[PATCH v1 0/2] clk: Rework initialization of i2c_device_ids

[PATCH v1 0/2] clk: Rework initialization of i2c_device_ids

[Uwe Kleine-König (The Capable Hub)]

Hello,

this series is a preparation for

	diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
	index 23ff24080dfd..aebd3a5e90af 100644
	--- a/include/linux/mod_devicetable.h
	+++ b/include/linux/mod_devicetable.h
	@@ -477,7 +477,11 @@ struct rpmsg_device_id {
	 
	 struct i2c_device_id {
		char name[I2C_NAME_SIZE];
	-	kernel_ulong_t driver_data;	/* Data private to the driver */
	+	union {
	+		/* Data private to the driver */
	+		kernel_ulong_t driver_data;
	+		const void *driver_data_ptr;
	+	};
	 };
	 
	 /* pci_epf */

and this requires that .driver_data is assigned via a named initializer
for static data. This requirement isn't a bad one because named
initializers are also much better readable than list initializers.

The union added to struct i2c_device_id enables further cleanups like:

	diff --git a/drivers/regulator/ad5398.c b/drivers/regulator/ad5398.c
	index 0123ca8157a8..84272ba65d08 100644
	--- a/drivers/regulator/ad5398.c
	+++ b/drivers/regulator/ad5398.c
	@@ -207,8 +207,8 @@ struct ad5398_current_data_format {
	 static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
	 
	 static const struct i2c_device_id ad5398_id[] = {
	-	{ .name = "ad5398", .driver_data = (kernel_ulong_t)&df_10_4_120 },
	-	{ .name = "ad5821", .driver_data = (kernel_ulong_t)&df_10_4_120 },
	+	{ .name = "ad5398", .driver_data_ptr = &df_10_4_120 },
	+	{ .name = "ad5821", .driver_data_ptr = &df_10_4_120 },
		{ }
	 };
	 MODULE_DEVICE_TABLE(i2c, ad5398_id);
	@@ -219,8 +219,7 @@ static int ad5398_probe(struct i2c_client *client)
		struct regulator_init_data *init_data = dev_get_platdata(&client->dev);
		struct regulator_config config = { };
		struct ad5398_chip_info *chip;
	-	const struct ad5398_current_data_format *df =
	-			(struct ad5398_current_data_format *)id->driver_data;
	+	const struct ad5398_current_data_format *df = id->driver_data_ptr;
	 
		chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
		if (!chip)

that are an improvement for readability (again!) and it keeps some
properties of the pointers (here: being const) without having to pay
attention for that. (I didn't find a good example in drivers/clk, so an
regulator driver was used to demonstrate the gain.)

My additional motivation for this effort is CHERI[1]. This is a hardware
extension that uses 128 bit pointers but unsigned long is still 64 bit.
So with CHERI you cannot store pointers in unsigned long variables.

The first patch drops unused assignments to .driver_data in one driver.
The second converts all clk drivers to use named initializers for
i2c_device_id.

Best regards
Uwe

Uwe Kleine-König (The Capable Hub) (2):
  clk: si5341: Drop unused i2c driver_data
  clk: Use named initializers for arrays of i2c_device_data

 drivers/clk/clk-cdce706.c      |  2 +-
 drivers/clk/clk-cdce925.c      |  8 ++++----
 drivers/clk/clk-cs2000-cp.c    |  4 ++--
 drivers/clk/clk-renesas-pcie.c |  6 +++---
 drivers/clk/clk-si514.c        |  2 +-
 drivers/clk/clk-si521xx.c      |  6 +++---
 drivers/clk/clk-si5341.c       | 10 +++++-----
 drivers/clk/clk-si5351.c       |  8 ++++----
 drivers/clk/clk-si544.c        |  6 +++---
 drivers/clk/clk-si570.c        |  8 ++++----
 drivers/clk/clk-versaclock5.c  | 16 ++++++++--------
 drivers/clk/clk-versaclock7.c  |  4 ++--
 12 files changed, 40 insertions(+), 40 deletions(-)


base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
-- 
2.47.3

[PATCH v1 1/2] clk: si5341: Drop unused i2c driver_data

[Uwe Kleine-König (The Capable Hub)]

The driver doesn't make use of the value that was explicitly assigned to
the .driver_data member. Drop the assignment.

Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>
---
 drivers/clk/clk-si5341.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/clk-si5341.c b/drivers/clk/clk-si5341.c
index 2499b771cd83..5311c23532b4 100644
--- a/drivers/clk/clk-si5341.c
+++ b/drivers/clk/clk-si5341.c
@@ -1825,11 +1825,11 @@ static void si5341_remove(struct i2c_client *client)
 }
 
 static const struct i2c_device_id si5341_id[] = {
-	{ "si5340", 0 },
-	{ "si5341", 1 },
-	{ "si5342", 2 },
-	{ "si5344", 4 },
-	{ "si5345", 5 },
+	{ .name = "si5340" },
+	{ .name = "si5341" },
+	{ .name = "si5342" },
+	{ .name = "si5344" },
+	{ .name = "si5345" },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, si5341_id);
-- 
2.47.3

[PATCH v1 2/2] clk: Use named initializers for arrays of i2c_device_data

[Uwe Kleine-König (The Capable Hub)]

While being less compact, using named initializers allows to more easily
see which members of the structs are assigned which value without having
to lookup the declaration of the struct. And it's also more robust
against changes to the struct definition.

The mentioned robustness is relevant for a planned change to struct
i2c_device_id that replaces .driver_data by an anonymous union.

While touching all these arrays, unify usage of whitespace and commas.

This patch doesn't modify the compiled arrays, only their representation
in source form benefits. The former was confirmed with x86 and arm64
builds.

Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>
---
 drivers/clk/clk-cdce706.c      |  2 +-
 drivers/clk/clk-cdce925.c      |  8 ++++----
 drivers/clk/clk-cs2000-cp.c    |  4 ++--
 drivers/clk/clk-renesas-pcie.c |  6 +++---
 drivers/clk/clk-si514.c        |  2 +-
 drivers/clk/clk-si521xx.c      |  6 +++---
 drivers/clk/clk-si5351.c       |  8 ++++----
 drivers/clk/clk-si544.c        |  6 +++---
 drivers/clk/clk-si570.c        |  8 ++++----
 drivers/clk/clk-versaclock5.c  | 16 ++++++++--------
 drivers/clk/clk-versaclock7.c  |  4 ++--
 11 files changed, 35 insertions(+), 35 deletions(-)

diff --git a/drivers/clk/clk-cdce706.c b/drivers/clk/clk-cdce706.c
index a495d313b02f..425a0481f46f 100644
--- a/drivers/clk/clk-cdce706.c
+++ b/drivers/clk/clk-cdce706.c
@@ -680,7 +680,7 @@ MODULE_DEVICE_TABLE(of, cdce706_dt_match);
 #endif
 
 static const struct i2c_device_id cdce706_id[] = {
-	{ "cdce706" },
+	{ .name = "cdce706" },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, cdce706_id);
diff --git a/drivers/clk/clk-cdce925.c b/drivers/clk/clk-cdce925.c
index 0b2ad21e6e4d..30d0493c7718 100644
--- a/drivers/clk/clk-cdce925.c
+++ b/drivers/clk/clk-cdce925.c
@@ -826,10 +826,10 @@ static const struct clk_cdce925_chip_info clk_cdce949_info = {
 };
 
 static const struct i2c_device_id cdce925_id[] = {
-	{ "cdce913", (kernel_ulong_t)&clk_cdce913_info },
-	{ "cdce925", (kernel_ulong_t)&clk_cdce925_info },
-	{ "cdce937", (kernel_ulong_t)&clk_cdce937_info },
-	{ "cdce949", (kernel_ulong_t)&clk_cdce949_info },
+	{ .name = "cdce913", .driver_data = (kernel_ulong_t)&clk_cdce913_info },
+	{ .name = "cdce925", .driver_data = (kernel_ulong_t)&clk_cdce925_info },
+	{ .name = "cdce937", .driver_data = (kernel_ulong_t)&clk_cdce937_info },
+	{ .name = "cdce949", .driver_data = (kernel_ulong_t)&clk_cdce949_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, cdce925_id);
diff --git a/drivers/clk/clk-cs2000-cp.c b/drivers/clk/clk-cs2000-cp.c
index 8800472ba63f..fd277dcefad7 100644
--- a/drivers/clk/clk-cs2000-cp.c
+++ b/drivers/clk/clk-cs2000-cp.c
@@ -122,8 +122,8 @@ static const struct of_device_id cs2000_of_match[] = {
 MODULE_DEVICE_TABLE(of, cs2000_of_match);
 
