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PWM and keyboard backlight driver for ARM Macs

PATCH RESEND Superseded Sasha Finkelstein 4 participants 10 messages Nov 21, 2022 – Nov 28, 2022

Subsystems (3)

v3 of 9 Superseded Latest is v9 →

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#0 lore raw

v3 cover PWM and keyboard backlight driver for ARM Macs

Hi,

This is a resend of the v3 of the patch series to add PWM and keyboard backlight driver for ARM macs.

Changes in v1:
Addressing the review comments.

Changes in v2:
Added the reviewed-by and acked-by tags.
Addressing a review comment.

v1: https://www.spinics.net/lists/linux-pwm/msg19500.html
v2: https://www.spinics.net/lists/linux-pwm/msg19562.html

Sasha Finkelstein (4):
dt-bindings: pwm: Add Apple PWM controller
pwm: Add Apple PWM controller
arm64: dts: apple: t8103: Add PWM controller
MAINTAINERS: Add entries for Apple PWM driver

 .../bindings/pwm/apple,s5l-fpwm.yaml          |  51 +++++++
 MAINTAINERS                                   |   2 +
 arch/arm64/boot/dts/apple/t8103-j293.dts      |  20 +++
 arch/arm64/boot/dts/apple/t8103-j313.dts      |  20 +++
 arch/arm64/boot/dts/apple/t8103.dtsi          |   9 ++
 drivers/pwm/Kconfig                           |  12 ++
 drivers/pwm/Makefile                          |   1 +
 drivers/pwm/pwm-apple.c                       | 127 ++++++++++++++++++
 8 files changed, 242 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/apple,s5l-fpwm.yaml
 create mode 100644 drivers/pwm/pwm-apple.c
Signature · 1 line
2.38.1
#1 lore raw

PATCH RESEND v3 1/4 dt-bindings: pwm: Add Apple PWM controller

Apple SoCs such as the M1 contain a PWM controller used among other things to control the keyboard backlight.

---
 .../bindings/pwm/apple,s5l-fpwm.yaml          | 51 +++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/apple,s5l-fpwm.yaml
Documentation/devicetree/bindings/pwm/apple,s5l-fpwm.yaml new file +51 -0
new file mode 100644
index 000000000000..142157bff0cd
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/apple,s5l-fpwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple FPWM controller
+
+maintainers:
+  - [email protected]
+  - Sasha Finkelstein <[email protected]>
+
+description: PWM controller used for keyboard backlight on ARM Macs
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - apple,t8103-fpwm
+          - apple,t6000-fpwm
+          - apple,t8112-fpwm
+      - const: apple,s5l-fpwm
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  "#pwm-cells":
+    const: 2
+
+required:
+  - compatible
+  - reg
+  - clocks
+
+additionalProperties: false
+
+examples:
+  - |
+    pwm@235044000 {
+      compatible = "apple,t8103-fpwm", "apple,s5l-fpwm";
+      reg = <0x35044000 0x4000>;
+      power-domains = <&ps_fpwm1>;
+      clocks = <&clkref>;
+      #pwm-cells = <2>;
+    };
Signature · 1 line
2.38.1
#2 lore raw

Re: [PATCH RESEND v3 1/4] dt-bindings: pwm: Add Apple PWM controller

Hello Sasha,

Quoted 6 lines · Sasha Finkelstein

Apple SoCs such as the M1 contain a PWM controller used among other things to control the keyboard backlight.

With the requested changes in the other patches of this series, I'm marking this and the addition to MAINTAINERS as changes-requested, too, in the assumption that when (and if) you address the feedback you will care for these two, too.

Best regards
Uwe

Signature · 2 lines
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |
#3 lore raw

PATCH RESEND v3 2/4 pwm: Add Apple PWM controller

In reply to Sasha Finkelstein

Adds the Apple PWM controller driver.

