Re: [RESEND v4 02/15] iio: adc: aspeed: completes the bitfield declare.

[Jonathan Cameron]

On Tue, 24 Aug 2021 17:12:30 +0800
Billy Tsai <billy_tsai@xxxxxxxxxxxxxx> wrote:

> This patch completes the declare of adc register bitfields and uses the
> same prefix ASPEED_ADC_* for these bitfields.
> 
> Signed-off-by: Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
> ---
>  drivers/iio/adc/aspeed_adc.c | 56 +++++++++++++++++++++++++-----------
>  1 file changed, 39 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c
> index 19efaa41bc34..7010d56ac3b9 100644
> --- a/drivers/iio/adc/aspeed_adc.c
> +++ b/drivers/iio/adc/aspeed_adc.c
> @@ -3,6 +3,7 @@
>   * Aspeed AST2400/2500 ADC
>   *
>   * Copyright (C) 2017 Google, Inc.
> + * Copyright (C) 2021 Aspeed Technology Inc.
>   */
>  
>  #include <linux/clk.h>
> @@ -16,6 +17,7 @@
>  #include <linux/reset.h>
>  #include <linux/spinlock.h>
>  #include <linux/types.h>
> +#include <linux/bitfield.h>
>  
>  #include <linux/iio/iio.h>
>  #include <linux/iio/driver.h>
> @@ -28,15 +30,31 @@
>  #define ASPEED_REG_INTERRUPT_CONTROL	0x04
>  #define ASPEED_REG_VGA_DETECT_CONTROL	0x08
>  #define ASPEED_REG_CLOCK_CONTROL	0x0C
> -#define ASPEED_REG_MAX			0xC0
> -
> -#define ASPEED_OPERATION_MODE_POWER_DOWN	(0x0 << 1)
> -#define ASPEED_OPERATION_MODE_STANDBY		(0x1 << 1)
> -#define ASPEED_OPERATION_MODE_NORMAL		(0x7 << 1)
> -
> -#define ASPEED_ENGINE_ENABLE		BIT(0)
> -
> -#define ASPEED_ADC_CTRL_INIT_RDY	BIT(8)
> +#define ASPEED_REG_COMPENSATION_TRIM	0xC4
> +#define ASPEED_REG_MAX			0xCC

This REG_MAX value is used as a sanity check for debugfs based access.
As this raises the limit for all devices supported by the driver, not just the
new ast2600, are we fine to read these non existent registers on the other
parts?  If so, perhaps a comment to say that here somewhere?

> +
> +#define ASPEED_ADC_ENGINE_ENABLE		BIT(0)

Are all the following in the same register?  Bit usual to have
overlapping fields, so if they are, perhaps a few comments to
explain what is going on would be good.

