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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * ADS7846 based touchscreen and sensor driver
  *
  * Copyright (c) 2005 David Brownell
  * Copyright (c) 2006 Nokia Corporation
  * Various changes: Imre Deak <imre.deak@nokia.com>
  *
  * 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
  */
 #include <linux/types.h>
 #include <linux/hwmon.h>
 #include <linux/err.h>
 #include <linux/sched.h>
 #include <linux/delay.h>
 #include <linux/input.h>
 #include <linux/input/touchscreen.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/pm.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
 #include <linux/of_device.h>
 #include <linux/gpio.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/ads7846.h>
 #include <linux/regulator/consumer.h>
 #include <linux/module.h>
 #include <asm/unaligned.h>
 
 /*
  * This code has been heavily tested on a Nokia 770, and lightly
  * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz).
  * TSC2046 is just newer ads7846 silicon.
  * Support for ads7843 tested on Atmel at91sam926x-EK.
  * Support for ads7845 has only been stubbed in.
  * Support for Analog Devices AD7873 and AD7843 tested.
  *
  * IRQ handling needs a workaround because of a shortcoming in handling
  * edge triggered IRQs on some platforms like the OMAP1/2. These
  * platforms don't handle the ARM lazy IRQ disabling properly, thus we
  * have to maintain our own SW IRQ disabled status. This should be
  * removed as soon as the affected platform's IRQ handling is fixed.
  *
  * 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.
  * This driver tries to utilize the measures described in the app
  * note. The strength of filtering can be set in the board-* specific
  * files.
  */
 
 #define TS_POLL_DELAY   1   /* ms delay before the first sample */
 #define TS_POLL_PERIOD  5   /* ms delay between samples */
 
 /* this driver doesn't aim at the peak continuous sample rate */
 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
 
 struct ads7846_buf {
     u8 cmd;
     __be16 data;
 } __packed;
 
 struct ads7846_buf_layout {
     unsigned int offset;
     unsigned int count;
     unsigned int skip;
 };
 
 /*
  * We allocate this separately to avoid cache line sharing issues when
  * driver is used with DMA-based SPI controllers (like atmel_spi) on
  * systems where main memory is not DMA-coherent (most non-x86 boards).
  */
 struct ads7846_packet {
     unsigned int count;
     unsigned int count_skip;
     unsigned int cmds;
     unsigned int last_cmd_idx;
     struct ads7846_buf_layout l[5];
     struct ads7846_buf *rx;
     struct ads7846_buf *tx;
 
     struct ads7846_buf pwrdown_cmd;
 
     bool ignore;
     u16 x, y, z1, z2;
 };
 
 struct ads7846 {
     struct input_dev    *input;
     char            phys[32];
     char            name[32];
 
     struct spi_device   *spi;
     struct regulator    *reg;
 
     u16         model;
     u16         vref_mv;
     u16         vref_delay_usecs;
     u16         x_plate_ohms;
     u16         pressure_max;
 
     bool            swap_xy;
     bool            use_internal;
 
     struct ads7846_packet   *packet;
 
     struct spi_transfer xfer[18];
     struct spi_message  msg[5];
     int         msg_count;
     wait_queue_head_t   wait;
 
     bool            pendown;
 
     int         read_cnt;
     int         read_rep;
     int         last_read;
 
     u16         debounce_max;
     u16         debounce_tol;
     u16         debounce_rep;
 
     u16         penirq_recheck_delay_usecs;
 
     struct touchscreen_properties core_prop;
 
     struct mutex        lock;
     bool            stopped;    /* P: lock */
     bool            disabled;   /* P: lock */
     bool            suspended;  /* P: lock */
 
     int         (*filter)(void *data, int data_idx, int *val);
     void            *filter_data;
     int         (*get_pendown_state)(void);
     int         gpio_pendown;
 
     void            (*wait_for_sync)(void);
 };
 
 enum ads7846_filter {
     ADS7846_FILTER_OK,
     ADS7846_FILTER_REPEAT,
     ADS7846_FILTER_IGNORE,
 };
 
 /* 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)    /* low power 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, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
     | ADS_12_BIT | ADS_DFR | \
     (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 
 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
 #define PWRDOWN     (READ_12BIT_DFR(y,  0, 0))  /* 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)
 