---
 drivers/pwm/Kconfig     |  12 ++++
 drivers/pwm/Makefile    |   1 +
 drivers/pwm/pwm-apple.c | 127 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 drivers/pwm/pwm-apple.c
drivers/pwm/Kconfig +12 -0
index 60d13a949bc5..c3be11468414 100644
@@ -51,6 +51,18 @@ config PWM_AB8500
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-ab8500.
 
+config PWM_APPLE
+	tristate "Apple SoC PWM support"
+	depends on ARCH_APPLE || COMPILE_TEST
+	help
+	  Generic PWM framework driver for PWM controller present on
+	  Apple SoCs
+
+	  Say Y here if you have an ARM Apple laptop, otherwise say N
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-apple.
+
 config PWM_ATMEL
 	tristate "Atmel PWM support"
 	depends on ARCH_AT91 || COMPILE_TEST
drivers/pwm/Makefile +1 -0
index 7bf1a29f02b8..19899b912e00 100644
@@ -2,6 +2,7 @@
 obj-$(CONFIG_PWM)		+= core.o
 obj-$(CONFIG_PWM_SYSFS)		+= sysfs.o
 obj-$(CONFIG_PWM_AB8500)	+= pwm-ab8500.o
+obj-$(CONFIG_PWM_APPLE)		+= pwm-apple.o
 obj-$(CONFIG_PWM_ATMEL)		+= pwm-atmel.o
 obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM)	+= pwm-atmel-hlcdc.o
 obj-$(CONFIG_PWM_ATMEL_TCB)	+= pwm-atmel-tcb.o
drivers/pwm/pwm-apple.c new file +127 -0

127 lines not on this page · raw message

Signature · 1 line
2.38.1
maintainer
#4 lore raw

Re: [PATCH RESEND v3 2/4] pwm: Add Apple PWM controller

Quoted 52 lines · Sasha Finkelstein

Adds the Apple PWM controller driver.

---
 drivers/pwm/Kconfig     |  12 ++++
 drivers/pwm/Makefile    |   1 +
 drivers/pwm/pwm-apple.c | 127 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 drivers/pwm/pwm-apple.c
drivers/pwm/Kconfig +12 -0
index 60d13a949bc5..c3be11468414 100644
@@ -51,6 +51,18 @@ config PWM_AB8500
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-ab8500.
 
+config PWM_APPLE
+	tristate "Apple SoC PWM support"
+	depends on ARCH_APPLE || COMPILE_TEST
+	help
+	  Generic PWM framework driver for PWM controller present on
+	  Apple SoCs
+
+	  Say Y here if you have an ARM Apple laptop, otherwise say N
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-apple.
+
 config PWM_ATMEL
 	tristate "Atmel PWM support"
 	depends on ARCH_AT91 || COMPILE_TEST
drivers/pwm/Makefile +1 -0
index 7bf1a29f02b8..19899b912e00 100644
@@ -2,6 +2,7 @@
 obj-$(CONFIG_PWM)		+= core.o
 obj-$(CONFIG_PWM_SYSFS)		+= sysfs.o
 obj-$(CONFIG_PWM_AB8500)	+= pwm-ab8500.o
+obj-$(CONFIG_PWM_APPLE)		+= pwm-apple.o
 obj-$(CONFIG_PWM_ATMEL)		+= pwm-atmel.o
 obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM)	+= pwm-atmel-hlcdc.o
 obj-$(CONFIG_PWM_ATMEL_TCB)	+= pwm-atmel-tcb.o
drivers/pwm/pwm-apple.c new file +0 -0
new file mode 100644
index 000000000000..b0c3f86fd578

drivers/pwm/pwm-apple.c line 1

Quoted 1 line
drivers/pwm/pwm-apple.c new file +1 -0
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT

Kernel code is generally GPL-2.0 only. No other PWM driver is MIT licensed. So why this one.

Mixing licenses is a problem because few people look at the licenses when copying code around.

