Message-ID: <20161108190751.GO25787@tuxbot>
Date:   Tue, 8 Nov 2016 11:07:51 -0800
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc:     Lee Jones <lee.jones@...aro.org>, Rob Herring <robh+dt@...nel.org>,
        Andy Gross <andy.gross@...aro.org>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-soc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 1/2] mfd: pm8921: add support to pm8821

On Tue 08 Nov 08:29 PST 2016, Srinivas Kandagatla wrote:

> This patch adds support to PM8821 PMIC and interrupt support.
> PM8821 is companion device that supplements primary PMIC PM8921 IC.
> 

Linus Walleij has a patch out for renaming a lot of things in this file,
so we should probably make sure that lands and then rebase this ontop.

> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> ---
> Tested this patch for MPP and IRQ functionality on IFC6410 and SD600 EVAL
> board with mpps PM8821 and PM8921.
> 
>  .../devicetree/bindings/mfd/qcom-pm8xxx.txt        |   1 +
>  drivers/mfd/pm8921-core.c                          | 368 +++++++++++++++++++--
>  2 files changed, 340 insertions(+), 29 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/qcom-pm8xxx.txt b/Documentation/devicetree/bindings/mfd/qcom-pm8xxx.txt
> index 37a088f..8f1b4ec 100644
> --- a/Documentation/devicetree/bindings/mfd/qcom-pm8xxx.txt
> +++ b/Documentation/devicetree/bindings/mfd/qcom-pm8xxx.txt
> @@ -11,6 +11,7 @@ voltages and other various functionality to Qualcomm SoCs.
>  	Definition: must be one of:
>  		    "qcom,pm8058"
>  		    "qcom,pm8921"
> +		    "qcom,pm8821"
>  
>  - #address-cells:
>  	Usage: required
> diff --git a/drivers/mfd/pm8921-core.c b/drivers/mfd/pm8921-core.c
> index 0e3a2ea..28c2470 100644
> --- a/drivers/mfd/pm8921-core.c
> +++ b/drivers/mfd/pm8921-core.c
> @@ -28,16 +28,26 @@
>  #include <linux/mfd/core.h>
>  
>  #define	SSBI_REG_ADDR_IRQ_BASE		0x1BB
> -
> -#define	SSBI_REG_ADDR_IRQ_ROOT		(SSBI_REG_ADDR_IRQ_BASE + 0)
> -#define	SSBI_REG_ADDR_IRQ_M_STATUS1	(SSBI_REG_ADDR_IRQ_BASE + 1)
> -#define	SSBI_REG_ADDR_IRQ_M_STATUS2	(SSBI_REG_ADDR_IRQ_BASE + 2)
> -#define	SSBI_REG_ADDR_IRQ_M_STATUS3	(SSBI_REG_ADDR_IRQ_BASE + 3)
> -#define	SSBI_REG_ADDR_IRQ_M_STATUS4	(SSBI_REG_ADDR_IRQ_BASE + 4)
> -#define	SSBI_REG_ADDR_IRQ_BLK_SEL	(SSBI_REG_ADDR_IRQ_BASE + 5)
> -#define	SSBI_REG_ADDR_IRQ_IT_STATUS	(SSBI_REG_ADDR_IRQ_BASE + 6)
> -#define	SSBI_REG_ADDR_IRQ_CONFIG	(SSBI_REG_ADDR_IRQ_BASE + 7)
> -#define	SSBI_REG_ADDR_IRQ_RT_STATUS	(SSBI_REG_ADDR_IRQ_BASE + 8)

Keep these (per argumentation that follows), but try to name them
appropriately.

> +#define	SSBI_PM8821_REG_ADDR_IRQ_BASE	0x100
> +
> +#define	SSBI_REG_ADDR_IRQ_ROOT		(0)
> +#define	SSBI_REG_ADDR_IRQ_M_STATUS1	(1)
> +#define	SSBI_REG_ADDR_IRQ_M_STATUS2	(2)
> +#define	SSBI_REG_ADDR_IRQ_M_STATUS3	(3)
> +#define	SSBI_REG_ADDR_IRQ_M_STATUS4	(4)
> +#define	SSBI_REG_ADDR_IRQ_BLK_SEL	(5)
> +#define	SSBI_REG_ADDR_IRQ_IT_STATUS	(6)
> +#define	SSBI_REG_ADDR_IRQ_CONFIG	(7)
> +#define	SSBI_REG_ADDR_IRQ_RT_STATUS	(8)

Unnecessary parenthesis.

