Input: add mc13783 touchscreen driver

This driver provides support for the touchscreen interface
integrated into the Freescale MC13783.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Luotao Fu <l.fu@pengutronix.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 258 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/mc13783_ts.c b/drivers/input/touchscreen/mc13783_ts.c
new file mode 100644
index 000000000000..be115b3b65eb
--- /dev/null
+++ b/drivers/input/touchscreen/mc13783_ts.c
@@ -0,0 +1,258 @@
+/*
+ * Driver for the Freescale Semiconductor MC13783 touchscreen.
+ *
+ * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright (C) 2009 Sascha Hauer, Pengutronix
+ *
+ * Initial development of this code was funded by
+ * Phytec Messtechnik GmbH, http://www.phytec.de/
+ *
+ * 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/platform_device.h>
+#include <linux/mfd/mc13783.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+
+#define MC13783_TS_NAME "mc13783-ts"
+
+#define DEFAULT_SAMPLE_TOLERANCE 300
+
+static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE;
+module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(sample_tolerance,
+                "If the minimal and maximal value read out for one axis (out "
+                "of three) differ by this value (default: "
+                __stringify(DEFAULT_SAMPLE_TOLERANCE) ") or more, the reading "
+                "is supposed to be wrong and is discarded.  Set to 0 to "
+                "disable this check.");
+
+struct mc13783_ts_priv {
+        struct input_dev *idev;
+        struct mc13783 *mc13783;
+        struct delayed_work work;
+        struct workqueue_struct *workq;
+        unsigned int sample[4];
+};
+
+static irqreturn_t mc13783_ts_handler(int irq, void *data)
+{
+        struct mc13783_ts_priv *priv = data;
+
+        mc13783_ackirq(priv->mc13783, irq);
+
+        /*
+         * Kick off reading coordinates. Note that if work happens already
+         * be queued for future execution (it rearms itself) it will not
+         * be rescheduled for immediate execution here. However the rearm
+         * delay is HZ / 50 which is acceptable.
+         */
+        queue_delayed_work(priv->workq, &priv->work, 0);
+
+        return IRQ_HANDLED;
+}
+
+#define sort3(a0, a1, a2) ({                                            \
+                if (a0 > a1)                                            \
+                        swap(a0, a1);                                   \
+                if (a1 > a2)                                            \
+                        swap(a1, a2);                                   \
+                if (a0 > a1)                                            \
+                        swap(a0, a1);                                   \
+                })
+
+static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
+{
+        struct input_dev *idev = priv->idev;
+        int x0, x1, x2, y0, y1, y2;
+        int cr0, cr1;
+
+        /*
+         * the values are 10-bit wide only, but the two least significant
+         * bits are for future 12 bit use and reading yields 0
+         */
+        x0 = priv->sample[0] & 0xfff;
+        x1 = priv->sample[1] & 0xfff;
+        x2 = priv->sample[2] & 0xfff;
+        y0 = priv->sample[3] & 0xfff;
+        y1 = (priv->sample[0] >> 12) & 0xfff;
+        y2 = (priv->sample[1] >> 12) & 0xfff;
+        cr0 = (priv->sample[2] >> 12) & 0xfff;
+        cr1 = (priv->sample[3] >> 12) & 0xfff;
+
+        dev_dbg(&idev->dev,
+                "x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n",
+                x0, x1, x2, y0, y1, y2, cr0, cr1);
+
+        sort3(x0, x1, x2);
+        sort3(y0, y1, y2);
+
+        cr0 = (cr0 + cr1) / 2;
+
+        if (!cr0 || !sample_tolerance ||
+                        (x2 - x0 < sample_tolerance &&
+                         y2 - y0 < sample_tolerance)) {
+                /* report the median coordinate and average pressure */
+                if (cr0) {
+                        input_report_abs(idev, ABS_X, x1);
+                        input_report_abs(idev, ABS_Y, y1);
+
+                        dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
+                                        x1, y1, 0x1000 - cr0);
+                        queue_delayed_work(priv->workq, &priv->work, HZ / 50);
+                } else
+                        dev_dbg(&idev->dev, "report release\n");
+
+                input_report_abs(idev, ABS_PRESSURE,