 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 
 /* Order commands in the most optimal way to reduce Vref switching and
  * settling time:
  * Measure:  X; Vref: X+, X-; IN: Y+
  * Measure:  Y; Vref: Y+, Y-; IN: X+
  * Measure: Z1; Vref: Y+, X-; IN: X+
  * Measure: Z2; Vref: Y+, X-; IN: Y-
  */
 enum ads7846_cmds {
     ADS7846_X,
     ADS7846_Y,
     ADS7846_Z1,
     ADS7846_Z2,
     ADS7846_PWDOWN,
 };
 
 static int get_pendown_state(struct ads7846 *ts)
 {
     if (ts->get_pendown_state)
         return ts->get_pendown_state();
 
     return !gpio_get_value(ts->gpio_pendown);
 }
 
 static void ads7846_report_pen_up(struct ads7846 *ts)
 {
     struct input_dev *input = ts->input;
 
     input_report_key(input, BTN_TOUCH, 0);
     input_report_abs(input, ABS_PRESSURE, 0);
     input_sync(input);
 
     ts->pendown = false;
     dev_vdbg(&ts->spi->dev, "UP\n");
 }
 
 /* Must be called with ts->lock held */
 static void ads7846_stop(struct ads7846 *ts)
 {
     if (!ts->disabled && !ts->suspended) {
         /* Signal IRQ thread to stop polling and disable the handler. */
         ts->stopped = true;
         mb();
         wake_up(&ts->wait);
         disable_irq(ts->spi->irq);
     }
 }
 
 /* Must be called with ts->lock held */
 static void ads7846_restart(struct ads7846 *ts)
 {
     if (!ts->disabled && !ts->suspended) {
         /* Check if pen was released since last stop */
         if (ts->pendown && !get_pendown_state(ts))
             ads7846_report_pen_up(ts);
 
         /* Tell IRQ thread that it may poll the device. */
         ts->stopped = false;
         mb();
         enable_irq(ts->spi->irq);
     }
 }
 
 /* Must be called with ts->lock held */
 static void __ads7846_disable(struct ads7846 *ts)
 {
     ads7846_stop(ts);
     regulator_disable(ts->reg);
 
     /*
      * We know the chip's in low power mode since we always
      * leave it that way after every request
      */
 }
 
 /* Must be called with ts->lock held */
 static void __ads7846_enable(struct ads7846 *ts)
 {
     int error;
 
     error = regulator_enable(ts->reg);
     if (error != 0)
         dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
 
     ads7846_restart(ts);
 }
 
 static void ads7846_disable(struct ads7846 *ts)
 {
     mutex_lock(&ts->lock);
 
     if (!ts->disabled) {
 
         if  (!ts->suspended)
             __ads7846_disable(ts);
 
         ts->disabled = true;
     }
 
     mutex_unlock(&ts->lock);
 }
 
 static void ads7846_enable(struct ads7846 *ts)
 {
     mutex_lock(&ts->lock);
 
     if (ts->disabled) {
 
         ts->disabled = false;
 
         if (!ts->suspended)
             __ads7846_enable(ts);
     }
 
     mutex_unlock(&ts->lock);
 }
 
 /*--------------------------------------------------------------------------*/
 
 /*
  * Non-touchscreen sensors only use single-ended conversions.
  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
  * ads7846 lets that pin be unconnected, to use internal vREF.
  */
 
 struct ser_req {
     u8          ref_on;
     u8          command;
     u8          ref_off;
     u16         scratch;
     struct spi_message  msg;
     struct spi_transfer xfer[6];
     /*
      * DMA (thus cache coherency maintenance) requires the
      * transfer buffers to live in their own cache lines.
      */
     __be16 sample ____cacheline_aligned;
 };
 
 struct ads7845_ser_req {
     u8          command[3];
     struct spi_message  msg;
     struct spi_transfer xfer[2];
     /*
      * DMA (thus cache coherency maintenance) requires the
      * transfer buffers to live in their own cache lines.
      */
     u8 sample[3] ____cacheline_aligned;
 };
 
 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;
     int status;
 
     req = kzalloc(sizeof *req, GFP_KERNEL);
     if (!req)
         return -ENOMEM;
 
     spi_message_init(&req->msg);
 
     /* maybe turn on internal vREF, and let it settle */
     if (ts->use_internal) {
         req->ref_on = REF_ON;
         req->xfer[0].tx_buf = &req->ref_on;
         req->xfer[0].len = 1;
         spi_message_add_tail(&req->xfer[0], &req->msg);
 
         req->xfer[1].rx_buf = &req->scratch;
         req->xfer[1].len = 2;
 
         /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
         req->xfer[1].delay.value = ts->vref_delay_usecs;
         req->xfer[1].delay.unit = SPI_DELAY_UNIT_USECS;
         spi_message_add_tail(&req->xfer[1], &req->msg);
 
         /* Enable reference voltage */
         command |= ADS_PD10_REF_ON;
     }
 
     /* Enable ADC in every case */
     command |= ADS_PD10_ADC_ON;
 
     /* take sample */
     req->command = (u8) command;
     req->xfer[2].tx_buf = &req->command;
     req->xfer[2].len = 1;
     spi_message_add_tail(&req->xfer[2], &req->msg);
 
     req->xfer[3].rx_buf = &req->sample;
     req->xfer[3].len = 2;
     spi_message_add_tail(&req->xfer[3], &req->msg);
 
