[PATCH v2 0/2] Add support for Si549 programmable clock

[PATCH v2 0/2] Add support for Si549 programmable clock

[Pavel Löbl]

This adds support for Si549 programmable oscillator. It's almost the
same as already supported Si544, except it uses different internal
oscillator frequency.

So new compatible strings are added, and driver data is extended
to carry both maximum output frequency and internal xtal frequency.

Changes in v2:
  Fixed obvious stuff found by Sashiko (extra unused struct member),
  removing unneeded data argument to calculation functions, xo_freq
  is now passed in settings struct.


Pavel Löbl (2):
  dt-bindings: clock: si544: add si549 compatible
  clk: si544: add support for si549

 .../bindings/clock/silabs,si544.yaml          | 10 ++-
 drivers/clk/Kconfig                           |  6 +-
 drivers/clk/clk-si544.c                       | 82 +++++++++++++++----
 3 files changed, 75 insertions(+), 23 deletions(-)

-- 
2.53.0

[PATCH v2 1/2] dt-bindings: clock: si544: add si549 compatible

[Pavel Löbl]

Adding Si549 compatible, which uses different internal oscillator
frequency. Like in Si544 case, there are three types ending with
latters a,b and c. Each with different maximum output frequency.

Also fix datasheet links after Silicon Labs acquisition by
Skyworks Solutions.

Signed-off-by: Pavel Löbl <pavel@loebl.cz>
---
 .../devicetree/bindings/clock/silabs,si544.yaml        | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/clock/silabs,si544.yaml b/Documentation/devicetree/bindings/clock/silabs,si544.yaml
index f87e71867108..c58171f1bc5b 100644
--- a/Documentation/devicetree/bindings/clock/silabs,si544.yaml
+++ b/Documentation/devicetree/bindings/clock/silabs,si544.yaml
@@ -4,7 +4,7 @@
 $id: http://devicetree.org/schemas/clock/silabs,si544.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Silicon Labs SI514/SI544 clock generator
+title: Silicon Labs SI514/SI544/SI549 clock generator
 
 maintainers:
   - Mike Looijmans <mike.looijmans@topic.nl>
@@ -13,8 +13,9 @@ description: >
   Silicon Labs 514/544 programmable I2C clock generator. Details about the device
   can be found in the datasheet:
 
-    https://www.silabs.com/Support%20Documents/TechnicalDocs/si514.pdf
-    https://www.silabs.com/documents/public/data-sheets/si544-datasheet.pdf
+    https://www.skyworksinc.com/-/media/Skyworks/SL/documents/public/data-sheets/Si514.pdf
+    https://www.skyworksinc.com/-/media/Skyworks/SL/documents/public/data-sheets/si544-datasheet.pdf
+    https://www.skyworksinc.com/-/media/Skyworks/SL/documents/public/data-sheets/si549-datasheet.pdf
 
 properties:
   compatible:
@@ -23,6 +24,9 @@ properties:
       - silabs,si544a
       - silabs,si544b
       - silabs,si544c
+      - silabs,si549a
+      - silabs,si549b
+      - silabs,si549c
 
   reg:
     maxItems: 1
-- 
2.53.0

[PATCH v2 2/2] clk: si544: add support for si549

[Pavel Löbl]

Add support for Si549, which only differs from Si544 in internal
oscilator frequency. Si549 also comes in three types A,B and C.
Each having different maximum output frequency.

This patch also fixes maximum frequency of Si544 C. Which should
be 325MHz according to datasheet.

Signed-off-by: Pavel Löbl <pavel@loebl.cz>
---
 drivers/clk/Kconfig     |  6 +--
 drivers/clk/clk-si544.c | 82 ++++++++++++++++++++++++++++++++---------
 2 files changed, 68 insertions(+), 20 deletions(-)

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 1717ce75a907..159f546a48f0 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -155,12 +155,12 @@ config COMMON_CLK_SI514
 	  generator.
 
 config COMMON_CLK_SI544
-	tristate "Clock driver for SiLabs 544 devices"
+	tristate "Clock driver for SiLabs 544 and compatible devices"
 	depends on I2C
 	select REGMAP_I2C
 	help
-	  This driver supports the Silicon Labs 544 programmable clock
-	  generator.
+	  This driver supports the Silicon Labs 544/549 programmable clock
+	  generators.
 
 config COMMON_CLK_SI570
 	tristate "Clock driver for SiLabs 570 and compatible devices"
diff --git a/drivers/clk/clk-si544.c b/drivers/clk/clk-si544.c
index 09c06ecec1a5..b13aeead9c02 100644
--- a/drivers/clk/clk-si544.c
+++ b/drivers/clk/clk-si544.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Driver for Silicon Labs Si544 Programmable Oscillator
+ * Driver for Silicon Labs Si544/Si549 Programmable Oscillator
  * Copyright (C) 2018 Topic Embedded Products
  * Author: Mike Looijmans <mike.looijmans@topic.nl>
  */
@@ -40,7 +40,9 @@
 #define SI544_MIN_FREQ	    200000U
 