Quoted 95 lines
drivers/pwm/pwm-apple.c new file +95 -0
+/*
+ * Driver for the Apple SoC PWM controller
+ *
+ * Copyright The Asahi Linux Contributors
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+
+#define PWM_CONTROL     0x00
+#define PWM_ON_CYCLES   0x1c
+#define PWM_OFF_CYCLES  0x18
+
+#define CTRL_ENABLE        BIT(0)
+#define CTRL_MODE          BIT(2)
+#define CTRL_UPDATE        BIT(5)
+#define CTRL_TRIGGER       BIT(9)
+#define CTRL_INVERT        BIT(10)
+#define CTRL_OUTPUT_ENABLE BIT(14)
+
+struct apple_pwm {
+	struct pwm_chip chip;
+	void __iomem *base;
+	u64 clkrate;
+};
+
+static int apple_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			   const struct pwm_state *state)
+{
+	struct apple_pwm *fpwm;
+	u64 on_cycles, off_cycles;
+
+	fpwm = container_of(chip, struct apple_pwm, chip);
+	if (state->enabled) {
+		on_cycles = mul_u64_u64_div_u64(fpwm->clkrate,
+						state->duty_cycle, NSEC_PER_SEC);
+		off_cycles = mul_u64_u64_div_u64(fpwm->clkrate,
+						 state->period, NSEC_PER_SEC) - on_cycles;
+		writel(on_cycles, fpwm->base + PWM_ON_CYCLES);
+		writel(off_cycles, fpwm->base + PWM_OFF_CYCLES);
+		writel(CTRL_ENABLE | CTRL_OUTPUT_ENABLE | CTRL_UPDATE,
+		       fpwm->base + PWM_CONTROL);
+	} else {
+		writel(0, fpwm->base + PWM_CONTROL);
+	}
+	return 0;
+}
+
+static void apple_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+			   struct pwm_state *state)
+{
+	struct apple_pwm *fpwm;
+	u32 on_cycles, off_cycles, ctrl;
+
+	fpwm = container_of(chip, struct apple_pwm, chip);
+
+	ctrl = readl(fpwm->base + PWM_CONTROL);
+	on_cycles = readl(fpwm->base + PWM_ON_CYCLES);
+	off_cycles = readl(fpwm->base + PWM_OFF_CYCLES);
+
+	state->enabled = (ctrl & CTRL_ENABLE) && (ctrl & CTRL_OUTPUT_ENABLE);
+	state->polarity = PWM_POLARITY_NORMAL;
+	state->duty_cycle = div_u64(on_cycles, fpwm->clkrate) * NSEC_PER_SEC;
+	state->period = div_u64(off_cycles + on_cycles, fpwm->clkrate) * NSEC_PER_SEC;
+}
+
+static const struct pwm_ops apple_pwm_ops = {
+	.apply = apple_pwm_apply,
+	.get_state = apple_pwm_get_state,
+	.owner = THIS_MODULE,
+};
+
+static int apple_pwm_probe(struct platform_device *pdev)
+{
+	struct apple_pwm *pwm;
+	struct clk *clk;
+	int ret;
+
+	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+	if (!pwm)
+		return -ENOMEM;
+
+	pwm->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(pwm->base))
+		return PTR_ERR(pwm->base);
+
+	platform_set_drvdata(pdev, pwm);
+

drivers/pwm/pwm-apple.c line 106

Quoted 10 lines
drivers/pwm/pwm-apple.c new file +10 -0
+	clk = devm_clk_get_enabled(&pdev->dev, NULL);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	pwm->clkrate = clk_get_rate(clk);
+	pwm->chip.dev = &pdev->dev;
+	pwm->chip.npwm = 1;
+	pwm->chip.ops = &apple_pwm_ops;
+
+	ret = devm_pwmchip_add(&pdev->dev, &pwm->chip);

This symbol is EXPORT_SYMBOL_GPL. So how can this module be MIT licensed?

Quoted 4 lines
drivers/pwm/pwm-apple.c new file +4 -0
+	return ret;
+}
+
+static const struct of_device_id apple_pwm_of_match[] = {

drivers/pwm/pwm-apple.c line 120

Quoted 10 lines
drivers/pwm/pwm-apple.c new file +10 -0
+	{ .compatible = "apple,s5l-fpwm" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, apple_pwm_of_match);
+
+static struct platform_driver apple_pwm_driver = {
+	.probe = apple_pwm_probe,
+	.driver = {
+		.name = "apple-pwm",
+		.owner = THIS_MODULE,

This line should be dropped.