     /* REVISIT:  take a few more samples, and compare ... */
 
     /* converter in low power mode & enable PENIRQ */
     req->ref_off = PWRDOWN;
     req->xfer[4].tx_buf = &req->ref_off;
     req->xfer[4].len = 1;
     spi_message_add_tail(&req->xfer[4], &req->msg);
 
     req->xfer[5].rx_buf = &req->scratch;
     req->xfer[5].len = 2;
     CS_CHANGE(req->xfer[5]);
     spi_message_add_tail(&req->xfer[5], &req->msg);
 
     mutex_lock(&ts->lock);
     ads7846_stop(ts);
     status = spi_sync(spi, &req->msg);
     ads7846_restart(ts);
     mutex_unlock(&ts->lock);
 
     if (status == 0) {
         /* on-wire is a must-ignore bit, a BE12 value, then padding */
         status = be16_to_cpu(req->sample);
         status = status >> 3;
         status &= 0x0fff;
     }
 
     kfree(req);
     return status;
 }
 
 static int ads7845_read12_ser(struct device *dev, unsigned command)
 {
     struct spi_device *spi = to_spi_device(dev);
     struct ads7846 *ts = dev_get_drvdata(dev);
     struct ads7845_ser_req *req;
     int status;
 
     req = kzalloc(sizeof *req, GFP_KERNEL);
     if (!req)
         return -ENOMEM;
 
     spi_message_init(&req->msg);
 
     req->command[0] = (u8) command;
     req->xfer[0].tx_buf = req->command;
     req->xfer[0].rx_buf = req->sample;
     req->xfer[0].len = 3;
     spi_message_add_tail(&req->xfer[0], &req->msg);
 
     mutex_lock(&ts->lock);
     ads7846_stop(ts);
     status = spi_sync(spi, &req->msg);
     ads7846_restart(ts);
     mutex_unlock(&ts->lock);
 
     if (status == 0) {
         /* BE12 value, then padding */
         status = get_unaligned_be16(&req->sample[1]);
         status = status >> 3;
         status &= 0x0fff;
     }
 
     kfree(req);
     return status;
 }
 
 #if IS_ENABLED(CONFIG_HWMON)
 
 #define SHOW(name, var, adjust) static ssize_t \
 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 { \
     struct ads7846 *ts = dev_get_drvdata(dev); \
     ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
             READ_12BIT_SER(var)); \
     if (v < 0) \
         return v; \
     return sprintf(buf, "%u\n", adjust(ts, v)); \
 } \
 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 
 
 /* Sysfs conventions report temperatures in millidegrees Celsius.
  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
  * accuracy scheme without calibration data.  For now we won't try either;
  * userspace sees raw sensor values, and must scale/calibrate appropriately.
  */
 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 {
     return v;
 }
 
 SHOW(temp0, temp0, null_adjust)     /* temp1_input */
 SHOW(temp1, temp1, null_adjust)     /* temp2_input */
 
 
 /* sysfs conventions report voltages in millivolts.  We can convert voltages
  * if we know vREF.  userspace may need to scale vAUX to match the board's
  * external resistors; we assume that vBATT only uses the internal ones.
  */
 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
 {
     unsigned retval = v;
 
     /* external resistors may scale vAUX into 0..vREF */
     retval *= ts->vref_mv;
     retval = retval >> 12;
 
     return retval;
 }
 
 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
 {
     unsigned retval = vaux_adjust(ts, v);
 
     /* ads7846 has a resistor ladder to scale this signal down */
     if (ts->model == 7846)
         retval *= 4;
 
     return retval;
 }
 
 SHOW(in0_input, vaux, vaux_adjust)
 SHOW(in1_input, vbatt, vbatt_adjust)
 
 static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
                   int index)
 {
     struct device *dev = kobj_to_dev(kobj);
     struct ads7846 *ts = dev_get_drvdata(dev);
 
     if (ts->model == 7843 && index < 2) /* in0, in1 */
         return 0;
     if (ts->model == 7845 && index != 2)    /* in0 */
         return 0;
 
     return attr->mode;
 }
 
 static struct attribute *ads7846_attributes[] = {
     &dev_attr_temp0.attr,       /* 0 */
     &dev_attr_temp1.attr,       /* 1 */
     &dev_attr_in0_input.attr,   /* 2 */
     &dev_attr_in1_input.attr,   /* 3 */
     NULL,
 };
 
 static const struct attribute_group ads7846_attr_group = {
     .attrs = ads7846_attributes,
     .is_visible = ads7846_is_visible,
 };
 __ATTRIBUTE_GROUPS(ads7846_attr);
 
 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
 {
     struct device *hwmon;
 
