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Date: Tue, 12 Jan 2016 16:36:36 +0100
From: Simon Guinot <simon.guinot@...uanux.org>
To: Peter Hung <hpeter@...il.com>
Cc: linus.walleij@...aro.org, gnurou@...il.com,
linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
tom_tsai@...tek.com.tw, peter_hong@...tek.com.tw,
Peter Hung <hpeter+linux_kernel@...il.com>
Subject: Re: [PATCH 2/2] gpio-f7188x: filter non-export gpio for F81866
On Tue, Jan 12, 2016 at 03:41:39PM +0800, Peter Hung wrote:
> Dont export gpios which not enabled by motherboard manufacturer.
>
> Signed-off-by: Peter Hung <hpeter+linux_kernel@...il.com>
Hi Peter,
> ---
> drivers/gpio/gpio-f7188x.c | 153 +++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 153 insertions(+)
>
> diff --git a/drivers/gpio/gpio-f7188x.c b/drivers/gpio/gpio-f7188x.c
> index a6a9641..f7fe7aa 100644
> --- a/drivers/gpio/gpio-f7188x.c
> +++ b/drivers/gpio/gpio-f7188x.c
> @@ -38,6 +38,12 @@
> #define SIO_F71889_ID 0x0909 /* F71889 chipset ID */
> #define SIO_F81866_ID 0x1010 /* F81866 chipset ID */
>
> +#define F81866_PORT_SEL_REG 0x27
> +#define F81866_MULTI_FUN1_REG 0x28
> +#define F81866_MULTI_FUN3_REG 0x29
> +#define F81866_MULTI_FUN4_REG 0x2B
> +#define F81866_GPIO_EN_REG 0x2C
> +
> enum chips { f71869, f71869a, f71882fg, f71889f, f81866 };
>
> static const char * const f7188x_names[] = {
> @@ -93,6 +99,15 @@ static inline void superio_outb(int base, int reg, int val)
> outb(val, base + 1);
> }
>
> +static inline void superio_mask_outb(int base, int reg, int mask, int val)
> +{
> + u8 tmp;
> +
> + tmp = superio_inb(base, reg);
> + tmp = (tmp & ~mask) | (val & mask);
> + superio_outb(base, reg, tmp);
> +}
> +
> static inline int superio_enter(int base)
> {
> /* Don't step on other drivers' I/O space by accident. */
> @@ -304,6 +319,125 @@ static void f7188x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
> superio_exit(sio->addr);
> }
>
> +static int f81866_verify_gpioset(int base, int set)
> +{
> + int err;
> + u8 tmp;
> +
> + err = superio_enter(base);
> + if (err)
> + return err;
> +
> + err = -ENODEV;
> +
> + switch (set) {
> + case 0:
> + superio_mask_outb(base, F81866_PORT_SEL_REG, BIT(3) | BIT(2) |
> + BIT(0), 0);
> + tmp = superio_inb(base, F81866_GPIO_EN_REG);
> + if ((tmp & 0x1f) != 0x1f)
> + break; /* one in GPIO00~GPIO04 is not enable */
> +
> + tmp = superio_inb(base, F81866_MULTI_FUN1_REG);
> + if ((tmp & 0xc) != 0x0)
> + break;
> +
> + err = 0; /* GPIO0x set is all enabled */
> + break;
> + case 1:
> + superio_mask_outb(base, F81866_PORT_SEL_REG, BIT(3) | BIT(2) |
> + BIT(0), BIT(2));
> + tmp = superio_inb(base, F81866_GPIO_EN_REG);
> + if ((tmp & 0xef) != 0xef)
> + break; /* one in GPIO10~GPIO17 is not enable */
> +
> + tmp = superio_inb(base, F81866_MULTI_FUN3_REG);
> + if ((tmp & 0x03) != 0x00)
> + break; /* one in GPIO12~GPIO13 is not enable */
> +
> + err = 0; /* GPIO1x set is all enabled */
> + break;
> + case 2:
> + superio_mask_outb(base, F81866_PORT_SEL_REG, BIT(3) | BIT(2) |
> + BIT(0), BIT(3));
> + tmp = superio_inb(base, F81866_GPIO_EN_REG);
> + if ((tmp & 0xff) != 0xff)