+                                cr0 ? 0x1000 - cr0 : cr0);
+                input_report_key(idev, BTN_TOUCH, cr0);
+                input_sync(idev);
+        } else
+                dev_dbg(&idev->dev, "discard event\n");
+}
+
+static void mc13783_ts_work(struct work_struct *work)
+{
+        struct mc13783_ts_priv *priv =
+                container_of(work, struct mc13783_ts_priv, work.work);
+        unsigned int mode = MC13783_ADC_MODE_TS;
+        unsigned int channel = 12;
+
+        if (mc13783_adc_do_conversion(priv->mc13783,
+                                mode, channel, priv->sample) == 0)
+                mc13783_ts_report_sample(priv);
+}
+
+static int mc13783_ts_open(struct input_dev *dev)
+{
+        struct mc13783_ts_priv *priv = input_get_drvdata(dev);
+        int ret;
+
+        mc13783_lock(priv->mc13783);
+
+        mc13783_ackirq(priv->mc13783, MC13783_IRQ_TS);
+
+        ret = mc13783_irq_request(priv->mc13783, MC13783_IRQ_TS,
+                mc13783_ts_handler, MC13783_TS_NAME, priv);
+        if (ret)
+                goto out;
+
+        ret = mc13783_reg_rmw(priv->mc13783, MC13783_ADC0,
+                        MC13783_ADC0_TSMOD_MASK, MC13783_ADC0_TSMOD0);
+        if (ret)
+                mc13783_irq_free(priv->mc13783, MC13783_IRQ_TS, priv);
+out:
+        mc13783_unlock(priv->mc13783);
+        return ret;
+}
+
+static void mc13783_ts_close(struct input_dev *dev)
+{
+        struct mc13783_ts_priv *priv = input_get_drvdata(dev);
+
+        mc13783_lock(priv->mc13783);
+        mc13783_reg_rmw(priv->mc13783, MC13783_ADC0,
+                        MC13783_ADC0_TSMOD_MASK, 0);
+        mc13783_irq_free(priv->mc13783, MC13783_IRQ_TS, priv);
+        mc13783_unlock(priv->mc13783);
+
+        cancel_delayed_work_sync(&priv->work);
+}
+
+static int __init mc13783_ts_probe(struct platform_device *pdev)
+{
+        struct mc13783_ts_priv *priv;
+        struct input_dev *idev;
+        int ret = -ENOMEM;
+
+        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+        idev = input_allocate_device();
+        if (!priv || !idev)
+                goto err_free_mem;
+
+        INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
+        priv->mc13783 = dev_get_drvdata(pdev->dev.parent);
+        priv->idev = idev;
+
+        /*
+         * We need separate workqueue because mc13783_adc_do_conversion
+         * uses keventd and thus would deadlock.
+         */
+        priv->workq = create_singlethread_workqueue("mc13783_ts");
+        if (!priv->workq)
+                goto err_free_mem;
+
+        idev->name = MC13783_TS_NAME;
+        idev->dev.parent = &pdev->dev;
+
+        idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+        idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+        input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
+        input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
+        input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0);
+
+        idev->open = mc13783_ts_open;
+        idev->close = mc13783_ts_close;
+
+        input_set_drvdata(idev, priv);
+
+        ret = input_register_device(priv->idev);
+        if (ret) {
+                dev_err(&pdev->dev,
+                        "register input device failed with %d\n", ret);
+                goto err_destroy_wq;
+        }
+
+        platform_set_drvdata(pdev, priv);
+        return 0;
+
+err_destroy_wq:
+        destroy_workqueue(priv->workq);
+err_free_mem:
+        input_free_device(idev);
+        kfree(priv);
+        return ret;
+}
+
+static int __devexit mc13783_ts_remove(struct platform_device *pdev)
+{
+        struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
+
+        platform_set_drvdata(pdev, NULL);
+
+        destroy_workqueue(priv->workq);
+        input_unregister_device(priv->idev);
+        kfree(priv);
+
+        return 0;
+}
+
+static struct platform_driver mc13783_ts_driver = {
+        .remove         = __devexit_p(mc13783_ts_remove),
+        .driver         = {
+                .owner  = THIS_MODULE,
+                .name   = MC13783_TS_NAME,
+        },
+};
+
+static int __init mc13783_ts_init(void)
+{
+        return platform_driver_probe(&mc13783_ts_driver, &mc13783_ts_probe);
+}
+module_init(mc13783_ts_init);
+
+static void __exit mc13783_ts_exit(void)
+{
+        platform_driver_unregister(&mc13783_ts_driver);
+}
+module_exit(mc13783_ts_exit);
+
+MODULE_DESCRIPTION("MC13783 input touchscreen driver");
+MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" MC13783_TS_NAME);