     /* hwmon sensors need a reference voltage */
     switch (ts->model) {
     case 7846:
         if (!ts->vref_mv) {
             dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
             ts->vref_mv = 2500;
             ts->use_internal = true;
         }
         break;
     case 7845:
     case 7843:
         if (!ts->vref_mv) {
             dev_warn(&spi->dev,
                 "external vREF for ADS%d not specified\n",
                 ts->model);
             return 0;
         }
         break;
     }
 
     hwmon = devm_hwmon_device_register_with_groups(&spi->dev,
                                spi->modalias, ts,
                                ads7846_attr_groups);
 
     return PTR_ERR_OR_ZERO(hwmon);
 }
 
 #else
 static inline int ads784x_hwmon_register(struct spi_device *spi,
                      struct ads7846 *ts)
 {
     return 0;
 }
 #endif
 
 static ssize_t ads7846_pen_down_show(struct device *dev,
                      struct device_attribute *attr, char *buf)
 {
     struct ads7846 *ts = dev_get_drvdata(dev);
 
     return sprintf(buf, "%u\n", ts->pendown);
 }
 
 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 
 static ssize_t ads7846_disable_show(struct device *dev,
                      struct device_attribute *attr, char *buf)
 {
     struct ads7846 *ts = dev_get_drvdata(dev);
 
     return sprintf(buf, "%u\n", ts->disabled);
 }
 
 static ssize_t ads7846_disable_store(struct device *dev,
                      struct device_attribute *attr,
                      const char *buf, size_t count)
 {
     struct ads7846 *ts = dev_get_drvdata(dev);
     unsigned int i;
     int err;
 
     err = kstrtouint(buf, 10, &i);
     if (err)
         return err;
 
     if (i)
         ads7846_disable(ts);
     else
         ads7846_enable(ts);
 
     return count;
 }
 
 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 
 static struct attribute *ads784x_attributes[] = {
     &dev_attr_pen_down.attr,
     &dev_attr_disable.attr,
     NULL,
 };
 
 static const struct attribute_group ads784x_attr_group = {
     .attrs = ads784x_attributes,
 };
 
 /*--------------------------------------------------------------------------*/
 
 static void null_wait_for_sync(void)
 {
 }
 
 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
 {
     struct ads7846 *ts = ads;
 
     if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
         /* Start over collecting consistent readings. */
         ts->read_rep = 0;
         /*
          * Repeat it, if this was the first read or the read
          * wasn't consistent enough.
          */
         if (ts->read_cnt < ts->debounce_max) {
             ts->last_read = *val;
             ts->read_cnt++;
             return ADS7846_FILTER_REPEAT;
         } else {
             /*
              * Maximum number of debouncing reached and still
              * not enough number of consistent readings. Abort
              * the whole sample, repeat it in the next sampling
              * period.
              */
             ts->read_cnt = 0;
             return ADS7846_FILTER_IGNORE;
         }
     } else {
         if (++ts->read_rep > ts->debounce_rep) {
             /*
              * Got a good reading for this coordinate,
              * go for the next one.
              */
             ts->read_cnt = 0;
             ts->read_rep = 0;
             return ADS7846_FILTER_OK;
         } else {
             /* Read more values that are consistent. */
             ts->read_cnt++;
             return ADS7846_FILTER_REPEAT;
         }
     }
 }
 
 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 {
     return ADS7846_FILTER_OK;
 }
 
 static int ads7846_get_value(struct ads7846_buf *buf)
 {
     int value;
 
     value = be16_to_cpup(&buf->data);
 
     /* enforce ADC output is 12 bits width */
     return (value >> 3) & 0xfff;
 }
 
 static void ads7846_set_cmd_val(struct ads7846 *ts, enum ads7846_cmds cmd_idx,
                 u16 val)
 {
     struct ads7846_packet *packet = ts->packet;
 
     switch (cmd_idx) {
     case ADS7846_Y:
         packet->y = val;
         break;
     case ADS7846_X:
         packet->x = val;
         break;
     case ADS7846_Z1:
         packet->z1 = val;
         break;
     case ADS7846_Z2:
         packet->z2 = val;
         break;
     default:
         WARN_ON_ONCE(1);
     }
 }
 
 static u8 ads7846_get_cmd(enum ads7846_cmds cmd_idx, int vref)
 {
     switch (cmd_idx) {
     case ADS7846_Y:
         return READ_Y(vref);
     case ADS7846_X:
         return READ_X(vref);
 
