| /* |
| * ADS7846 based touchscreen and sensor driver |
| * |
| * Copyright (c) 2005 David Brownell |
| * |
| * Using code from: |
| * - 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/device.h> |
| #include <linux/init.h> |
| #include <linux/delay.h> |
| #include <linux/input.h> |
| #include <linux/interrupt.h> |
| #include <linux/slab.h> |
| #include <linux/spi/spi.h> |
| #include <linux/spi/ads7846.h> |
| |
| #ifdef CONFIG_ARM |
| #include <asm/mach-types.h> |
| #ifdef CONFIG_ARCH_OMAP |
| #include <asm/arch/gpio.h> |
| #endif |
| |
| #else |
| #define set_irq_type(irq,type) do{}while(0) |
| #endif |
| |
| |
| /* |
| * This code has been lightly tested on an ads7846. |
| * Support for ads7843 and ads7845 has only been stubbed in. |
| * |
| * Not yet done: investigate the values reported. Are x/y/pressure |
| * event values sane enough for X11? How accurate are the temperature |
| * and voltage readings? (System-specific calibration should support |
| * accuracy of 0.3 degrees C; otherwise it's 2.0 degrees.) |
| * |
| * app note sbaa036 talks in more detail about accurate sampling... |
| * that ought to help in situations like LCDs inducing noise (which |
| * can also be helped by using synch signals) and more generally. |
| */ |
| |
| #define TS_POLL_PERIOD msecs_to_jiffies(10) |
| |
| struct ts_event { |
| /* For portability, we can't read 12 bit values using SPI (which |
| * would make the controller deliver them as native byteorder u16 |
| * with msbs zeroed). Instead, we read them as two 8-byte values, |
| * which need byteswapping then range adjustment. |
| */ |
| __be16 x; |
| __be16 y; |
| __be16 z1, z2; |
| }; |
| |
| struct ads7846 { |
| struct input_dev input; |
| char phys[32]; |
| |
| struct spi_device *spi; |
| u16 model; |
| u16 vref_delay_usecs; |
| u16 x_plate_ohms; |
| |
| struct ts_event tc; |
| |
| struct spi_transfer xfer[8]; |
| struct spi_message msg; |
| |
| spinlock_t lock; |
| struct timer_list timer; /* P: lock */ |
| unsigned pendown:1; /* P: lock */ |
| unsigned pending:1; /* P: lock */ |
| // FIXME remove "irq_disabled" |
| unsigned irq_disabled:1; /* P: lock */ |
| }; |
| |
| /* leave chip selected when we're done, for quicker re-select? */ |
| #if 0 |
| #define CS_CHANGE(xfer) ((xfer).cs_change = 1) |
| #else |
| #define CS_CHANGE(xfer) ((xfer).cs_change = 0) |
| #endif |
| |
| /*--------------------------------------------------------------------------*/ |
| |
| /* The ADS7846 has touchscreen and other sensors. |
| * Earlier ads784x chips are somewhat compatible. |
| */ |
| #define ADS_START (1 << 7) |
| #define ADS_A2A1A0_d_y (1 << 4) /* differential */ |
| #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */ |
| #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */ |
| #define ADS_A2A1A0_d_x (5 << 4) /* differential */ |
| #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */ |
| #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */ |
| #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */ |
| #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */ |
| #define ADS_8_BIT (1 << 3) |
| #define ADS_12_BIT (0 << 3) |
| #define ADS_SER (1 << 2) /* non-differential */ |
| #define ADS_DFR (0 << 2) /* differential */ |
| #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */ |
| #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */ |
| #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */ |
| #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */ |
| |
| #define MAX_12BIT ((1<<12)-1) |
