diff options
Diffstat (limited to 'drivers/input/touchscreen/ti_am335x_tsc.c')
| -rw-r--r-- | drivers/input/touchscreen/ti_am335x_tsc.c | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c new file mode 100644 index 000000000000..7a18a8a15228 --- /dev/null +++ b/drivers/input/touchscreen/ti_am335x_tsc.c @@ -0,0 +1,398 @@ +/* + * TI Touch Screen driver + * + * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/ + * + * 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/init.h> +#include <linux/kernel.h> +#include <linux/err.h> +#include <linux/module.h> +#include <linux/input.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/clk.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/input/ti_am335x_tsc.h> +#include <linux/delay.h> + +#include <linux/mfd/ti_am335x_tscadc.h> + +#define ADCFSM_STEPID 0x10 +#define SEQ_SETTLE 275 +#define MAX_12BIT ((1 << 12) - 1) + +struct titsc { + struct input_dev *input; + struct ti_tscadc_dev *mfd_tscadc; + unsigned int irq; + unsigned int wires; + unsigned int x_plate_resistance; + bool pen_down; + int steps_to_configure; +}; + +static unsigned int titsc_readl(struct titsc *ts, unsigned int reg) +{ + return readl(ts->mfd_tscadc->tscadc_base + reg); +} + +static void titsc_writel(struct titsc *tsc, unsigned int reg, + unsigned int val) +{ + writel(val, tsc->mfd_tscadc->tscadc_base + reg); +} + +static void titsc_step_config(struct titsc *ts_dev) +{ + unsigned int config; + int i, total_steps; + + /* Configure the Step registers */ + total_steps = 2 * ts_dev->steps_to_configure; + + config = STEPCONFIG_MODE_HWSYNC | + STEPCONFIG_AVG_16 | STEPCONFIG_XPP; + switch (ts_dev->wires) { + case 4: + config |= STEPCONFIG_INP_AN2 | STEPCONFIG_XNN; + break; + case 5: + config |= STEPCONFIG_YNN | + STEPCONFIG_INP_AN4 | STEPCONFIG_XNN | + STEPCONFIG_YPP; + break; + case 8: + config |= STEPCONFIG_INP_AN2 | STEPCONFIG_XNN; + break; + } + + for (i = 1; i <= ts_dev->steps_to_configure; i++) { + titsc_writel(ts_dev, REG_STEPCONFIG(i), config); + titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY); + } + + config = 0; + config = STEPCONFIG_MODE_HWSYNC | + STEPCONFIG_AVG_16 | STEPCONFIG_YNN | + STEPCONFIG_INM_ADCREFM | STEPCONFIG_FIFO1; + switch (ts_dev->wires) { + case 4: + config |= STEPCONFIG_YPP; + break; + case 5: + config |= STEPCONFIG_XPP | STEPCONFIG_INP_AN4 | + STEPCONFIG_XNP | STEPCONFIG_YPN; + break; + case 8: + config |= STEPCONFIG_YPP; + break; + } + + for (i = (ts_dev->steps_to_configure + 1); i <= total_steps; i++) { + titsc_writel(ts_dev, REG_STEPCONFIG(i), config); + titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY); + } + + config = 0; + /* Charge step configuration */ + config = STEPCONFIG_XPP | STEPCONFIG_YNN | + STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR | + STEPCHARGE_INM_AN1 | STEPCHARGE_INP_AN1; + + titsc_writel(ts_dev, REG_CHARGECONFIG, config); + titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY); + + config = 0; + /* Configure to calculate pressure */ + config = STEPCONFIG_MODE_HWSYNC | + STEPCONFIG_AVG_16 | STEPCONFIG_YPP | + STEPCONFIG_XNN | STEPCONFIG_INM_ADCREFM; + titsc_writel(ts_dev, REG_STEPCONFIG(total_steps + 1), config); + titsc_writel(ts_dev, REG_STEPDELAY(total_steps + 1), + STEPCONFIG_OPENDLY); + + config |= STEPCONFIG_INP_AN3 | STEPCONFIG_FIFO1; + titsc_writel(ts_dev, REG_STEPCONFIG(total_steps + 2), config); + titsc_writel(ts_dev, REG_STEPDELAY(total_steps + 