> +
> +#define	PM8821_TOTAL_IRQ_MASTERS	2

Unused.

> +#define	PM8821_BLOCKS_PER_MASTER	7
> +#define	PM8821_IRQ_MASTER1_SET		0x01

BIT(0), but I would prefer that you just inline this with a comment.

> +#define	PM8821_IRQ_CLEAR_OFFSET		0x01

Rather than having a single define for this and add in the base and
block numbers I think you should split it into a master0 and master1
define. (And it's not a offset as much as a register)

> +#define	PM8821_IRQ_RT_STATUS_OFFSET	0x0f

Dito

> +#define	PM8821_IRQ_MASK_REG_OFFSET	0x08

Dito

> +#define	SSBI_REG_ADDR_IRQ_MASTER0	0x30
> +#define	SSBI_REG_ADDR_IRQ_MASTER1	0xb0

Fold these two into the registers above.

>  
>  #define	PM_IRQF_LVL_SEL			0x01	/* level select */
>  #define	PM_IRQF_MASK_FE			0x02	/* mask falling edge */
> @@ -54,30 +64,41 @@
>  #define REG_HWREV_2		0x0E8  /* PMIC4 revision 2 */
>  
>  #define PM8921_NR_IRQS		256
> +#define PM8821_NR_IRQS		112
>  
>  struct pm_irq_chip {
>  	struct regmap		*regmap;
>  	spinlock_t		pm_irq_lock;
>  	struct irq_domain	*irqdomain;
> +	unsigned int		irq_reg_base;
>  	unsigned int		num_irqs;
>  	unsigned int		num_blocks;
>  	unsigned int		num_masters;
>  	u8			config[0];
>  };
>  
> +struct pm8xxx_data {
> +	int num_irqs;
> +	unsigned int		irq_reg_base;

As far as I can see this is always SSBI_PM8821_REG_ADDR_IRQ_BASE in the
8821 functions and SSBI_REG_ADDR_IRQ_BASE in the pm8xxx functions. If
you have disjunct code paths I think it's better to not obscure this
with a variable.

Try renaming the constants appropriately instead. This also has the
benefit of reducing the size of the patch slightly.

> +	const struct irq_domain_ops  *irq_domain_ops;
> +	void (*irq_handler)(struct irq_desc *desc);
> +};
> +
>  static int pm8xxx_read_block_irq(struct pm_irq_chip *chip, unsigned int bp,
>  				 unsigned int *ip)
>  {
>  	int	rc;
>  
>  	spin_lock(&chip->pm_irq_lock);
> -	rc = regmap_write(chip->regmap, SSBI_REG_ADDR_IRQ_BLK_SEL, bp);
> +	rc = regmap_write(chip->regmap,
> +			  chip->irq_reg_base + SSBI_REG_ADDR_IRQ_BLK_SEL, bp);
>  	if (rc) {
>  		pr_err("Failed Selecting Block %d rc=%d\n", bp, rc);
>  		goto bail;
>  	}
>  
> -	rc = regmap_read(chip->regmap, SSBI_REG_ADDR_IRQ_IT_STATUS, ip);
> +	rc = regmap_read(chip->regmap,
> +			 chip->irq_reg_base + SSBI_REG_ADDR_IRQ_IT_STATUS, ip);
>  	if (rc)
>  		pr_err("Failed Reading Status rc=%d\n", rc);
>  bail:
> @@ -91,14 +112,16 @@ pm8xxx_config_irq(struct pm_irq_chip *chip, unsigned int bp, unsigned int cp)
>  	int	rc;
>  
>  	spin_lock(&chip->pm_irq_lock);
> -	rc = regmap_write(chip->regmap, SSBI_REG_ADDR_IRQ_BLK_SEL, bp);
> +	rc = regmap_write(chip->regmap,
> +			  chip->irq_reg_base + SSBI_REG_ADDR_IRQ_BLK_SEL, bp);
>  	if (rc) {
>  		pr_err("Failed Selecting Block %d rc=%d\n", bp, rc);
>  		goto bail;
>  	}
>  
>  	cp |= PM_IRQF_WRITE;
> -	rc = regmap_write(chip->regmap, SSBI_REG_ADDR_IRQ_CONFIG, cp);
> +	rc = regmap_write(chip->regmap,
> +			  chip->irq_reg_base + SSBI_REG_ADDR_IRQ_CONFIG, cp);
>  	if (rc)
>  		pr_err("Failed Configuring IRQ rc=%d\n", rc);
>  bail:
> @@ -137,8 +160,8 @@ static int pm8xxx_irq_master_handler(struct pm_irq_chip *chip, int master)
>  	unsigned int blockbits;
>  	int block_number, i, ret = 0;
>  
> -	ret = regmap_read(chip->regmap, SSBI_REG_ADDR_IRQ_M_STATUS1 + master,
> -			  &blockbits);
> +	ret = regmap_read(chip->regmap, chip->irq_reg_base +
> +			  SSBI_REG_ADDR_IRQ_M_STATUS1 + master, &blockbits);
>  	if (ret) {
>  		pr_err("Failed to read master %d ret=%d\n", master, ret);
>  		return ret;
> @@ -165,7 +188,8 @@ static void pm8xxx_irq_handler(struct irq_desc *desc)
>  
>  	chained_irq_enter(irq_chip, desc);
>  
> -	ret = regmap_read(chip->regmap, SSBI_REG_ADDR_IRQ_ROOT, &root);
> +	ret = regmap_read(chip->regmap,
> +			  chip->irq_reg_base + SSBI_REG_ADDR_IRQ_ROOT, &root);
>  	if (ret) {
>  		pr_err("Can't read root status ret=%d\n", ret);
>  		return;
> @@ -182,6 +206,122 @@ static void pm8xxx_irq_handler(struct irq_desc *desc)
>  	chained_irq_exit(irq_chip, desc);
>  }
>  
> +static int pm8821_read_master_irq(const struct pm_irq_chip *chip,
> +				  int m, unsigned int *master)
> +{

