf[0] & 0x0f) << 4);
> > + rbuf[0] = rbuf[0] >> 4;
> > +
> > + val = *((unsigned short *) rbuf);
> > + val = be16_to_cpu(val);
> > +
> > + dev_dbg(&client->dev, "cmd [0x%x], rbuf [0x%x, 0x%x] => val [%u]\n",
> > + cmd, rbuf[0], rbuf[1], val);
> > +
> > + return (int) val;
> > +
> > +cmd_fail:
> > + return -EIO;
> > +}
so you really need to go that low level ?? Did you try
i2c_smbus_write_*() ??
> > +static void tsc2007_send_event(void *tsc)
> > +{
> > + struct tsc2007 *ts = tsc;
> > + u32 Rt;
> > + u16 x, y, z1, z2;
> > +
> > + x = ts->tc.x;
> > + y = ts->tc.y;
> > + z1 = ts->tc.z1;
> > + z2 = ts->tc.z2;
> > +
> > + /* range filtering */
> > + if (x == MAX_12BIT)
> > + x = 0;
> > +
> > + if (likely(x && z1)) {
> > + /* compute touch pressure resistance using equation #1 */
> > + Rt = z2;
> > + Rt -= z1;
> > + Rt *= x;
> > + Rt *= ts->x_plate_ohms;
> > + Rt /= z1;
> > + Rt = (Rt + 2047) >> 12;
> > + } else
> > + Rt = 0;
> > +
> > + /* Sample found inconsistent by debouncing or pressure is beyond
> > + * the maximum. Don't report it to user space, repeat at least
> > + * once more the measurement
> > + */
> > + if (Rt > MAX_12BIT) {
> > + dev_dbg(&ts->client->dev, "ignored pressure %d\n", Rt);
> > +
> > + hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
> > + HRTIMER_MODE_REL);
> > + return;
> > + }
> > +
> > + /* NOTE: We can't rely on the pressure to determine the pen down
> > + * state, even this controller has a pressure sensor. The pressure
> > + * value can fluctuate for quite a while after lifting the pen and
> > + * in some cases may not even settle at the expected value.
> > + *
> > + * The only safe way to check for the pen up condition is in the
> > + * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
> > + */
> > + if (Rt) {
> > + struct input_dev *input = ts->input;
> > +
> > + if (!ts->pendown) {
> > + dev_dbg(&ts->client->dev, "DOWN\n");
> > +
> > + input_report_key(input, BTN_TOUCH, 1);
> > + ts->pendown = 1;
> > + }
> > +
> > + input_report_abs(input, ABS_X, x);
> > + input_report_abs(input, ABS_Y, y);
> > + input_report_abs(input, ABS_PRESSURE, Rt);
> > +
> > + input_sync(input);
> > +
> > + dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
> > + x, y, Rt);
> > + }
> > +
> > + hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
> > + HRTIMER_MODE_REL);
> > +}
> > +
> > +static int tsc2007_read_values(struct tsc2007 *tsc)
> > +{
> > + struct tsc2007 *ts = tsc;
> > +
> > + /* y- still on; turn on only y+ (and ADC) */
> > + ts->tc.y = tsc2007_xfer(ts, READ_Y);
> > +
> > + /* turn y- off, x+ on, then leave in lowpower */
> > + ts->tc.x = tsc2007_xfer(ts, READ_X);
> > +
> > + /* turn y+ off, x- on; we'll use formula #1 */
> > + ts->tc.z1 = tsc2007_xfer(ts, READ_Z1);
> > + ts->tc.z2 = tsc2007_xfer(ts, READ_Z2);
> > +
> > + /* power down */
> > + tsc2007_xfer(ts, PWRDOWN);
> > + return 0;
> > +}
> > +
> > +static enum hrtimer_restart tsc2007_timer(struct hrtimer *handle)
> > +{
> > + struct tsc2007 *ts = container_of(handle, struct tsc2007, timer);
> > +
> > + spin_lock_irq(&ts->lock);
> > +
> > + if (unlikely(!ts->get_pendown_state() && ts->pendown)) {
> > + struct input_dev *input = ts->input;
> > +