     /* 7846 specific commands  */
     case ADS7846_Z1:
         return READ_Z1(vref);
     case ADS7846_Z2:
         return READ_Z2(vref);
     case ADS7846_PWDOWN:
         return PWRDOWN;
     default:
         WARN_ON_ONCE(1);
     }
 
     return 0;
 }
 
 static bool ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx)
 {
     switch (cmd_idx) {
     case ADS7846_X:
     case ADS7846_Y:
     case ADS7846_Z1:
     case ADS7846_Z2:
         return true;
     case ADS7846_PWDOWN:
         return false;
     default:
         WARN_ON_ONCE(1);
     }
 
     return false;
 }
 
 static int ads7846_filter(struct ads7846 *ts)
 {
     struct ads7846_packet *packet = ts->packet;
     int action;
     int val;
     unsigned int cmd_idx, b;
 
     packet->ignore = false;
     for (cmd_idx = packet->last_cmd_idx; cmd_idx < packet->cmds - 1; cmd_idx++) {
         struct ads7846_buf_layout *l = &packet->l[cmd_idx];
 
         packet->last_cmd_idx = cmd_idx;
 
         for (b = l->skip; b < l->count; b++) {
             val = ads7846_get_value(&packet->rx[l->offset + b]);
 
             action = ts->filter(ts->filter_data, cmd_idx, &val);
             if (action == ADS7846_FILTER_REPEAT) {
                 if (b == l->count - 1)
                     return -EAGAIN;
             } else if (action == ADS7846_FILTER_OK) {
                 ads7846_set_cmd_val(ts, cmd_idx, val);
                 break;
             } else {
                 packet->ignore = true;
                 return 0;
             }
         }
     }
 
     return 0;
 }
 
 static void ads7846_read_state(struct ads7846 *ts)
 {
     struct ads7846_packet *packet = ts->packet;
     struct spi_message *m;
     int msg_idx = 0;
     int error;
 
     packet->last_cmd_idx = 0;
 
     while (true) {
         ts->wait_for_sync();
 
         m = &ts->msg[msg_idx];
         error = spi_sync(ts->spi, m);
         if (error) {
             dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
             packet->ignore = true;
             return;
         }
 
         error = ads7846_filter(ts);
         if (error)
             continue;
 
         return;
     }
 }
 
 static void ads7846_report_state(struct ads7846 *ts)
 {
     struct ads7846_packet *packet = ts->packet;
     unsigned int Rt;
     u16 x, y, z1, z2;
 
     x = packet->x;
     y = packet->y;
     if (ts->model == 7845) {
         z1 = 0;
         z2 = 0;
     } else {
         z1 = packet->z1;
         z2 = packet->z2;
     }
 
     /* range filtering */
     if (x == MAX_12BIT)
         x = 0;
 
     if (ts->model == 7843) {
         Rt = ts->pressure_max / 2;
     } else if (ts->model == 7845) {
         if (get_pendown_state(ts))
             Rt = ts->pressure_max / 2;
         else
             Rt = 0;
         dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
     } else if (likely(x && z1)) {
         /* compute touch pressure resistance using equation #2 */
         Rt = z2;
         Rt -= z1;
         Rt *= ts->x_plate_ohms;
         Rt = DIV_ROUND_CLOSEST(Rt, 16);
         Rt *= x;
         Rt /= z1;
         Rt = DIV_ROUND_CLOSEST(Rt, 256);
     } 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 (packet->ignore || Rt > ts->pressure_max) {
         dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
              packet->ignore, Rt);
         return;
     }
 
     /*
      * Maybe check the pendown state before reporting. This discards
      * false readings when the pen is lifted.
      */
     if (ts->penirq_recheck_delay_usecs) {
         udelay(ts->penirq_recheck_delay_usecs);
         if (!get_pendown_state(ts))
             Rt = 0;
     }
 
     /*
      * 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) {
             input_report_key(input, BTN_TOUCH, 1);
             ts->pendown = true;
             dev_vdbg(&ts->spi->dev, "DOWN\n");
         }
 
         touchscreen_report_pos(input, &ts->core_prop, x, y, false);
         input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
 
         input_sync(input);
         dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
     }
 }
 
 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
 {
     struct ads7846 *ts = handle;
 
     return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 }
 
 
 static irqreturn_t ads7846_irq(int irq, void *handle)
 {
     struct ads7846 *ts = handle;
 
     /* Start with a small delay before checking pendown state */
     msleep(TS_POLL_DELAY);
 
     while (!ts->stopped && get_pendown_state(ts)) {
 
         /* pen is down, continue with the measurement */
         ads7846_read_state(ts);
 
         if (!ts->stopped)
             ads7846_report_state(ts);
 
         wait_event_timeout(ts->wait, ts->stopped,
                    msecs_to_jiffies(TS_POLL_PERIOD));
     }
 
     if (ts->pendown && !ts->stopped)
         ads7846_report_pen_up(ts);
 
     return IRQ_HANDLED;
 }
 
 static int __maybe_unused ads7846_suspend(struct device *dev)
 {
     struct ads7846 *ts = dev_get_drvdata(dev);
 