2), + STEPCONFIG_OPENDLY); + + titsc_writel(ts_dev, REG_SE, STPENB_STEPENB_TC); +} + +static void titsc_read_coordinates(struct titsc *ts_dev, + unsigned int *x, unsigned int *y) +{ + unsigned int fifocount = titsc_readl(ts_dev, REG_FIFO0CNT); + unsigned int prev_val_x = ~0, prev_val_y = ~0; + unsigned int prev_diff_x = ~0, prev_diff_y = ~0; + unsigned int read, diff; + unsigned int i, channel; + + /* + * Delta filter is used to remove large variations in sampled + * values from ADC. The filter tries to predict where the next + * coordinate could be. This is done by taking a previous + * coordinate and subtracting it form current one. Further the + * algorithm compares the difference with that of a present value, + * if true the value is reported to the sub system. + */ + for (i = 0; i < fifocount - 1; i++) { + read = titsc_readl(ts_dev, REG_FIFO0); + channel = read & 0xf0000; + channel = channel >> 0x10; + if ((channel >= 0) && (channel < ts_dev->steps_to_configure)) { + read &= 0xfff; + diff = abs(read - prev_val_x); + if (diff < prev_diff_x) { + prev_diff_x = diff; + *x = read; + } + prev_val_x = read; + } + + read = titsc_readl(ts_dev, REG_FIFO1); + channel = read & 0xf0000; + channel = channel >> 0x10; + if ((channel >= ts_dev->steps_to_configure) && + (channel < (2 * ts_dev->steps_to_configure - 1))) { + read &= 0xfff; + diff = abs(read - prev_val_y); + if (diff < prev_diff_y) { + prev_diff_y = diff; + *y = read; + } + prev_val_y = read; + } + } +} + +static irqreturn_t titsc_irq(int irq, void *dev) +{ + struct titsc *ts_dev = dev; + struct input_dev *input_dev = ts_dev->input; + unsigned int status, irqclr = 0; + unsigned int x = 0, y = 0; + unsigned int z1, z2, z; + unsigned int fsm; + unsigned int fifo1count, fifo0count; + int i; + + status = titsc_readl(ts_dev, REG_IRQSTATUS); + if (status & IRQENB_FIFO0THRES) { + titsc_read_coordinates(ts_dev, &x, &y); + + z1 = titsc_readl(ts_dev, REG_FIFO0) & 0xfff; + z2 = titsc_readl(ts_dev, REG_FIFO1) & 0xfff; + + fifo1count = titsc_readl(ts_dev, REG_FIFO1CNT); + for (i = 0; i < fifo1count; i++) + titsc_readl(ts_dev, REG_FIFO1); + + fifo0count = titsc_readl(ts_dev, REG_FIFO0CNT); + for (i = 0; i < fifo0count; i++) + titsc_readl(ts_dev, REG_FIFO0); + + if (ts_dev->pen_down && z1 != 0 && z2 != 0) { + /* + * Calculate pressure using formula + * Resistance(touch) = x plate resistance * + * x postion/4096 * ((z2 / z1) - 1) + */ + z = z2 - z1; + z *= x; + z *= ts_dev->x_plate_resistance; + z /= z1; + z = (z + 2047) >> 12; + + if (z <= MAX_12BIT) { + input_report_abs(input_dev, ABS_X, x); + input_report_abs(input_dev, ABS_Y, y); + input_report_abs(input_dev, ABS_PRESSURE, z); + input_report_key(input_dev, BTN_TOUCH, 1); + input_sync(input_dev); + } + } + irqclr |= IRQENB_FIFO0THRES; + } + + /* + * Time for sequencer to settle, to read + * correct state of the sequencer. + */ + udelay(SEQ_SETTLE); + + status = titsc_readl(ts_dev, REG_RAWIRQSTATUS); + if (status & IRQENB_PENUP) { + /* Pen up event */ + fsm = titsc_readl(ts_dev, REG_ADCFSM); + if (fsm == ADCFSM_STEPID) { + ts_dev->pen_down = false; + input_report_key(input_dev, BTN_TOUCH, 0); + input_report_abs(input_dev, ABS_PRESSURE, 0); + input_sync(input_dev); + } else { + ts_dev->pen_down = true; + } + irqclr |= IRQENB_PENUP; + } + + titsc_writel(ts_dev, REG_IRQSTATUS, irqclr); + + titsc_writel(ts_dev, REG_SE, STPENB_STEPENB_TC); + return IRQ_HANDLED; +} + +/* + * The functions for inserting/removing driver as a module. + */ + +static int __devinit titsc_probe(struct platform_device *pdev) +{ + struct titsc *ts_dev; + struct input_dev *input_dev; + struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data; + struct mfd_tscadc_board *pdata; + int err; + + pdata = tscadc_dev->dev->platform_data; + + if (!pdata) { + dev_err(&pdev->dev, "Could not find platform data\n"); + return -EINVAL; + } + + /* Allocate memory for device */ + ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL); + input_dev = input_allocate_device(); + if (!ts_dev || !input_dev) { + dev_err(&pdev->dev, "failed to allocate memory.\n"); + err = -ENOMEM; + goto err_free_mem; + } + + tscadc_dev->tsc = ts_dev; + ts_dev->mfd_tscadc = tscadc_dev; + ts_dev->input = input_dev; + ts_dev->irq = tscadc_dev->irq; + ts_dev->wires = pdata->tsc_init->wires; + ts_dev->x_plate_resistance = pdata->tsc_init->x_plate_resistance; + ts_dev->steps_to_configure = pdata->tsc_init->steps_to_configure; + + err = request_irq(ts_dev->irq, titsc_irq, + 0, pdev->dev.driver->name, ts_dev); + if (err) { + dev_err(&pdev->dev, "failed to allocate irq.\n"); + goto err_free_mem; + } + + titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES); + titsc_step_config(ts_dev); + titsc_writel(ts_dev, REG_FIFO0THR, ts_dev->steps_to_configure); + + input_dev->name = "ti-tsc"; + input_dev->dev.parent = &pdev->dev; + + 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); + + /* register to the input system */ + err = input_register_device(input_dev); + if (err) + goto err_free_irq; + + platform_set_drvdata(pdev, ts_dev); + return 0; + +err_free_irq: + free_irq(ts_dev->irq, ts_dev); +err_free_mem: + input_free_device(input_dev); + kfree(ts_dev); + return err; +} + +static int __devexit titsc_remove(struct platform_device *pdev) +{ + struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data; + struct titsc *ts_dev = tscadc_dev->tsc; + + free_irq(ts_dev->irq, ts_dev); + + input_unregister_device(ts_dev->input); + + platform_set_drvdata(pdev, NULL); + kfree(ts_dev); + return 0; +} + +#ifdef CONFIG_PM +static int titsc_suspend(struct device *dev) +{ + struct ti_tscadc_dev *tscadc_dev = dev->platform_data; + struct titsc *ts_dev = tscadc_dev->tsc; + unsigned int idle; + + if (device_may_wakeup(tscadc_dev->dev)) { + idle = titsc_readl(ts_dev, REG_IRQENABLE); + titsc_writel(ts_dev, REG_IRQENABLE, + (idle | IRQENB_HW_PEN)); + titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB); + } + return 0; +} + +static int titsc_resume(struct device *dev) +{ + struct ti_tscadc_dev *tscadc_dev = dev->platform_data; + struct titsc *ts_dev = tscadc_dev->tsc; + + if (device_may_wakeup(tscadc_dev->dev)) { + titsc_writel(ts_dev, REG_IRQWAKEUP, + 0x00); + titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN); + } + titsc_step_config(ts_dev); + titsc_writel(ts_dev, REG_FIFO0THR, + ts_dev->steps_to_configure); + return 0; +} + +static const struct dev_pm_ops titsc_pm_ops = { + .suspend = titsc_suspend, + .resume = titsc_resume, +}; +#define TITSC_PM_OPS (&titsc_pm_ops) +#else +#define TITSC_PM_OPS NULL +#endif + +static struct platform_driver ti_tsc_driver = { + .probe = titsc_probe, + .remove = __devexit_p(titsc_remove), + .driver = { + .name = "tsc", + .owner = THIS_MODULE, + .pm = TITSC_PM_OPS, + }, +}; +module_platform_driver(ti_tsc_driver); + +MODULE_DESCRIPTION("TI touchscreen controller driver"); +MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); +MODULE_LICENSE("GPL"); |