> > + dev_dbg(&ts->client->dev, "UP\n");
> > +
> > + input_report_key(input, BTN_TOUCH, 0);
> > + input_report_abs(input, ABS_PRESSURE, 0);
> > + input_sync(input);
> > +
> > + ts->pendown = 0;
> > + enable_irq(ts->irq);
> > + } else {
> > + /* pen is still down, continue with the measurement */
> > + dev_dbg(&ts->client->dev, "pen is still down\n");
> > +
> > + tsc2007_read_values(ts);
> > + tsc2007_send_event(ts);
> > + }
> > +
> > + spin_unlock_irq(&ts->lock);
> > + return HRTIMER_NORESTART;
> > +}
> > +
> > +static irqreturn_t tsc2007_irq(int irq, void *handle)
> > +{
> > + struct tsc2007 *ts = handle;
> > + unsigned long flags;
> > +
> > + spin_lock_irqsave(&ts->lock, flags);
> > + if (likely(ts->get_pendown_state())) {
> > + disable_irq(ts->irq);
> > + hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
> > + HRTIMER_MODE_REL);
> > + }
> > +
> > + if (ts->clear_penirq)
> > + ts->clear_penirq();
> > +
> > + spin_unlock_irqrestore(&ts->lock, flags);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static int tsc2007_probe(struct i2c_client *client,
> > + const struct i2c_device_id *id)
> > +{
> > + struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
why ??
> > + struct tsc2007 *ts;
> > + struct tsc2007_platform_data *pdata;
> > + struct input_dev *input_dev;
> > + int err;
> > +
> > + pdata = client->dev.platform_data;
> > + if (pdata == NULL) {
> > + dev_err(&client->dev, "platform data is required!\n");
> > + return -EINVAL;
> > + }
> > +
> > + if (!i2c_check_functionality(adapter,
> > + I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
> > + return -EIO;
should not be in this driver, I'd say.
> > +
> > + ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
> > + input_dev = input_allocate_device();
> > + if (!ts || !input_dev) {
> > + err = -ENOMEM;
> > + goto err_free_mem;
> > + }
> > +
> > + ts->client = client;
> > + i2c_set_clientdata(client, ts);
> > +
> > + ts->input = input_dev;
> > +
> > + hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> > + ts->timer.function = tsc2007_timer;
> > +
> > + spin_lock_init(&ts->lock);
> > +
> > + ts->model = pdata->model;
> > + ts->x_plate_ohms = pdata->x_plate_ohms;
> > + ts->get_pendown_state = pdata->get_pendown_state;
> > + ts->clear_penirq = pdata->clear_penirq;
> > +
> > + pdata->init_platform_hw();
> > +
> > + snprintf(ts->phys, sizeof(ts->phys), "%s/input0", client->dev.bus_id);
> > +
> > + input_dev->name = "TSC2007 Touchscreen";
> > + input_dev->phys = ts->phys;
> > +
> > + input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
> > + input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
> > +
> > + input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
> > + input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
> > + input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
> > +
> > + tsc2007_read_values(ts);
> > +
> > + ts->irq = client->irq;
> > + if (request_irq(ts->irq, tsc2007_irq, 0,
> > + client->dev.driver->name, ts)) {
> > + dev_err(&client->dev, "irq %d busy?\n", ts->irq);
> > + err = -EBUSY;
> > + goto err_free_mem;
would be better to:
err = request_irq(...)
if (err < 0) {
dev_err(..)
...
}
Then we see the error request_irq() returned, which is more useful.
