linux-kernel - [PATCH RFC v4 6/6] input: ads7846: Move wait_for

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Message-Id: <20231001-pxa-gpio-v4-6-0f3b975e6ed5@skole.hr>
Date:   Sun, 01 Oct 2023 16:12:57 +0200
From:   Duje Mihanović <duje.mihanovic@...le.hr>
To:     Daniel Mack <daniel@...que.org>,
        Haojian Zhuang <haojian.zhuang@...il.com>,
        Robert Jarzmik <robert.jarzmik@...e.fr>,
        Russell King <linux@...linux.org.uk>,
        Alan Stern <stern@...land.harvard.edu>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Andy Shevchenko <andy@...nel.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-input@...r.kernel.org, linux-spi@...r.kernel.org,
        Duje Mihanović <duje.mihanovic@...le.hr>
Subject: [PATCH RFC v4 6/6] input: ads7846: Move wait_for_sync() logic to
 driver

If this code is left in the board file, the sync GPIO would have to be
separated into another lookup table during conversion to the GPIO
descriptor API (which is also done in this patch).

The only user of this code (Sharp Spitz) is also converted in this
patch.

Signed-off-by: Duje Mihanović <duje.mihanovic@...le.hr>
---
 arch/arm/mach-pxa/spitz.c           | 12 ++----------
 drivers/input/touchscreen/ads7846.c | 22 +++++++++++++++-------
 include/linux/spi/ads7846.h         |  1 -
 3 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/arch/arm/mach-pxa/spitz.c b/arch/arm/mach-pxa/spitz.c
index 701fba130ac4..22d5c5645b8f 100644
--- a/arch/arm/mach-pxa/spitz.c
+++ b/arch/arm/mach-pxa/spitz.c
@@ -520,22 +520,12 @@ static inline void spitz_leds_init(void) {}
  * SSP Devices
  ******************************************************************************/
 #if defined(CONFIG_SPI_PXA2XX) || defined(CONFIG_SPI_PXA2XX_MODULE)
-static void spitz_ads7846_wait_for_hsync(void)
-{
-	while (gpio_get_value(SPITZ_GPIO_HSYNC))
-		cpu_relax();
-
-	while (!gpio_get_value(SPITZ_GPIO_HSYNC))
-		cpu_relax();
-}
-
 static struct ads7846_platform_data spitz_ads7846_info = {
 	.model			= 7846,
 	.vref_delay_usecs	= 100,
 	.x_plate_ohms		= 419,
 	.y_plate_ohms		= 486,
 	.pressure_max		= 1024,
-	.wait_for_sync		= spitz_ads7846_wait_for_hsync,
 };
 
 static struct gpiod_lookup_table spitz_ads7846_gpio_table = {
@@ -543,6 +533,8 @@ static struct gpiod_lookup_table spitz_ads7846_gpio_table = {
 	.table = {
 		GPIO_LOOKUP("gpio-pxa", SPITZ_GPIO_TP_INT,
 			    "pendown", GPIO_ACTIVE_LOW),
+		GPIO_LOOKUP("gpio-pxa", SPITZ_GPIO_HSYNC,
+			    "sync", GPIO_ACTIVE_LOW),
 		{ }
 	},
 };
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index faea40dd66d0..894f179bfa8d 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -138,8 +138,7 @@ struct ads7846 {
 	void			*filter_data;
 	int			(*get_pendown_state)(void);
 	struct gpio_desc	*gpio_pendown;
-
-	void			(*wait_for_sync)(void);
+	struct gpio_desc	*sync;
 };
 
 enum ads7846_filter {
@@ -636,9 +635,14 @@ static const struct attribute_group ads784x_attr_group = {
 };
 
 /*--------------------------------------------------------------------------*/
-
-static void null_wait_for_sync(void)
+static void ads7846_wait_for_sync(struct ads7846 *ts)
 {
+	if (!ts->sync) return;
+	while (!gpiod_get_value(ts->sync))
+		cpu_relax();
+
+	while (gpiod_get_value(ts->sync))
+		cpu_relax();
 }
 
 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
@@ -803,7 +807,7 @@ static void ads7846_read_state(struct ads7846 *ts)
 	packet->last_cmd_idx = 0;
 
 	while (true) {
-		ts->wait_for_sync();
+		ads7846_wait_for_sync(ts);
 
 		m = &ts->msg[msg_idx];
 		error = spi_sync(ts->spi, m);
@@ -1261,8 +1265,6 @@ static int ads7846_probe(struct spi_device *spi)
 		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);
 
@@ -1361,6 +1363,12 @@ static int ads7846_probe(struct spi_device *spi)
 	if (err)
 		return err;
 
+	ts->sync = devm_gpiod_get_optional(dev, "sync", GPIOD_IN);
+	if (IS_ERR(ts->sync)) {
+		dev_err(dev, "Failed to get sync GPIO: %pe\n", ts->sync);
+		return PTR_ERR(ts->sync);
+	}
+
 	err = input_register_device(input_dev);
 	if (err)
 		return err;
diff --git a/include/linux/spi/ads7846.h b/include/linux/spi/ads7846.h
index a04c1c34c344..fa7c4f119023 100644
--- a/include/linux/spi/ads7846.h
+++ b/include/linux/spi/ads7846.h
@@ -38,7 +38,6 @@ struct ads7846_platform_data {
 	int	gpio_pendown_debounce;	/* platform specific debounce time for
 					 * the gpio_pendown */
 	int	(*get_pendown_state)(void);
-	void	(*wait_for_sync)(void);
 	bool	wakeup;
 	unsigned long irq_flags;
 };

-- 
2.42.0