pinctrl: at91: drive strength control
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Mon Jan 20 21:19:25 EST 2014
On 20:07 Mon 20 Jan , Marek Roszko wrote:
> Hello Nick and Jean-Christophe,
>
> I submit a idea/patch for comments. The current pintctrl driver is missing the ability to set the drive strength in the SAMA5D3s and a few of the SAM9s.
> A little feature I myself need for the SAMA5D3s because somebody let an analog engineer do the hardware design.
>
> Issues with this patch I need help with:
> 1. Atmel for some reason shifted the PIO_DRIVER1 and PIO_DRIVER2 registers by one register address between the SAM9 chips and the SAMA5D3s
>
> i.e. this is the SAM9s
> #define PIO_DRIVER1_V1 0x114
> #define PIO_DRIVER2_V1 0x118
>
> this is the SAMA5D3s
> #define PIO_DRIVER1_V2 0x118
> #define PIO_DRIVER2_V2 0x11C
>
>
> 2. Atmel changed the meaning of value of "low", "medium" and "high" drive strengths between the two sets of chips as well.
>
> SAM9s do:
> 00 = high
> 01 = medium
> 10 = low
> 11 = reserved/undefined
>
> SAMA5D3s do:
> 00 = low
> 01 = low
> 10 = medium
> 11 = high
>
> 3. The SAM9G25, SAM9G35 have the PIO_DRIVER but the SAM9G45 does not have the PIO_DRIVER register as an example of
> how oddly the behavior doesn't appear everywhere. This could also be because the datasheets for the G45 and G46 are
> not updated to the new style while the others already have been?
>
> Side note: The SAMA5D3 datasheet says the default drive strength is "low" with register values 0x00000000,
> in reality the default is "medium" with 0xAAAAAAAA as the default value.
> Confirmed with the JLINK debugger and by Atmel support. Not an real issue, just a note when testing.
check the coding style tab for indentatnion, 80 charrs per line max etc...
>
>
> So the only simple way I see is to #ifdef the SOC type/chip.
> There's probably better far better ways I don't know.
>
> ---
> arch/arm/mach-at91/include/mach/at91_pio.h | 9 +++++
> drivers/pinctrl/pinctrl-at91.c | 54 +++++++++++++++++++++++++++-
> include/dt-bindings/pinctrl/at91.h | 13 +++++++
> 3 files changed, 75 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/mach-at91/include/mach/at91_pio.h b/arch/arm/mach-at91/include/mach/at91_pio.h
> index 732b11c..28e8801 100644
> --- a/arch/arm/mach-at91/include/mach/at91_pio.h
> +++ b/arch/arm/mach-at91/include/mach/at91_pio.h
> @@ -66,6 +66,15 @@
> #define PIO_FRLHSR 0xd8 /* Fall/Rise - Low/High Status Register */
> #define PIO_SCHMITT 0x100 /* Schmitt Trigger Register */
>
> +/*
> + * SoC Specific PIO Address Offsets
> + */
> +#define PIO_DRIVER1_V1 0x114
> +#define PIO_DRIVER2_V1 0x118
> +
> +#define PIO_DRIVER1_V2 0x118
> +#define PIO_DRIVER2_V2 0x11C
> +
> #define ABCDSR_PERIPH_A 0x0
> #define ABCDSR_PERIPH_B 0x1
> #define ABCDSR_PERIPH_C 0x2
> diff --git a/drivers/pinctrl/pinctrl-at91.c b/drivers/pinctrl/pinctrl-at91.c
> index a7549c4..ccf456e 100644
> --- a/drivers/pinctrl/pinctrl-at91.c
> +++ b/drivers/pinctrl/pinctrl-at91.c
> @@ -62,10 +62,37 @@ static int gpio_banks;
> #define DEGLITCH (1 << 2)