> > + }
> > +
> > + err = input_register_device(input_dev);
> > + if (err)
> > + goto err_free_irq;
> > +
> > + dev_info(&client->dev, "registered with irq (%d)\n", ts->irq);
> > +
> > + return 0;
> > +
> > + err_free_irq:
> > + free_irq(ts->irq, ts);
> > + err_free_mem:
> > + input_free_device(input_dev);
> > + kfree(ts);
> > + return err;
> > +}
> > +
> > +static int tsc2007_remove(struct i2c_client *client)
> > +{
> > + struct tsc2007 *ts = i2c_get_clientdata(client);
> > + struct tsc2007_platform_data *pdata;
> > +
> > + pdata = client->dev.platform_data;
> > + pdata->exit_platform_hw();
> > +
> > + input_unregister_device(ts->input);
> > + free_irq(ts->irq, ts);
> > + kfree(ts);
> > +
> > + dev_info(&client->dev, "unregistered\n");
> > + return 0;
> > +}
> > +
> > +static struct i2c_device_id tsc2007_idtable[] = {
> > + { "tsc2007", 0 },
> > + { }
> > +};
> > +
> > +MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
> > +
> > +static struct i2c_driver tsc2007_driver = {
> > + .driver = {
> > + .owner = THIS_MODULE,
> > + .name = "tsc2007"
> > + },
> > + .id_table = tsc2007_idtable,
> > + .probe = tsc2007_probe,
> > + .remove = tsc2007_remove,
> > +};
> > +
> > +static int __init tsc2007_init(void)
> > +{
> > + return i2c_add_driver(&tsc2007_driver);
> > +}
> > +
> > +static void __exit tsc2007_exit(void)
> > +{
> > + i2c_del_driver(&tsc2007_driver);
> > +}
> > +
> > +module_init(tsc2007_init);
> > +module_exit(tsc2007_exit);
> > +
> > +MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
> > +MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
> > +MODULE_LICENSE("GPL");
Would be nice to get comments from Jean Delvare and Ben Dooks as well.
--
balbi
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Add tsc2007 based touchscreen driver.
2008-12-03 11:21 ` Trilok Soni
2008-12-03 12:01 ` Felipe Balbi
@ 2008-12-03 20:18 ` David Brownell
2008-12-04 4:37 ` Kwangwoo Lee
2 siblings, 0 replies; 9+ messages in thread
From: David Brownell @ 2008-12-03 20:18 UTC (permalink / raw)
To: Trilok Soni
Cc: Kwangwoo Lee, dmitry.torokhov, linux-kernel,
linux-omap@vger.kernel.org Mailing List
On Wednesday 03 December 2008, Trilok Soni wrote:
> Adding linux-omap mailing list. Sometime I am thinking that same chip
> might have interface to be connected on another board/cpu through SPI
> too, so in this case we will have two drivers doing the same thing and
> difference is just a change of the bus interface.
Is this chip an example of that? It's I2C-only, and a quick
scan of TI's touchscreen chip page didn't show a sibling chip
with a logically-identical interface using SPI.
> We should do something v4l2_subdev framework right now going on on
> v4l2 mailing list to abstract the sensor drivers from bus.
I'll disagree. When it's needed, this is easy to do ... bus
glue talking to chip-specific code, and including some kind of
bus-specific register access wrapper. No framework necessary,
just straightforward design for any such drivers.
- Dave
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Add tsc2007 based touchscreen driver.
2008-12-03 11:21 ` Trilok Soni
2008-12-03 12:01 ` Felipe Balbi
2008-12-03 20:18 ` David Brownell
@ 2008-12-04 4:37 ` Kwangwoo Lee
2 siblings, 0 replies; 9+ messages in thread
From: Kwangwoo Lee @ 2008-12-04 4:37 UTC (permalink / raw)
To: Trilok Soni
Cc: dmitry.torokhov, linux-kernel, David Brownell,
linux-omap@vger.kernel.org Mailing List
On Wed, Dec 3, 2008 at 8:21 PM, Trilok Soni <soni.trilok@gmail.com> wrote:
> Hi Lee
>
> Adding linux-omap mailing list. Sometime I am thinking that same chip
> might have interface to be connected on another board/cpu through SPI
> too, so in this case we will have two drivers doing the same thing and
> difference is just a change of the bus interface.
Hi Soni,
At first, I tried to support tsc2007 with ads7846.c. But it required
some kind of
common logic to support both SPI and I2C for the driver, as you thought.
If I modified the ads7846.c to support tsc2007, the driver might be a
bit more complicate.
I do not know which method is better, but making a different driver
was simppler for me.
Thank you.
> We should do something v4l2_subdev framework right now going on on
> v4l2 mailing list to abstract the sensor drivers from bus.
