Re: [PATCH 1/1] iio: adc: stm32-adc: add id registers support

[Fabrice Gasnier]

On 9/15/22 15:54, Olivier Moysan wrote:
> Add support of identification registers to STM32 ADC.
> 
> By default the ADC hardware instance number is retrieved from
> the compatible configuration data. Get the available ADC number
> per ADC block, from hardware configuration register,
> when this register exists.
> 
> Signed-off-by: Olivier Moysan <olivier.moysan@xxxxxxxxxxx>

Hi Olivier,

You can add my:
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>

Thanks and Best Regards,
Fabrice

> ---
>  drivers/iio/adc/stm32-adc-core.c | 59 ++++++++++++++++++++++++++++++--
>  drivers/iio/adc/stm32-adc-core.h | 31 +++++++++++++++++
>  2 files changed, 87 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
> index 1ce52af3fe8b..81d5db91c67b 100644
> --- a/drivers/iio/adc/stm32-adc-core.c
> +++ b/drivers/iio/adc/stm32-adc-core.c
> @@ -9,6 +9,7 @@
>   *
>   */
>  
> +#include <linux/bitfield.h>
>  #include <linux/clk.h>
>  #include <linux/interrupt.h>
>  #include <linux/irqchip/chained_irq.h>
> @@ -62,6 +63,7 @@ struct stm32_adc_priv;
>   * @regs:	common registers for all instances
>   * @clk_sel:	clock selection routine
>   * @max_clk_rate_hz: maximum analog clock rate (Hz, from datasheet)
> + * @ipid:	adc identification number
>   * @has_syscfg: SYSCFG capability flags
>   * @num_irqs:	number of interrupt lines
>   * @num_adcs:   maximum number of ADC instances in the common registers
> @@ -70,6 +72,7 @@ struct stm32_adc_priv_cfg {
>  	const struct stm32_adc_common_regs *regs;
>  	int (*clk_sel)(struct platform_device *, struct stm32_adc_priv *);
>  	u32 max_clk_rate_hz;
> +	u32 ipid;
>  	unsigned int has_syscfg;
>  	unsigned int num_irqs;
>  	unsigned int num_adcs;
> @@ -78,6 +81,7 @@ struct stm32_adc_priv_cfg {
>  /**
>   * struct stm32_adc_priv - stm32 ADC core private data
>   * @irq:		irq(s) for ADC block
> + * @nb_adc_max:		actual maximum number of instance per ADC block
>   * @domain:		irq domain reference
>   * @aclk:		clock reference for the analog circuitry
>   * @bclk:		bus clock common for all ADCs, depends on part used
> @@ -95,6 +99,7 @@ struct stm32_adc_priv_cfg {
>   */
>  struct stm32_adc_priv {
>  	int				irq[STM32_ADC_MAX_ADCS];
> +	unsigned int			nb_adc_max;
>  	struct irq_domain		*domain;
>  	struct clk			*aclk;
>  	struct clk			*bclk;
> @@ -354,7 +359,7 @@ static void stm32_adc_irq_handler(struct irq_desc *desc)
>  	 * before invoking the interrupt handler (e.g. call ISR only for
>  	 * IRQ-enabled ADCs).
>  	 */
> -	for (i = 0; i < priv->cfg->num_adcs; i++) {
> +	for (i = 0; i < priv->nb_adc_max; i++) {
>  		if ((status & priv->cfg->regs->eoc_msk[i] &&
>  		     stm32_adc_eoc_enabled(priv, i)) ||
>  		     (status & priv->cfg->regs->ovr_msk[i]))
> @@ -424,7 +429,7 @@ static void stm32_adc_irq_remove(struct platform_device *pdev,
>  	int hwirq;
>  	unsigned int i;
>  
> -	for (hwirq = 0; hwirq < STM32_ADC_MAX_ADCS; hwirq++)
> +	for (hwirq = 0; hwirq < priv->nb_adc_max; hwirq++)
>  		irq_dispose_mapping(irq_find_mapping(priv->domain, hwirq));
>  	irq_domain_remove(priv->domain);
>  
> @@ -642,6 +647,49 @@ static int stm32_adc_core_switches_probe(struct device *dev,
>  	return 0;
>  }
>  
> +static int stm32_adc_probe_identification(struct platform_device *pdev,
> +					  struct stm32_adc_priv *priv)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct device_node *child;
> +	const char *compat;
> +	int ret, count = 0;
> +	u32 id, val;
> +
> +	if (!priv->cfg->ipid)
> +		return 0;
> +
> +	id = FIELD_GET(STM32MP1_IPIDR_MASK,
> +		       readl_relaxed(priv->common.base + STM32MP1_ADC_IPDR));
> +	if (id != priv->cfg->ipid) {
> +		dev_err(&pdev->dev, "Unexpected IP version: 0x%x", id);
> +		return -EINVAL;
> +	}
> +
> +	for_each_child_of_node(np, child) {
> +		ret = of_property_read_string(child, "compatible", &compat);
> +		if (ret)
