Re: [PATCH v2 2/3] pinctrl: bcm2835: Add support for generic pinctrl binding

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Hi Eric,

thanks for reviewing it. I will send the v3 of the patch with your notes. 
I will just wait for the Linus considerations.

Best Regards
Matheus Castello

On 03/05/2018 07:21 PM, Eric Anholt wrote:
> Matheus Castello <matheus@xxxxxxxxxxxxxxx> writes:
> 
>> To keep driver up to date we add generic pinctrl binding support, which covers
>> the features used in this driver and has additional node properties that this
>> SoC has compatibility, so enabling future implementations of these properties
>> without the need to create new node properties in the device trees.
>>
>> The logic of this change maintain the old brcm legacy binding support in order
>> to keep the ABI stable.
>>
>> Signed-off-by: Matheus Castello <matheus@xxxxxxxxxxxxxxx>
>> ---
>>
>> A brief explanation of what I did:
>>
>> Add pinconf-generic header for use the defines and pinctrl-generic API.
>>
>> Add dt-bindings pinctrl bcm2835 header to use functions selections and
>> pulls definitions, which functions definitions where duplicated in the
>> enum bcm2835_fsel, I removed the duplicate defines from enum.
>>
>> In the bcm2835_pctl_dt_node_to_map_pull I used the generic macro for
>> pack the legacy param and arguments, since it will be unpacked along with
>> generic properties that is packed with this same macro.
>>
>> In bcm2835_pctl_dt_node_to_map I thougt it was better, and simpler, to use
>> pinctrl-generic parse code instead of parsing it inside the driver, so code
>> first check for generic binding parse, if something is parsed then it is
>> assumed that are using the new generic style, and when nothing is found then
>> parse continues to search for legacy properties.
>>
>> In the bcm2835_pinconf_set was changed the unpack legacy by the generic, and
>> was added a switch for the parameter tests, since pinctrl generic uses 3
>> properties to define the states of the pull instead of one with arguments, that
>> was the reason too that bcm2835_pull_config_set function was added, for reuse
>> the code that set state of pull.
>>
>>  drivers/pinctrl/bcm/pinctrl-bcm2835.c | 83 +++++++++++++++++++++++------------
>>  1 file changed, 54 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
>> index 785c366..755ea90 100644
>> --- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
>> +++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
>> @@ -36,11 +36,13 @@
>>  #include <linux/pinctrl/pinconf.h>
>>  #include <linux/pinctrl/pinctrl.h>
>>  #include <linux/pinctrl/pinmux.h>
>> +#include <linux/pinctrl/pinconf-generic.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/seq_file.h>
>>  #include <linux/slab.h>
>>  #include <linux/spinlock.h>
>>  #include <linux/types.h>
>> +#include <dt-bindings/pinctrl/bcm2835.h>
>>
>>  #define MODULE_NAME "pinctrl-bcm2835"
>>  #define BCM2835_NUM_GPIOS 54
>> @@ -213,14 +215,6 @@ static const char * const bcm2835_gpio_groups[] = {
>>  };
>>
>>  enum bcm2835_fsel {
>> -	BCM2835_FSEL_GPIO_IN = 0,
>> -	BCM2835_FSEL_GPIO_OUT = 1,
>> -	BCM2835_FSEL_ALT0 = 4,
>> -	BCM2835_FSEL_ALT1 = 5,
>> -	BCM2835_FSEL_ALT2 = 6,
>> -	BCM2835_FSEL_ALT3 = 7,
>> -	BCM2835_FSEL_ALT4 = 3,
>> -	BCM2835_FSEL_ALT5 = 2,
>>  	BCM2835_FSEL_COUNT = 8,
>>  	BCM2835_FSEL_MASK = 0x7,
>>  };
>> @@ -714,7 +708,7 @@ static int bcm2835_pctl_dt_node_to_map_pull(struct bcm2835_pinctrl *pc,
>>  	configs = kzalloc(sizeof(*configs), GFP_KERNEL);
>>  	if (!configs)
>>  		return -ENOMEM;
>> -	configs[0] = BCM2835_PINCONF_PACK(BCM2835_PINCONF_PARAM_PULL, pull);