 static const struct i2c_device_id cs2000_id[] = {
-	{ "cs2000-cp", },
-	{}
+	{ .name = "cs2000-cp" },
+	{ }
 };
 MODULE_DEVICE_TABLE(i2c, cs2000_id);
 
diff --git a/drivers/clk/clk-renesas-pcie.c b/drivers/clk/clk-renesas-pcie.c
index aa108df12e44..b59607e3e659 100644
--- a/drivers/clk/clk-renesas-pcie.c
+++ b/drivers/clk/clk-renesas-pcie.c
@@ -395,9 +395,9 @@ static const struct rs9_chip_info renesas_9fgv0841_info = {
 };
 
 static const struct i2c_device_id rs9_id[] = {
-	{ "9fgv0241", .driver_data = (kernel_ulong_t)&renesas_9fgv0241_info },
-	{ "9fgv0441", .driver_data = (kernel_ulong_t)&renesas_9fgv0441_info },
-	{ "9fgv0841", .driver_data = (kernel_ulong_t)&renesas_9fgv0841_info },
+	{ .name = "9fgv0241", .driver_data = (kernel_ulong_t)&renesas_9fgv0241_info },
+	{ .name = "9fgv0441", .driver_data = (kernel_ulong_t)&renesas_9fgv0441_info },
+	{ .name = "9fgv0841", .driver_data = (kernel_ulong_t)&renesas_9fgv0841_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, rs9_id);
diff --git a/drivers/clk/clk-si514.c b/drivers/clk/clk-si514.c
index f61590d70575..c0b433ad9372 100644
--- a/drivers/clk/clk-si514.c
+++ b/drivers/clk/clk-si514.c
@@ -379,7 +379,7 @@ static int si514_probe(struct i2c_client *client)
 }
 
 static const struct i2c_device_id si514_id[] = {
-	{ "si514" },
+	{ .name = "si514" },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, si514_id);
diff --git a/drivers/clk/clk-si521xx.c b/drivers/clk/clk-si521xx.c
index 4ed4e1a5f4f2..e41d922437ee 100644
--- a/drivers/clk/clk-si521xx.c
+++ b/drivers/clk/clk-si521xx.c
@@ -365,9 +365,9 @@ static int __maybe_unused si521xx_resume(struct device *dev)
 }
 
 static const struct i2c_device_id si521xx_id[] = {
-	{ "si52144", .driver_data = SI521XX_OE_MAP(0x5, 0xc0) },
-	{ "si52146", .driver_data = SI521XX_OE_MAP(0x15, 0xe0) },
-	{ "si52147", .driver_data = SI521XX_OE_MAP(0x17, 0xf8) },
+	{ .name = "si52144", .driver_data = SI521XX_OE_MAP(0x5, 0xc0) },
+	{ .name = "si52146", .driver_data = SI521XX_OE_MAP(0x15, 0xe0) },
+	{ .name = "si52147", .driver_data = SI521XX_OE_MAP(0x17, 0xf8) },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, si521xx_id);
diff --git a/drivers/clk/clk-si5351.c b/drivers/clk/clk-si5351.c
index e755db545e2e..20b0c3c48b86 100644
--- a/drivers/clk/clk-si5351.c
+++ b/drivers/clk/clk-si5351.c
@@ -1425,10 +1425,10 @@ si53351_of_clk_get(struct of_phandle_args *clkspec, void *data)
 #endif /* CONFIG_OF */
 
 static const struct i2c_device_id si5351_i2c_ids[] = {
-	{ "si5351a", SI5351_VARIANT_A },
-	{ "si5351a-msop", SI5351_VARIANT_A3 },
-	{ "si5351b", SI5351_VARIANT_B },
-	{ "si5351c", SI5351_VARIANT_C },
+	{ .name = "si5351a", .driver_data = SI5351_VARIANT_A },
+	{ .name = "si5351a-msop", .driver_data = SI5351_VARIANT_A3 },
+	{ .name = "si5351b", .driver_data = SI5351_VARIANT_B },
+	{ .name = "si5351c", .driver_data = SI5351_VARIANT_C },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, si5351_i2c_ids);
diff --git a/drivers/clk/clk-si544.c b/drivers/clk/clk-si544.c
index 09c06ecec1a5..f45f3f73aa82 100644
--- a/drivers/clk/clk-si544.c
+++ b/drivers/clk/clk-si544.c
@@ -479,9 +479,9 @@ static int si544_probe(struct i2c_client *client)
 }
 
