Re: [PATCH v9 3/3] gpio: nuvoton: Add Nuvoton NPCM sgpio driver
From: Andy Shevchenko
Date: Wed Dec 13 2023 - 10:35:38 EST
On Tue, Dec 12, 2023 at 02:51:47PM +0800, Jim Liu wrote:
> Add Nuvoton BMC NPCM7xx/NPCM8xx sgpio driver support.
> Nuvoton NPCM SGPIO module is combine serial to parallel IC (HC595)
> and parallel to serial IC (HC165), and use APB3 clock to control it.
> This interface has 4 pins (D_out , D_in, S_CLK, LDSH).
> BMC can use this driver to increase 64 GPI pins and 64 GPO pins to use.
...
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/hashtable.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
Is this a proxy to some other headers like array_size.h? Please use respective
headers directly.
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +#include <linux/string.h>
...
> +#define NPCM_CLK_MHZ 8000000
HZ_PER_MHZ from units.h?
...
> +struct npcm_sgpio {
> + struct gpio_chip chip;
> + struct clk *pclk;
> + struct irq_chip intc;
> + raw_spinlock_t lock; /*protect event config*/
Missing spaces.
> + void __iomem *base;
> + int irq;
> + u8 nin_sgpio;
> + u8 nout_sgpio;
> + u8 in_port;
> + u8 out_port;
> + u8 int_type[MAX_NR_HW_SGPIO];
> +};
...
> + {
> + .wdata_reg = 0x07,
> + .rdata_reg = 0x0f,
> + .event_config = 0x1e,
> + .event_status = 0x27,
> + },
> +
Redundant blank line.
...
> +static void __iomem *bank_reg(struct npcm_sgpio *gpio,
> + const struct npcm_sgpio_bank *bank,
> + const enum npcm_sgpio_reg reg)
> +{
> + switch (reg) {
> + case READ_DATA:
> + return gpio->base + bank->rdata_reg;
> + case WRITE_DATA:
> + return gpio->base + bank->wdata_reg;
> + case EVENT_CFG:
> + return gpio->base + bank->event_config;
> + case EVENT_STS:
> + return gpio->base + bank->event_status;
> + default:
> + /* actually if code runs to here, it's an error case */
> + dev_WARN(gpio->chip.parent, "Getting here is an error condition");
...then return an error here.
> + }
> + return 0;
See above.
> +}
> +static void irqd_to_npcm_sgpio_data(struct irq_data *d,
Respect namespace, here it's better to have npcm_sgpio_irqd_to_data().
> + struct npcm_sgpio **gpio,
> + const struct npcm_sgpio_bank **bank,
> + u8 *bit, unsigned int *offset)
...
> +static int npcm_sgpio_init_port(struct npcm_sgpio *gpio)
> +{
> + u8 in_port, out_port, set_port, reg;
> +
> + in_port = GPIO_BANK(gpio->nin_sgpio);
> + if (GPIO_BIT(gpio->nin_sgpio) > 0)
> + in_port += 1;
This is strange... So, you are telling that offsets start from 1 and not 0?
> + out_port = GPIO_BANK(gpio->nout_sgpio);
> + if (GPIO_BIT(gpio->nout_sgpio) > 0)
> + out_port += 1;
Ditto.
...
> + set_port = ((out_port & NPCM_IOXCFG2_PORT) << 4) | (in_port & NPCM_IOXCFG2_PORT);
Outer parentheses are redundant.
...
> +static int npcm_sgpio_dir_out(struct gpio_chip *gc, unsigned int offset, int val)
> +{
> + gc->set(gc, offset, val);
> +
> + return 0;
> +
Redundant blank line.
> +}
> +
> +static int npcm_sgpio_get_direction(struct gpio_chip *gc, unsigned int offset)
> +{
> + struct npcm_sgpio *gpio = gpiochip_get_data(gc);
> + if (offset > gpio->chip.ngpio)
> + return -EINVAL;
Why do you need this check?
> + if (offset < gpio->nout_sgpio)
> + return GPIO_LINE_DIRECTION_OUT;
> +
> + return GPIO_LINE_DIRECTION_IN;
> +}
...
> +static void npcm_sgpio_set(struct gpio_chip *gc, unsigned int offset, int val)
> +{
> + struct npcm_sgpio *gpio = gpiochip_get_data(gc);
> + const struct npcm_sgpio_bank *bank = offset_to_bank(offset);
> + void __iomem *addr;
> + u8 reg = 0;
> +
> + addr = bank_reg(gpio, bank, WRITE_DATA);
> + reg = ioread8(addr);
> +
> + if (val)
> + reg |= (val << GPIO_BIT(offset));
...and if val is not 1?..
