Re: [PATCH v6 3/5] platform/x86: int3472/discrete: Create a LED class device for the privacy LED

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 1/30/23 11:12, Sakari Ailus wrote:
> Hi Hans,
> 
> On Fri, Jan 27, 2023 at 09:37:27PM +0100, Hans de Goede wrote:
>> On some systems, e.g. the Lenovo ThinkPad X1 Yoga gen 7 and the ThinkPad
>> X1 Nano gen 2 there is no clock-enable pin, triggering the:
>> "No clk GPIO. The privacy LED won't work" warning and causing the privacy
>> LED to not work.
>>
>> Fix this by modeling the privacy LED as a LED class device rather then
>> integrating it with the registered clock.
>>
>> Note this relies on media subsys changes to actually turn the LED on/off
>> when the sensor's v4l2_subdev's s_stream() operand gets called.
>>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>> Changes in v4:
>> - Make struct led_classdev the first member of the pled struct
>> - Use strchr to replace the : with _ in the acpi_dev_name()
>> ---
>>  drivers/platform/x86/intel/int3472/Makefile   |  2 +-
>>  .../x86/intel/int3472/clk_and_regulator.c     |  3 -
>>  drivers/platform/x86/intel/int3472/common.h   | 15 +++-
>>  drivers/platform/x86/intel/int3472/discrete.c | 58 ++++-----------
>>  drivers/platform/x86/intel/int3472/led.c      | 74 +++++++++++++++++++
>>  5 files changed, 105 insertions(+), 47 deletions(-)
>>  create mode 100644 drivers/platform/x86/intel/int3472/led.c
>>
>> diff --git a/drivers/platform/x86/intel/int3472/Makefile b/drivers/platform/x86/intel/int3472/Makefile
>> index cfec7784c5c9..9f16cb514397 100644
>> --- a/drivers/platform/x86/intel/int3472/Makefile
>> +++ b/drivers/platform/x86/intel/int3472/Makefile
>> @@ -1,4 +1,4 @@
>>  obj-$(CONFIG_INTEL_SKL_INT3472)		+= intel_skl_int3472_discrete.o \
>>  					   intel_skl_int3472_tps68470.o
>> -intel_skl_int3472_discrete-y		:= discrete.o clk_and_regulator.o common.o
>> +intel_skl_int3472_discrete-y		:= discrete.o clk_and_regulator.o led.o common.o
>>  intel_skl_int3472_tps68470-y		:= tps68470.o tps68470_board_data.o common.o
>> diff --git a/drivers/platform/x86/intel/int3472/clk_and_regulator.c b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
>> index 74dc2cff799e..e3b597d93388 100644
>> --- a/drivers/platform/x86/intel/int3472/clk_and_regulator.c
>> +++ b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
>> @@ -23,8 +23,6 @@ static int skl_int3472_clk_prepare(struct clk_hw *hw)
>>  	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
>>  
>>  	gpiod_set_value_cansleep(clk->ena_gpio, 1);
>> -	gpiod_set_value_cansleep(clk->led_gpio, 1);
>> -
>>  	return 0;
>>  }
>>  
>> @@ -33,7 +31,6 @@ static void skl_int3472_clk_unprepare(struct clk_hw *hw)
>>  	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
>>  
>>  	gpiod_set_value_cansleep(clk->ena_gpio, 0);
>> -	gpiod_set_value_cansleep(clk->led_gpio, 0);
>>  }
>>  
>>  static int skl_int3472_clk_enable(struct clk_hw *hw)
>> diff --git a/drivers/platform/x86/intel/int3472/common.h b/drivers/platform/x86/intel/int3472/common.h
>> index 53270d19c73a..82dc37e08882 100644
>> --- a/drivers/platform/x86/intel/int3472/common.h
>> +++ b/drivers/platform/x86/intel/int3472/common.h
>> @@ -6,6 +6,7 @@
>>  
>>  #include <linux/clk-provider.h>
>>  #include <linux/gpio/machine.h>
>> +#include <linux/leds.h>
>>  #include <linux/regulator/driver.h>
>>  #include <linux/regulator/machine.h>
>>  #include <linux/types.h>
>> @@ -28,6 +29,8 @@
>>  #define GPIO_REGULATOR_NAME_LENGTH				21
>>  #define GPIO_REGULATOR_SUPPLY_NAME_LENGTH			9
>>  
>> +#define INT3472_LED_MAX_NAME_LEN				32
>> +
>>  #define CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET			86
>>  
>>  #define INT3472_REGULATOR(_name, _supply, _ops)			\
>> @@ -96,10 +99,16 @@ struct int3472_discrete_device {
>>  		struct clk_hw clk_hw;
>>  		struct clk_lookup *cl;
>>  		struct gpio_desc *ena_gpio;
>> -		struct gpio_desc *led_gpio;
>>  		u32 frequency;
>>  	} clock;
>>  
>> +	struct int3472_pled {
>> +		struct led_classdev classdev;
>> +		struct led_lookup_data lookup;
>> +		char name[INT3472_LED_MAX_NAME_LEN];
>> +		struct gpio_desc *gpio;
>> +	} pled;
>> +
>>  	unsigned int ngpios; /* how many GPIOs have we seen */
>>  	unsigned int n_sensor_gpios; /* how many have we mapped to sensor */
>>  	struct gpiod_lookup_table gpios;
>> @@ -119,4 +128,8 @@ int skl_int3472_register_regulator(struct int3472_discrete_device *int3472,
>>  				   struct acpi_resource_gpio *agpio);
>>  void skl_int3472_unregister_regulator(struct int3472_discrete_device *int3472);
>>  
>> +int skl_int3472_register_pled(struct int3472_discrete_device *int3472,
>> +			      struct acpi_resource_gpio *agpio, u32 polarity);
>> +void skl_int3472_unregister_pled(struct int3472_discrete_device *int3472);
>> +
>>  #endif
>> diff --git a/drivers/platform/x86/intel/int3472/discrete.c b/drivers/platform/x86/intel/int3472/discrete.c
>> index 708d51f9b41d..38b1372e0745 100644
>> --- a/drivers/platform/x86/intel/int3472/discrete.c
>> +++ b/drivers/platform/x86/intel/int3472/discrete.c
>> @@ -155,37 +155,21 @@ static int skl_int3472_map_gpio_to_sensor(struct int3472_discrete_device *int347
>>  }
>>  
>>  static int skl_int3472_map_gpio_to_clk(struct int3472_discrete_device *int3472,
