Message-Id: <f3805ca3-3d77-4482-b75f-3e869625e0bc@www.fastmail.com>
Date:   Tue, 08 Jun 2021 09:13:59 +0930
From:   "Andrew Jeffery" <andrew@...id.au>
To:     "Steven Lee" <steven_lee@...eedtech.com>,
        "Linus Walleij" <linus.walleij@...aro.org>,
        "Bartosz Golaszewski" <bgolaszewski@...libre.com>,
        "Rob Herring" <robh+dt@...nel.org>,
        "Joel Stanley" <joel@....id.au>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        "moderated list:ARM/ASPEED MACHINE SUPPORT" 
        <linux-arm-kernel@...ts.infradead.org>,
        "moderated list:ARM/ASPEED MACHINE SUPPORT" 
        <linux-aspeed@...ts.ozlabs.org>,
        "open list" <linux-kernel@...r.kernel.org>
Cc:     "Hongwei Zhang" <Hongweiz@....com>,
        "Ryan Chen" <ryan_chen@...eedtech.com>,
        "Billy Tsai" <billy_tsai@...eedtech.com>
Subject: Re: [PATCH v4 4/7] gpio: gpio-aspeed-sgpio: Add AST2600 sgpio support



On Mon, 7 Jun 2021, at 16:45, Steven Lee wrote:
> AST2600 SoC has 2 SGPIO master interfaces one with 128 pins another one
> with 80 pins.
> In the current driver, the maximum number of gpio pins of SoC is hardcoded
> as 80 and the gpio pin count mask for GPIO Configuration register is
> hardcode as GENMASK(9,6). In addition, some functions use the hardcoded
> value to calculate the gpio offset.
> The patch adds ast2600 compatibles and platform data that includes the
> max number of gpio pins supported by ast2600 and gpio pin count mask for
> GPIO Configuration register.
> The patch also modifies some functions to pass aspeed_sgpio struct for
> calculating gpio offset without using the hardcoded value.
> 
> Signed-off-by: Steven Lee <steven_lee@...eedtech.com>
> ---
>  drivers/gpio/gpio-aspeed-sgpio.c | 110 +++++++++++++++++++++----------
>  1 file changed, 76 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-aspeed-sgpio.c b/drivers/gpio/gpio-aspeed-sgpio.c
> index 64e54f8c30d2..8b893356f0ca 100644
> --- a/drivers/gpio/gpio-aspeed-sgpio.c
> +++ b/drivers/gpio/gpio-aspeed-sgpio.c
> @@ -35,12 +35,18 @@
>  #define ASPEED_SGPIO_CLK_DIV_MASK	GENMASK(31, 16)
>  #define ASPEED_SGPIO_ENABLE		BIT(0)
>  
> +struct aspeed_sgpio_pdata {
> +	const u32 pin_mask;
> +	int max_ngpios;
> +};
> +
>  struct aspeed_sgpio {
>  	struct gpio_chip chip;
>  	struct clk *pclk;
>  	spinlock_t lock;
>  	void __iomem *base;
>  	int irq;
> +	int max_ngpios;
>  	int n_sgpio;
>  };
>  
> @@ -75,7 +81,13 @@ static const struct aspeed_sgpio_bank 
> aspeed_sgpio_banks[] = {
>  		.val_regs = 0x0038,
>  		.rdata_reg = 0x0078,
>  		.irq_regs = 0x003C,
> -		.names = { "I", "J" },
> +		.names = { "I", "J", "K", "L" },
> +	},
> +	{
> +		.val_regs = 0x0090,
> +		.rdata_reg = 0x007C,
> +		.irq_regs = 0x0094,
> +		.names = { "M", "N", "O", "P" },
>  	},
>  };
>  
> @@ -121,15 +133,15 @@ static void __iomem *bank_reg(struct aspeed_sgpio *gpio,
>  	}
>  }
>  
> -#define GPIO_BANK(x)    ((x % SGPIO_OUTPUT_OFFSET) >> 5)
> -#define GPIO_OFFSET(x)  ((x % SGPIO_OUTPUT_OFFSET) & 0x1f)
> -#define GPIO_BIT(x)     BIT(GPIO_OFFSET(x))
> +#define GPIO_BANK(x, gpio)    ((x % (gpio)->max_ngpios) >> 5)