 /* Si544 Internal oscillator runs at 55.05 MHz */
-#define FXO		  55050000U
+#define SI544_XO_FREQ	55050000U
+/* Si549 Internal oscilator runs at 152.60 MHz */
+#define SI549_XO_FREQ	152600000U
 
 /* VCO range is 10.8 .. 12.1 GHz, max depends on speed grade */
 #define FVCO_MIN       10800000000ULL
@@ -56,11 +58,16 @@
 #define DELTA_M_FRAC_NUM	19
 #define DELTA_M_FRAC_DEN	20000
 
+struct si544_clk_desc {
+	unsigned long max_freq;
+	unsigned long xo_freq;
+};
+
 struct clk_si544 {
 	struct clk_hw hw;
 	struct regmap *regmap;
 	struct i2c_client *i2c_client;
-	unsigned long  max_freq;
+	const struct si544_clk_desc *chip_info;
 };
 #define to_clk_si544(_hw)	container_of(_hw, struct clk_si544, hw)
 
@@ -79,6 +86,7 @@ struct clk_si544_muldiv {
 	u16 hs_div;
 	u8 ls_div_bits;
 	s32 delta_m;
+	u32 xo_freq;
 };
 
 /* Enables or disables the output driver */
@@ -145,6 +153,8 @@ static int si544_get_muldiv(struct clk_si544 *data,
 	settings->delta_m = reg[0] << 8 | reg[1] << 16 | reg[2] << 24;
 	settings->delta_m >>= 8;
 
+	settings->xo_freq = data->chip_info->xo_freq;
+
 	return 0;
 }
 
@@ -193,7 +203,7 @@ static bool is_valid_frequency(const struct clk_si544 *data,
 	if (frequency < SI544_MIN_FREQ)
 		return false;
 
-	return frequency <= data->max_freq;
+	return frequency <= data->chip_info->max_freq;
 }
 
 /* Calculate divider settings for a given frequency */
@@ -201,6 +211,7 @@ static int si544_calc_muldiv(struct clk_si544_muldiv *settings,
 	unsigned long frequency)
 {
 	u64 vco;
+	u32 fxo = settings->xo_freq;
 	u32 ls_freq;
 	u32 tmp;
 	u8 res;
@@ -238,13 +249,13 @@ static int si544_calc_muldiv(struct clk_si544_muldiv *settings,
 	vco = (u64)ls_freq * settings->hs_div;
 
 	/* Calculate the integer part of the feedback divider */
-	tmp = do_div(vco, FXO);
+	tmp = do_div(vco, fxo);
 	settings->fb_div_int = vco;
 
 	/* And the fractional bits using the remainder */
 	vco = (u64)tmp << 32;
-	vco += FXO / 2; /* Round to nearest multiple */
-	do_div(vco, FXO);
+	vco += fxo / 2; /* Round to nearest multiple */
+	do_div(vco, fxo);
 	settings->fb_div_frac = vco;
 
 	/* Reset the frequency adjustment */
@@ -258,15 +269,16 @@ static unsigned long si544_calc_center_rate(
 		const struct clk_si544_muldiv *settings)
 {
 	u32 d = settings->hs_div * BIT(settings->ls_div_bits);
+	u32 fxo = settings->xo_freq;
 	u64 vco;
 
 	/* Calculate VCO from the fractional part */
-	vco = (u64)settings->fb_div_frac * FXO;
-	vco += (FXO / 2);
+	vco = (u64)settings->fb_div_frac * fxo;
+	vco += (fxo / 2);
 	vco >>= 32;
 
 	/* Add the integer part of the VCO frequency */
-	vco += (u64)settings->fb_div_int * FXO;
+	vco += (u64)settings->fb_div_int * fxo;
 
 	/* Apply divider to obtain the generated frequency */
 	do_div(vco, d);
@@ -446,7 +458,7 @@ static int si544_probe(struct i2c_client *client)
 	init.num_parents = 0;
 	data->hw.init = &init;
 	data->i2c_client = client;
-	data->max_freq = (uintptr_t)i2c_get_match_data(client);
+	data->chip_info = i2c_get_match_data(client);
 
 	if (of_property_read_string(client->dev.of_node, "clock-output-names",
 			&init.name))
@@ -478,18 +490,54 @@ static int si544_probe(struct i2c_client *client)
 	return 0;
 }
 