I think you should inline this, as you already have the calls unrolled
in pm8821_irq_handler().

> +	unsigned int base;
> +
> +	if (!m)
> +		base = chip->irq_reg_base + SSBI_REG_ADDR_IRQ_MASTER0;
> +	else
> +		base = chip->irq_reg_base + SSBI_REG_ADDR_IRQ_MASTER1;
> +
> +	return regmap_read(chip->regmap, base, master);
> +}
> +
> +static int pm8821_read_block_irq(struct pm_irq_chip *chip, int master,
> +				 u8 block, unsigned int *bits)
> +{
> +	int rc;
> +
> +	unsigned int base;

Odd empty line between rc and base. (And btw, sorting your local
variables in descending length make things pretty).

> +
> +	if (!master)
> +		base = chip->irq_reg_base + SSBI_REG_ADDR_IRQ_MASTER0;
> +	else
> +		base = chip->irq_reg_base + SSBI_REG_ADDR_IRQ_MASTER1;
> +
> +	spin_lock(&chip->pm_irq_lock);

The reason why this is done under a lock in the other case is because
the status register is paged, so you shouldn't need it here.

With this updated I think you can favorably inline this into
pm8821_irq_block_handler().

> +
> +	rc = regmap_read(chip->regmap, base + block, bits);
> +	if (rc)
> +		pr_err("Failed Reading Status rc=%d\n", rc);
> +
> +	spin_unlock(&chip->pm_irq_lock);
> +	return rc;
> +}
> +
> +static int pm8821_irq_block_handler(struct pm_irq_chip *chip,
> +				    int master_number, int block)
> +{
> +	int pmirq, irq, i, ret;
> +	unsigned int bits;
> +
> +	ret = pm8821_read_block_irq(chip, master_number, block, &bits);
> +	if (ret) {
> +		pr_err("Failed reading %d block ret=%d", block, ret);
> +		return ret;
> +	}
> +	if (!bits) {
> +		pr_err("block bit set in master but no irqs: %d", block);
> +		return 0;
> +	}
> +
> +	/* Convert block offset to global block number */
> +	block += (master_number * PM8821_BLOCKS_PER_MASTER) - 1;

So this is block -= 1 for master 0 and block += 6 for master 1, is the
latter correct?

> +
> +	/* Check IRQ bits */
> +	for (i = 0; i < 8; i++) {
> +		if (bits & BIT(i)) {
> +			pmirq = block * 8 + i;
> +			irq = irq_find_mapping(chip->irqdomain, pmirq);
> +			generic_handle_irq(irq);
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int pm8821_irq_read_master(struct pm_irq_chip *chip,
> +				int master_number, u8 master_val)

This isn't so much a matter of "reading master X" as "handle master X".

Also, you don't care about the return value, so no need to return one...