I couldn't stop myself from commenting on this: The 'context' parameter should be first (by convention), so:

#define GPIO_BANK(gpio, x) ((x % (gpio)->max_ngpios) >> 5)

There's another fix necessary here too - the x needs to be parenthesised:

#define GPIO_BANK(gpio, x) (((x) % (gpio)->max_ngpios) >> 5)

> +#define GPIO_OFFSET(x)        ((x) & GENMASK(4, 0))
> +#define GPIO_BIT(x, gpio)     BIT(GPIO_OFFSET(x % (gpio)->max_ngpios))

Again, put the context parameter first. And again we should add the parentheses around x in the expression.

>  
> -static const struct aspeed_sgpio_bank *to_bank(unsigned int offset)
> +static const struct aspeed_sgpio_bank *to_bank(unsigned int offset, 
> const struct aspeed_sgpio *gpio)
>  {
>  	unsigned int bank;
>  
> -	bank = GPIO_BANK(offset);
> +	bank = GPIO_BANK(offset, gpio);
>  
>  	WARN_ON(bank >= ARRAY_SIZE(aspeed_sgpio_banks));
>  	return &aspeed_sgpio_banks[bank];
> @@ -139,18 +151,19 @@ static int aspeed_sgpio_init_valid_mask(struct 
> gpio_chip *gc,
>  		unsigned long *valid_mask, unsigned int ngpios)
>  {
>  	struct aspeed_sgpio *sgpio = gpiochip_get_data(gc);
> +	int max_ngpios = sgpio->max_ngpios;
>  	int n = sgpio->n_sgpio;
> -	int c = SGPIO_OUTPUT_OFFSET - n;
> +	int c = max_ngpios - n;
>  
> -	WARN_ON(ngpios < MAX_NR_HW_SGPIO * 2);
> +	WARN_ON(ngpios < max_ngpios * 2);
>  
>  	/* input GPIOs in the lower range */
>  	bitmap_set(valid_mask, 0, n);
>  	bitmap_clear(valid_mask, n, c);
>  
> -	/* output GPIOS above SGPIO_OUTPUT_OFFSET */
> -	bitmap_set(valid_mask, SGPIO_OUTPUT_OFFSET, n);
> -	bitmap_clear(valid_mask, SGPIO_OUTPUT_OFFSET + n, c);
> +	/* output GPIOS above max_ngpios */
> +	bitmap_set(valid_mask, max_ngpios, n);
> +	bitmap_clear(valid_mask, max_ngpios + n, c);
>  
>  	return 0;
>  }
> @@ -161,30 +174,30 @@ static void 
> aspeed_sgpio_irq_init_valid_mask(struct gpio_chip *gc,
>  	struct aspeed_sgpio *sgpio = gpiochip_get_data(gc);
>  	int n = sgpio->n_sgpio;
>  
> -	WARN_ON(ngpios < MAX_NR_HW_SGPIO * 2);
> +	WARN_ON(ngpios < sgpio->max_ngpios * 2);
>  
>  	/* input GPIOs in the lower range */
>  	bitmap_set(valid_mask, 0, n);
>  	bitmap_clear(valid_mask, n, ngpios - n);
>  }
>  
> -static bool aspeed_sgpio_is_input(unsigned int offset)
> +static bool aspeed_sgpio_is_input(unsigned int offset, const struct 
> aspeed_sgpio *gpio)
>  {
> -	return offset < SGPIO_OUTPUT_OFFSET;
> +	return offset < gpio->max_ngpios;
>  }
>  
>  static int aspeed_sgpio_get(struct gpio_chip *gc, unsigned int offset)
>  {
>  	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
> -	const struct aspeed_sgpio_bank *bank = to_bank(offset);
> +	const struct aspeed_sgpio_bank *bank = to_bank(offset, gpio);
>  	unsigned long flags;
>  	enum aspeed_sgpio_reg reg;
>  	int rc = 0;
>  
>  	spin_lock_irqsave(&gpio->lock, flags);
>  
> -	reg = aspeed_sgpio_is_input(offset) ? reg_val : reg_rdata;
> -	rc = !!(ioread32(bank_reg(gpio, bank, reg)) & GPIO_BIT(offset));
