diff options
Diffstat (limited to 'drivers/input/touchscreen/ti_am335x_tsc.c')
| -rw-r--r-- | drivers/input/touchscreen/ti_am335x_tsc.c | 530 |
1 files changed, 530 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 00000000000..2ce649520fe --- /dev/null +++ b/drivers/input/touchscreen/ti_am335x_tsc.c @@ -0,0 +1,530 @@ +/* + * 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/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/delay.h> +#include <linux/of.h> +#include <linux/of_device.h> + +#include <linux/mfd/ti_am335x_tscadc.h> + +#define ADCFSM_STEPID 0x10 +#define SEQ_SETTLE 275 +#define MAX_12BIT ((1 << 12) - 1) + +static const int config_pins[] = { + STEPCONFIG_XPP, + STEPCONFIG_XNN, + STEPCONFIG_YPP, + STEPCONFIG_YNN, +}; + +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 coordinate_readouts; + u32 config_inp[4]; + u32 bit_xp, bit_xn, bit_yp, bit_yn; + u32 inp_xp, inp_xn, inp_yp, inp_yn; + u32 step_mask; +}; + +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 int titsc_config_wires(struct titsc *ts_dev) +{ + u32 analog_line[4]; + u32 wire_order[4]; + int i, bit_cfg; + + for (i = 0; i < 4; i++) { + /* + * Get the order in which TSC wires are attached + * w.r.t. each of the analog input lines on the EVM. + */ + analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4; + wire_order[i] = ts_dev->config_inp[i] & 0x0F; + if (WARN_ON(analog_line[i] > 7)) + return -EINVAL; + if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins))) + return -EINVAL; + } + + for (i = 0; i < 4; i++) { + int an_line; + int wi_order; + + an_line = analog_line[i]; + wi_order = wire_order[i]; + bit_cfg = config_pins[wi_order]; + if (bit_cfg == 0) + return -EINVAL; + switch (wi_order) { + case 0: + ts_dev->bit_xp = bit_cfg; + ts_dev->inp_xp = an_line; + break; + + case 1: + ts_dev->bit_xn = bit_cfg; + ts_dev->inp_xn = an_line; + break; + + case 2: + ts_dev->bit_yp = bit_cfg; + ts_dev->inp_yp = an_line; + break; + case 3: + ts_dev->bit_yn = bit_cfg; + ts_dev->inp_yn = an_line; + break; + } + } + return 0; +} + +static void titsc_step_config(struct titsc *ts_dev) +{ + unsigned int config; + int i; + int end_step; + u32 stepenable; + + config = STEPCONFIG_MODE_HWSYNC | + STEPCONFIG_AVG_16 | ts_dev->bit_xp; + switch (ts_dev->wires) { + case 4: + config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn; + break; + case 5: + config |= ts_dev->bit_yn | + STEPCONFIG_INP_AN4 | ts_dev->bit_xn | + ts_dev->bit_yp; + break; + case 8: + config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn; + break; + } + + /* 1 … coordinate_readouts is for X */ + end_step = ts_dev->coordinate_readouts; + for (i = 0; i < end_step; 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 | ts_dev->bit_yn | + STEPCONFIG_INM_ADCREFM; + switch (ts_dev->wires) { + case 4: + config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp); + break; + case 5: + config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 | + ts_dev->bit_xn | ts_dev->bit_yp; + break; + case 8: + config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp); + break; + } + + /* coordinate_readouts … coordinate_readouts * 2 is for Y */ + end_step = ts_dev->coordinate_readouts * 2; + for (i = ts_dev->coordinate_readouts; i < end_step; i++) { + titsc_writel(ts_dev, REG_STEPCONFIG(i), config); + titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY); + } + + /* Charge step configuration */ + config = ts_dev->bit_xp | ts_dev->bit_yn | + STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR | + STEPCHARGE_INM_AN1 | STEPCHARGE_INP(ts_dev->inp_yp); + + titsc_writel(ts_dev, REG_CHARGECONFIG, config); + titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY); + + /* coordinate_readouts * 2 … coordinate_readouts * 2 + 2 is for Z */ + config = STEPCONFIG_MODE_HWSYNC | + STEPCONFIG_AVG_16 | ts_dev->bit_yp | + ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM | + STEPCONFIG_INP(ts_dev->inp_xp); + titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config); + titsc_writel(ts_dev, REG_STEPDELAY(end_step), + STEPCONFIG_OPENDLY); + + end_step++; + config |= STEPCONFIG_INP(ts_dev->inp_yn); + titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config); + titsc_writel(ts_dev, REG_STEPDELAY(end_step), + STEPCONFIG_OPENDLY); + + /* The steps1 … end and bit 0 for TS_Charge */ + stepenable = (1 << (end_step + 2)) - 1; + ts_dev->step_mask = stepenable; + am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask); +} + +static void titsc_read_coordinates(struct titsc *ts_dev, + u32 *x, u32 *y, u32 *z1, u32 *z2) +{ + 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; + unsigned int creads = ts_dev->coordinate_readouts; + + *z1 = *z2 = 0; + if (fifocount % (creads * 2 + 2)) + fifocount -= fifocount % (creads * 2 + 2); + /* + * 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; i++) { + read = titsc_readl(ts_dev, REG_FIFO0); + + channel = (read & 0xf0000) >> 16; + read &= 0xfff; + if (channel < creads) { + diff = abs(read - prev_val_x); + if (diff < prev_diff_x) { + prev_diff_x = diff; + *x = read; + } + prev_val_x = read; + + } else if (channel < creads * 2) { + diff = abs(read - prev_val_y); + if (diff < prev_diff_y) { + prev_diff_y = diff; + *y = read; + } + prev_val_y = read; + + } else if (channel < creads * 2 + 1) { + *z1 = read; + + } else if (channel < creads * 2 + 2) { + *z2 = 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; + + status = titsc_readl(ts_dev, REG_IRQSTATUS); + /* + * ADC and touchscreen share the IRQ line. + * FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only + */ + if (status & IRQENB_FIFO0THRES) { + + titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2); + + 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 = z1 - z2; + z *= x; + z *= ts_dev->x_plate_resistance; + z /= z2; + 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; + } + + if (status & IRQENB_HW_PEN) { + + titsc_writel(ts_dev, REG_IRQWAKEUP, 0x00); + titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN); + } + + if (irqclr) { + titsc_writel(ts_dev, REG_IRQSTATUS, irqclr); + am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask); + return IRQ_HANDLED; + } + return IRQ_NONE; +} + +static int titsc_parse_dt(struct platform_device *pdev, + struct titsc *ts_dev) +{ + struct device_node *node = pdev->dev.of_node; + int err; + + if (!node) + return -EINVAL; + + err = of_property_read_u32(node, "ti,wires", &ts_dev->wires); + if (err < 0) + return err; + switch (ts_dev->wires) { + case 4: + case 5: + case 8: + break; + default: + return -EINVAL; + } + + err = of_property_read_u32(node, "ti,x-plate-resistance", + &ts_dev->x_plate_resistance); + if (err < 0) + return err; + + /* + * Try with the new binding first. If it fails, try again with + * bogus, miss-spelled version. + */ + err = of_property_read_u32(node, "ti,coordinate-readouts", + &ts_dev->coordinate_readouts); + if (err < 0) { + dev_warn(&pdev->dev, "please use 'ti,coordinate-readouts' instead\n"); + err = of_property_read_u32(node, "ti,coordiante-readouts", + &ts_dev->coordinate_readouts); + } + + if (err < 0) + return err; + + return of_property_read_u32_array(node, "ti,wire-config", + ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp)); +} + +/* + * The functions for inserting/removing driver as a module. + */ + +static int titsc_probe(struct platform_device *pdev) +{ + struct titsc *ts_dev; + struct input_dev *input_dev; + struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev); + int err; + + /* 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; + + err = titsc_parse_dt(pdev, ts_dev); + if (err) { + dev_err(&pdev->dev, "Could not find valid DT data.\n"); + goto err_free_mem; + } + + err = request_irq(ts_dev->irq, titsc_irq, + IRQF_SHARED, 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); + err = titsc_config_wires(ts_dev); + if (err) { + dev_err(&pdev->dev, "wrong i/p wire configuration\n"); + goto err_free_irq; + } + titsc_step_config(ts_dev); + titsc_writel(ts_dev, REG_FIFO0THR, + ts_dev->coordinate_readouts * 2 + 2 - 1); + + 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 titsc_remove(struct platform_device *pdev) +{ + struct titsc *ts_dev = platform_get_drvdata(pdev); + u32 steps; + + free_irq(ts_dev->irq, ts_dev); + + /* total steps followed by the enable mask */ + steps = 2 * ts_dev->coordinate_readouts + 2; + steps = (1 << steps) - 1; + am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps); + + input_unregister_device(ts_dev->input); + + kfree(ts_dev); + return 0; +} + +#ifdef CONFIG_PM +static int titsc_suspend(struct device *dev) +{ + struct titsc *ts_dev = dev_get_drvdata(dev); + struct ti_tscadc_dev *tscadc_dev; + unsigned int idle; + + tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); + 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 titsc *ts_dev = dev_get_drvdata(dev); + struct ti_tscadc_dev *tscadc_dev; + + tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); + 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->coordinate_readouts * 2 + 2 - 1); + 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 const struct of_device_id ti_tsc_dt_ids[] = { + { .compatible = "ti,am3359-tsc", }, + { } +}; +MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids); + +static struct platform_driver ti_tsc_driver = { + .probe = titsc_probe, + .remove = titsc_remove, + .driver = { + .name = "TI-am335x-tsc", + .owner = THIS_MODULE, + .pm = TITSC_PM_OPS, + .of_match_table = ti_tsc_dt_ids, + }, +}; +module_platform_driver(ti_tsc_driver); + +MODULE_DESCRIPTION("TI touchscreen controller driver"); +MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); +MODULE_LICENSE("GPL"); |