| |
| /* leave ADC powered up (disables penirq) between differential samples */ |
| #define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \ |
| | ADS_12_BIT | ADS_DFR) |
| |
| static const u8 read_y = READ_12BIT_DFR(y) | ADS_PD10_ADC_ON; |
| static const u8 read_z1 = READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON; |
| static const u8 read_z2 = READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON; |
| static const u8 read_x = READ_12BIT_DFR(x) | ADS_PD10_PDOWN; /* LAST */ |
| |
| /* single-ended samples need to first power up reference voltage; |
| * we leave both ADC and VREF powered |
| */ |
| #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ |
| | ADS_12_BIT | ADS_SER) |
| |
| static const u8 ref_on = READ_12BIT_DFR(x) | ADS_PD10_ALL_ON; |
| static const u8 ref_off = READ_12BIT_DFR(y) | ADS_PD10_PDOWN; |
| |
| /*--------------------------------------------------------------------------*/ |
| |
| /* |
| * Non-touchscreen sensors only use single-ended conversions. |
| */ |
| |
| struct ser_req { |
| u8 command; |
| u16 scratch; |
| __be16 sample; |
| struct spi_message msg; |
| struct spi_transfer xfer[6]; |
| }; |
| |
| static int ads7846_read12_ser(struct device *dev, unsigned command) |
| { |
| struct spi_device *spi = to_spi_device(dev); |
| struct ads7846 *ts = dev_get_drvdata(dev); |
| struct ser_req *req = kzalloc(sizeof *req, SLAB_KERNEL); |
| int status; |
| int sample; |
| int i; |
| |
| if (!req) |
| return -ENOMEM; |
| |
| INIT_LIST_HEAD(&req->msg.transfers); |
| |
| /* activate reference, so it has time to settle; */ |
| req->xfer[0].tx_buf = &ref_on; |
| req->xfer[0].len = 1; |
| req->xfer[1].rx_buf = &req->scratch; |
| req->xfer[1].len = 2; |
| |
| /* |
| * for external VREF, 0 usec (and assume it's always on); |
| * for 1uF, use 800 usec; |
| * no cap, 100 usec. |
| */ |
| req->xfer[1].delay_usecs = ts->vref_delay_usecs; |
| |
| /* take sample */ |
| req->command = (u8) command; |
| req->xfer[2].tx_buf = &req->command; |
| req->xfer[2].len = 1; |
| req->xfer[3].rx_buf = &req->sample; |
| req->xfer[3].len = 2; |
| |
| /* REVISIT: take a few more samples, and compare ... */ |
| |
| /* turn off reference */ |
| req->xfer[4].tx_buf = &ref_off; |
| req->xfer[4].len = 1; |
| req->xfer[5].rx_buf = &req->scratch; |
| req->xfer[5].len = 2; |
| |
| CS_CHANGE(req->xfer[5]); |
| |
| /* group all the transfers together, so we can't interfere with |
| * reading touchscreen state; disable penirq while sampling |
| */ |
| for (i = 0; i < 6; i++) |
| spi_message_add_tail(&req->xfer[i], &req->msg); |
| |
| disable_irq(spi->irq); |
| status = spi_sync(spi, &req->msg); |
| enable_irq(spi->irq); |
| |
| if (req->msg.status) |
| status = req->msg.status; |
| sample = be16_to_cpu(req->sample); |
| sample = sample >> 4; |
| kfree(req); |
| |
| return status ? status : sample; |
| } |
| |
| #define SHOW(name) static ssize_t \ |
| name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ |
| { \ |
| ssize_t v = ads7846_read12_ser(dev, \ |
| READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \ |
| if (v < 0) \ |
| return v; \ |
| return sprintf(buf, "%u\n", (unsigned) v); \ |
| } \ |
| static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL); |
| |
| SHOW(temp0) |
| SHOW(temp1) |
| SHOW(vaux) |
| SHOW(vbatt) |
| |
| /*--------------------------------------------------------------------------*/ |
| |
| /* |
| * PENIRQ only kicks the timer. The timer only reissues the SPI transfer, |
