RE: [PATCH v3 2/2] pinctrl: zynqmp: Support muxing individual pins

[Potthuri, Sai Krishna]

> -----Original Message-----
> From: Sean Anderson <sean.anderson@xxxxxxxxx>
> Sent: Tuesday, June 11, 2024 4:06 AM
> To: Linus Walleij <linus.walleij@xxxxxxxxxx>; Simek, Michal
> <michal.simek@xxxxxxx>; linux-gpio@xxxxxxxxxxxxxxx
> Cc: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>; Potthuri, Sai Krishna
> <sai.krishna.potthuri@xxxxxxx>; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; Sean Anderson <sean.anderson@xxxxxxxxx>
> Subject: [PATCH v3 2/2] pinctrl: zynqmp: Support muxing individual pins
> 
> While muxing groups of pins at once can be convenient for large interfaces,
> it can also be rigid. This is because the group is set to all pins which support
> a particular function, even though not all pins may be used. For example,
> the sdhci0 function may be used with a 8-bit eMMC, 4-bit SD card, or even a
> 1-bit SD card. In these cases, the extra pins may be repurposed for other
> uses, but this is not currently allowed.
> 
> There is not too much point in pin "groups" when there are not actual pin
> groups at the hardware level. The pins can all be muxed individually, so
> there's no point in adding artificial groups on top.
> Just mux the pins like the hardware allows.
> 
> To this effect, add a new group for each pin which can be muxed. These
> groups are part of each function the pin can be muxed to. We treat group
> selectors beyond the number of groups as "pin" groups. To set this up, we
> initialize groups before functions, and then create a bitmap of used pins for
> each function. These used pins are appended to the function's list of
> groups.
> 
> Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxxx>
Reviewed-by: Sai Krishna Potthuri <sai.krishna.potthuri@xxxxxxx>