     mutex_lock(&ts->lock);
 
     if (!ts->suspended) {
 
         if (!ts->disabled)
             __ads7846_disable(ts);
 
         if (device_may_wakeup(&ts->spi->dev))
             enable_irq_wake(ts->spi->irq);
 
         ts->suspended = true;
     }
 
     mutex_unlock(&ts->lock);
 
     return 0;
 }
 
 static int __maybe_unused ads7846_resume(struct device *dev)
 {
     struct ads7846 *ts = dev_get_drvdata(dev);
 
     mutex_lock(&ts->lock);
 
     if (ts->suspended) {
 
         ts->suspended = false;
 
         if (device_may_wakeup(&ts->spi->dev))
             disable_irq_wake(ts->spi->irq);
 
         if (!ts->disabled)
             __ads7846_enable(ts);
     }
 
     mutex_unlock(&ts->lock);
 
     return 0;
 }
 
 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 
 static int ads7846_setup_pendown(struct spi_device *spi,
                  struct ads7846 *ts,
                  const struct ads7846_platform_data *pdata)
 {
     int err;
 
     /*
      * REVISIT when the irq can be triggered active-low, or if for some
      * reason the touchscreen isn't hooked up, we don't need to access
      * the pendown state.
      */
 
     if (pdata->get_pendown_state) {
         ts->get_pendown_state = pdata->get_pendown_state;
     } else if (gpio_is_valid(pdata->gpio_pendown)) {
 
         err = devm_gpio_request_one(&spi->dev, pdata->gpio_pendown,
                         GPIOF_IN, "ads7846_pendown");
         if (err) {
             dev_err(&spi->dev,
                 "failed to request/setup pendown GPIO%d: %d\n",
                 pdata->gpio_pendown, err);
             return err;
         }
 
         ts->gpio_pendown = pdata->gpio_pendown;
 
         if (pdata->gpio_pendown_debounce)
             gpio_set_debounce(pdata->gpio_pendown,
                       pdata->gpio_pendown_debounce);
     } else {
         dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
         return -EINVAL;
     }
 
     return 0;
 }
 
 /*
  * Set up the transfers to read touchscreen state; this assumes we
  * use formula #2 for pressure, not #3.
  */
 static int ads7846_setup_spi_msg(struct ads7846 *ts,
                   const struct ads7846_platform_data *pdata)
 {
     struct spi_message *m = &ts->msg[0];
     struct spi_transfer *x = ts->xfer;
     struct ads7846_packet *packet = ts->packet;
     int vref = pdata->keep_vref_on;
     unsigned int count, offset = 0;
     unsigned int cmd_idx, b;
     unsigned long time;
     size_t size = 0;
 
     /* time per bit */
     time = NSEC_PER_SEC / ts->spi->max_speed_hz;
 
     count = pdata->settle_delay_usecs * NSEC_PER_USEC / time;
     packet->count_skip = DIV_ROUND_UP(count, 24);
 
     if (ts->debounce_max && ts->debounce_rep)
         /* ads7846_debounce_filter() is making ts->debounce_rep + 2
          * reads. So we need to get all samples for normal case. */
         packet->count = ts->debounce_rep + 2;
     else
         packet->count = 1;
 
     if (ts->model == 7846)
         packet->cmds = 5; /* x, y, z1, z2, pwdown */
     else
         packet->cmds = 3; /* x, y, pwdown */
 
     for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
         struct ads7846_buf_layout *l = &packet->l[cmd_idx];
         unsigned int max_count;
 
         if (ads7846_cmd_need_settle(cmd_idx))
             max_count = packet->count + packet->count_skip;
         else
             max_count = packet->count;
 
         l->offset = offset;
         offset += max_count;
         l->count = max_count;
         l->skip = packet->count_skip;
         size += sizeof(*packet->tx) * max_count;
     }
 
     packet->tx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
     if (!packet->tx)
         return -ENOMEM;
 
     packet->rx = devm_kzalloc(&ts->spi->dev, size, GFP_KERNEL);
     if (!packet->rx)
         return -ENOMEM;
 
     if (ts->model == 7873) {
         /*
          * The AD7873 is almost identical to the ADS7846
          * keep VREF off during differential/ratiometric
          * conversion modes.
          */
         ts->model = 7846;
         vref = 0;
     }
 
     ts->msg_count = 1;
     spi_message_init(m);
     m->context = ts;
 
     for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
         struct ads7846_buf_layout *l = &packet->l[cmd_idx];
         u8 cmd = ads7846_get_cmd(cmd_idx, vref);
 
         for (b = 0; b < l->count; b++)
             packet->tx[l->offset + b].cmd = cmd;
     }
 
     x->tx_buf = packet->tx;
     x->rx_buf = packet->rx;
     x->len = size;
     spi_message_add_tail(x, m);
 
     return 0;
 }
 
 #ifdef CONFIG_OF
 static const struct of_device_id ads7846_dt_ids[] = {
     { .compatible = "ti,tsc2046",   .data = (void *) 7846 },
     { .compatible = "ti,ads7843",   .data = (void *) 7843 },
     { .compatible = "ti,ads7845",   .data = (void *) 7845 },
     { .compatible = "ti,ads7846",   .data = (void *) 7846 },
     { .compatible = "ti,ads7873",   .data = (void *) 7873 },
     { }
 };
 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
 
