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Date: Tue, 6 Jun 2023 12:22:15 +0300
From: andy.shevchenko@...il.com
To: nick.hawkins@....com
Cc: verdun@....com, linus.walleij@...aro.org, brgl@...ev.pl,
robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
jdelvare@...e.com, linux@...ck-us.net, andy.shevchenko@...il.com,
linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org
Subject: Re: [PATCH v3 2/5] gpio: gxp: Add HPE GXP GPIO
Mon, Jun 05, 2023 at 08:42:31PM -0500, nick.hawkins@....com kirjoitti:
> From: Nick Hawkins <nick.hawkins@....com>
>
> The GXP SoC supports GPIO on multiple interfaces. The interfaces are
> CPLD and Host. The GPIOs is a combination of both physical and virtual
> I/O across the interfaces. The gpio-gxp driver specifically covers the
> CSM(physical), FN2(virtual), and VUHC(virtual) which are the host. The
> gpio-gxp-pl driver covers the CPLD which takes physical I/O from the
> board and shares it with GXP via a propriety interface that maps the I/O
> onto a specific register area of the GXP. The drivers both support
> interrupts but from different interrupt parents.
Thank you.
This needs some work to be done. See my comments below.
...
> +/* Remember last PSU config */
Would be nice to add why this is a global variable.
> +u8 psu_presence;
...
> +struct gxp_gpio_drvdata {
> + struct regmap *base;
> + struct regmap *interrupt;
> + struct gpio_chip chip;
Making this the first member might save a few bytes of code.
> + int irq;
> +};
> +static struct regmap *gxp_gpio_init_regmap(struct platform_device *pdev,
> + char *reg_name, u8 bits)
> +{
> + struct regmap_config regmap_config = {
> + .reg_bits = 32,
> + .reg_stride = 4,
> + .val_bits = 32,
> + };
Move it out and make static const.
> + void __iomem *base;
> + if (bits == 8) {
> + regmap_config.reg_bits = 8;
> + regmap_config.reg_stride = 1;
> + regmap_config.val_bits = 8;
> + regmap_config.max_register = 0xff;
> + }
Just make two regmap configs and choose them based on the bits.
> + base = devm_platform_ioremap_resource_byname(pdev, reg_name);
> + if (IS_ERR(base))
> + return ERR_CAST(base);
> +
> + regmap_config.name = reg_name;
> +
> + return devm_regmap_init_mmio(&pdev->dev, base, ®map_config);
Why are you not using gpio-regmap?
> +}
...
> +static int gxp_gpio_pl_get(struct gpio_chip *chip, unsigned int offset)
> +{
> + struct gxp_gpio_drvdata *drvdata = dev_get_drvdata(chip->parent);
> + unsigned int val;
> + int ret = 0;
Unneeded.
> + switch (offset) {
> + case IOP_LED1 ... IOP_LED8:
> + regmap_read(drvdata->base, PLREG_IOP_LED, &val);
> + ret = (val & BIT(offset)) ? 1 : 0;
> + break;
> + case FAN1_INST ...FAN8_INST:
> + regmap_read(drvdata->base, PLREG_FAN_INST, &val);
> + ret = (val & BIT((offset - FAN1_INST))) ? 1 : 0;
> + break;
> + case FAN1_FAIL ... FAN8_FAIL:
> + regmap_read(drvdata->base, PLREG_FAN_FAIL, &val);
> + ret = (val & BIT((offset - FAN1_FAIL))) ? 1 : 0;
> + break;
> + case PWR_BTN_INT ... SLP_INT:
> + regmap_read(drvdata->base, PLREG_INT_GRP5_FLAG, &val);
> + /* Active low */
> + ret = (val & BIT((offset - PWR_BTN_INT) + 16)) ? 0 : 1;
> + break;
> + case PSU1_INST ... PSU8_INST:
> + regmap_read(drvdata->base, PLREG_PSU_INST, &val);
> + psu_presence = (u8)val;
> + ret = (psu_presence & BIT((offset - PSU1_INST))) ? 1 : 0;
> + break;
> + case PSU1_AC ... PSU8_AC:
> + regmap_read(drvdata->base, PLREG_PSU_AC, &val);
> + ret = (val & BIT((offset - PSU1_AC))) ? 1 : 0;
> + break;
> + case PSU1_DC ... PSU8_DC:
> + regmap_read(drvdata->base, PLREG_PSU_DC, &val);
> + ret = (val & BIT((offset - PSU1_DC))) ? 1 : 0;
> + break;
> + default:
> + break;
> + }
Obviously what needs to be done in a switch case is to assing offset adjustment
and register name. Then here you read and return the value based on that.
Same approach may be used in other switch-cases in the driver.
> + return ret;
> +}
...
> +static int gxp_gpio_pl_get_direction(struct gpio_chip *chip, unsigned int offset)
> +{
> + int ret = GXP_GPIO_DIR_IN;
Useless variable. Return directly.
> + switch (offset) {
> + case IOP_LED1 ... IOP_LED8:
> + case LED_IDENTIFY ... LED_HEALTH_AMBER:
> + case ACM_FORCE_OFF:
> + case ACM_REQ_N:
> + ret = GXP_GPIO_DIR_OUT;
> + break;
> + default:
> + break;
> + }
> +
> + return ret;
> +}
...
> +static int gxp_gpio_pl_direction_input(struct gpio_chip *chip,
> + unsigned int offset)
> +{
> + int ret = -EOPNOTSUPP;
Ditto.
