[PATCH v1 0/2] hwmon:

["Uwe Kleine-König (The Capable Hub)" <u.kleine-koenig@baylibre.com>]

Hello,

this series targets to use named initializers for platform_device_id
arrays. In general these are better readable for humans and more robust
to changes in the respective struct definition.

This robustness is needed as I want to do

	diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
	--- a/include/linux/mod_devicetable.h
	+++ b/include/linux/mod_devicetable.h
	@@ -610,4 +610,7 @@ struct dmi_system_id {
	 struct platform_device_id {
		char name[PLATFORM_NAME_SIZE];
	-	kernel_ulong_t driver_data;
	+	union {
	+		kernel_ulong_t driver_data;
	+		const void *driver_data_ptr;
	+	};
	 };

which allows dropping several casts and eases porting CHERI to mainline
linux. A possible follow-up change is the following example:

	diff --git a/drivers/gpio/gpio-pxa.c b/drivers/gpio/gpio-pxa.c
	index 5d61053e0596..03bc8e859d73 100644
	--- a/drivers/gpio/gpio-pxa.c
	+++ b/drivers/gpio/gpio-pxa.c
	@@ -534,7 +534,7 @@ static struct irq_chip pxa_muxed_gpio_chip = {
	 static int pxa_gpio_nums(struct platform_device *pdev)
	 {
		const struct platform_device_id *id = platform_get_device_id(pdev);
	-	struct pxa_gpio_id *pxa_id = (struct pxa_gpio_id *)id->driver_data;
	+	struct pxa_gpio_id *pxa_id = id->driver_data_ptr;
		int count = 0;
	 
		switch (pxa_id->type) {
	@@ -708,14 +708,14 @@ static int pxa_gpio_probe(struct platform_device *pdev)
	 }
	 
	 static const struct platform_device_id gpio_id_table[] = {
	-	{ .name = "pxa25x-gpio",	.driver_data = (unsigned long)&pxa25x_id },
	-	{ .name = "pxa26x-gpio",	.driver_data = (unsigned long)&pxa26x_id },
	-	{ .name = "pxa27x-gpio",	.driver_data = (unsigned long)&pxa27x_id },
	-	{ .name = "pxa3xx-gpio",	.driver_data = (unsigned long)&pxa3xx_id },
	-	{ .name = "pxa93x-gpio",	.driver_data = (unsigned long)&pxa93x_id },
	-	{ .name = "mmp-gpio",		.driver_data = (unsigned long)&mmp_id },
	-	{ .name = "mmp2-gpio",		.driver_data = (unsigned long)&mmp2_id },
	-	{ .name = "pxa1928-gpio",	.driver_data = (unsigned long)&pxa1928_id },
	+	{ .name = "pxa25x-gpio",	.driver_data_ptr = &pxa25x_id },
	+	{ .name = "pxa26x-gpio",	.driver_data_ptr = &pxa26x_id },
	+	{ .name = "pxa27x-gpio",	.driver_data_ptr = &pxa27x_id },
	+	{ .name = "pxa3xx-gpio",	.driver_data_ptr = &pxa3xx_id },
	+	{ .name = "pxa93x-gpio",	.driver_data_ptr = &pxa93x_id },
	+	{ .name = "mmp-gpio",		.driver_data_ptr = &mmp_id },
	+	{ .name = "mmp2-gpio",		.driver_data_ptr = &mmp2_id },
	+	{ .name = "pxa1928-gpio",	.driver_data_ptr = &pxa1928_id },
		{ }
	 };
 
increasing readability due to less casting. Also this results in the
compiler warning:

	drivers/gpio/gpio-pxa.c: In function ‘pxa_gpio_nums’:
	drivers/gpio/gpio-pxa.c:537:38: error: initialization discards ‘const’ qualifier from pointer target type [-Werror=discarded-qualifiers]
	  537 |         struct pxa_gpio_id *pxa_id = id->driver_data_ptr;
	      |                                      ^~

which is a good thing as adding the needed const to fix this warning
improves type safety. (There is no hwmon driver that benefits from this
change, so a driver from a different subsystem was used to show the
benefit.)

Best regards
Uwe

Uwe Kleine-König (The Capable Hub) (2):
  hwmon: cros_ec: Drop unused assignment of platform_device_id driver
    data
  hwmon: Use named initializers for platform_device_id arrays

 drivers/hwmon/cros_ec_hwmon.c  |  4 ++--
 drivers/hwmon/max197.c         |  4 ++--
 drivers/hwmon/ntc_thermistor.c | 24 ++++++++++++------------
 drivers/hwmon/sht15.c          | 10 +++++-----
 4 files changed, 21 insertions(+), 21 deletions(-)


base-commit: e7e28506af98ce4e1059e5ec59334b335c00a246
-- 
2.47.3