On Mon, Jan 25, 2021 at 12:19:13PM +0200, Claudiu Beznea wrote:
> SAMA7G5 supports slew rate configuration. Adapt the driver for this.
> For switching frequencies lower than 50MHz the slew rate needs to
> be enabled. Since most of the pins on SAMA7G5 fall into this category
> enabled the slew rate by default.
>
> Signed-off-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
> ---
> drivers/pinctrl/pinctrl-at91-pio4.c | 27 +++++++++++++++++++++++++++
> 1 file changed, 27 insertions(+)
>
> diff --git a/drivers/pinctrl/pinctrl-at91-pio4.c b/drivers/pinctrl/pinctrl-at91-pio4.c
> index d267367d94b9..c59ab0bfb945 100644
> --- a/drivers/pinctrl/pinctrl-at91-pio4.c
> +++ b/drivers/pinctrl/pinctrl-at91-pio4.c
> @@ -36,6 +36,7 @@
> #define ATMEL_PIO_DIR_MASK BIT(8)
> #define ATMEL_PIO_PUEN_MASK BIT(9)
> #define ATMEL_PIO_PDEN_MASK BIT(10)
> +#define ATMEL_PIO_SR_MASK BIT(11)
> #define ATMEL_PIO_IFEN_MASK BIT(12)
> #define ATMEL_PIO_IFSCEN_MASK BIT(13)
> #define ATMEL_PIO_OPD_MASK BIT(14)
> @@ -76,10 +77,12 @@
> * @nbanks: number of PIO banks
> * @last_bank_count: number of lines in the last bank (can be less than
> * the rest of the banks).
> + * @sr: slew rate support
> */
> struct atmel_pioctrl_data {
> unsigned nbanks;
> unsigned last_bank_count;
> + unsigned int sr;
Hi Claudiu,
Nitpicking: I tend to prefer a verbose name as slew_rate or even
slew_rate_support.
Otherwise,
Acked-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>
Regards
Ludovic
> };
>
> struct atmel_group {
> @@ -117,6 +120,7 @@ struct atmel_pin {
> * @pm_suspend_backup: backup/restore register values on suspend/resume
> * @dev: device entry for the Atmel PIO controller.
> * @node: node of the Atmel PIO controller.
> + * @sr: slew rate support
> */
> struct atmel_pioctrl {
> void __iomem *reg_base;
> @@ -138,6 +142,7 @@ struct atmel_pioctrl {
> } *pm_suspend_backup;
> struct device *dev;
> struct device_node *node;
> + unsigned int sr;
> };
>
> static const char * const atmel_functions[] = {
> @@ -760,6 +765,13 @@ static int atmel_conf_pin_config_group_get(struct pinctrl_dev *pctldev,
> return -EINVAL;
> arg = 1;
> break;
> + case PIN_CONFIG_SLEW_RATE:
> + if (!atmel_pioctrl->sr)
> + return -EOPNOTSUPP;
> + if (!(res & ATMEL_PIO_SR_MASK))
> + return -EINVAL;
> + arg = 1;
> + break;
> case ATMEL_PIN_CONFIG_DRIVE_STRENGTH:
> if (!(res & ATMEL_PIO_DRVSTR_MASK))
> return -EINVAL;
> @@ -793,6 +805,10 @@ static int atmel_conf_pin_config_group_set(struct pinctrl_dev *pctldev,
> dev_dbg(pctldev->dev, "%s: pin=%u, config=0x%lx\n",
> __func__, pin_id, configs[i]);
>
> + /* Keep slew rate enabled by default. */
> + if (atmel_pioctrl->sr)
> + conf |= ATMEL_PIO_SR_MASK;
> +
> switch (param) {
> case PIN_CONFIG_BIAS_DISABLE:
> conf &= (~ATMEL_PIO_PUEN_MASK);
> @@ -850,6 +866,13 @@ static int atmel_conf_pin_config_group_set(struct pinctrl_dev *pctldev,
> ATMEL_PIO_SODR);
> }
> break;
> + case PIN_CONFIG_SLEW_RATE:
> + if (!atmel_pioctrl->sr)
> + break;
> + /* And remove it if explicitly requested. */
> + if (arg == 0)
> + conf &= ~ATMEL_PIO_SR_MASK;
> + break;
> case ATMEL_PIN_CONFIG_DRIVE_STRENGTH:
> switch (arg) {
> case ATMEL_PIO_DRVSTR_LO:
> @@ -901,6 +924,8 @@ static void atmel_conf_pin_config_dbg_show(struct pinctrl_dev *pctldev,
> seq_printf(s, "%s ", "open-drain");
> if (conf & ATMEL_PIO_SCHMITT_MASK)
> seq_printf(s, "%s ", "schmitt");
> + if (atmel_pioctrl->sr && (conf & ATMEL_PIO_SR_MASK))
> + seq_printf(s, "%s ", "slew-rate");
> if (conf & ATMEL_PIO_DRVSTR_MASK) {
> switch ((conf & ATMEL_PIO_DRVSTR_MASK) >> ATMEL_PIO_DRVSTR_OFFSET) {
> case ATMEL_PIO_DRVSTR_ME:
> @@ -994,6 +1019,7 @@ static const struct atmel_pioctrl_data atmel_sama5d2_pioctrl_data = {
> static const struct atmel_pioctrl_data microchip_sama7g5_pioctrl_data = {
> .nbanks = 5,
> .last_bank_count = 8, /* sama7g5 has only PE0 to PE7 */
> + .sr = 1,
> };
>
> static const struct of_device_id atmel_pctrl_of_match[] = {
> @@ -1039,6 +1065,7 @@ static int atmel_pinctrl_probe(struct platform_device *pdev)
> atmel_pioctrl->npins -= ATMEL_PIO_NPINS_PER_BANK;
> atmel_pioctrl->npins += atmel_pioctrl_data->last_bank_count;
> }
> + atmel_pioctrl->sr = atmel_pioctrl_data->sr;
>
> atmel_pioctrl->reg_base = devm_platform_ioremap_resource(pdev, 0);
> if (IS_ERR(atmel_pioctrl->reg_base))
> --
> 2.7.4
>