| * to retrieve touchscreen status. |
| * |
| * The SPI transfer completion callback does the real work. It reports |
| * touchscreen events and reactivates the timer (or IRQ) as appropriate. |
| */ |
| |
| static void ads7846_rx(void *ads) |
| { |
| struct ads7846 *ts = ads; |
| unsigned Rt; |
| unsigned sync = 0; |
| u16 x, y, z1, z2; |
| unsigned long flags; |
| |
| /* adjust: 12 bit samples (left aligned), built from |
| * two 8 bit values writen msb-first. |
| */ |
| x = be16_to_cpu(ts->tc.x) >> 4; |
| y = be16_to_cpu(ts->tc.y) >> 4; |
| z1 = be16_to_cpu(ts->tc.z1) >> 4; |
| z2 = be16_to_cpu(ts->tc.z2) >> 4; |
| |
| /* range filtering */ |
| if (x == MAX_12BIT) |
| x = 0; |
| |
| if (x && z1 && ts->spi->dev.power.power_state.event == PM_EVENT_ON) { |
| /* compute touch pressure resistance using equation #2 */ |
| Rt = z2; |
| Rt -= z1; |
| Rt *= x; |
| Rt *= ts->x_plate_ohms; |
| Rt /= z1; |
| Rt = (Rt + 2047) >> 12; |
| } else |
| Rt = 0; |
| |
| /* NOTE: "pendown" is inferred from pressure; we don't rely on |
| * being able to check nPENIRQ status, or "friendly" trigger modes |
| * (both-edges is much better than just-falling or low-level). |
| * |
| * REVISIT: some boards may require reading nPENIRQ; it's |
| * needed on 7843. and 7845 reads pressure differently... |
| * |
| * REVISIT: the touchscreen might not be connected; this code |
| * won't notice that, even if nPENIRQ never fires ... |
| */ |
| if (!ts->pendown && Rt != 0) { |
| input_report_key(&ts->input, BTN_TOUCH, 1); |
| sync = 1; |
| } else if (ts->pendown && Rt == 0) { |
| input_report_key(&ts->input, BTN_TOUCH, 0); |
| sync = 1; |
| } |
| |
| if (Rt) { |
| input_report_abs(&ts->input, ABS_X, x); |
| input_report_abs(&ts->input, ABS_Y, y); |
| input_report_abs(&ts->input, ABS_PRESSURE, Rt); |
| sync = 1; |
| } |
| if (sync) |
| input_sync(&ts->input); |
| |
| #ifdef VERBOSE |
| if (Rt || ts->pendown) |
| pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id, |
| x, y, Rt, Rt ? "" : " UP"); |
| #endif |
| |
| /* don't retrigger while we're suspended */ |
| spin_lock_irqsave(&ts->lock, flags); |
| |
| ts->pendown = (Rt != 0); |
| ts->pending = 0; |
| |
| if (ts->spi->dev.power.power_state.event == PM_EVENT_ON) { |
| if (ts->pendown) |
| mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD); |
| else if (ts->irq_disabled) { |
| ts->irq_disabled = 0; |
| enable_irq(ts->spi->irq); |
| } |
| } |
| |
| spin_unlock_irqrestore(&ts->lock, flags); |
| } |
| |
| static void ads7846_timer(unsigned long handle) |
| { |
| struct ads7846 *ts = (void *)handle; |
| int status = 0; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ts->lock, flags); |
| if (!ts->pending) { |
| ts->pending = 1; |
| if (!ts->irq_disabled) { |
| ts->irq_disabled = 1; |
| disable_irq(ts->spi->irq); |
| } |
| status = spi_async(ts->spi, &ts->msg); |
| if (status) |
| dev_err(&ts->spi->dev, "spi_async --> %d\n", |
| status); |
| } |
| spin_unlock_irqrestore(&ts->lock, flags); |
| } |
| |
| static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs) |
| { |
| ads7846_timer((unsigned long) handle); |
| return IRQ_HANDLED; |
| } |
| |
| /*--------------------------------------------------------------------------*/ |
| |
| static int |
| ads7846_suspend(struct spi_device *spi, pm_message_t message) |
| { |
| struct ads7846 *ts = dev_get_drvdata(&spi->dev); |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ts->lock, flags); |
| |
| spi->dev.power.power_state = message; |
| |
| /* are we waiting for IRQ, or polling? */ |