> #define PULL_DOWN (1 << 3)
> #define DIS_SCHMIT (1 << 4)
> +#define SET_DRIVE_STRENGTH (1 << 5)
> +#define DRIVE_STRENGTH_SHIFT 6
> +#define DRIVE_STRENGTH (0x3 << DRIVE_STRENGTH_SHIFT)
> #define DEBOUNCE (1 << 16)
> #define DEBOUNCE_VAL_SHIFT 17
> #define DEBOUNCE_VAL (0x3fff << DEBOUNCE_VAL_SHIFT)
>
> +#define DRIVE_STRENGTH_MASK 0x3
> +
> +#define NUM_PINS_PER_DRIVE_STRENGTH_REG 16
> +
> +#define TWO_BIT_PIN_TO_SHIFT(pin)\
> + (2*((pin >= NUM_PINS_PER_DRIVE_STRENGTH_REG) ? \
> + pin - NUM_PINS_PER_DRIVE_STRENGTH_REG : pin))
> +
> +#define TWO_BIT_PIN_TO_MASK(pin)\
> + (DRIVE_STRENGTH_MASK << TWO_BIT_PIN_TO_SHIFT(pin))
> +
> +#if defined(CONFIG_SOC_SAMA5D3)
> + #define PIO_DRIVER1 PIO_DRIVER1_V2 /* Drive Strength Register 1 */
> + #define PIO_DRIVER2 PIO_DRIVER2_V2 /* Drive Strength Register 2 */
> +#elif defined(CONFIG_SOC_AT91SAM9X5) || defined(SOC_AT91SAM9G35) || defined(SOC_AT91SAM9G25)
> + #define PIO_DRIVER1 PIO_DRIVER1_V1 /* Drive Strength Register 1 */
> + #define PIO_DRIVER2 PIO_DRIVER2_V1 /* Drive Strength Register 2 */
> +#endif
no ifdef this is choose at runtime
> +
> +#if defined(PIO_DRIVER1) && defined(PIO_DRIVER2)
> + #define PIO_DRIVER(pin)\
> + ((pin > NUM_PINS_PER_DRIVE_STRENGTH_REG-1) ? PIO_DRIVER2 : PIO_DRIVER1)
> +#endif
use inline function
> +
> /**
> * struct at91_pmx_func - describes AT91 pinmux functions
> * @name: the name of this specific function
> @@ -148,6 +175,8 @@ struct at91_pinctrl_mux_ops {
> void (*set_deglitch)(void __iomem *pio, unsigned mask, bool is_on);
> bool (*get_debounce)(void __iomem *pio, unsigned pin, u32 *div);
> void (*set_debounce)(void __iomem *pio, unsigned mask, bool is_on, u32 div);
> + int (*get_drivestrength)(void __iomem *pio, unsigned pin);
> + void (*set_drivestrength)(void __iomem *pio, unsigned pin, u32 strength);
> bool (*get_pulldown)(void __iomem *pio, unsigned pin);
> void (*set_pulldown)(void __iomem *pio, unsigned mask, bool is_on);
> bool (*get_schmitt_trig)(void __iomem *pio, unsigned pin);
> @@ -462,6 +491,20 @@ static void at91_mux_pio3_set_pulldown(void __iomem *pio, unsigned mask, bool is
> __raw_writel(mask, pio + (is_on ? PIO_PPDER : PIO_PPDDR));
> }
>
> +static int at91_mux_pio3_get_drivestrength(void __iomem *pio, unsigned pin)
> +{
> + return (__raw_readl(pio + PIO_DRIVER(pin)) >> TWO_BIT_PIN_TO_SHIFT(pin)) & DRIVE_STRENGTH_MASK;
> +}
> +
> +static void at91_mux_pio3_set_drivestrength(void __iomem *pio, unsigned pin, u32 strength)
> +{
> + unsigned tmp = __raw_readl(pio + PIO_DRIVER(pin));
> + tmp &= ~TWO_BIT_PIN_TO_MASK(pin);
> + tmp |= strength << TWO_BIT_PIN_TO_SHIFT(pin);
> +
> + __raw_writel(tmp, pio + PIO_DRIVER(pin));
> +}
> +
> static void at91_mux_pio3_disable_schmitt_trig(void __iomem *pio, unsigned mask)
> {
> __raw_writel(__raw_readl(pio + PIO_SCHMITT) | mask, pio + PIO_SCHMITT);
> @@ -491,6 +534,8 @@ static struct at91_pinctrl_mux_ops at91sam9x5_ops = {
> .set_deglitch = at91_mux_pio3_set_deglitch,
> .get_debounce = at91_mux_pio3_get_debounce,
> .set_debounce = at91_mux_pio3_set_debounce,