>> -				       struct acpi_resource_gpio *agpio, u8 type)
>> +				       struct acpi_resource_gpio *agpio)
>>  {
>>  	char *path = agpio->resource_source.string_ptr;
>>  	u16 pin = agpio->pin_table[0];
>>  	struct gpio_desc *gpio;
>>  
>> -	switch (type) {
>> -	case INT3472_GPIO_TYPE_CLK_ENABLE:
>> -		gpio = acpi_get_and_request_gpiod(path, pin, "int3472,clk-enable");
>> -		if (IS_ERR(gpio))
>> -			return (PTR_ERR(gpio));
>> -
>> -		int3472->clock.ena_gpio = gpio;
>> -		/* Ensure the pin is in output mode and non-active state */
>> -		gpiod_direction_output(int3472->clock.ena_gpio, 0);
>> -		break;
>> -	case INT3472_GPIO_TYPE_PRIVACY_LED:
>> -		gpio = acpi_get_and_request_gpiod(path, pin, "int3472,privacy-led");
>> -		if (IS_ERR(gpio))
>> -			return (PTR_ERR(gpio));
>> +	gpio = acpi_get_and_request_gpiod(path, pin, "int3472,clk-enable");
>> +	if (IS_ERR(gpio))
>> +		return (PTR_ERR(gpio));
>>  
>> -		int3472->clock.led_gpio = gpio;
>> -		/* Ensure the pin is in output mode and non-active state */
>> -		gpiod_direction_output(int3472->clock.led_gpio, 0);
>> -		break;
>> -	default:
>> -		dev_err(int3472->dev, "Invalid GPIO type 0x%02x for clock\n", type);
>> -		break;
>> -	}
>> +	int3472->clock.ena_gpio = gpio;
>> +	/* Ensure the pin is in output mode and non-active state */
>> +	gpiod_direction_output(int3472->clock.ena_gpio, 0);
>>  
>> -	return 0;
>> +	return skl_int3472_register_clock(int3472);
>>  }
>>  
>>  static void int3472_get_func_and_polarity(u8 type, const char **func, u32 *polarity)
>> @@ -293,11 +277,16 @@ static int skl_int3472_handle_gpio_resources(struct acpi_resource *ares,
>>  
>>  		break;
>>  	case INT3472_GPIO_TYPE_CLK_ENABLE:
>> -	case INT3472_GPIO_TYPE_PRIVACY_LED:
>> -		ret = skl_int3472_map_gpio_to_clk(int3472, agpio, type);
>> +		ret = skl_int3472_map_gpio_to_clk(int3472, agpio);
>>  		if (ret)
>>  			err_msg = "Failed to map GPIO to clock\n";
>>  
>> +		break;
>> +	case INT3472_GPIO_TYPE_PRIVACY_LED:
>> +		ret = skl_int3472_register_pled(int3472, agpio, polarity);
>> +		if (ret)
>> +			err_msg = "Failed to register LED\n";
>> +
>>  		break;
>>  	case INT3472_GPIO_TYPE_POWER_ENABLE:
>>  		ret = skl_int3472_register_regulator(int3472, agpio);
>> @@ -341,21 +330,6 @@ static int skl_int3472_parse_crs(struct int3472_discrete_device *int3472)
>>  
>>  	acpi_dev_free_resource_list(&resource_list);
>>  
>> -	/*
>> -	 * If we find no clock enable GPIO pin then the privacy LED won't work.
>> -	 * We've never seen that situation, but it's possible. Warn the user so
>> -	 * it's clear what's happened.
>> -	 */
>> -	if (int3472->clock.ena_gpio) {
>> -		ret = skl_int3472_register_clock(int3472);
>> -		if (ret)
>> -			return ret;
>> -	} else {
>> -		if (int3472->clock.led_gpio)
>> -			dev_warn(int3472->dev,
>> -				 "No clk GPIO. The privacy LED won't work\n");
>> -	}
>> -
>>  	int3472->gpios.dev_id = int3472->sensor_name;
>>  	gpiod_add_lookup_table(&int3472->gpios);
>>  
>> @@ -372,8 +346,8 @@ static int skl_int3472_discrete_remove(struct platform_device *pdev)
>>  		skl_int3472_unregister_clock(int3472);
>>  
>>  	gpiod_put(int3472->clock.ena_gpio);
>> -	gpiod_put(int3472->clock.led_gpio);
>>  
>> +	skl_int3472_unregister_pled(int3472);
>>  	skl_int3472_unregister_regulator(int3472);
>>  
>>  	return 0;
>> diff --git a/drivers/platform/x86/intel/int3472/led.c b/drivers/platform/x86/intel/int3472/led.c
>> new file mode 100644
>> index 000000000000..251c6524458e
>> --- /dev/null
>> +++ b/drivers/platform/x86/intel/int3472/led.c
>> @@ -0,0 +1,74 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/* Author: Hans de Goede <hdegoede@redhat.com> */
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/leds.h>
>> +#include "common.h"
>> +
>> +static int int3472_pled_set(struct led_classdev *led_cdev,
>> +				     enum led_brightness brightness)
>> +{
>> +	struct int3472_discrete_device *int3472 =
>> +		container_of(led_cdev, struct int3472_discrete_device, pled.classdev);
>> +
>> +	gpiod_set_value_cansleep(int3472->pled.gpio, brightness);
>> +	return 0;
>> +}
>> +
>> +int skl_int3472_register_pled(struct int3472_discrete_device *int3472,
>> +			      struct acpi_resource_gpio *agpio, u32 polarity)
>> +{
>> +	char *p, *path = agpio->resource_source.string_ptr;
>> +	int ret;
>> +
>> +	if (int3472->pled.classdev.dev)
>> +		return -EBUSY;
>> +
>> +	int3472->pled.gpio = acpi_get_and_request_gpiod(path, agpio->pin_table[0],
>> +							     "int3472,privacy-led");
>> +	if (IS_ERR(int3472->pled.gpio))
>> +		return dev_err_probe(int3472->dev, PTR_ERR(int3472->pled.gpio),
>> +				     "getting privacy LED GPIO\n");
>> +
>> +	if (polarity == GPIO_ACTIVE_LOW)
>> +		gpiod_toggle_active_low(int3472->pled.gpio);
>> +
>> +	/* Ensure the pin is in output mode and non-active state */
>> +	gpiod_direction_output(int3472->pled.gpio, 0);
>> +
>> +	/* Generate the name, replacing the ':' in the ACPI devname with '_' */
>> +	snprintf(int3472->pled.name, sizeof(int3472->pled.name),
>> +		 "%s::privacy_led", acpi_dev_name(int3472->sensor));
>> +	p = strchr(int3472->pled.name, ':');
>> +	*p = '_';
> 
> While I suppose ACPI device names generally are shorter than
> sizeof(int3472->pled.name), it'd be nice to still check p is non-NULL here,
> just to be sure.