Quoted 11 lines
drivers/pwm/pwm-apple.c new file +7 -0
+		.of_match_table = apple_pwm_of_match,
+	},
+};
+module_platform_driver(apple_pwm_driver);
+
+MODULE_DESCRIPTION("Apple SoC PWM driver");
+MODULE_LICENSE("Dual MIT/GPL");
Signature · 1 line
2.38.1
#5 lore raw

Re: [PATCH RESEND v3 2/4] pwm: Add Apple PWM controller

Quoted 12 lines · Rob Herring

drivers/pwm/pwm-apple.c line 1

Quoted 7 lines · Sasha Finkelstein
drivers/pwm/pwm-apple.c new file +1 -0
new file mode 100644
index 000000000000..b0c3f86fd578
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT

Kernel code is generally GPL-2.0 only. No other PWM driver is MIT licensed. So why this one.

Quoted 2 lines

Mixing licenses is a problem because few people look at the licenses when copying code around.

*Sigh*. We encourage the use of MIT dual-licensing as a project to allow other OSes to port the drivers over without having to rewrite them, for any driver written from scratch. We've had this conversation quite a few times already...

Quoted 5 lines

drivers/pwm/pwm-apple.c line 3

Quoted 2 lines
drivers/pwm/pwm-apple.c new file +2 -0
+
+	ret = devm_pwmchip_add(&pdev->dev, &pwm->chip);

This symbol is EXPORT_SYMBOL_GPL. So how can this module be MIT licensed?

Because they are compatible licenses. The combination of this driver and the kernel is GPL, but this driver itself is MIT. People are free to port it to other OSes and reimplement devm_pwmchip_add or replace the call with something else.

The EXPORT_SYMBOL_GPL stuff is about blocking *proprietary* GPL-incompatible modules from using those symbols. This is a GPL-compatible, explicitly dual-licensed module.

In this case the driver is trivial enough there isn't much to gain from dual-licensing since the parts that matter (the reverse engineering) are not copyrightable, but I still find it silly that we keep getting told more permissive licensing is a problem. People are free to dual-license their work as they see fit, it's a fundamental freedom in free software, and plenty of kernel code is dual-licensed like this (including much of DRM and entire GPU drivers).

- Hector

#6 lore raw

Re: [PATCH RESEND v3 2/4] pwm: Add Apple PWM controller

In reply to Sasha Finkelstein

Hello,

Quoted 69 lines · Sasha Finkelstein

Adds the Apple PWM controller driver.

---
 drivers/pwm/Kconfig     |  12 ++++
 drivers/pwm/Makefile    |   1 +
 drivers/pwm/pwm-apple.c | 127 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 drivers/pwm/pwm-apple.c
drivers/pwm/Kconfig +12 -0
index 60d13a949bc5..c3be11468414 100644
@@ -51,6 +51,18 @@ config PWM_AB8500
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-ab8500.
 
+config PWM_APPLE
+	tristate "Apple SoC PWM support"
+	depends on ARCH_APPLE || COMPILE_TEST
+	help
+	  Generic PWM framework driver for PWM controller present on
+	  Apple SoCs
+
+	  Say Y here if you have an ARM Apple laptop, otherwise say N
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-apple.
+
 config PWM_ATMEL
 	tristate "Atmel PWM support"
 	depends on ARCH_AT91 || COMPILE_TEST
drivers/pwm/Makefile +1 -0
index 7bf1a29f02b8..19899b912e00 100644
@@ -2,6 +2,7 @@
 obj-$(CONFIG_PWM)		+= core.o
 obj-$(CONFIG_PWM_SYSFS)		+= sysfs.o
 obj-$(CONFIG_PWM_AB8500)	+= pwm-ab8500.o
+obj-$(CONFIG_PWM_APPLE)		+= pwm-apple.o
 obj-$(CONFIG_PWM_ATMEL)		+= pwm-atmel.o
 obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM)	+= pwm-atmel-hlcdc.o
 obj-$(CONFIG_PWM_ATMEL_TCB)	+= pwm-atmel-tcb.o
drivers/pwm/pwm-apple.c new file +17 -0
new file mode 100644
index 000000000000..b0c3f86fd578
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Driver for the Apple SoC PWM controller
+ *
+ * Copyright The Asahi Linux Contributors
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+

