diff options
author | Petr Cvek <petr.cvek@tul.cz> | 2017-03-13 09:05:49 +0100 |
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committer | Robert Jarzmik <robert.jarzmik@free.fr> | 2017-06-14 08:32:21 +0200 |
commit | 7ade445c26269d5af6c34ee50be97d54a3992d02 (patch) | |
tree | d95f31a5ea302a4d014d104270b1d05a2ee3a5f6 /arch/arm/mach-pxa/magician.c | |
parent | 2ea659a9ef488125eb46da6eb571de5eae5c43f6 (diff) | |
download | linux-7ade445c26269d5af6c34ee50be97d54a3992d02.tar.bz2 |
ARM: pxa: magician: Add support for ADS7846 touchscreen
This patch adds a support for ADS7846 touchscreen driver.
The basic functionality was tested, x_plate_ohms and y_plate_ohms were
physically measured. The value pressure_max was empirically set to match
the measured range, which is affected by x_plate_ohms and ADS samples.
The value of keep_vref_on should be set. A tested model (T-Mobile MDA
Compact PM10A) doesn't seem to use Vref pin as the input from an external
source. On this model the unset keep_vref_on cause high jitter of measured
values.
SPI framing pin (gpio_cs) must be used in GPIO mode due to an incompatible
autoframing of PXA27x controller and ADS7846 device.
Signed-off-by: Petr Cvek <petr.cvek@tul.cz>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Diffstat (limited to 'arch/arm/mach-pxa/magician.c')
-rw-r--r-- | arch/arm/mach-pxa/magician.c | 84 |
1 files changed, 83 insertions, 1 deletions
diff --git a/arch/arm/mach-pxa/magician.c b/arch/arm/mach-pxa/magician.c index b413e36506af..7f3566c93733 100644 --- a/arch/arm/mach-pxa/magician.c +++ b/arch/arm/mach-pxa/magician.c @@ -54,6 +54,10 @@ #include "devices.h" #include "generic.h" +#include <linux/spi/spi.h> +#include <linux/spi/pxa2xx_spi.h> +#include <linux/spi/ads7846.h> + static unsigned long magician_pin_config[] __initdata = { /* SDRAM and Static Memory I/O Signals */ @@ -85,7 +89,7 @@ static unsigned long magician_pin_config[] __initdata = { /* SSP 2 TSC2046 touchscreen */ GPIO19_SSP2_SCLK, - GPIO14_SSP2_SFRM, + MFP_CFG_OUT(GPIO14, AF0, DRIVE_HIGH), /* frame as GPIO */ GPIO89_SSP2_TXD, GPIO88_SSP2_RXD, @@ -675,6 +679,37 @@ static struct platform_device bq24022 = { }; /* + * fixed regulator for ads7846 + */ + +static struct regulator_consumer_supply ads7846_supply = + REGULATOR_SUPPLY("vcc", "spi2.0"); + +static struct regulator_init_data vads7846_regulator = { + .constraints = { + .valid_ops_mask = REGULATOR_CHANGE_STATUS, + }, + .num_consumer_supplies = 1, + .consumer_supplies = &ads7846_supply, +}; + +static struct fixed_voltage_config vads7846 = { + .supply_name = "vads7846", + .microvolts = 3300000, /* probably */ + .gpio = -EINVAL, + .startup_delay = 0, + .init_data = &vads7846_regulator, +}; + +static struct platform_device vads7846_device = { + .name = "reg-fixed-voltage", + .id = -1, + .dev = { + .platform_data = &vads7846, + }, +}; + +/* * Vcore regulator MAX1587A */ @@ -852,6 +887,49 @@ static struct i2c_pxa_platform_data magician_i2c_power_info = { }; /* + * Touchscreen + */ + +static struct ads7846_platform_data ads7846_pdata = { + .model = 7846, + .x_plate_ohms = 317, + .y_plate_ohms = 500, + .pressure_max = 1023, /* with x plate ohms it will overflow 255 */ + .debounce_max = 3, /* first readout is always bad */ + .debounce_tol = 30, + .debounce_rep = 0, + .gpio_pendown = GPIO115_MAGICIAN_nPEN_IRQ, + .keep_vref_on = 1, + .wakeup = true, + .vref_delay_usecs = 100, + .penirq_recheck_delay_usecs = 100, +}; + +struct pxa2xx_spi_chip tsc2046_chip_info = { + .tx_threshold = 1, + .rx_threshold = 2, + .timeout = 64, + /* NOTICE must be GPIO, incompatibility with hw PXA SPI framing */ + .gpio_cs = GPIO14_MAGICIAN_TSC2046_CS, +}; + +static struct pxa2xx_spi_master magician_spi_info = { + .num_chipselect = 1, + .enable_dma = 1, +}; + +static struct spi_board_info ads7846_spi_board_info[] __initdata = { + { + .modalias = "ads7846", + .bus_num = 2, + .max_speed_hz = 2500000, + .platform_data = &ads7846_pdata, + .controller_data = &tsc2046_chip_info, + .irq = PXA_GPIO_TO_IRQ(GPIO115_MAGICIAN_nPEN_IRQ), + }, +}; + +/* * Platform devices */ @@ -865,6 +943,7 @@ static struct platform_device *devices[] __initdata = { &power_supply, &strataflash, &leds_gpio, + &vads7846_device, }; static struct gpio magician_global_gpios[] = { @@ -922,6 +1001,9 @@ static void __init magician_init(void) } else pr_err("LCD detection: CPLD mapping failed\n"); + pxa2xx_set_spi_info(2, &magician_spi_info); + spi_register_board_info(ARRAY_AND_SIZE(ads7846_spi_board_info)); + regulator_register_always_on(0, "power", pwm_backlight_supply, ARRAY_SIZE(pwm_backlight_supply), 5000000); |