>
--
Kwangwoo Lee <kwangwoo.lee@gmail.com>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Add tsc2007 based touchscreen driver.
2008-12-03 12:01 ` Felipe Balbi
@ 2008-12-04 5:07 ` Kwangwoo Lee
2008-12-04 9:37 ` Felipe Balbi
0 siblings, 1 reply; 9+ messages in thread
From: Kwangwoo Lee @ 2008-12-04 5:07 UTC (permalink / raw)
To: felipe.balbi
Cc: ext Trilok Soni, dmitry.torokhov, linux-kernel, David Brownell,
linux-omap@vger.kernel.org Mailing List
On Wed, Dec 3, 2008 at 9:01 PM, Felipe Balbi <felipe.balbi@nokia.com> wrote:
...
>> > +
>> > +static int tsc2007_xfer(void *tsc, unsigned char cmd)
>> > +{
>> > + struct tsc2007 *ts = tsc;
>> > + struct i2c_client *client = ts->client;
>> > +
>> > + unsigned char rbuf[2];
>> > + unsigned short val;
>> > + int result;
>> > +
>> > + result = i2c_master_send(client, &cmd, 1);
>> > + if (result != 1) {
>> > + dev_err(&client->dev, "send failed, cmd 0x%x\n", cmd);
>> > + goto cmd_fail;
>> > + }
>> > +
>> > + result = i2c_master_recv(client, rbuf, 2);
>> > + if (result != 2) {
>> > + dev_err(&client->dev, "recv failed, cmd 0x%x\n", cmd);
>> > + goto cmd_fail;
>> > + }
>> > +
>> > + rbuf[1] = (rbuf[1] >> 4) | ((rbuf[0] & 0x0f) << 4);
>> > + rbuf[0] = rbuf[0] >> 4;
>> > +
>> > + val = *((unsigned short *) rbuf);
>> > + val = be16_to_cpu(val);
>> > +
>> > + dev_dbg(&client->dev, "cmd [0x%x], rbuf [0x%x, 0x%x] => val [%u]\n",
>> > + cmd, rbuf[0], rbuf[1], val);
>> > +
>> > + return (int) val;
>> > +
>> > +cmd_fail:
>> > + return -EIO;
>> > +}
>
> so you really need to go that low level ?? Did you try
> i2c_smbus_write_*() ??
>
Because the platform which I use did not implement smbus_xfer yet,
it only implemented master_xfer in struct i2c_algorithm.
I can add smbus_xfer for my platform. I have one question and
I know that smbus is a subset from the I2C protocol.
Is smbus_xfer method better than master_xfer or is there any
special reason to use smbus_xfer?
>> > +
>> > +static int tsc2007_probe(struct i2c_client *client,
>> > + const struct i2c_device_id *id)
>> > +{
>> > + struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
>
> why ??
It's for i2c_check_functionality(). This function requried struct
i2c_adapter as an argument.
>> > + struct tsc2007 *ts;
>> > + struct tsc2007_platform_data *pdata;
>> > + struct input_dev *input_dev;
>> > + int err;
>> > +
>> > + pdata = client->dev.platform_data;
>> > + if (pdata == NULL) {
>> > + dev_err(&client->dev, "platform data is required!\n");
>> > + return -EINVAL;
>> > + }
>> > +
>> > + if (!i2c_check_functionality(adapter,
>> > + I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
>> > + return -EIO;
>
> should not be in this driver, I'd say.
I saw that some I2C driver uses this function, for example - max6875.c.
Is i2c_check_functionality() not necessary for a I2C client driver?
>> > + ts->irq = client->irq;
>> > + if (request_irq(ts->irq, tsc2007_irq, 0,
>> > + client->dev.driver->name, ts)) {
>> > + dev_err(&client->dev, "irq %d busy?\n", ts->irq);
>> > + err = -EBUSY;
>> > + goto err_free_mem;
>
> would be better to:
>
> err = request_irq(...)
> if (err < 0) {
> dev_err(..)
> ...
> }
>
> Then we see the error request_irq() returned, which is more useful.
Thank you very much for your kind comments.