drivers/pwm/pwm-apple.c line 27

Quoted 10 lines
drivers/pwm/pwm-apple.c new file +10 -0
+#define PWM_CONTROL     0x00
+#define PWM_ON_CYCLES   0x1c
+#define PWM_OFF_CYCLES  0x18
+
+#define CTRL_ENABLE        BIT(0)
+#define CTRL_MODE          BIT(2)
+#define CTRL_UPDATE        BIT(5)
+#define CTRL_TRIGGER       BIT(9)
+#define CTRL_INVERT        BIT(10)
+#define CTRL_OUTPUT_ENABLE BIT(14)

Please use a driver specific prefix on these defines to make it obvious that they are driver specific.

drivers/pwm/pwm-apple.c line 41

Quoted 13 lines
drivers/pwm/pwm-apple.c new file +13 -0
+struct apple_pwm {
+	struct pwm_chip chip;
+	void __iomem *base;
+	u64 clkrate;
+};
+
+static int apple_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			   const struct pwm_state *state)
+{
+	struct apple_pwm *fpwm;
+	u64 on_cycles, off_cycles;
+
+	fpwm = container_of(chip, struct apple_pwm, chip);

Please introduce a macro or static inline for that.

drivers/pwm/pwm-apple.c line 44

Quoted 3 lines
drivers/pwm/pwm-apple.c new file +3 -0
+	if (state->enabled) {
+		on_cycles = mul_u64_u64_div_u64(fpwm->clkrate,
+						state->duty_cycle, NSEC_PER_SEC);

This might overflow for big values of clkrate and duty_cycle. The usual approach is to check for clkrate <= NSEC_PER_SEC. See pwm-lpc18xx-sct.c for an example.

drivers/pwm/pwm-apple.c line 47

Quoted 3 lines
drivers/pwm/pwm-apple.c new file +3 -0
+		off_cycles = mul_u64_u64_div_u64(fpwm->clkrate,
+						 state->period, NSEC_PER_SEC) - on_cycles;
+		writel(on_cycles, fpwm->base + PWM_ON_CYCLES);

You're assuming on_cycles to fit into an u32 here. Please ensure that's a valid claim.

drivers/pwm/pwm-apple.c line 50

Quoted 3 lines
drivers/pwm/pwm-apple.c new file +3 -0
+		writel(off_cycles, fpwm->base + PWM_OFF_CYCLES);
+		writel(CTRL_ENABLE | CTRL_OUTPUT_ENABLE | CTRL_UPDATE,
+		       fpwm->base + PWM_CONTROL);

How does the hardware behave on updates? Are the register values shadowed until PWM_CONTROL is written? Or until the next period starts?

Please document this at the top of the driver file, in the same format as e.g. pwm-sl28cpld.c does. (The relevant section is called "Limitations", actually "Hardware properties" would be a better name, but please stick to the former for easier greppability.)

Quoted 12 lines
drivers/pwm/pwm-apple.c new file +12 -0
+	} else {
+		writel(0, fpwm->base + PWM_CONTROL);
+	}
+	return 0;
+}
+
+static void apple_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+			   struct pwm_state *state)
+{
+	struct apple_pwm *fpwm;
+	u32 on_cycles, off_cycles, ctrl;
+

