forked from Minki/linux
Input: ads7846 - be more compatible with the hwmon framework
- Hook up to hwmon
* show sensor attributes only if hwmon is present
* ... and the board's reference voltage is known
* otherwise be just a touchscreen
- Report voltages per hwmon convention
* measure in millivolts
* voltages are named in[0-8]_input (ugh)
* for 7846 chips, properly range-adjust vBATT/in1_input
Battery measurements help during recharge monitoring. On OSK/Mistral,
the measured voltage agreed with a multimeter to several decimal places.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
David Brownell
Dmitry Torokhov
parent
15e3589e59
commit
2c8dc07151
@ -12,13 +12,18 @@ menuconfig INPUT_TOUCHSCREEN
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if INPUT_TOUCHSCREEN
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config TOUCHSCREEN_ADS7846
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tristate "ADS 7846 based touchscreens"
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tristate "ADS 7846/7843 based touchscreens"
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depends on SPI_MASTER
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depends on HWMON = n || HWMON
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help
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Say Y here if you have a touchscreen interface using the
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ADS7846 controller, and your board-specific initialization
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ADS7846 or ADS7843 controller, and your board-specific setup
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code includes that in its table of SPI devices.
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If HWMON is selected, and the driver is told the reference voltage
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on your board, you will also get hwmon interfaces for the voltage
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(and on ads7846, temperature) sensors of this chip.
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If unsure, say N (but it's safe to say "Y").
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To compile this driver as a module, choose M here: the
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@ -17,8 +17,9 @@
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/device.h>
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#include <linux/hwmon.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/input.h>
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#include <linux/interrupt.h>
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@ -69,7 +70,7 @@ struct ts_event {
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u16 x;
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u16 y;
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u16 z1, z2;
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int ignore;
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int ignore;
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};
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struct ads7846 {
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@ -77,7 +78,12 @@ struct ads7846 {
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char phys[32];
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struct spi_device *spi;
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#if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
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struct attribute_group *attr_group;
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struct class_device *hwmon;
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#endif
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u16 model;
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u16 vref_delay_usecs;
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u16 x_plate_ohms;
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@ -170,7 +176,12 @@ struct ads7846 {
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/*
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* Non-touchscreen sensors only use single-ended conversions.
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* The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
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* ads7846 lets that pin be unconnected, to use internal vREF.
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*/
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static unsigned vREF_mV;
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module_param(vREF_mV, uint, 0);
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MODULE_PARM_DESC(vREF_mV, "external vREF voltage, in milliVolts");
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struct ser_req {
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u8 ref_on;
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@ -198,50 +209,55 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
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struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL);
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int status;
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int sample;
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int i;
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int use_internal;
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if (!req)
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return -ENOMEM;
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spi_message_init(&req->msg);
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/* activate reference, so it has time to settle; */
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req->ref_on = REF_ON;
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req->xfer[0].tx_buf = &req->ref_on;
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req->xfer[0].len = 1;
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req->xfer[1].rx_buf = &req->scratch;
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req->xfer[1].len = 2;
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/* FIXME boards with ads7846 might use external vref instead ... */
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use_internal = (ts->model == 7846);
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/*
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* for external VREF, 0 usec (and assume it's always on);
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* for 1uF, use 800 usec;
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* no cap, 100 usec.
