[PATCH v3] backlight: lms283gf05: Convert to GPIO descriptors

[PATCH v3] backlight: lms283gf05: Convert to GPIO descriptors

[Linus Walleij]

This converts the lms283gf05 backlight driver to use GPIO
descriptors and switches the single PXA Palm Z2 device
over to defining these.

Since the platform data was only used to convey GPIO
information we can delete the platform data header.

Notice that we define the proper active low semantics in
the board file GPIO descriptor table (active low) and
assert the reset line by bringing it to "1" (asserted).

Cc: Marek Vasut <marex@denx.de>
Cc: Daniel Mack <daniel@zonque.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v2->v3:
- Fix a use-before-allocated bug discovered by compile tests.
- Remove unused ret variable as autobuilders complained.
ChangeLog v1->v2:
- Bring up the GPIO de-asserted in probe()

Marek: I saw this was written by you, are you regularly
testing the Z2 device?
---
 arch/arm/mach-pxa/z2.c               | 12 +++++---
 drivers/video/backlight/lms283gf05.c | 42 +++++++++++-----------------
 include/linux/spi/lms283gf05.h       | 16 -----------
 3 files changed, 24 insertions(+), 46 deletions(-)
 delete mode 100644 include/linux/spi/lms283gf05.h

diff --git a/arch/arm/mach-pxa/z2.c b/arch/arm/mach-pxa/z2.c
index 21fd76bb09cd..89eb5243c85f 100644
--- a/arch/arm/mach-pxa/z2.c
+++ b/arch/arm/mach-pxa/z2.c
@@ -20,7 +20,6 @@
 #include <linux/spi/spi.h>
 #include <linux/spi/pxa2xx_spi.h>
 #include <linux/spi/libertas_spi.h>
-#include <linux/spi/lms283gf05.h>
 #include <linux/power_supply.h>
 #include <linux/mtd/physmap.h>
 #include <linux/gpio.h>
@@ -578,8 +577,13 @@ static struct pxa2xx_spi_chip lms283_chip_info = {
 	.gpio_cs	= GPIO88_ZIPITZ2_LCD_CS,
 };
 
-static const struct lms283gf05_pdata lms283_pdata = {
-	.reset_gpio	= GPIO19_ZIPITZ2_LCD_RESET,
+static struct gpiod_lookup_table lms283_gpio_table = {
+	.dev_id = "spi2.0", /* SPI bus 2 chip select 0 */
+	.table = {
+		GPIO_LOOKUP("gpio-pxa", GPIO19_ZIPITZ2_LCD_RESET,
+			    "reset", GPIO_ACTIVE_LOW),
+		{ },
+	},
 };
 
 static struct spi_board_info spi_board_info[] __initdata = {
@@ -595,7 +599,6 @@ static struct spi_board_info spi_board_info[] __initdata = {
 {
 	.modalias		= "lms283gf05",
 	.controller_data	= &lms283_chip_info,
-	.platform_data		= &lms283_pdata,
 	.max_speed_hz		= 400000,
 	.bus_num		= 2,
 	.chip_select		= 0,
@@ -615,6 +618,7 @@ static void __init z2_spi_init(void)
 {
 	pxa2xx_set_spi_info(1, &pxa_ssp1_master_info);
 	pxa2xx_set_spi_info(2, &pxa_ssp2_master_info);
+	gpiod_add_lookup_table(&lms283_gpio_table);
 	spi_register_board_info(spi_board_info, ARRAY_SIZE(spi_board_info));
 }
 #else
diff --git a/drivers/video/backlight/lms283gf05.c b/drivers/video/backlight/lms283gf05.c
index 0e45685bcc1c..529c415eb03b 100644
--- a/drivers/video/backlight/lms283gf05.c
+++ b/drivers/video/backlight/lms283gf05.c
@@ -9,16 +9,16 @@
 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/lcd.h>
 