drivers/pwm/pwm-apple.c line 72

Quoted 10 lines
drivers/pwm/pwm-apple.c new file +10 -0
+	fpwm = container_of(chip, struct apple_pwm, chip);
+
+	ctrl = readl(fpwm->base + PWM_CONTROL);
+	on_cycles = readl(fpwm->base + PWM_ON_CYCLES);
+	off_cycles = readl(fpwm->base + PWM_OFF_CYCLES);
+
+	state->enabled = (ctrl & CTRL_ENABLE) && (ctrl & CTRL_OUTPUT_ENABLE);
+	state->polarity = PWM_POLARITY_NORMAL;
+	state->duty_cycle = div_u64(on_cycles, fpwm->clkrate) * NSEC_PER_SEC;
+	state->period = div_u64(off_cycles + on_cycles, fpwm->clkrate) * NSEC_PER_SEC;

You're loosing precision here, always do the division last. Also the rounding is wrong. Enabling PWM_DEBUG + some non-trivial testing should tell you that.

drivers/pwm/pwm-apple.c line 83

Quoted 11 lines
drivers/pwm/pwm-apple.c new file +11 -0
+}
+
+static const struct pwm_ops apple_pwm_ops = {
+	.apply = apple_pwm_apply,
+	.get_state = apple_pwm_get_state,
+	.owner = THIS_MODULE,
+};
+
+static int apple_pwm_probe(struct platform_device *pdev)
+{
+	struct apple_pwm *pwm;

The name "pwm" is usually (only) used for struct pwm_device variables.

Please pick another name (something like ddata or pc are usual names), above you picked "fpwm", which I could live with, too.

drivers/pwm/pwm-apple.c line 95

Quoted 12 lines
drivers/pwm/pwm-apple.c new file +12 -0
+	struct clk *clk;
+	int ret;
+
+	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+	if (!pwm)
+		return -ENOMEM;
+
+	pwm->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(pwm->base))
+		return PTR_ERR(pwm->base);
+
+	platform_set_drvdata(pdev, pwm);

This is unused.

drivers/pwm/pwm-apple.c line 98

Quoted 2 lines
drivers/pwm/pwm-apple.c new file +2 -0
+	clk = devm_clk_get_enabled(&pdev->dev, NULL);
+	if (IS_ERR(clk))

Error message please, preferably using dev_err_probe.

drivers/pwm/pwm-apple.c line 106

Quoted 8 lines
drivers/pwm/pwm-apple.c new file +8 -0
+		return PTR_ERR(clk);
+
+	pwm->clkrate = clk_get_rate(clk);
+	pwm->chip.dev = &pdev->dev;
+	pwm->chip.npwm = 1;
+	pwm->chip.ops = &apple_pwm_ops;
+
+	ret = devm_pwmchip_add(&pdev->dev, &pwm->chip);

Ditto.

Quoted 21 lines
drivers/pwm/pwm-apple.c new file +21 -0
+	return ret;
+}
+
+static const struct of_device_id apple_pwm_of_match[] = {
+	{ .compatible = "apple,s5l-fpwm" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, apple_pwm_of_match);
+
+static struct platform_driver apple_pwm_driver = {
+	.probe = apple_pwm_probe,
+	.driver = {
+		.name = "apple-pwm",
+		.owner = THIS_MODULE,
+		.of_match_table = apple_pwm_of_match,
+	},
+};
+module_platform_driver(apple_pwm_driver);
+
+MODULE_DESCRIPTION("Apple SoC PWM driver");
+MODULE_LICENSE("Dual MIT/GPL");
Signature · 2 lines
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |
#7 lore raw

PATCH RESEND v3 3/4 arm64: dts: apple: t8103: Add PWM controller

In reply to Sasha Finkelstein

Adds PWM controller and keyboard backlight bindings for M1 MacBooks

---
 arch/arm64/boot/dts/apple/t8103-j293.dts | 20 ++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8103-j313.dts | 20 ++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8103.dtsi     |  9 +++++++++
 3 files changed, 49 insertions(+)
arch/arm64/boot/dts/apple/t8103-j293.dts +20 -0
index ecb10d237a05..0b4b7e8e0726 100644
@@ -11,6 +11,7 @@
 