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*/
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req->xfer[1].delay_usecs = ts->vref_delay_usecs;
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/* maybe turn on internal vREF, and let it settle */
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if (use_internal) {
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req->ref_on = REF_ON;
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req->xfer[0].tx_buf = &req->ref_on;
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req->xfer[0].len = 1;
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spi_message_add_tail(&req->xfer[0], &req->msg);
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req->xfer[1].rx_buf = &req->scratch;
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req->xfer[1].len = 2;
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/* for 1uF, settle for 800 usec; no cap, 100 usec. */
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req->xfer[1].delay_usecs = ts->vref_delay_usecs;
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spi_message_add_tail(&req->xfer[1], &req->msg);
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}
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/* take sample */
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req->command = (u8) command;
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req->xfer[2].tx_buf = &req->command;
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req->xfer[2].len = 1;
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spi_message_add_tail(&req->xfer[2], &req->msg);
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req->xfer[3].rx_buf = &req->sample;
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req->xfer[3].len = 2;
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spi_message_add_tail(&req->xfer[3], &req->msg);
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/* REVISIT: take a few more samples, and compare ... */
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/* turn off reference */
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req->ref_off = REF_OFF;
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req->xfer[4].tx_buf = &req->ref_off;
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req->xfer[4].len = 1;
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req->xfer[5].rx_buf = &req->scratch;
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req->xfer[5].len = 2;
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/* maybe off internal vREF */
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if (use_internal) {
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req->ref_off = REF_OFF;
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req->xfer[4].tx_buf = &req->ref_off;
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req->xfer[4].len = 1;
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spi_message_add_tail(&req->xfer[4], &req->msg);
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CS_CHANGE(req->xfer[5]);
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/* group all the transfers together, so we can't interfere with
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* reading touchscreen state; disable penirq while sampling
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*/
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for (i = 0; i < 6; i++)
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spi_message_add_tail(&req->xfer[i], &req->msg);
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req->xfer[5].rx_buf = &req->scratch;
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req->xfer[5].len = 2;
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CS_CHANGE(req->xfer[5]);
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spi_message_add_tail(&req->xfer[5], &req->msg);
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}
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ts->irq_disabled = 1;
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disable_irq(spi->irq);
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@ -261,25 +277,173 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
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return status ? status : sample;
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}
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#define SHOW(name) static ssize_t \
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#if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
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#define SHOW(name, var, adjust) static ssize_t \
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name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
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{ \
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struct ads7846 *ts = dev_get_drvdata(dev); \
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ssize_t v = ads7846_read12_ser(dev, \
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READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
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READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
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if (v < 0) \
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return v; \
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return sprintf(buf, "%u\n", (unsigned) v); \
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return sprintf(buf, "%u\n", adjust(ts, v)); \
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} \
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static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
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SHOW(temp0)
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SHOW(temp1)
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SHOW(vaux)
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SHOW(vbatt)
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/* Sysfs conventions report temperatures in millidegrees Celcius.
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* ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
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* accuracy scheme without calibration data. For now we won't try either;
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* userspace sees raw sensor values, and must scale/calibrate appropriately.
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*/
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static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
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{
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return v;
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}
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SHOW(temp0, temp0, null_adjust) /* temp1_input */
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SHOW(temp1, temp1, null_adjust) /* temp2_input */
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/* sysfs conventions report voltages in millivolts. We can convert voltages
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* if we know vREF. userspace may need to scale vAUX to match the board's
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* external resistors; we assume that vBATT only uses the internal ones.
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*/
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static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
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{
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unsigned retval = v;
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/* external resistors may scale vAUX into 0..vREF */
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retval *= vREF_mV;
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retval = retval >> 12;
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return retval;
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}
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static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
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{
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unsigned retval = vaux_adjust(ts, v);
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/* ads7846 has a resistor ladder to scale this signal down */
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if (ts->model == 7846)
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retval *= 4;
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return retval;
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}
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SHOW(in0_input, vaux, vaux_adjust)
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SHOW(in1_input, vbatt, vbatt_adjust)
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static struct attribute *ads7846_attributes[] = {
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&dev_attr_temp0.attr,
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&dev_attr_temp1.attr,
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&dev_attr_in0_input.attr,
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&dev_attr_in1_input.attr,
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NULL,
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};
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static struct attribute_group ads7846_attr_group = {
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.attrs = ads7846_attributes,
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};
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static struct attribute *ads7843_attributes[] = {
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&dev_attr_in0_input.attr,
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&dev_attr_in1_input.attr,
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NULL,
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};
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static struct attribute_group ads7843_attr_group = {
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.attrs = ads7843_attributes,
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};
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static struct attribute *ads7845_attributes[] = {
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&dev_attr_in0_input.attr,
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NULL,
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};
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static struct attribute_group ads7845_attr_group = {
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.attrs = ads7845_attributes,
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};
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static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
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{
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struct class_device *hwmon;
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int err;
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/* hwmon sensors need a reference voltage */
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switch (ts->model) {
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case 7846:
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if (!vREF_mV) {
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dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
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vREF_mV = 2500;
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}
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break;
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case 7845:
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case 7843:
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if (!vREF_mV) {
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dev_warn(&spi->dev,