> +#define ASPEED_ADC_OP_MODE			GENMASK(3, 1)
> +#define ASPEED_ADC_OP_MODE_PWR_DOWN		0
> +#define ASPEED_ADC_OP_MODE_STANDBY		1
> +#define ASPEED_ADC_OP_MODE_NORMAL		7
> +#define ASPEED_ADC_CTRL_COMPENSATION		BIT(4)
> +#define ASPEED_ADC_AUTO_COMPENSATION		BIT(5)
> +#define ASPEED_ADC_REF_VOLTAGE			GENMASK(7, 6)
> +#define ASPEED_ADC_REF_VOLTAGE_2500mV		0
> +#define ASPEED_ADC_REF_VOLTAGE_1200mV		1
> +#define ASPEED_ADC_REF_VOLTAGE_EXT_HIGH		2
> +#define ASPEED_ADC_REF_VOLTAGE_EXT_LOW		3
> +#define ASPEED_ADC_BAT_SENSING_DIV		BIT(6)
> +#define ASPEED_ADC_BAT_SENSING_DIV_2_3		0
> +#define ASPEED_ADC_BAT_SENSING_DIV_1_3		1
> +#define ASPEED_ADC_CTRL_INIT_RDY		BIT(8)
> +#define ASPEED_ADC_CH7_MODE			BIT(12)
> +#define ASPEED_ADC_CH7_NORMAL			0
> +#define ASPEED_ADC_CH7_BAT			1
> +#define ASPEED_ADC_BAT_SENSING_ENABLE		BIT(13)
> +#define ASPEED_ADC_CTRL_CHANNEL			GENMASK(31, 16)
> +#define ASPEED_ADC_CTRL_CHANNEL_ENABLE(ch)	FIELD_PREP(ASPEED_ADC_CTRL_CHANNEL, BIT(ch))
>  
>  #define ASPEED_ADC_INIT_POLLING_TIME	500
>  #define ASPEED_ADC_INIT_TIMEOUT		500000
> @@ -226,7 +244,9 @@ static int aspeed_adc_probe(struct platform_device *pdev)
>  
>  	if (model_data->wait_init_sequence) {
>  		/* Enable engine in normal mode. */
> -		writel(ASPEED_OPERATION_MODE_NORMAL | ASPEED_ENGINE_ENABLE,
> +		writel(FIELD_PREP(ASPEED_ADC_OP_MODE,
> +				  ASPEED_ADC_OP_MODE_NORMAL) |
> +			       ASPEED_ADC_ENGINE_ENABLE,
>  		       data->base + ASPEED_REG_ENGINE_CONTROL);
>  
>  		/* Wait for initial sequence complete. */
> @@ -245,10 +265,12 @@ static int aspeed_adc_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto clk_enable_error;
>  
> -	adc_engine_control_reg_val = GENMASK(31, 16) |
> -		ASPEED_OPERATION_MODE_NORMAL | ASPEED_ENGINE_ENABLE;
> +	adc_engine_control_reg_val =
> +		ASPEED_ADC_CTRL_CHANNEL |
> +		FIELD_PREP(ASPEED_ADC_OP_MODE, ASPEED_ADC_OP_MODE_NORMAL) |
> +		ASPEED_ADC_ENGINE_ENABLE;
>  	writel(adc_engine_control_reg_val,
> -		data->base + ASPEED_REG_ENGINE_CONTROL);
> +	       data->base + ASPEED_REG_ENGINE_CONTROL);
>  
>  	model_data = of_device_get_match_data(&pdev->dev);
>  	indio_dev->name = model_data->model_name;
> @@ -264,8 +286,8 @@ static int aspeed_adc_probe(struct platform_device *pdev)
>  	return 0;
>  
>  iio_register_error:
> -	writel(ASPEED_OPERATION_MODE_POWER_DOWN,
> -		data->base + ASPEED_REG_ENGINE_CONTROL);
> +	writel(FIELD_PREP(ASPEED_ADC_OP_MODE, ASPEED_ADC_OP_MODE_PWR_DOWN),
> +	       data->base + ASPEED_REG_ENGINE_CONTROL);
>  	clk_disable_unprepare(data->clk_scaler->clk);
>  clk_enable_error:
>  poll_timeout_error:
> @@ -283,8 +305,8 @@ static int aspeed_adc_remove(struct platform_device *pdev)
>  	struct aspeed_adc_data *data = iio_priv(indio_dev);
>  
>  	iio_device_unregister(indio_dev);
> -	writel(ASPEED_OPERATION_MODE_POWER_DOWN,
> -		data->base + ASPEED_REG_ENGINE_CONTROL);
> +	writel(FIELD_PREP(ASPEED_ADC_OP_MODE, ASPEED_ADC_OP_MODE_PWR_DOWN),
> +	       data->base + ASPEED_REG_ENGINE_CONTROL);

Ideally these white space changes would be in a precursor patch.
At the very least mention them in the patch description.  They are good
thing to tidy up, but they do add noise to this patch.

>  	clk_disable_unprepare(data->clk_scaler->clk);
>  	reset_control_assert(data->rst);
>  	clk_hw_unregister_divider(data->clk_scaler);