> +	reg = aspeed_sgpio_is_input(offset, gpio) ? reg_val : reg_rdata;
> +	rc = !!(ioread32(bank_reg(gpio, bank, reg)) & GPIO_BIT(offset, gpio));
>  
>  	spin_unlock_irqrestore(&gpio->lock, flags);
>  
> @@ -194,11 +207,11 @@ static int aspeed_sgpio_get(struct gpio_chip *gc, 
> unsigned int offset)
>  static int sgpio_set_value(struct gpio_chip *gc, unsigned int offset, 
> int val)
>  {
>  	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
> -	const struct aspeed_sgpio_bank *bank = to_bank(offset);
> +	const struct aspeed_sgpio_bank *bank = to_bank(offset, gpio);
>  	void __iomem *addr_r, *addr_w;
>  	u32 reg = 0;
>  
> -	if (aspeed_sgpio_is_input(offset))
> +	if (aspeed_sgpio_is_input(offset, gpio))
>  		return -EINVAL;
>  
>  	/* Since this is an output, read the cached value from rdata, then
> @@ -209,9 +222,9 @@ static int sgpio_set_value(struct gpio_chip *gc, 
> unsigned int offset, int val)
>  	reg = ioread32(addr_r);
>  
>  	if (val)
> -		reg |= GPIO_BIT(offset);
> +		reg |= GPIO_BIT(offset, gpio);
>  	else
> -		reg &= ~GPIO_BIT(offset);
> +		reg &= ~GPIO_BIT(offset, gpio);
>  
>  	iowrite32(reg, addr_w);
>  
> @@ -232,7 +245,9 @@ static void aspeed_sgpio_set(struct gpio_chip *gc, 
> unsigned int offset, int val)
>  
>  static int aspeed_sgpio_dir_in(struct gpio_chip *gc, unsigned int offset)
>  {
> -	return aspeed_sgpio_is_input(offset) ? 0 : -EINVAL;
> +	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
> +
> +	return aspeed_sgpio_is_input(offset, gpio) ? 0 : -EINVAL;
>  }
>  
>  static int aspeed_sgpio_dir_out(struct gpio_chip *gc, unsigned int 
> offset, int val)
> @@ -253,7 +268,9 @@ static int aspeed_sgpio_dir_out(struct gpio_chip 
> *gc, unsigned int offset, int v
>  
>  static int aspeed_sgpio_get_direction(struct gpio_chip *gc, unsigned 
> int offset)
>  {
> -	return !!aspeed_sgpio_is_input(offset);
> +	struct aspeed_sgpio *gpio = gpiochip_get_data(gc);
> +
> +	return !!aspeed_sgpio_is_input(offset, gpio);
>  }
>  
>  static void irqd_to_aspeed_sgpio_data(struct irq_data *d,
> @@ -268,8 +285,8 @@ static void irqd_to_aspeed_sgpio_data(struct irq_data *d,
>  	WARN_ON(!internal);
>  
>  	*gpio = internal;
> -	*bank = to_bank(*offset);
> -	*bit = GPIO_BIT(*offset);
> +	*bank = to_bank(*offset, internal);
> +	*bit = GPIO_BIT(*offset, internal);
>  }
>  
>  static void aspeed_sgpio_irq_ack(struct irq_data *d)
> @@ -466,9 +483,21 @@ static int aspeed_sgpio_setup_irqs(struct 
> aspeed_sgpio *gpio,
>  	return 0;
>  }
>  
> +static const struct aspeed_sgpio_pdata ast2600_sgpiom_128_pdata = {
> +	.max_ngpios = 128,
> +	.pin_mask = GENMASK(10, 6),
> +};
> +
> +static const struct aspeed_sgpio_pdata ast2600_sgpiom_80_pdata = {
> +	.max_ngpios = 80,
> +	.pin_mask = GENMASK(10, 6),
> +};
> +
>  static const struct of_device_id aspeed_sgpio_of_table[] = {
>  	{ .compatible = "aspeed,ast2400-sgpio" },
>  	{ .compatible = "aspeed,ast2500-sgpio" },

Add .data for these too.