> +{
> +	int ret = 0;
> +	int block;
> +
> +	for (block = 1; block < 8; block++) {
> +		if (master_val & BIT(block)) {
> +			ret |= pm8821_irq_block_handler(chip,
> +					master_number, block);
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static void pm8821_irq_handler(struct irq_desc *desc)
> +{
> +	struct pm_irq_chip *chip = irq_desc_get_handler_data(desc);
> +	struct irq_chip *irq_chip = irq_desc_get_chip(desc);
> +	int ret;
> +	unsigned int master;
> +
> +	chained_irq_enter(irq_chip, desc);
> +	/* check master 0 */
> +	ret = pm8821_read_master_irq(chip, 0, &master);
> +	if (ret) {
> +		pr_err("Failed to re:Qad master 0 ret=%d\n", ret);
> +		return;
> +	}
> +
> +	if (master & ~PM8821_IRQ_MASTER1_SET)

Rather than having a define for MASTER1_SET use BIT(0) here and write a
comment like:

"bits 1 through 7 marks the first 7 blocks"

> +		pm8821_irq_read_master(chip, 0, master);
> +

and then

"bit 0 is set if second master contains any bits"

Or just skip this optimization and check the two masters unconditionally
in a loop.

> +	/* check master 1 */
> +	if (!(master & PM8821_IRQ_MASTER1_SET))
> +		goto done;
> +
> +	ret = pm8821_read_master_irq(chip, 1, &master);
> +	if (ret) {
> +		pr_err("Failed to read master 1 ret=%d\n", ret);
> +		return;
> +	}
> +
> +	pm8821_irq_read_master(chip, 1, master);
> +
> +done:
> +	chained_irq_exit(irq_chip, desc);
> +}
> +
>  static void pm8xxx_irq_mask_ack(struct irq_data *d)
>  {
>  	struct pm_irq_chip *chip = irq_data_get_irq_chip_data(d);
> @@ -254,13 +394,15 @@ static int pm8xxx_irq_get_irqchip_state(struct irq_data *d,
>  	irq_bit = pmirq % 8;
>  
>  	spin_lock(&chip->pm_irq_lock);
> -	rc = regmap_write(chip->regmap, SSBI_REG_ADDR_IRQ_BLK_SEL, block);
> +	rc = regmap_write(chip->regmap, chip->irq_reg_base +
> +			  SSBI_REG_ADDR_IRQ_BLK_SEL, block);
>  	if (rc) {
>  		pr_err("Failed Selecting Block %d rc=%d\n", block, rc);
>  		goto bail;
>  	}
>  
> -	rc = regmap_read(chip->regmap, SSBI_REG_ADDR_IRQ_RT_STATUS, &bits);
> +	rc = regmap_read(chip->regmap, chip->irq_reg_base +
> +			 SSBI_REG_ADDR_IRQ_RT_STATUS, &bits);
>  	if (rc) {
>  		pr_err("Failed Reading Status rc=%d\n", rc);
>  		goto bail;
> @@ -299,6 +441,151 @@ static const struct irq_domain_ops pm8xxx_irq_domain_ops = {
>  	.map = pm8xxx_irq_domain_map,
>  };
>  
> +static void pm8821_irq_mask_ack(struct irq_data *d)
> +{
> +	struct pm_irq_chip *chip = irq_data_get_irq_chip_data(d);
> +	unsigned int base, pmirq = irqd_to_hwirq(d);
> +	u8 block, master;
> +	int irq_bit, rc;
> +
> +	block = pmirq / 8;
> +	master = block / PM8821_BLOCKS_PER_MASTER;
> +	irq_bit = pmirq % 8;
> +	block %= PM8821_BLOCKS_PER_MASTER;

You can deobfuscate this somewhat by instead of testing for !master
below you just do:

if (block < PM8821_BLOCKS_PER_MASTER) {
	base = 
} else {
	base = 
	block -= PM8821_BLOCKS_PER_MASTER;
}

> +
> +	if (!master)
> +		base = chip->irq_reg_base + SSBI_REG_ADDR_IRQ_MASTER0;
> +	else
> +		base = chip->irq_reg_base + SSBI_REG_ADDR_IRQ_MASTER1;
> +
> +	spin_lock(&chip->pm_irq_lock);

The irqchip code grabs a lock on the irq_desc, so this can't race with
unmask - and the regmap_update_bits() is internally protecting the
read/write cycle.

So you shouldn't need to lock around this section.