 #include "t8103.dtsi"
 #include "t8103-jxxx.dtsi"
+#include <dt-bindings/leds/common.h>
 
 / {
 	compatible = "apple,j293", "apple,t8103", "apple,arm-platform";
@@ -43,3 +44,22 @@ &i2c2 {
 &i2c4 {
 	status = "okay";
 };
+
+/ {
+	led-controller {
+		compatible = "pwm-leds";
+		led-0 {
+			pwms = <&fpwm1 0 40000>;
+			pwm-names = "kbd-backlight";
+			label = "kbd_backlight";
+			function = LED_FUNCTION_KBD_BACKLIGHT;
+			color = <LED_COLOR_ID_WHITE>;
+			max-brightness = <255>;
+			default-state = "keep";
+		};
+	};
+};
+
+&fpwm1 {
+	status = "okay";
+};
arch/arm64/boot/dts/apple/t8103-j313.dts +20 -0
index df741737b8e6..0e0f57dee96b 100644
@@ -11,6 +11,7 @@
 
 #include "t8103.dtsi"
 #include "t8103-jxxx.dtsi"
+#include <dt-bindings/leds/common.h>
 
 / {
 	compatible = "apple,j313", "apple,t8103", "apple,arm-platform";
@@ -35,3 +36,22 @@ &pcie0_dart_2 {
 
 /delete-node/ &port01;
 /delete-node/ &port02;
+
+/ {
+	led-controller {
+		compatible = "pwm-leds";
+		led-0 {
+			pwms = <&fpwm1 0 40000>;
+			pwm-names = "kbd-backlight";
+			label = "kbd_backlight";
+			function = LED_FUNCTION_KBD_BACKLIGHT;
+			color = <LED_COLOR_ID_WHITE>;
+			max-brightness = <255>;
+			default-state = "keep";
+		};
+	};
+};
+
+&fpwm1 {
+	status = "okay";
+};
arch/arm64/boot/dts/apple/t8103.dtsi +9 -0
index 51a63b29d404..ccdb26ef6b22 100644
@@ -191,6 +191,15 @@ i2c4: i2c@235020000 {
 			status = "disabled"; /* only used in J293 */
 		};
 
+		fpwm1: pwm@235044000 {
+			compatible = "apple,t8103-fpwm", "apple,s5l-fpwm";
+			reg = <0x2 0x35044000 0x0 0x4000>;
+			power-domains = <&ps_fpwm1>;
+			clocks = <&clkref>;
+			#pwm-cells = <2>;
+			status = "disabled";
+		};
+
 		serial0: serial@235200000 {
 			compatible = "apple,s5l-uart";
 			reg = <0x2 0x35200000 0x0 0x1000>;
Signature · 1 line
2.38.1
maintainer
#8 lore raw

Re: [PATCH RESEND v3 3/4] arm64: dts: apple: t8103: Add PWM controller

Quoted 23 lines · Sasha Finkelstein

Adds PWM controller and keyboard backlight bindings for M1 MacBooks

---
 arch/arm64/boot/dts/apple/t8103-j293.dts | 20 ++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8103-j313.dts | 20 ++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8103.dtsi     |  9 +++++++++
 3 files changed, 49 insertions(+)
arch/arm64/boot/dts/apple/t8103-j293.dts +1 -0
index ecb10d237a05..0b4b7e8e0726 100644
@@ -11,6 +11,7 @@
 
 #include "t8103.dtsi"
 #include "t8103-jxxx.dtsi"
+#include <dt-bindings/leds/common.h>
 
 / {
 	compatible = "apple,j293", "apple,t8103", "apple,arm-platform";

arch/arm64/boot/dts/apple/t8103-j293.dts &i2c2 { · line 53

Quoted 10 lines
arch/arm64/boot/dts/apple/t8103-j293.dts +7 -0
@@ -43,3 +44,22 @@ &i2c2 {
 &i2c4 {
 	status = "okay";
 };
+
+/ {
+	led-controller {
+		compatible = "pwm-leds";
+		led-0 {
+			pwms = <&fpwm1 0 40000>;
+			pwm-names = "kbd-backlight";

While allowed pwm-names isn't really needed here as there is only ever 1 PWM and it is redundant with 'label'.