Regards
Sai Krishna

> ---
> 
> Changes in v3:
> - Fix zynqmp_pinmux_set_mux and zynqmp_pinconf_group_set not
> handling
>   "pin" groups (thanks Sai Krishna).
> 
> Changes in v2:
> - Use __set_bit instead of set_bit
> - Use size_add when calculating the number of kcalloc members
> - Expand commit message with some more motivation
> 
>  drivers/pinctrl/pinctrl-zynqmp.c | 83 +++++++++++++++++++++-----------
>  1 file changed, 54 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-zynqmp.c b/drivers/pinctrl/pinctrl-
> zynqmp.c
> index 5c46b7d7ebcb..e4ff3c55b87d 100644
> --- a/drivers/pinctrl/pinctrl-zynqmp.c
> +++ b/drivers/pinctrl/pinctrl-zynqmp.c
> @@ -10,6 +10,7 @@
> 
>  #include <dt-bindings/pinctrl/pinctrl-zynqmp.h>
> 
> +#include <linux/bitmap.h>
>  #include <linux/init.h>
>  #include <linux/module.h>
>  #include <linux/of_address.h>
> @@ -97,7 +98,7 @@ static int zynqmp_pctrl_get_groups_count(struct
> pinctrl_dev *pctldev)  {
>  	struct zynqmp_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
> 
> -	return pctrl->ngroups;
> +	return pctrl->ngroups + zynqmp_desc.npins;
>  }
> 
>  static const char *zynqmp_pctrl_get_group_name(struct pinctrl_dev
> *pctldev, @@ -105,7 +106,10 @@ static const char
> *zynqmp_pctrl_get_group_name(struct pinctrl_dev *pctldev,  {
>  	struct zynqmp_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
> 
> -	return pctrl->groups[selector].name;
> +	if (selector < pctrl->ngroups)
> +		return pctrl->groups[selector].name;
> +
> +	return zynqmp_desc.pins[selector - pctrl->ngroups].name;
>  }
> 
>  static int zynqmp_pctrl_get_group_pins(struct pinctrl_dev *pctldev, @@ -
> 115,8 +119,13 @@ static int zynqmp_pctrl_get_group_pins(struct
> pinctrl_dev *pctldev,  {
>  	struct zynqmp_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
> 
> -	*pins = pctrl->groups[selector].pins;
> -	*npins = pctrl->groups[selector].npins;
> +	if (selector < pctrl->ngroups) {
> +		*pins = pctrl->groups[selector].pins;
> +		*npins = pctrl->groups[selector].npins;
> +	} else {
> +		*pins = &zynqmp_desc.pins[selector - pctrl-
> >ngroups].number;
> +		*npins = 1;
> +	}
> 
>  	return 0;
>  }
> @@ -197,17 +206,16 @@ static int zynqmp_pinmux_set_mux(struct
> pinctrl_dev *pctldev,
>  				 unsigned int function,
>  				 unsigned int group)
>  {
> -	struct zynqmp_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
> -	const struct zynqmp_pctrl_group *pgrp = &pctrl->groups[group];
> +	const unsigned int *pins;
> +	unsigned int npins;
>  	int ret, i;
> 
> -	for (i = 0; i < pgrp->npins; i++) {
> -		unsigned int pin = pgrp->pins[i];
> -
> -		ret = zynqmp_pm_pinctrl_set_function(pin, function);
> +	zynqmp_pctrl_get_group_pins(pctldev, group, &pins, &npins);
> +	for (i = 0; i < npins; i++) {
> +		ret = zynqmp_pm_pinctrl_set_function(pins[i], function);
>  		if (ret) {
>  			dev_err(pctldev->dev, "set mux failed for pin %u\n",
> -				pin);
> +				pins[i]);
>  			return ret;
>  		}
>  	}
> @@ -467,12 +475,13 @@ static int zynqmp_pinconf_group_set(struct
> pinctrl_dev *pctldev,
>  				    unsigned long *configs,
>  				    unsigned int num_configs)
>  {
> +	const unsigned int *pins;
> +	unsigned int npins;
>  	int i, ret;
> -	struct zynqmp_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
> -	const struct zynqmp_pctrl_group *pgrp = &pctrl->groups[selector];
> 
> -	for (i = 0; i < pgrp->npins; i++) {
> -		ret = zynqmp_pinconf_cfg_set(pctldev, pgrp->pins[i], configs,
> +	zynqmp_pctrl_get_group_pins(pctldev, selector, &pins, &npins);
> +	for (i = 0; i < npins; i++) {
> +		ret = zynqmp_pinconf_cfg_set(pctldev, pins[i], configs,
>  					     num_configs);
>  		if (ret)
>  			return ret;
> @@ -560,10 +569,12 @@ static int
> zynqmp_pinctrl_prepare_func_groups(struct device *dev, u32 fid,  {
>  	u16 resp[NUM_GROUPS_PER_RESP] = {0};
>  	const char **fgroups;
> -	int ret, index, i;
> +	int ret, index, i, pin;
> +	unsigned int npins;
> +	unsigned long *used_pins __free(bitmap) =
> +		bitmap_zalloc(zynqmp_desc.npins, GFP_KERNEL);
> 
> -	fgroups = devm_kcalloc(dev, func->ngroups, sizeof(*fgroups),
> GFP_KERNEL);
> -	if (!fgroups)
> +	if (!used_pins)
>  		return -ENOMEM;
> 
>  	for (index = 0; index < func->ngroups; index +=
> NUM_GROUPS_PER_RESP) { @@ -578,23 +589,37 @@ static int
> zynqmp_pinctrl_prepare_func_groups(struct device *dev, u32 fid,
>  			if (resp[i] == RESERVED_GROUP)
>  				continue;
> 
> -			fgroups[index + i] = devm_kasprintf(dev,
> GFP_KERNEL,
> -							    "%s_%d_grp",
> -							    func->name,
> -							    index + i);
> -			if (!fgroups[index + i])
> -				return -ENOMEM;
> -
>  			groups[resp[i]].name = devm_kasprintf(dev,
> GFP_KERNEL,
>  							      "%s_%d_grp",
>  							      func->name,
>  							      index + i);
>  			if (!groups[resp[i]].name)
>  				return -ENOMEM;
> +
> +			for (pin = 0; pin < groups[resp[i]].npins; pin++)
> +				__set_bit(groups[resp[i]].pins[pin],
> used_pins);
>  		}
>  	}
>  done:
> +	npins = bitmap_weight(used_pins, zynqmp_desc.npins);
> +	fgroups = devm_kcalloc(dev, size_add(func->ngroups, npins),
> +			       sizeof(*fgroups), GFP_KERNEL);
> +	if (!fgroups)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < func->ngroups; i++) {
> +		fgroups[i] = devm_kasprintf(dev, GFP_KERNEL, "%s_%d_grp",
> +					    func->name, i);
> +		if (!fgroups[i])
> +			return -ENOMEM;
> +	}
> +
> +	pin = 0;
> +	for_each_set_bit(pin, used_pins, zynqmp_desc.npins)
> +		fgroups[i++] = zynqmp_desc.pins[pin].name;
> +
>  	func->groups = fgroups;
> +	func->ngroups += npins;
> 
>  	return 0;
>  }
> @@ -772,6 +797,10 @@ static int
> zynqmp_pinctrl_prepare_function_info(struct device *dev,
>  	if (!groups)
>  		return -ENOMEM;
> 
> +	ret = zynqmp_pinctrl_prepare_group_pins(dev, groups, pctrl-
> >ngroups);
> +	if (ret)
> +		return ret;
> +
>  	for (i = 0; i < pctrl->nfuncs; i++) {
>  		ret = zynqmp_pinctrl_prepare_func_groups(dev, i, &funcs[i],
>  							 groups);
> @@ -779,10 +808,6 @@ static int
> zynqmp_pinctrl_prepare_function_info(struct device *dev,
>  			return ret;
>  	}
> 
> -	ret = zynqmp_pinctrl_prepare_group_pins(dev, groups, pctrl-
> >ngroups);
> -	if (ret)
> -		return ret;
> -
>  	pctrl->funcs = funcs;
>  	pctrl->groups = groups;
> 
> --
> 2.35.1.1320.gc452695387.dirty