> +			continue;
> +		/* Count child nodes with stm32 adc compatible */
> +		if (strstr(compat, "st,stm32") && strstr(compat, "adc"))
> +			count++;
> +	}
> +
> +	val = readl_relaxed(priv->common.base + STM32MP1_ADC_HWCFGR0);
> +	priv->nb_adc_max = FIELD_GET(STM32MP1_ADCNUM_MASK, val);
> +	if (count > priv->nb_adc_max) {
> +		dev_err(&pdev->dev, "Unexpected child number: %d", count);
> +		return -EINVAL;
> +	}
> +
> +	val = readl_relaxed(priv->common.base + STM32MP1_ADC_VERR);
> +	dev_dbg(&pdev->dev, "ADC version: %lu.%lu\n",
> +		FIELD_GET(STM32MP1_MAJREV_MASK, val),
> +		FIELD_GET(STM32MP1_MINREV_MASK, val));
> +
> +	return 0;
> +}
> +
>  static int stm32_adc_probe(struct platform_device *pdev)
>  {
>  	struct stm32_adc_priv *priv;
> @@ -661,6 +709,7 @@ static int stm32_adc_probe(struct platform_device *pdev)
>  
>  	priv->cfg = (const struct stm32_adc_priv_cfg *)
>  		of_match_device(dev->driver->of_match_table, dev)->data;
> +	priv->nb_adc_max = priv->cfg->num_adcs;
>  	spin_lock_init(&priv->common.lock);
>  
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> @@ -703,6 +752,10 @@ static int stm32_adc_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto err_pm_stop;
>  
> +	ret = stm32_adc_probe_identification(pdev, priv);
> +	if (ret < 0)
> +		goto err_hw_stop;
> +
>  	ret = regulator_get_voltage(priv->vref);
>  	if (ret < 0) {
>  		dev_err(&pdev->dev, "vref get voltage failed, %d\n", ret);
> @@ -811,8 +864,8 @@ static const struct stm32_adc_priv_cfg stm32mp1_adc_priv_cfg = {
>  	.clk_sel = stm32h7_adc_clk_sel,
>  	.max_clk_rate_hz = 36000000,
>  	.has_syscfg = HAS_VBOOSTER | HAS_ANASWVDD,
> +	.ipid = STM32MP15_IPIDR_NUMBER,
>  	.num_irqs = 2,
> -	.num_adcs = 2,
>  };
>  
>  static const struct of_device_id stm32_adc_of_match[] = {
> diff --git a/drivers/iio/adc/stm32-adc-core.h b/drivers/iio/adc/stm32-adc-core.h
> index faedf7a49555..2118ef63843d 100644
> --- a/drivers/iio/adc/stm32-adc-core.h
> +++ b/drivers/iio/adc/stm32-adc-core.h
> @@ -24,6 +24,7 @@
>   * | 0x300  |         Master & Slave common regs          |
>   * --------------------------------------------------------
>   */
> +/* Maximum ADC instances number per ADC block for all supported SoCs */
>  #define STM32_ADC_MAX_ADCS		3
>  #define STM32_ADC_OFFSET		0x100
>  #define STM32_ADCX_COMN_OFFSET		0x300
> @@ -105,6 +106,12 @@
>  /* STM32MP1 - ADC2 instance option register */
>  #define STM32MP1_ADC2_OR		0xD0
>  
> +/* STM32MP1 - Identification registers */
> +#define STM32MP1_ADC_HWCFGR0		0x3F0
> +#define STM32MP1_ADC_VERR		0x3F4
> +#define STM32MP1_ADC_IPDR		0x3F8
> +#define STM32MP1_ADC_SIDR		0x3FC
> +
>  /* STM32H7 - common registers for all ADC instances */
>  #define STM32H7_ADC_CSR			(STM32_ADCX_COMN_OFFSET + 0x00)
>  #define STM32H7_ADC_CCR			(STM32_ADCX_COMN_OFFSET + 0x08)
> @@ -181,6 +188,30 @@ enum stm32h7_adc_dmngt {
>  /* STM32MP1_ADC2_OR - bit fields */
>  #define STM32MP1_VDDCOREEN		BIT(0)
>  
> +/* STM32MP1_ADC_HWCFGR0 - bit fields */
> +#define STM32MP1_ADCNUM_SHIFT		0
> +#define STM32MP1_ADCNUM_MASK		GENMASK(3, 0)
> +#define STM32MP1_MULPIPE_SHIFT		4
> +#define STM32MP1_MULPIPE_MASK		GENMASK(7, 4)
> +#define STM32MP1_OPBITS_SHIFT		8
> +#define STM32MP1_OPBITS_MASK		GENMASK(11, 8)
> +#define STM32MP1_IDLEVALUE_SHIFT	12
> +#define STM32MP1_IDLEVALUE_MASK	GENMASK(15, 12)
> +
> +/* STM32MP1_ADC_VERR - bit fields */
> +#define STM32MP1_MINREV_SHIFT		0
> +#define STM32MP1_MINREV_MASK		GENMASK(3, 0)
> +#define STM32MP1_MAJREV_SHIFT		4
> +#define STM32MP1_MAJREV_MASK		GENMASK(7, 4)
> +
> +/* STM32MP1_ADC_IPDR - bit fields */
> +#define STM32MP1_IPIDR_MASK		GENMASK(31, 0)
> +
> +/* STM32MP1_ADC_SIDR - bit fields */
> +#define STM32MP1_SIDR_MASK		GENMASK(31, 0)
> +
> +#define STM32MP15_IPIDR_NUMBER		0x00110005
> +
>  /**
>   * struct stm32_adc_common - stm32 ADC driver common data (for all instances)
>   * @base:		control registers base cpu addr