| if (!ts->pendown) { |
| if (!ts->irq_disabled) { |
| ts->irq_disabled = 1; |
| disable_irq(ts->spi->irq); |
| } |
| } else { |
| /* polling; force a final SPI completion; |
| * that will clean things up neatly |
| */ |
| if (!ts->pending) |
| mod_timer(&ts->timer, jiffies); |
| |
| while (ts->pendown || ts->pending) { |
| spin_unlock_irqrestore(&ts->lock, flags); |
| udelay(10); |
| spin_lock_irqsave(&ts->lock, flags); |
| } |
| } |
| |
| /* we know the chip's in lowpower mode since we always |
| * leave it that way after every request |
| */ |
| |
| spin_unlock_irqrestore(&ts->lock, flags); |
| return 0; |
| } |
| |
| static int ads7846_resume(struct spi_device *spi) |
| { |
| struct ads7846 *ts = dev_get_drvdata(&spi->dev); |
| |
| ts->irq_disabled = 0; |
| enable_irq(ts->spi->irq); |
| spi->dev.power.power_state = PMSG_ON; |
| return 0; |
| } |
| |
| static int __devinit ads7846_probe(struct spi_device *spi) |
| { |
| struct ads7846 *ts; |
| struct ads7846_platform_data *pdata = spi->dev.platform_data; |
| struct spi_transfer *x; |
| int i; |
| |
| if (!spi->irq) { |
| dev_dbg(&spi->dev, "no IRQ?\n"); |
| return -ENODEV; |
| } |
| |
| if (!pdata) { |
| dev_dbg(&spi->dev, "no platform data?\n"); |
| return -ENODEV; |
| } |
| |
| /* don't exceed max specified sample rate */ |
| if (spi->max_speed_hz > (125000 * 16)) { |
| dev_dbg(&spi->dev, "f(sample) %d KHz?\n", |
| (spi->max_speed_hz/16)/1000); |
| return -EINVAL; |
| } |
| |
| /* We'd set the wordsize to 12 bits ... except that some controllers |
| * will then treat the 8 bit command words as 12 bits (and drop the |
| * four MSBs of the 12 bit result). Result: inputs must be shifted |
| * to discard the four garbage LSBs. |
| */ |
| |
| if (!(ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL))) |
| return -ENOMEM; |
| |
| dev_set_drvdata(&spi->dev, ts); |
| |
| ts->spi = spi; |
| spi->dev.power.power_state = PMSG_ON; |
| |
| init_timer(&ts->timer); |
| ts->timer.data = (unsigned long) ts; |
| ts->timer.function = ads7846_timer; |
| |
| ts->model = pdata->model ? : 7846; |
| ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; |
| ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; |
| |
| init_input_dev(&ts->input); |
| |
| ts->input.dev = &spi->dev; |
| ts->input.name = "ADS784x Touchscreen"; |
| snprintf(ts->phys, sizeof ts->phys, "%s/input0", spi->dev.bus_id); |
| ts->input.phys = ts->phys; |
| |
| ts->input.evbit[0] = BIT(EV_KEY) | BIT(EV_ABS); |
| ts->input.keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH); |
| input_set_abs_params(&ts->input, ABS_X, |
| pdata->x_min ? : 0, |
| pdata->x_max ? : MAX_12BIT, |
| 0, 0); |
| input_set_abs_params(&ts->input, ABS_Y, |
| pdata->y_min ? : 0, |
| pdata->y_max ? : MAX_12BIT, |
| 0, 0); |
| input_set_abs_params(&ts->input, ABS_PRESSURE, |
| pdata->pressure_min, pdata->pressure_max, 0, 0); |
| |
| input_register_device(&ts->input); |
| |
| /* set up the transfers to read touchscreen state; this assumes we |
| * use formula #2 for pressure, not #3. |
| */ |
| x = ts->xfer; |
| |
| /* y- still on; turn on only y+ (and ADC) */ |
| x->tx_buf = &read_y; |
| x->len = 1; |
| x++; |
| x->rx_buf = &ts->tc.y; |
| x->len = 2; |
| x++; |
| |
| /* turn y+ off, x- on; we'll use formula #2 */ |
| if (ts->model == 7846) { |
| x->tx_buf = &read_z1; |
| x->len = 1; |
| x++; |
| x->rx_buf = &ts->tc.z1; |
| x->len = 2; |
| x++; |
| |
| x->tx_buf = &read_z2; |
| x->len = 1; |
| x++; |
| x->rx_buf = &ts->tc.z2; |
| x->len = 2; |
| x++; |