> Would be nice to get comments from Jean Delvare and Ben Dooks as well.
I also want to get more comments. Thank you, again.
--
Kwangwoo Lee <kwangwoo.lee@gmail.com>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Add tsc2007 based touchscreen driver.
2008-12-04 5:07 ` Kwangwoo Lee
@ 2008-12-04 9:37 ` Felipe Balbi
2008-12-04 9:56 ` David Brownell
0 siblings, 1 reply; 9+ messages in thread
From: Felipe Balbi @ 2008-12-04 9:37 UTC (permalink / raw)
To: ext Kwangwoo Lee
Cc: felipe.balbi, ext Trilok Soni, dmitry.torokhov, linux-kernel,
David Brownell, linux-omap@vger.kernel.org Mailing List
On Thu, Dec 04, 2008 at 02:07:30PM +0900, ext Kwangwoo Lee wrote:
> Because the platform which I use did not implement smbus_xfer yet,
> it only implemented master_xfer in struct i2c_algorithm.
> I can add smbus_xfer for my platform. I have one question and
> I know that smbus is a subset from the I2C protocol.
> Is smbus_xfer method better than master_xfer or is there any
> special reason to use smbus_xfer?
i2c subsystem has smbus emulation. The special reason is just that it's
simpler for the driver writer ;-)
--
balbi
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Add tsc2007 based touchscreen driver.
2008-12-04 9:37 ` Felipe Balbi
@ 2008-12-04 9:56 ` David Brownell
2008-12-05 1:09 ` Kwangwoo Lee
0 siblings, 1 reply; 9+ messages in thread
From: David Brownell @ 2008-12-04 9:56 UTC (permalink / raw)
To: felipe.balbi, ext Kwangwoo Lee
Cc: ext Trilok Soni, dmitry.torokhov, linux-kernel,
linux-omap@vger.kernel.org Mailing List
On Thursday 04 December 2008, Felipe Balbi wrote:
> i2c subsystem has smbus emulation. The special reason is just that it's
> simpler for the driver writer ;-)
I'd have said "more portable", actually. I2C hosts can
do pretty much everything an SMBus host can, but the
converse is not true.
And re i2c_check_functionality() ... yes, use it to make
sure each I2C or SMBus call the driver makes is supported
by the underlying controller.
- Dave
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Add tsc2007 based touchscreen driver.
2008-12-04 9:56 ` David Brownell
@ 2008-12-05 1:09 ` Kwangwoo Lee
0 siblings, 0 replies; 9+ messages in thread
From: Kwangwoo Lee @ 2008-12-05 1:09 UTC (permalink / raw)
To: David Brownell, felipe.balbi
Cc: ext Trilok Soni, dmitry.torokhov, linux-kernel,
linux-omap@vger.kernel.org Mailing List
On Thu, Dec 4, 2008 at 6:56 PM, David Brownell <david-b@pacbell.net> wrote:
> On Thursday 04 December 2008, Felipe Balbi wrote:
>> i2c subsystem has smbus emulation. The special reason is just that it's
>> simpler for the driver writer ;-)
>
> I'd have said "more portable", actually. I2C hosts can
> do pretty much everything an SMBus host can, but the
> converse is not true.
>
> And re i2c_check_functionality() ... yes, use it to make
> sure each I2C or SMBus call the driver makes is supported
> by the underlying controller.
>
Thank you Brownell and Balbi.
Your comments are very helpful for me. I'll fix some part of the
driver and send it again later.
--
Kwangwoo Lee <kwangwoo.lee@gmail.com>
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2008-12-05 1:09 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-12-02 13:39 [PATCH] Add tsc2007 based touchscreen driver Kwangwoo Lee
2008-12-03 11:21 ` Trilok Soni
2008-12-03 12:01 ` Felipe Balbi
2008-12-04 5:07 ` Kwangwoo Lee
2008-12-04 9:37 ` Felipe Balbi
2008-12-04 9:56 ` David Brownell
2008-12-05 1:09 ` Kwangwoo Lee
2008-12-03 20:18 ` David Brownell
2008-12-04 4:37 ` Kwangwoo Lee
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