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"external vREF for ADS%d not specified\n",
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ts->model);
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return 0;
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}
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break;
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}
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/* different chips have different sensor groups */
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switch (ts->model) {
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case 7846:
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ts->attr_group = &ads7846_attr_group;
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break;
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case 7845:
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ts->attr_group = &ads7845_attr_group;
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break;
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case 7843:
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ts->attr_group = &ads7843_attr_group;
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break;
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default:
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dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model);
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return 0;
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}
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err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
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if (err)
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return err;
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hwmon = hwmon_device_register(&spi->dev);
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if (IS_ERR(hwmon)) {
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sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
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return PTR_ERR(hwmon);
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}
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ts->hwmon = hwmon;
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return 0;
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}
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static void ads784x_hwmon_unregister(struct spi_device *spi,
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struct ads7846 *ts)
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{
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if (ts->hwmon) {
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sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
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hwmon_device_unregister(ts->hwmon);
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}
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}
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#else
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static inline int ads784x_hwmon_register(struct spi_device *spi,
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struct ads7846 *ts)
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{
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return 0;
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}
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static inline void ads784x_hwmon_unregister(struct spi_device *spi,
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struct ads7846 *ts)
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{
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}
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#endif
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static int is_pen_down(struct device *dev)
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{
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struct ads7846 *ts = dev_get_drvdata(dev);
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struct ads7846 *ts = dev_get_drvdata(dev);
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return ts->pendown;
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}
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@ -323,46 +487,14 @@ static ssize_t ads7846_disable_store(struct device *dev,
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static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
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static struct attribute *ads7846_attributes[] = {
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&dev_attr_temp0.attr,
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&dev_attr_temp1.attr,
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&dev_attr_vbatt.attr,
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&dev_attr_vaux.attr,
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static struct attribute *ads784x_attributes[] = {
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&dev_attr_pen_down.attr,
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&dev_attr_disable.attr,
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NULL,
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};
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static struct attribute_group ads7846_attr_group = {
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.attrs = ads7846_attributes,
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};
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/*
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* ads7843/7845 don't have temperature sensors, and
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* use the other sensors a bit differently too
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*/
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static struct attribute *ads7843_attributes[] = {
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&dev_attr_vbatt.attr,
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&dev_attr_vaux.attr,
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&dev_attr_pen_down.attr,
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&dev_attr_disable.attr,
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NULL,
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};
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static struct attribute_group ads7843_attr_group = {
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.attrs = ads7843_attributes,
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};
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static struct attribute *ads7845_attributes[] = {
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&dev_attr_vaux.attr,
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&dev_attr_pen_down.attr,
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&dev_attr_disable.attr,
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NULL,
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};
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static struct attribute_group ads7845_attr_group = {
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.attrs = ads7845_attributes,
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static struct attribute_group ads784x_attr_group = {
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.attrs = ads784x_attributes,
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};
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/*--------------------------------------------------------------------------*/
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@ -886,28 +1018,21 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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goto err_cleanup_filter;
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}
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err = ads784x_hwmon_register(spi, ts);
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if (err)
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goto err_free_irq;
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dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
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/* take a first sample, leaving nPENIRQ active; avoid
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/* take a first sample, leaving nPENIRQ active and vREF off; avoid
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* the touchscreen, in case it's not connected.
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*/
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(void) ads7846_read12_ser(&spi->dev,
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READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
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switch (ts->model) {
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case 7846:
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ts->attr_group = &ads7846_attr_group;
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break;
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case 7845:
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ts->attr_group = &ads7845_attr_group;
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break;
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default:
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ts->attr_group = &ads7843_attr_group;
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break;
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}
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err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
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err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
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if (err)
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goto err_free_irq;
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goto err_remove_hwmon;
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err = input_register_device(input_dev);
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if (err)
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@ -916,7 +1041,9 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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return 0;
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err_remove_attr_group:
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sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
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sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
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err_remove_hwmon:
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ads784x_hwmon_unregister(spi, ts);
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err_free_irq:
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free_irq(spi->irq, ts);
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err_cleanup_filter:
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@ -932,11 +1059,12 @@ static int __devexit ads7846_remove(struct spi_device *spi)
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{
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struct ads7846 *ts = dev_get_drvdata(&spi->dev);
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ads784x_hwmon_unregister(spi, ts);
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input_unregister_device(ts->input);
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ads7846_suspend(spi, PMSG_SUSPEND);
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sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
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sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
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free_irq(ts->spi->irq, ts);
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/* suspend left the IRQ disabled */
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