| } |
| |
| /* turn y- off, x+ on, then leave in lowpower */ |
| x->tx_buf = &read_x; |
| x->len = 1; |
| x++; |
| x->rx_buf = &ts->tc.x; |
| x->len = 2; |
| x++; |
| |
| CS_CHANGE(x[-1]); |
| |
| for (i = 0; i < x - ts->xfer; i++) |
| spi_message_add_tail(&ts->xfer[i], &ts->msg); |
| ts->msg.complete = ads7846_rx; |
| ts->msg.context = ts; |
| |
| if (request_irq(spi->irq, ads7846_irq, SA_SAMPLE_RANDOM, |
| spi->dev.bus_id, ts)) { |
| dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); |
| input_unregister_device(&ts->input); |
| kfree(ts); |
| return -EBUSY; |
| } |
| set_irq_type(spi->irq, IRQT_FALLING); |
| |
| dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq); |
| |
| /* take a first sample, leaving nPENIRQ active; avoid |
| * the touchscreen, in case it's not connected. |
| */ |
| (void) ads7846_read12_ser(&spi->dev, |
| READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON); |
| |
| /* ads7843/7845 don't have temperature sensors, and |
| * use the other sensors a bit differently too |
| */ |
| if (ts->model == 7846) { |
| device_create_file(&spi->dev, &dev_attr_temp0); |
| device_create_file(&spi->dev, &dev_attr_temp1); |
| } |
| if (ts->model != 7845) |
| device_create_file(&spi->dev, &dev_attr_vbatt); |
| device_create_file(&spi->dev, &dev_attr_vaux); |
| |
| return 0; |
| } |
| |
| static int __devexit ads7846_remove(struct spi_device *spi) |
| { |
| struct ads7846 *ts = dev_get_drvdata(&spi->dev); |
| |
| ads7846_suspend(spi, PMSG_SUSPEND); |
| free_irq(ts->spi->irq, ts); |
| if (ts->irq_disabled) |
| enable_irq(ts->spi->irq); |
| |
| if (ts->model == 7846) { |
| device_remove_file(&spi->dev, &dev_attr_temp0); |
| device_remove_file(&spi->dev, &dev_attr_temp1); |
| } |
| if (ts->model != 7845) |
| device_remove_file(&spi->dev, &dev_attr_vbatt); |
| device_remove_file(&spi->dev, &dev_attr_vaux); |
| |
| input_unregister_device(&ts->input); |
| kfree(ts); |
| |
| dev_dbg(&spi->dev, "unregistered touchscreen\n"); |
| return 0; |
| } |
| |
| static struct spi_driver ads7846_driver = { |
| .driver = { |
| .name = "ads7846", |
| .bus = &spi_bus_type, |
| .owner = THIS_MODULE, |
| }, |
| .probe = ads7846_probe, |
| .remove = __devexit_p(ads7846_remove), |
| .suspend = ads7846_suspend, |
| .resume = ads7846_resume, |
| }; |
| |
| static int __init ads7846_init(void) |
| { |
| /* grr, board-specific init should stay out of drivers!! */ |
| |
| #ifdef CONFIG_ARCH_OMAP |
| if (machine_is_omap_osk()) { |
| /* GPIO4 = PENIRQ; GPIO6 = BUSY */ |
| omap_request_gpio(4); |
| omap_set_gpio_direction(4, 1); |
| omap_request_gpio(6); |
| omap_set_gpio_direction(6, 1); |
| } |
| // also TI 1510 Innovator, bitbanging through FPGA |
| // also Nokia 770 |
| // also Palm Tungsten T2 |
| #endif |
| |
| // PXA: |
| // also Dell Axim X50 |
| // also HP iPaq H191x/H192x/H415x/H435x |
| // also Intel Lubbock (additional to UCB1400; as temperature sensor) |
| // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky) |
| |
| // Atmel at91sam9261-EK uses ads7843 |
| |
| // also various AMD Au1x00 devel boards |
| |
| return spi_register_driver(&ads7846_driver); |
| } |
| module_init(ads7846_init); |
| |
| static void __exit ads7846_exit(void) |
| { |
| spi_unregister_driver(&ads7846_driver); |
| |
| #ifdef CONFIG_ARCH_OMAP |
| if (machine_is_omap_osk()) { |
| omap_free_gpio(4); |
| omap_free_gpio(6); |
| } |
| #endif |
| |
| } |
| module_exit(ads7846_exit); |
| |
| MODULE_DESCRIPTION("ADS7846 TouchScreen Driver"); |
| MODULE_LICENSE("GPL"); |