Also note, GPIOLIB uses ENOTSUPP.
> + switch (offset) {
> + case 8 ... 55:
> + ret = GXP_GPIO_DIR_OUT;
> + break;
> + case 59 ... 65:
> + ret = GXP_GPIO_DIR_OUT;
> + break;
> + default:
> + break;
> + }
> +
> + return ret;
> +}
Same comments as above may be applied to other function implementations in the
driver.
...
> +static irqreturn_t gxp_gpio_pl_irq_handle(int irq, void *_drvdata)
> +{
> + struct gxp_gpio_drvdata *drvdata = (struct gxp_gpio_drvdata *)_drvdata;
Redundant casting.
> + unsigned int val, girq, i;
> +
> + /* Check group 5 interrupts */
> +
> + regmap_read(drvdata->base, PLREG_INT_GRP5_FLAG, &val);
No error check? So it will spit a spurious interrupts here and there?
> + if (val) {
Redundant conditional.
> + for_each_set_bit(i, (unsigned long *)&val, 3) {
This casting is red flag. It has 3 issues. So, no. Just make the copy in the
unsigned long type.
> + girq = irq_find_mapping(drvdata->chip.irq.domain,
> + i + PWR_BTN_INT);
> + generic_handle_irq(girq);
generic_handle_domain_irq()
> + }
> +
> + /* Clear latched interrupt */
> + regmap_update_bits(drvdata->interrupt, PLREG_INT_GRP5_FLAG,
> + 0xFF, 0xFF);
GENMASK()
> + regmap_update_bits(drvdata->interrupt, PLREG_INT_GRP5_BASE,
> + BIT(0) | BIT(2), 0);
> + }
> +
> + /* Check group 6 interrupts */
> +
> + regmap_read(drvdata->base, PLREG_INT_GRP6_FLAG, &val);
> +
> + if (val & BIT(2)) {
> + u8 old_psu = psu_presence;
> +
> + regmap_read(drvdata->base, PLREG_PSU_INST, &val);
> + psu_presence = (u8)val;
> +
> + if (old_psu != psu_presence) {
> + /* Identify all bits which differs */
> + u8 current_val = psu_presence;
> + u8 old_val = old_psu;
> + for (i = 0 ; i < 8 ; i++) {
> + if ((current_val & 0x1) != (old_val & 0x1)) {
Make them unsigned long, use bitmap_xor() or just ^ followed by
for_each_set_bit().
> + /* PSU state has changed */
> + girq = irq_find_mapping(drvdata->chip.irq.domain,
> + i + PSU1_INST);
> + if (girq)
> + generic_handle_irq(girq);
See above.
> + }
> + current_val = current_val >> 1;
> + old_val = old_val >> 1;
No need with the above suggestion.
> + }
> + }
> + }
> +
> + /* Clear latched interrupt */
> + regmap_update_bits(drvdata->interrupt, PLREG_INT_GRP6_FLAG,
> + 0xFF, 0xFF);
GENMASK()
> + regmap_update_bits(drvdata->interrupt, PLREG_INT_GRP6_BASE,
> + BIT(2), 0);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static struct gpio_chip plreg_chip = {
Make it const and mark as a template (in the name).
> + .label = "gxp_gpio_plreg",
> + .owner = THIS_MODULE,
> + .get = gxp_gpio_pl_get,
> + .set = gxp_gpio_pl_set,
> + .get_direction = gxp_gpio_pl_get_direction,
> + .direction_input = gxp_gpio_pl_direction_input,
> + .direction_output = gxp_gpio_pl_direction_output,
> + .base = -1,
> +};
> +
> +static struct irq_chip gxp_plreg_irqchip = {
Make it const and immutable.
> + .name = "gxp_plreg",
> + .irq_ack = gxp_gpio_pl_irq_ack,
> + .irq_mask = gxp_gpio_pl_irq_mask,
> + .irq_unmask = gxp_gpio_pl_irq_unmask,
> + .irq_set_type = gxp_gpio_pl_set_type,
> +};
...
> + psu_presence = (u8)val;
Why casting?
...
> + ret = devm_gpiochip_add_data(&pdev->dev, &drvdata->chip, drvdata);
> + if (ret < 0)
What is the meaning of positive returned value? Why do we not care about it?
> + dev_err_probe(&pdev->dev, ret, "Could not register gpiochip for plreg\n");
...
> + ret = platform_get_irq(pdev, 0);
> + if (ret < 0)
> + return dev_err_probe(&pdev->dev, ret, "Get irq from platform fail\n");
No need to repeat what the API already messages to the user.
...
> + ret = devm_request_irq(&pdev->dev, drvdata->irq, gxp_gpio_pl_irq_handle,
> + IRQF_SHARED, "gxp-pl", drvdata);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
return devm_request_irq(...);
> +}
...
> +static int gxp_gpio_probe(struct platform_device *pdev)
> +{
> + int ret;
> + struct gxp_gpio_drvdata *drvdata;
> +
> + /* Initialize global vars */
> + psu_presence = 0;
> + drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
> + if (!drvdata)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, drvdata);
> + ret = gxp_gpio_pl_init(pdev);
> +
> + return ret;
return gxp_...;
But why that function is separate?
> +}
...
> +++ b/drivers/gpio/gpio-gxp.c
Take all above comments and apply here as well.
...
Split this to two patches, one per driver. It makes easier reviews and flexible
handling of the driver maintenance.
--
With Best Regards,
Andy Shevchenko
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