 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
 {
     struct ads7846_platform_data *pdata;
     struct device_node *node = dev->of_node;
     const struct of_device_id *match;
     u32 value;
 
     if (!node) {
         dev_err(dev, "Device does not have associated DT data\n");
         return ERR_PTR(-EINVAL);
     }
 
     match = of_match_device(ads7846_dt_ids, dev);
     if (!match) {
         dev_err(dev, "Unknown device model\n");
         return ERR_PTR(-EINVAL);
     }
 
     pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
     if (!pdata)
         return ERR_PTR(-ENOMEM);
 
     pdata->model = (unsigned long)match->data;
 
     of_property_read_u16(node, "ti,vref-delay-usecs",
                  &pdata->vref_delay_usecs);
     of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
     pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
 
     pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
 
     of_property_read_u16(node, "ti,settle-delay-usec",
                  &pdata->settle_delay_usecs);
     of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
                  &pdata->penirq_recheck_delay_usecs);
 
     of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
     of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
 
     of_property_read_u16(node, "ti,x-min", &pdata->x_min);
     of_property_read_u16(node, "ti,y-min", &pdata->y_min);
     of_property_read_u16(node, "ti,x-max", &pdata->x_max);
     of_property_read_u16(node, "ti,y-max", &pdata->y_max);
 
     /*
      * touchscreen-max-pressure gets parsed during
      * touchscreen_parse_properties()
      */
     of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
     if (!of_property_read_u32(node, "touchscreen-min-pressure", &value))
         pdata->pressure_min = (u16) value;
     of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
 
     of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
     if (!of_property_read_u32(node, "touchscreen-average-samples", &value))
         pdata->debounce_max = (u16) value;
     of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
     of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
 
     of_property_read_u32(node, "ti,pendown-gpio-debounce",
                  &pdata->gpio_pendown_debounce);
 
     pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
             of_property_read_bool(node, "linux,wakeup");
 
     pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
 
     return pdata;
 }
 #else
 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
 {
     dev_err(dev, "no platform data defined\n");
     return ERR_PTR(-EINVAL);
 }
 #endif
 
 static void ads7846_regulator_disable(void *regulator)
 {
     regulator_disable(regulator);
 }
 
 static int ads7846_probe(struct spi_device *spi)
 {
     const struct ads7846_platform_data *pdata;
     struct ads7846 *ts;
     struct device *dev = &spi->dev;
     struct ads7846_packet *packet;
     struct input_dev *input_dev;
     unsigned long irq_flags;
     int err;
 
     if (!spi->irq) {
         dev_dbg(dev, "no IRQ?\n");
         return -EINVAL;
     }
 
     /* don't exceed max specified sample rate */
     if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
         dev_err(dev, "f(sample) %d KHz?\n",
             (spi->max_speed_hz/SAMPLE_BITS)/1000);
         return -EINVAL;
     }
 
     /*
      * We'd set TX word size 8 bits and RX word size to 13 bits ... except
      * that even if the hardware can do that, the SPI controller driver
      * may not.  So we stick to very-portable 8 bit words, both RX and TX.
      */
     spi->bits_per_word = 8;
     spi->mode &= ~SPI_MODE_X_MASK;
     spi->mode |= SPI_MODE_0;
     err = spi_setup(spi);
     if (err < 0)
         return err;
 
     ts = devm_kzalloc(dev, sizeof(struct ads7846), GFP_KERNEL);
     if (!ts)
         return -ENOMEM;
 
     packet = devm_kzalloc(dev, sizeof(struct ads7846_packet), GFP_KERNEL);
     if (!packet)
         return -ENOMEM;
 
     input_dev = devm_input_allocate_device(dev);
     if (!input_dev)
         return -ENOMEM;
 
     spi_set_drvdata(spi, ts);
 
     ts->packet = packet;
     ts->spi = spi;
     ts->input = input_dev;
 
     mutex_init(&ts->lock);
     init_waitqueue_head(&ts->wait);
 
     pdata = dev_get_platdata(dev);
     if (!pdata) {
         pdata = ads7846_probe_dt(dev);
         if (IS_ERR(pdata))
             return PTR_ERR(pdata);
     }
 
     ts->model = pdata->model ? : 7846;
     ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
     ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
     ts->vref_mv = pdata->vref_mv;
 