Quoted 71 lines
arch/arm64/boot/dts/apple/t8103-j293.dts +12 -0
+			label = "kbd_backlight";
+			function = LED_FUNCTION_KBD_BACKLIGHT;
+			color = <LED_COLOR_ID_WHITE>;
+			max-brightness = <255>;
+			default-state = "keep";
+		};
+	};
+};
+
+&fpwm1 {
+	status = "okay";
+};
arch/arm64/boot/dts/apple/t8103-j313.dts +20 -0
index df741737b8e6..0e0f57dee96b 100644
@@ -11,6 +11,7 @@
 
 #include "t8103.dtsi"
 #include "t8103-jxxx.dtsi"
+#include <dt-bindings/leds/common.h>
 
 / {
 	compatible = "apple,j313", "apple,t8103", "apple,arm-platform";
@@ -35,3 +36,22 @@ &pcie0_dart_2 {
 
 /delete-node/ &port01;
 /delete-node/ &port02;
+
+/ {
+	led-controller {
+		compatible = "pwm-leds";
+		led-0 {
+			pwms = <&fpwm1 0 40000>;
+			pwm-names = "kbd-backlight";
+			label = "kbd_backlight";
+			function = LED_FUNCTION_KBD_BACKLIGHT;
+			color = <LED_COLOR_ID_WHITE>;
+			max-brightness = <255>;
+			default-state = "keep";
+		};
+	};
+};
+
+&fpwm1 {
+	status = "okay";
+};
arch/arm64/boot/dts/apple/t8103.dtsi +9 -0
index 51a63b29d404..ccdb26ef6b22 100644
@@ -191,6 +191,15 @@ i2c4: i2c@235020000 {
 			status = "disabled"; /* only used in J293 */
 		};
 
+		fpwm1: pwm@235044000 {
+			compatible = "apple,t8103-fpwm", "apple,s5l-fpwm";
+			reg = <0x2 0x35044000 0x0 0x4000>;
+			power-domains = <&ps_fpwm1>;
+			clocks = <&clkref>;
+			#pwm-cells = <2>;
+			status = "disabled";
+		};
+
 		serial0: serial@235200000 {
 			compatible = "apple,s5l-uart";
 			reg = <0x2 0x35200000 0x0 0x1000>;
Signature · 1 line
2.38.1
#9 lore raw

PATCH RESEND v3 4/4 MAINTAINERS: Add entries for Apple PWM driver

In reply to Sasha Finkelstein

Add the MAINTAINERS entries for the driver

---
 MAINTAINERS | 2 ++
 1 file changed, 2 insertions(+)
MAINTAINERS +2 -0
index 046ff06ff97f..69f56f7cf907 100644
@@ -1908,6 +1908,7 @@ F:	Documentation/devicetree/bindings/nvmem/apple,efuses.yaml
 F:	Documentation/devicetree/bindings/pci/apple,pcie.yaml
 F:	Documentation/devicetree/bindings/pinctrl/apple,pinctrl.yaml
 F:	Documentation/devicetree/bindings/power/apple*
+F:	Documentation/devicetree/bindings/pwm/pwm-apple.yaml
 F:	Documentation/devicetree/bindings/watchdog/apple,wdt.yaml
 F:	arch/arm64/boot/dts/apple/
 F:	drivers/clk/clk-apple-nco.c
@@ -1921,6 +1922,7 @@ F:	drivers/mailbox/apple-mailbox.c
 F:	drivers/nvme/host/apple.c
 F:	drivers/nvmem/apple-efuses.c
 F:	drivers/pinctrl/pinctrl-apple-gpio.c
+F:	drivers/pwm/pwm-apple.c
 F:	drivers/soc/apple/*
 F:	drivers/watchdog/apple_wdt.c
 F:	include/dt-bindings/interrupt-controller/apple-aic.h
Signature · 1 line
2.38.1