 #include <linux/spi/spi.h>
-#include <linux/spi/lms283gf05.h>
 #include <linux/module.h>
 
 struct lms283gf05_state {
 	struct spi_device	*spi;
 	struct lcd_device	*ld;
+	struct gpio_desc	*reset;
 };
 
 struct lms283gf05_seq {
@@ -90,13 +90,13 @@ static const struct lms283gf05_seq disp_pdwnseq[] = {
 };
 
 
-static void lms283gf05_reset(unsigned long gpio, bool inverted)
+static void lms283gf05_reset(struct gpio_desc *gpiod)
 {
-	gpio_set_value(gpio, !inverted);
+	gpiod_set_value(gpiod, 0); /* De-asserted */
 	mdelay(100);
-	gpio_set_value(gpio, inverted);
+	gpiod_set_value(gpiod, 1); /* Asserted */
 	mdelay(20);
-	gpio_set_value(gpio, !inverted);
+	gpiod_set_value(gpiod, 0); /* De-asserted */
 	mdelay(20);
 }
 
@@ -125,18 +125,15 @@ static int lms283gf05_power_set(struct lcd_device *ld, int power)
 {
 	struct lms283gf05_state *st = lcd_get_data(ld);
 	struct spi_device *spi = st->spi;
-	struct lms283gf05_pdata *pdata = dev_get_platdata(&spi->dev);
 
 	if (power <= FB_BLANK_NORMAL) {
-		if (pdata)
-			lms283gf05_reset(pdata->reset_gpio,
-					pdata->reset_inverted);
+		if (st->reset)
+			lms283gf05_reset(st->reset);
 		lms283gf05_toggle(spi, disp_initseq, ARRAY_SIZE(disp_initseq));
 	} else {
 		lms283gf05_toggle(spi, disp_pdwnseq, ARRAY_SIZE(disp_pdwnseq));
-		if (pdata)
-			gpio_set_value(pdata->reset_gpio,
-					pdata->reset_inverted);
+		if (st->reset)
+			gpiod_set_value(st->reset, 1); /* Asserted */
 	}
 
 	return 0;
@@ -150,24 +147,17 @@ static struct lcd_ops lms_ops = {
 static int lms283gf05_probe(struct spi_device *spi)
 {
 	struct lms283gf05_state *st;
-	struct lms283gf05_pdata *pdata = dev_get_platdata(&spi->dev);
 	struct lcd_device *ld;
-	int ret = 0;
-
-	if (pdata != NULL) {
-		ret = devm_gpio_request_one(&spi->dev, pdata->reset_gpio,
-				GPIOF_DIR_OUT | (!pdata->reset_inverted ?
-				GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
-				"LMS283GF05 RESET");
-		if (ret)
-			return ret;
-	}
 
 	st = devm_kzalloc(&spi->dev, sizeof(struct lms283gf05_state),
 				GFP_KERNEL);
 	if (st == NULL)
 		return -ENOMEM;
 
+	st->reset = gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
+	if (st->reset)
+		gpiod_set_consumer_name(st->reset, "LMS283GF05 RESET");
+
 	ld = devm_lcd_device_register(&spi->dev, "lms283gf05", &spi->dev, st,
 					&lms_ops);
 	if (IS_ERR(ld))
@@ -179,8 +169,8 @@ static int lms283gf05_probe(struct spi_device *spi)
 	spi_set_drvdata(spi, st);
 
 	/* kick in the LCD */
-	if (pdata)
-		lms283gf05_reset(pdata->reset_gpio, pdata->reset_inverted);
+	if (st->reset)
+		lms283gf05_reset(st->reset);
 	lms283gf05_toggle(spi, disp_initseq, ARRAY_SIZE(disp_initseq));
 
 	return 0;
diff --git a/include/linux/spi/lms283gf05.h b/include/linux/spi/lms283gf05.h
deleted file mode 100644
index f237b2d062e9..000000000000
--- a/include/linux/spi/lms283gf05.h
+++ /dev/null
@@ -1,16 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * lms283gf05.h - Platform glue for Samsung LMS283GF05 LCD
- *
- * Copyright (C) 2009 Marek Vasut <marek.vasut@gmail.com>
-*/
-
-#ifndef _INCLUDE_LINUX_SPI_LMS283GF05_H_
-#define _INCLUDE_LINUX_SPI_LMS283GF05_H_
-
-struct lms283gf05_pdata {
-	unsigned long	reset_gpio;
-	bool		reset_inverted;
-};
-
-#endif /* _INCLUDE_LINUX_SPI_LMS283GF05_H_ */
-- 
2.25.2