+static const struct si544_clk_desc clk_si544a_info = {
+	.xo_freq = SI544_XO_FREQ,
+	.max_freq = 1500000000,
+};
+
+static const struct si544_clk_desc clk_si544b_info = {
+	.xo_freq = SI544_XO_FREQ,
+	.max_freq = 800000000,
+};
+
+static const struct si544_clk_desc clk_si544c_info = {
+	.xo_freq = SI544_XO_FREQ,
+	.max_freq = 325000000,
+};
+
+static const struct si544_clk_desc clk_si549a_info = {
+	.xo_freq = SI549_XO_FREQ,
+	.max_freq = 1500000000,
+};
+
+static const struct si544_clk_desc clk_si549b_info = {
+	.xo_freq = SI549_XO_FREQ,
+	.max_freq = 800000000,
+};
+
+static const struct si544_clk_desc clk_si549c_info = {
+	.xo_freq = SI549_XO_FREQ,
+	.max_freq = 325000000,
+};
+
 static const struct i2c_device_id si544_id[] = {
-	{ "si544a", 1500000000 },
-	{ "si544b", 800000000 },
-	{ "si544c", 350000000 },
+	{ "si544a", (kernel_ulong_t)&clk_si544a_info },
+	{ "si544b", (kernel_ulong_t)&clk_si544b_info },
+	{ "si544c", (kernel_ulong_t)&clk_si544c_info },
+	{ "si549a", (kernel_ulong_t)&clk_si549a_info },
+	{ "si549b", (kernel_ulong_t)&clk_si549b_info },
+	{ "si549c", (kernel_ulong_t)&clk_si549c_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, si544_id);
 
 static const struct of_device_id clk_si544_of_match[] = {
-	{ .compatible = "silabs,si544a", .data = (void *)1500000000 },
-	{ .compatible = "silabs,si544b", .data = (void *)800000000 },
-	{ .compatible = "silabs,si544c", .data = (void *)350000000 },
+	{ .compatible = "silabs,si544a", .data = &clk_si544a_info },
+	{ .compatible = "silabs,si544b", .data = &clk_si544b_info },
+	{ .compatible = "silabs,si544c", .data = &clk_si544c_info },
+	{ .compatible = "silabs,si549a", .data = &clk_si549a_info },
+	{ .compatible = "silabs,si549b", .data = &clk_si549b_info },
+	{ .compatible = "silabs,si549c", .data = &clk_si549c_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, clk_si544_of_match);
-- 
2.53.0

Re: [PATCH v2 2/2] clk: si544: add support for si549

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

Pre-existing issues:
- [High] Unconditional dereference of `client->dev.of_node` during probe fallback path causes a kernel panic on non-DT systems.
- [High] Untrusted or unprogrammed hardware input causes a divide-by-zero kernel panic.
--

commit 8414d21feff1150c560a77278d7dec845cbe570f
Author: Pavel Löbl <pavel@loebl.cz>

clk: si544: add support for si549

Add support for Si549, which only differs from Si544 in internal
oscilator frequency. Si549 also comes in three types A,B and C.
Each having different maximum output frequency.

This patch also fixes maximum frequency of Si544 C. Which should
be 325MHz according to datasheet.

> diff --git a/drivers/clk/clk-si544.c b/drivers/clk/clk-si544.c
> index 09c06ecec1a52..b13aeead9c028 100644
> --- a/drivers/clk/clk-si544.c
> +++ b/drivers/clk/clk-si544.c

[ ... ]

> @@ -145,6 +153,8 @@ static int si544_get_muldiv(struct clk_si544 *data,
>  	settings->delta_m = reg[0] << 8 | reg[1] << 16 | reg[2] << 24;
>  	settings->delta_m >>= 8;
>  
> +	settings->xo_freq = data->chip_info->xo_freq;
> +
>  	return 0;
>  }

[Severity: High]
This is a pre-existing issue, but I noticed that si544_get_muldiv() reads the
high-speed divider (hs_div) directly from the I2C device registers without
validation.

Could this lead to a division by zero later?

If the hardware is unprogrammed or an I2C device returns zero for these
registers, settings->hs_div becomes 0. Then, when si544_calc_center_rate() is
called:

si544_calc_center_rate() {
	u32 d = settings->hs_div * BIT(settings->ls_div_bits);
	...
	do_div(vco, d);
}

d would evaluate to 0, triggering a divide-by-zero kernel panic. Is it worth
adding a check for hs_div == 0 after reading the registers?

[ ... ]

> @@ -446,7 +458,7 @@ static int si544_probe(struct i2c_client *client)
>  	init.num_parents = 0;
>  	data->hw.init = &init;
>  	data->i2c_client = client;
> -	data->max_freq = (uintptr_t)i2c_get_match_data(client);
> +	data->chip_info = i2c_get_match_data(client);
>  
>  	if (of_property_read_string(client->dev.of_node, "clock-output-names",
>  			&init.name))

[Severity: High]
This isn't a bug introduced by this patch, but can this fallback cause a NULL
pointer dereference on non-DT systems?

If the driver is instantiated via a mechanism that does not use Device Tree
(such as sysfs new_device), client->dev.of_node will be NULL.

When of_property_read_string() detects the NULL node, it returns an error,
which triggers the fallback logic right below this diff:

		init.name = client->dev.of_node->name;

This unconditionally dereferences the NULL of_node pointer. Should this code
check if client->dev.of_node is valid before attempting to use it?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260701145101.3932655-1-pavel@loebl.cz?part=2

Re: [PATCH v2 1/2] dt-bindings: clock: si544: add si549 compatible

[Conor Dooley]

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Acked-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: not-applicable

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