Sure, I've added a check for this while merging this.

Regards,

Hans



> 
>> +
>> +	int3472->pled.classdev.name = int3472->pled.name;
>> +	int3472->pled.classdev.max_brightness = 1;
>> +	int3472->pled.classdev.brightness_set_blocking = int3472_pled_set;
>> +
>> +	ret = led_classdev_register(int3472->dev, &int3472->pled.classdev);
>> +	if (ret)
>> +		goto err_free_gpio;
>> +
>> +	int3472->pled.lookup.provider = int3472->pled.name;
>> +	int3472->pled.lookup.dev_id = int3472->sensor_name;
>> +	int3472->pled.lookup.con_id = "privacy-led";
>> +	led_add_lookup(&int3472->pled.lookup);
>> +
>> +	return 0;
>> +
>> +err_free_gpio:
>> +	gpiod_put(int3472->pled.gpio);
>> +	return ret;
>> +}
>> +
>> +void skl_int3472_unregister_pled(struct int3472_discrete_device *int3472)
>> +{
>> +	if (IS_ERR_OR_NULL(int3472->pled.classdev.dev))
>> +		return;
>> +
>> +	led_remove_lookup(&int3472->pled.lookup);
>> +	led_classdev_unregister(&int3472->pled.classdev);
>> +	gpiod_put(int3472->pled.gpio);
>> +}
>