> + .get_drivestrength = at91_mux_pio3_get_drivestrength,
> + .set_drivestrength = at91_mux_pio3_set_drivestrength,
> .get_pulldown = at91_mux_pio3_get_pulldown,
> .set_pulldown = at91_mux_pio3_set_pulldown,
> .get_schmitt_trig = at91_mux_pio3_get_schmitt_trig,
> @@ -736,6 +781,8 @@ static int at91_pinconf_get(struct pinctrl_dev *pctldev,
> *config |= DEGLITCH;
> if (info->ops->get_debounce && info->ops->get_debounce(pio, pin, &div))
> *config |= DEBOUNCE | (div << DEBOUNCE_VAL_SHIFT);
> + if (info->ops->get_drivestrength)
> + *config |= DRIVE_STRENGTH | (info->ops->get_drivestrength(pio, pin) << DRIVE_STRENGTH_SHIFT);
> if (info->ops->get_pulldown && info->ops->get_pulldown(pio, pin))
> *config |= PULL_DOWN;
> if (info->ops->get_schmitt_trig && info->ops->get_schmitt_trig(pio, pin))
> @@ -753,6 +800,7 @@ static int at91_pinconf_set(struct pinctrl_dev *pctldev,
> void __iomem *pio;
> int i;
> unsigned long config;
> + unsigned pin;
>
> for (i = 0; i < num_configs; i++) {
> config = configs[i];
> @@ -761,7 +809,8 @@ static int at91_pinconf_set(struct pinctrl_dev *pctldev,
> "%s:%d, pin_id=%d, config=0x%lx",
> __func__, __LINE__, pin_id, config);
> pio = pin_to_controller(info, pin_to_bank(pin_id));
> - mask = pin_to_mask(pin_id % MAX_NB_GPIO_PER_BANK);
> + pin = pin_id % MAX_NB_GPIO_PER_BANK;
> + mask = pin_to_mask(pin);
>
> if (config & PULL_UP && config & PULL_DOWN)
> return -EINVAL;
> @@ -773,6 +822,9 @@ static int at91_pinconf_set(struct pinctrl_dev *pctldev,
> if (info->ops->set_debounce)
> info->ops->set_debounce(pio, mask, config & DEBOUNCE,
> (config & DEBOUNCE_VAL) >> DEBOUNCE_VAL_SHIFT);
> + if (info->ops->set_drivestrength && config & SET_DRIVE_STRENGTH)
> + info->ops->set_drivestrength(pio, pin,
> + (config & DRIVE_STRENGTH) >> DRIVE_STRENGTH_SHIFT);
> if (info->ops->set_pulldown)
> info->ops->set_pulldown(pio, mask, config & PULL_DOWN);
> if (info->ops->disable_schmitt_trig && config & DIS_SCHMIT)
> diff --git a/include/dt-bindings/pinctrl/at91.h b/include/dt-bindings/pinctrl/at91.h
> index 0fee6ff..78621a4 100644
> --- a/include/dt-bindings/pinctrl/at91.h
> +++ b/include/dt-bindings/pinctrl/at91.h
> @@ -20,6 +20,19 @@
>
> #define AT91_PINCTRL_PULL_UP_DEGLITCH (AT91_PINCTRL_PULL_UP | AT91_PINCTRL_DEGLITCH)
>
> +#define AT91_PINCTRL_SET_DRIVE_STRENGTH (1 << 5)
> +
> +#if defined(CONFIG_SOC_SAMA5D3)
> + #define AT91_PINCTRL_DRIVE_STRENGTH_LOW (0x2 << 6)
> + #define AT91_PINCTRL_DRIVE_STRENGTH_MED (0x1 << 6)
> + #define AT91_PINCTRL_DRIVE_STRENGTH_HI (0x0 << 6)
> +#elif defined(CONFIG_SOC_AT91SAM9X5) || defined(SOC_AT91SAM9G35) || defined(SOC_AT91SAM9G25)
> + #define AT91_PINCTRL_DRIVE_STRENGTH_LOW (0x1 << 6)
> + #define AT91_PINCTRL_DRIVE_STRENGTH_MED (0x2 << 6)
> + #define AT91_PINCTRL_DRIVE_STRENGTH_HI (0x3 << 6)
> +#endif
no only one binding we do not care of the IP details
0 means no drive strength specified
> +
> +
> #define AT91_PIOA 0
> #define AT91_PIOB 1
> #define AT91_PIOC 2
> --
> 1.7.10.4
>
>
>
>
> --
> Mark
>
>
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