> + break; /* one in GPIO20~GPIO27 is not enable */
> +
> + tmp = superio_inb(base, F81866_MULTI_FUN3_REG);
> + if ((tmp & 0x08) != 0x00)
> + break; /* GPIO20 is not enable */
> +
> + err = 0; /* GPIO2x set is all enabled */
> + break;
> + case 3:
> + superio_mask_outb(base, F81866_PORT_SEL_REG, BIT(0), 0);
> + tmp = superio_inb(base, F81866_MULTI_FUN3_REG);
> + if ((tmp & 0x30) != 0x00)
> + break; /* GPIO3x is not enable */
> +
> + err = 0; /* GPIO3x set is all enabled */
> + break;
> + case 4:
> + superio_mask_outb(base, F81866_PORT_SEL_REG, BIT(0), 0);
> + tmp = superio_inb(base, F81866_MULTI_FUN3_REG);
> + if ((tmp & 0xc0) != 0x00)
> + break; /* GPIO4x is not enable */
> +
> + err = 0; /* GPIO4x set is all enabled */
> + break;
> + case 5:
> + superio_mask_outb(base, F81866_PORT_SEL_REG, BIT(3) | BIT(2),
> + 0);
> + tmp = superio_inb(base, F81866_MULTI_FUN1_REG);
> + if ((tmp & 0x43) != 0x40)
> + break; /* GPIO5x is not enable */
> +
> + err = 0; /* GPIO5x set is all enabled */
> + break;
> + case 6:
> + superio_mask_outb(base, F81866_PORT_SEL_REG, BIT(3) | BIT(2) |
> + BIT(0), 0);
> + tmp = superio_inb(base, F81866_MULTI_FUN1_REG);
> + if ((tmp & 0x4c) != 0x40)
> + break; /* GPIO60~64 is not enable */
> +
> + tmp = superio_inb(base, F81866_MULTI_FUN4_REG);
> + if ((tmp & 0xe0) != 0xe0)
> + break; /* GPIO65~67 is not enable */
> +
> + err = 0; /* GPIO6x set is all enabled */
> + break;
> + case 7:
> + superio_mask_outb(base, F81866_PORT_SEL_REG, BIT(3) | BIT(2) |
> + BIT(0), 0);
> + tmp = superio_inb(base, F81866_MULTI_FUN1_REG);
> + if ((tmp & 0x20) != 0x20)
> + break; /* GPIO7x is not enable */
> +
> + tmp = superio_inb(base, F81866_MULTI_FUN4_REG);
> + if ((tmp & 0x01) != 0x00)
> + break; /* GPIO70 is not enable */
> +
> + err = 0; /* GPIO7x set is all enabled */
> + break;
> + case 8:
> + superio_mask_outb(base, F81866_PORT_SEL_REG, BIT(3) | BIT(2),
> + 0);
> + tmp = superio_inb(base, F81866_MULTI_FUN1_REG);
> + if ((tmp & 0x20) != 0x20)
> + break; /* GPIO8x is not enable */
> +
> + err = 0; /* GPIO8x set is all enabled */
> + break;
> + default:
> + break;
> + }
> +
> + superio_exit(base);
> + return err;
> +}
> +
> /*
> * Platform device and driver.
> */
> @@ -351,6 +485,15 @@ static int f7188x_gpio_probe(struct platform_device *pdev)
> for (i = 0; i < data->nr_bank; i++) {
> struct f7188x_gpio_bank *bank = &data->bank[i];
>
> + /*
> + * Dont export GPIO sysfs if pin set is not enable by MB
> + * manufacturer.
What does MB stands for ?
> + */
> + if (sio->type == f81866 && f81866_verify_gpioset(sio->addr, i))
> + continue;
This whole filtering mechanism relies on the fact that the multiplexing
configuration has been correctly applied by the BIOS (if applied at
all). But I wonder if it is often the case. For example, I have several
boards for which it is not true. And to make the GPIOs available, I need
first to fix the multiplexing pin configuration of the Super I/O.
Maybe it would be more correct to rely on the hardware description of a
board (Device Tree or ACPI) to decide which GPIO bank can be enabled or
not.
Simon
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