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Re: [PATCH v3] backlight: lms283gf05: Convert to GPIO descriptors

[Daniel Thompson]

On Wed, Apr 29, 2020 at 02:43:54PM +0200, Linus Walleij wrote:
> This converts the lms283gf05 backlight driver to use GPIO
> descriptors and switches the single PXA Palm Z2 device
> over to defining these.
> 
> Since the platform data was only used to convey GPIO
> information we can delete the platform data header.
> 
> Notice that we define the proper active low semantics in
> the board file GPIO descriptor table (active low) and
> assert the reset line by bringing it to "1" (asserted).
> 
> Cc: Marek Vasut <marex@denx.de>
> Cc: Daniel Mack <daniel@zonque.org>
> Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
> Cc: Robert Jarzmik <robert.jarzmik@free.fr>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> ChangeLog v2->v3:
> - Fix a use-before-allocated bug discovered by compile tests.
> - Remove unused ret variable as autobuilders complained.
> ChangeLog v1->v2:
> - Bring up the GPIO de-asserted in probe()
> 
> Marek: I saw this was written by you, are you regularly
> testing the Z2 device?
> ---
>  arch/arm/mach-pxa/z2.c               | 12 +++++---
>  drivers/video/backlight/lms283gf05.c | 42 +++++++++++-----------------
>  include/linux/spi/lms283gf05.h       | 16 -----------
>  3 files changed, 24 insertions(+), 46 deletions(-)
>  delete mode 100644 include/linux/spi/lms283gf05.h
> 
> diff --git a/drivers/video/backlight/lms283gf05.c b/drivers/video/backlight/lms283gf05.c
> index 0e45685bcc1c..529c415eb03b 100644
> --- a/drivers/video/backlight/lms283gf05.c
> +++ b/drivers/video/backlight/lms283gf05.c
> @@ -150,24 +147,17 @@ static struct lcd_ops lms_ops = {
>  static int lms283gf05_probe(struct spi_device *spi)
>  {
>  	struct lms283gf05_state *st;
> -	struct lms283gf05_pdata *pdata = dev_get_platdata(&spi->dev);
>  	struct lcd_device *ld;
> -	int ret = 0;
> -
> -	if (pdata != NULL) {
> -		ret = devm_gpio_request_one(&spi->dev, pdata->reset_gpio,
> -				GPIOF_DIR_OUT | (!pdata->reset_inverted ?
> -				GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
> -				"LMS283GF05 RESET");
> -		if (ret)
> -			return ret;
> -	}
>  
>  	st = devm_kzalloc(&spi->dev, sizeof(struct lms283gf05_state),
>  				GFP_KERNEL);
>  	if (st == NULL)
>  		return -ENOMEM;
>  
> +	st->reset = gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
> +	if (st->reset)
> +		gpiod_set_consumer_name(st->reset, "LMS283GF05 RESET");
> +


Sorry, I should have picked this up before but shouldn't st->reset have
an IS_ERR() check. There are certainly no other examples of this API
within the kernel that are not followed by an IS_ERR() check!

In fact I understood that the gpiod API is intended to tolerate NULLs
so I would have expected this code to be:

	st->reset = gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
	if (IS_ERR(st->reset))
		return PTR_ERR(st->reset);
	gpiod_set_consumer_name(st->reset, "LMS283GF05 RESET");


>  	ld = devm_lcd_device_register(&spi->dev, "lms283gf05", &spi->dev, st,
>  					&lms_ops);
>  	if (IS_ERR(ld))


Daniel.
> 
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