> +	rc = regmap_update_bits(chip->regmap,
> +				base + PM8821_IRQ_MASK_REG_OFFSET + block,
> +				BIT(irq_bit), BIT(irq_bit));
> +
> +	if (rc) {
> +		pr_err("Failed to read/write mask IRQ:%d rc=%d\n", pmirq, rc);
> +		goto fail;
> +	}
> +
> +	rc = regmap_update_bits(chip->regmap,
> +				base + PM8821_IRQ_CLEAR_OFFSET + block,
> +				BIT(irq_bit), BIT(irq_bit));
> +
> +	if (rc) {
> +		pr_err("Failed to read/write IT_CLEAR IRQ:%d rc=%d\n",
> +								pmirq, rc);
> +	}
> +
> +fail:
> +	spin_unlock(&chip->pm_irq_lock);
> +}
> +
> +static void pm8821_irq_unmask(struct irq_data *d)
> +{
> +	struct pm_irq_chip *chip = irq_data_get_irq_chip_data(d);
> +	unsigned int base, pmirq = irqd_to_hwirq(d);
> +	int irq_bit, rc;
> +	u8 block, master;
> +
> +	block = pmirq / 8;
> +	master = block / PM8821_BLOCKS_PER_MASTER;
> +	irq_bit = pmirq % 8;
> +	block %= PM8821_BLOCKS_PER_MASTER;

As mask().

> +
> +	if (!master)
> +		base = chip->irq_reg_base + SSBI_REG_ADDR_IRQ_MASTER0;
> +	else
> +		base = chip->irq_reg_base + SSBI_REG_ADDR_IRQ_MASTER1;
> +
> +	spin_lock(&chip->pm_irq_lock);

As mask().

> +
> +	rc = regmap_update_bits(chip->regmap,
> +				base + PM8821_IRQ_MASK_REG_OFFSET + block,
> +				BIT(irq_bit), ~BIT(irq_bit));
> +
> +	if (rc)
> +		pr_err("Failed to read/write unmask IRQ:%d rc=%d\n", pmirq, rc);
> +
> +	spin_unlock(&chip->pm_irq_lock);
> +}
> +
> +static int pm8821_irq_set_type(struct irq_data *d, unsigned int flow_type)
> +{
> +
> +	/*
> +	 * PM8821 IRQ controller does not have explicit software support for
> +	 * IRQ flow type.
> +	 */

Is returning "success" here the right thing to do? Shouldn't we just
omit the function? Or did you perhaps hit some clients that wouldn't
deal with that?

> +	return 0;
> +}
> +
> +static int pm8821_irq_get_irqchip_state(struct irq_data *d,
> +					enum irqchip_irq_state which,
> +					bool *state)
> +{
> +	struct pm_irq_chip *chip = irq_data_get_irq_chip_data(d);
> +	int pmirq, rc;
> +	u8 block, irq_bit, master;
> +	unsigned int bits;
> +	unsigned int base;
> +	unsigned long flags;
> +
> +	pmirq = irqd_to_hwirq(d);
> +
> +	block = pmirq / 8;
> +	master = block / PM8821_BLOCKS_PER_MASTER;
> +	irq_bit = pmirq % 8;
> +	block %= PM8821_BLOCKS_PER_MASTER;
> +

Simplify as in mask().

> +	if (!master)
> +		base = chip->irq_reg_base + SSBI_REG_ADDR_IRQ_MASTER0;
> +	else
> +		base = chip->irq_reg_base + SSBI_REG_ADDR_IRQ_MASTER1;
> +
> +	spin_lock_irqsave(&chip->pm_irq_lock, flags);

No need to lock here as we're just reading a single register.

> +
> +	rc = regmap_read(chip->regmap,
> +		base + PM8821_IRQ_RT_STATUS_OFFSET + block, &bits);
> +	if (rc) {
> +		pr_err("Failed Reading Status rc=%d\n", rc);
> +		goto bail_out;
> +	}
> +
> +	*state = !!(bits & BIT(irq_bit));
> +
> +bail_out:
> +	spin_unlock_irqrestore(&chip->pm_irq_lock, flags);
> +
> +	return rc;
> +}
> +
> +static struct irq_chip pm8821_irq_chip = {
> +	.name		= "pm8821",
> +	.irq_mask_ack	= pm8821_irq_mask_ack,
> +	.irq_unmask	= pm8821_irq_unmask,
> +	.irq_set_type	= pm8821_irq_set_type,
> +	.irq_get_irqchip_state = pm8821_irq_get_irqchip_state,
> +	.flags		= IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_SKIP_SET_WAKE,
> +};
> +

Regards,
Bjorn

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