> +	{ .compatible = "aspeed,ast2600-sgpiom-128", .data = 
> &ast2600_sgpiom_128_pdata, },
> +	{ .compatible = "aspeed,ast2600-sgpiom-80", .data = 
> &ast2600_sgpiom_80_pdata, },
>  	{}
>  };
>  
> @@ -476,10 +505,11 @@ MODULE_DEVICE_TABLE(of, aspeed_sgpio_of_table);
>  
>  static int __init aspeed_sgpio_probe(struct platform_device *pdev)
>  {
> +	u32 nr_gpios, sgpio_freq, sgpio_clk_div, gpio_cnt_regval, pin_mask;
> +	const struct aspeed_sgpio_pdata *pdata;
>  	struct aspeed_sgpio *gpio;
> -	u32 nr_gpios, sgpio_freq, sgpio_clk_div;
> -	int rc;
>  	unsigned long apb_freq;
> +	int rc;
>  
>  	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
>  	if (!gpio)
> @@ -489,13 +519,26 @@ static int __init aspeed_sgpio_probe(struct 
> platform_device *pdev)
>  	if (IS_ERR(gpio->base))
>  		return PTR_ERR(gpio->base);
>  
> +	pdata = device_get_match_data(&pdev->dev);
> +	if (pdata) {
> +		gpio->max_ngpios = pdata->max_ngpios;
> +		pin_mask = pdata->pin_mask;
> +	} else {
> +		gpio->max_ngpios = MAX_NR_HW_SGPIO;
> +		pin_mask = ASPEED_SGPIO_PINS_MASK;

Given the refactor I think the MAX_NR_HW_SGPIO and ASPEED_SGPIO_PINS_MASK macros are confusing and should be dropped.

Further, I think it would be better to just define these 'default' values in .data for the 2400 and 2500 compatibles and drop this if/else entirely.

> +	}
> +
>  	rc = of_property_read_u32(pdev->dev.of_node, "ngpios", &nr_gpios);
>  	if (rc < 0) {
>  		dev_err(&pdev->dev, "Could not read ngpios property\n");
>  		return -EINVAL;
> -	} else if (nr_gpios > MAX_NR_HW_SGPIO) {
> +	} else if (nr_gpios % 8) {
> +		dev_err(&pdev->dev, "Number of GPIOs not multiple of 8: %d\n",
> +			nr_gpios);
> +		return -EINVAL;
> +	} else if (nr_gpios > gpio->max_ngpios) {

I'd prefer this in a separate patch.

>  		dev_err(&pdev->dev, "Number of GPIOs exceeds the maximum of %d: 
> %d\n",
> -			MAX_NR_HW_SGPIO, nr_gpios);
> +			gpio->max_ngpios, nr_gpios);
>  		return -EINVAL;
>  	}
>  	gpio->n_sgpio = nr_gpios;
> @@ -531,15 +574,14 @@ static int __init aspeed_sgpio_probe(struct 
> platform_device *pdev)
>  	if (sgpio_clk_div > (1 << 16) - 1)
>  		return -EINVAL;
>  
> -	iowrite32(FIELD_PREP(ASPEED_SGPIO_CLK_DIV_MASK, sgpio_clk_div) |
> -		  FIELD_PREP(ASPEED_SGPIO_PINS_MASK, (nr_gpios / 8)) |
> -		  ASPEED_SGPIO_ENABLE,
> -		  gpio->base + ASPEED_SGPIO_CTRL);
> +	gpio_cnt_regval = ((nr_gpios / 8) << 6) & pin_mask;

Add a #define for the field starting at bit 6.

Andrew

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