// 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 <[email protected]> * * 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/property.h> #include <linux/gpio/consumer.h> #include <linux/spi/spi.h> #include <linux/spi/ads7846.h> #include <linux/regulator/consumer.h> #include <linux/module.h> #include <linux/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 … #define TS_POLL_PERIOD … /* this driver doesn't aim at the peak continuous sample rate */ #define SAMPLE_BITS … struct ads7846_buf { … } __packed; struct ads7846_buf_layout { … }; /* * 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 { … }; struct ads7846 { … }; enum ads7846_filter { … }; /* leave chip selected when we're done, for quicker re-select? */ #if 0 #define CS_CHANGE … #else #define CS_CHANGE(xfer) … #endif /*--------------------------------------------------------------------------*/ /* The ADS7846 has touchscreen and other sensors. * Earlier ads784x chips are somewhat compatible. */ #define ADS_START … #define ADS_A2A1A0_d_y … #define ADS_A2A1A0_d_z1 … #define ADS_A2A1A0_d_z2 … #define ADS_A2A1A0_d_x … #define ADS_A2A1A0_temp0 … #define ADS_A2A1A0_vbatt … #define ADS_A2A1A0_vaux … #define ADS_A2A1A0_temp1 … #define ADS_8_BIT … #define ADS_12_BIT … #define ADS_SER … #define ADS_DFR … #define ADS_PD10_PDOWN … #define ADS_PD10_ADC_ON … #define ADS_PD10_REF_ON … #define ADS_PD10_ALL_ON … #define MAX_12BIT … /* leave ADC powered up (disables penirq) between differential samples */ #define READ_12BIT_DFR(x, adc, vref) … #define READ_Y(vref) … #define READ_Z1(vref) … #define READ_Z2(vref) … #define READ_X(vref) … #define PWRDOWN … /* single-ended samples need to first power up reference voltage; * we leave both ADC and VREF powered */ #define READ_12BIT_SER(x) … #define REF_ON … #define REF_OFF … /* 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 { … }; static int get_pendown_state(struct ads7846 *ts) { … } static void ads7846_report_pen_up(struct ads7846 *ts) { … } /* Must be called with ts->lock held */ static void ads7846_stop(struct ads7846 *ts) { … } /* Must be called with ts->lock held */ static void ads7846_restart(struct ads7846 *ts) { … } /* Must be called with ts->lock held */ static void __ads7846_disable(struct ads7846 *ts) { … } /* Must be called with ts->lock held */ static void __ads7846_enable(struct ads7846 *ts) { … } static void ads7846_disable(struct ads7846 *ts) { … } static void ads7846_enable(struct ads7846 *ts) { … } /*--------------------------------------------------------------------------*/ /* * 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 { … }; struct ads7845_ser_req { … }; static int ads7846_read12_ser(struct device *dev, unsigned command) { … } static int ads7845_read12_ser(struct device *dev, unsigned command) { … } #if IS_ENABLED(CONFIG_HWMON) #define SHOW(name, var, adjust) … /* 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) { … } SHOW(…) /* temp1_input */ SHOW(…) /* 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) { … } static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v) { … } SHOW(…) SHOW(…) static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr, int index) { … } static struct attribute *ads7846_attributes[] = …; static const struct attribute_group ads7846_attr_group = …; __ATTRIBUTE_GROUPS(…); static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) { … } #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) { … } 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) { … } static ssize_t ads7846_disable_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { … } static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store); static struct attribute *ads784x_attrs[] = …; ATTRIBUTE_GROUPS(…); /*--------------------------------------------------------------------------*/ static int ads7846_debounce_filter(void *ads, int data_idx, int *val) { … } static int ads7846_no_filter(void *ads, int data_idx, int *val) { … } static int ads7846_get_value(struct ads7846_buf *buf) { … } static void ads7846_set_cmd_val(struct ads7846 *ts, enum ads7846_cmds cmd_idx, u16 val) { … } static u8 ads7846_get_cmd(enum ads7846_cmds cmd_idx, int vref) { … } static bool ads7846_cmd_need_settle(enum ads7846_cmds cmd_idx) { … } static int ads7846_filter(struct ads7846 *ts) { … } static void ads7846_wait_for_hsync(struct ads7846 *ts) { … } static void ads7846_read_state(struct ads7846 *ts) { … } static void ads7846_report_state(struct ads7846 *ts) { … } static irqreturn_t ads7846_hard_irq(int irq, void *handle) { … } static irqreturn_t ads7846_irq(int irq, void *handle) { … } static int ads7846_suspend(struct device *dev) { … } static int ads7846_resume(struct device *dev) { … } static DEFINE_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) { … } /* * 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) { … } static const struct of_device_id ads7846_dt_ids[] = …; MODULE_DEVICE_TABLE(of, ads7846_dt_ids); static const struct spi_device_id ads7846_spi_ids[] = …; MODULE_DEVICE_TABLE(spi, ads7846_spi_ids); static const struct ads7846_platform_data *ads7846_get_props(struct device *dev) { … } static void ads7846_regulator_disable(void *regulator) { … } static int ads7846_probe(struct spi_device *spi) { … } static void ads7846_remove(struct spi_device *spi) { … } static struct spi_driver ads7846_driver = …; module_spi_driver(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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