 static const struct i2c_device_id si544_id[] = {
-	{ "si544a", 1500000000 },
-	{ "si544b", 800000000 },
-	{ "si544c", 350000000 },
+	{ .name = "si544a", .driver_data = 1500000000 },
+	{ .name = "si544b", .driver_data = 800000000 },
+	{ .name = "si544c", .driver_data = 350000000 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, si544_id);
diff --git a/drivers/clk/clk-si570.c b/drivers/clk/clk-si570.c
index b0b1830dd430..3063e38c66da 100644
--- a/drivers/clk/clk-si570.c
+++ b/drivers/clk/clk-si570.c
@@ -503,10 +503,10 @@ static const struct clk_si570_info clk_si590_info = {
 };
 
 static const struct i2c_device_id si570_id[] = {
-	{ "si570", (kernel_ulong_t)&clk_si570_info },
-	{ "si571", (kernel_ulong_t)&clk_si570_info },
-	{ "si598", (kernel_ulong_t)&clk_si590_info },
-	{ "si599", (kernel_ulong_t)&clk_si590_info },
+	{ .name = "si570", .driver_data = (kernel_ulong_t)&clk_si570_info },
+	{ .name = "si571", .driver_data = (kernel_ulong_t)&clk_si570_info },
+	{ .name = "si598", .driver_data = (kernel_ulong_t)&clk_si590_info },
+	{ .name = "si599", .driver_data = (kernel_ulong_t)&clk_si590_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, si570_id);
diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
index 57228e88e81d..484b02726b3a 100644
--- a/drivers/clk/clk-versaclock5.c
+++ b/drivers/clk/clk-versaclock5.c
@@ -1311,14 +1311,14 @@ static const struct vc5_chip_info idt_5p49v6975_info = {
 };
 
 static const struct i2c_device_id vc5_id[] = {
-	{ "5p49v5923", .driver_data = (kernel_ulong_t)&idt_5p49v5923_info },
-	{ "5p49v5925", .driver_data = (kernel_ulong_t)&idt_5p49v5925_info },
-	{ "5p49v5933", .driver_data = (kernel_ulong_t)&idt_5p49v5933_info },
-	{ "5p49v5935", .driver_data = (kernel_ulong_t)&idt_5p49v5935_info },
-	{ "5p49v60", .driver_data = (kernel_ulong_t)&idt_5p49v60_info },
-	{ "5p49v6901", .driver_data = (kernel_ulong_t)&idt_5p49v6901_info },
-	{ "5p49v6965", .driver_data = (kernel_ulong_t)&idt_5p49v6965_info },
-	{ "5p49v6975", .driver_data = (kernel_ulong_t)&idt_5p49v6975_info },
+	{ .name = "5p49v5923", .driver_data = (kernel_ulong_t)&idt_5p49v5923_info },
+	{ .name = "5p49v5925", .driver_data = (kernel_ulong_t)&idt_5p49v5925_info },
+	{ .name = "5p49v5933", .driver_data = (kernel_ulong_t)&idt_5p49v5933_info },
+	{ .name = "5p49v5935", .driver_data = (kernel_ulong_t)&idt_5p49v5935_info },
+	{ .name = "5p49v60", .driver_data = (kernel_ulong_t)&idt_5p49v60_info },
+	{ .name = "5p49v6901", .driver_data = (kernel_ulong_t)&idt_5p49v6901_info },
+	{ .name = "5p49v6965", .driver_data = (kernel_ulong_t)&idt_5p49v6965_info },
+	{ .name = "5p49v6975", .driver_data = (kernel_ulong_t)&idt_5p49v6975_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, vc5_id);
diff --git a/drivers/clk/clk-versaclock7.c b/drivers/clk/clk-versaclock7.c
index adcc603e3259..e0b57e7022b2 100644
--- a/drivers/clk/clk-versaclock7.c
+++ b/drivers/clk/clk-versaclock7.c
@@ -1288,8 +1288,8 @@ static const struct regmap_config vc7_regmap_config = {
 };
 
 static const struct i2c_device_id vc7_i2c_id[] = {
-	{ "rc21008a", .driver_data = (kernel_ulong_t)&vc7_rc21008a_info },
-	{}
+	{ .name = "rc21008a", .driver_data = (kernel_ulong_t)&vc7_rc21008a_info },
+	{ }
 };
 MODULE_DEVICE_TABLE(i2c, vc7_i2c_id);
 
-- 
2.47.3