>> +	configs[0] = PIN_CONF_PACKED(BCM2835_PINCONF_PARAM_PULL, pull);
>>
>>  	map->type = PIN_MAP_TYPE_CONFIGS_PIN;
>>  	map->data.configs.group_or_pin = bcm2835_gpio_pins[pin].name;
>> @@ -736,6 +730,12 @@ static int bcm2835_pctl_dt_node_to_map(struct pinctrl_dev *pctldev,
>>  	int i, err;
>>  	u32 pin, func, pull;
>>
>> +	/* Check for generic binding in this node */
>> +	err = pinconf_generic_dt_node_to_map_all(pctldev, np, map, num_maps);
>> +	if (err || *num_maps)
>> +		return err;
>> +
>> +	/* Generic binding did not find anything continue with legacy parse */
>>  	pins = of_find_property(np, "brcm,pins", NULL);
>>  	if (!pins) {
>>  		dev_err(pc->dev, "%pOF: missing brcm,pins property\n", np);
>> @@ -917,37 +917,62 @@ static int bcm2835_pinconf_get(struct pinctrl_dev *pctldev,
>>  	return -ENOTSUPP;
>>  }
>>
>> +static void bcm2835_pull_config_set(struct bcm2835_pinctrl *pc,
>> +		unsigned pin, unsigned arg)
>> +{
>> +	u32 off, bit;
>> +
>> +	off = GPIO_REG_OFFSET(pin);
>> +	bit = GPIO_REG_SHIFT(pin);
>> +
>> +	bcm2835_gpio_wr(pc, GPPUD, arg & 3);
>> +	/*
>> +	* BCM2835 datasheet say to wait 150 cycles, but not of what.
>> +	* But the VideoCore firmware delay for this operation
>> +	* based nearly on the same amount of VPU cycles and this clock
>> +	* runs at 250 MHz.
>> +	*/
>> +	udelay(1);
>> +	bcm2835_gpio_wr(pc, GPPUDCLK0 + (off * 4), BIT(bit));
>> +	udelay(1);
>> +	bcm2835_gpio_wr(pc, GPPUDCLK0 + (off * 4), 0);
>> +}
>> +
>>  static int bcm2835_pinconf_set(struct pinctrl_dev *pctldev,
>>  			unsigned pin, unsigned long *configs,
>>  			unsigned num_configs)
>>  {
>>  	struct bcm2835_pinctrl *pc = pinctrl_dev_get_drvdata(pctldev);
>> -	enum bcm2835_pinconf_param param;
>> -	u16 arg;
>> -	u32 off, bit;
>> +	u16 param, arg;
>>  	int i;
>>
>>  	for (i = 0; i < num_configs; i++) {
>> -		param = BCM2835_PINCONF_UNPACK_PARAM(configs[i]);
>> -		arg = BCM2835_PINCONF_UNPACK_ARG(configs[i]);
>> +		param = configs[i] & 0xffUL;
>> +		arg = configs[i] >> 8;
> 
> If you're removing the usage of BCM2835_PINCONF_PACK() and UNPACK, let's
> delete those macros, too.  Also, it looks like there's
> "pinconf_to_config_param()" for unpacking, instead of rolling your own.
> 
> Other than that, it looks good to me.  I'll let Linus comment on whether
> this is handling the generic properties correctly.
> 
>>
>> -		if (param != BCM2835_PINCONF_PARAM_PULL)
>> -			return -EINVAL;
>> +		switch (param) {
>> +		/* Set legacy brcm,pull */
>> +		case BCM2835_PINCONF_PARAM_PULL:
>> +			bcm2835_pull_config_set(pc, pin, arg);
>> +			break;
>>
>> -		off = GPIO_REG_OFFSET(pin);
>> -		bit = GPIO_REG_SHIFT(pin);
>> +		/* Set pull generic bindings */
>> +		case PIN_CONFIG_BIAS_DISABLE:
>> +			bcm2835_pull_config_set(pc, pin, BCM2835_PUD_OFF);
>> +			break;
>>
>> -		bcm2835_gpio_wr(pc, GPPUD, arg & 3);
>> -		/*
>> -		 * BCM2835 datasheet say to wait 150 cycles, but not of what.
>> -		 * But the VideoCore firmware delay for this operation
>> -		 * based nearly on the same amount of VPU cycles and this clock
>> -		 * runs at 250 MHz.
>> -		 */
>> -		udelay(1);
>> -		bcm2835_gpio_wr(pc, GPPUDCLK0 + (off * 4), BIT(bit));
>> -		udelay(1);
>> -		bcm2835_gpio_wr(pc, GPPUDCLK0 + (off * 4), 0);
>> +		case PIN_CONFIG_BIAS_PULL_DOWN:
>> +			bcm2835_pull_config_set(pc, pin, BCM2835_PUD_DOWN);
>> +			break;
>> +
>> +		case PIN_CONFIG_BIAS_PULL_UP:
>> +			bcm2835_pull_config_set(pc, pin, BCM2835_PUD_UP);
>> +			break;
>> +
>> +		default:
>> +			return -EINVAL;
>> +
>> +		} /* switch param type */
>>  	} /* for each config */
>>
>>  	return 0;
>> --
>> 2.7.4
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