     if (pdata->debounce_max) {
         ts->debounce_max = pdata->debounce_max;
         if (ts->debounce_max < 2)
             ts->debounce_max = 2;
         ts->debounce_tol = pdata->debounce_tol;
         ts->debounce_rep = pdata->debounce_rep;
         ts->filter = ads7846_debounce_filter;
         ts->filter_data = ts;
     } else {
         ts->filter = ads7846_no_filter;
     }
 
     err = ads7846_setup_pendown(spi, ts, pdata);
     if (err)
         return err;
 
     if (pdata->penirq_recheck_delay_usecs)
         ts->penirq_recheck_delay_usecs =
                 pdata->penirq_recheck_delay_usecs;
 
     ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
 
     snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
     snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
 
     input_dev->name = ts->name;
     input_dev->phys = ts->phys;
 
     input_dev->id.bustype = BUS_SPI;
     input_dev->id.product = pdata->model;
 
     input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
     input_set_abs_params(input_dev, ABS_X,
             pdata->x_min ? : 0,
             pdata->x_max ? : MAX_12BIT,
             0, 0);
     input_set_abs_params(input_dev, ABS_Y,
             pdata->y_min ? : 0,
             pdata->y_max ? : MAX_12BIT,
             0, 0);
     input_set_abs_params(input_dev, ABS_PRESSURE,
             pdata->pressure_min, pdata->pressure_max, 0, 0);
 
     /*
      * Parse common framework properties. Must be done here to ensure the
      * correct behaviour in case of using the legacy vendor bindings. The
      * general binding value overrides the vendor specific one.
      */
     touchscreen_parse_properties(ts->input, false, &ts->core_prop);
     ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
 
     /*
      * Check if legacy ti,swap-xy binding is used instead of
      * touchscreen-swapped-x-y
      */
     if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
         swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
         ts->core_prop.swap_x_y = true;
     }
 
     ads7846_setup_spi_msg(ts, pdata);
 
     ts->reg = devm_regulator_get(dev, "vcc");
     if (IS_ERR(ts->reg)) {
         err = PTR_ERR(ts->reg);
         dev_err(dev, "unable to get regulator: %d\n", err);
         return err;
     }
 
     err = regulator_enable(ts->reg);
     if (err) {
         dev_err(dev, "unable to enable regulator: %d\n", err);
         return err;
     }
 
     err = devm_add_action_or_reset(dev, ads7846_regulator_disable, ts->reg);
     if (err)
         return err;
 
     irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
     irq_flags |= IRQF_ONESHOT;
 
     err = devm_request_threaded_irq(dev, spi->irq,
                     ads7846_hard_irq, ads7846_irq,
                     irq_flags, dev->driver->name, ts);
     if (err && err != -EPROBE_DEFER && !pdata->irq_flags) {
         dev_info(dev,
             "trying pin change workaround on irq %d\n", spi->irq);
         irq_flags |= IRQF_TRIGGER_RISING;
         err = devm_request_threaded_irq(dev, spi->irq,
                         ads7846_hard_irq, ads7846_irq,
                         irq_flags, dev->driver->name,
                         ts);
     }
 
     if (err) {
         dev_dbg(dev, "irq %d busy?\n", spi->irq);
         return err;
     }
 
     err = ads784x_hwmon_register(spi, ts);
     if (err)
         return err;
 
     dev_info(dev, "touchscreen, irq %d\n", spi->irq);
 
     /*
      * Take a first sample, leaving nPENIRQ active and vREF off; avoid
      * the touchscreen, in case it's not connected.
      */
     if (ts->model == 7845)
         ads7845_read12_ser(dev, PWRDOWN);
     else
         (void) ads7846_read12_ser(dev, READ_12BIT_SER(vaux));
 
     err = devm_device_add_group(dev, &ads784x_attr_group);
     if (err)
         return err;
 
     err = input_register_device(input_dev);
     if (err)
         return err;
 
     device_init_wakeup(dev, pdata->wakeup);
 
     /*
      * If device does not carry platform data we must have allocated it
      * when parsing DT data.
      */
     if (!dev_get_platdata(dev))
         devm_kfree(dev, (void *)pdata);
 
     return 0;
 }
 
 static void ads7846_remove(struct spi_device *spi)
 {
     struct ads7846 *ts = spi_get_drvdata(spi);
 
     ads7846_stop(ts);
 }
 
 static struct spi_driver ads7846_driver = {
     .driver = {
         .name   = "ads7846",
         .pm = &ads7846_pm,
         .of_match_table = of_match_ptr(ads7846_dt_ids),
     },
     .probe      = ads7846_probe,
     .remove     = ads7846_remove,
 };
 
 module_spi_driver(ads7846_driver);
 
 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("spi:ads7846");

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