> + else
> + reg &= ~(1 << GPIO_BIT(offset));
In both cases use BIT().
> + iowrite8(reg, addr);
> +}
...
> + dir = npcm_sgpio_get_direction(gc, offset);
> + if (dir == 0) {
> + bank = offset_to_bank(offset);
> +
> + addr = bank_reg(gpio, bank, WRITE_DATA);
> + reg = ioread8(addr);
> + reg = !!(reg & GPIO_BIT(offset));
> + } else {
> + offset -= gpio->nout_sgpio;
> + bank = offset_to_bank(offset);
> +
> + addr = bank_reg(gpio, bank, READ_DATA);
> + reg = ioread8(addr);
> + reg = !!(reg & GPIO_BIT(offset));
> + }
Instead of conditional(s) use arithmetics. You can get all these directly
from the properly formed calculations.
...
> +static void npcm_sgpio_setup_enable(struct npcm_sgpio *gpio, bool enable)
> +{
> + u8 reg = 0;
Redundant assignment.
> + reg = ioread8(gpio->base + NPCM_IOXCTS);
> + reg = reg & ~NPCM_IOXCTS_RD_MODE;
> + reg = reg | NPCM_IOXCTS_RD_MODE_PERIODIC;
Combine them.
> + if (enable) {
> + reg |= NPCM_IOXCTS_IOXIF_EN;
> + iowrite8(reg, gpio->base + NPCM_IOXCTS);
> + } else {
> + reg &= ~NPCM_IOXCTS_IOXIF_EN;
> + iowrite8(reg, gpio->base + NPCM_IOXCTS);
> + }
> +}
...
> +static int npcm_sgpio_setup_clk(struct npcm_sgpio *gpio,
> + const struct npcm_clk_cfg *clk_cfg)
> +{
> + unsigned long apb_freq;
> + u32 val;
> + u8 tmp;
> + int i;
> +
> + apb_freq = clk_get_rate(gpio->pclk);
> + tmp = ioread8(gpio->base + NPCM_IOXCFG1) & ~NPCM_IOXCFG1_SFT_CLK;
> +
> + for (i = 0; i < clk_cfg->cfg_opt; i++) {
> + val = apb_freq / clk_cfg->sft_clk[i];
> + if ((NPCM_CLK_MHZ < val) && (i != 0) ) {
> + iowrite8(clk_cfg->clk_sel[i-1] | tmp, gpio->base + NPCM_IOXCFG1);
> + return 0;
> + } else if (i == (clk_cfg->cfg_opt-1) && (NPCM_CLK_MHZ > val)) {
> + iowrite8(clk_cfg->clk_sel[i] | tmp, gpio->base + NPCM_IOXCFG1);
> + return 0;
> + }
These i == / i != checks probably due to wrong operator be chosen. Consider using
while-loop, or do-while. I believe it will make code better.
> + }
> +
> + return -EINVAL;
> +}
...
> +static void npcm_sgpio_irq_init_valid_mask(struct gpio_chip *gc,
> + unsigned long *valid_mask, unsigned int ngpios)
> +{
> + struct npcm_sgpio *gpio = gpiochip_get_data(gc);
> + int n = gpio->nin_sgpio;
Why do you need this variable, what for?
> + /* input GPIOs in the high range */
> + bitmap_set(valid_mask, gpio->nout_sgpio, n);
> + bitmap_clear(valid_mask, 0, gpio->nout_sgpio);
> +}
...
> + raw_spin_lock_irqsave(&gpio->lock, flags);
Don't you need to use spin lock in the other APIs? It seem whole driver works by luck.
> + npcm_sgpio_setup_enable(gpio, false);
> +
> + reg = ioread16(addr);
> + if (set) {
> + reg &= ~(NPCM_IXOEVCFG_MASK << (bit * 2));
> + } else {
> + type = gpio->int_type[offset];
> + reg |= (type << (bit * 2));
At least the calculations can be done outside of the lock.
> + }
> +
> + iowrite16(reg, addr);
> +
> + npcm_sgpio_setup_enable(gpio, true);
> +
> + addr = bank_reg(gpio, bank, EVENT_STS);
> + reg = ioread8(addr);
> + reg |= BIT(bit);
> + iowrite8(reg, addr);
> +
> + raw_spin_unlock_irqrestore(&gpio->lock, flags);
...
> + switch (type & IRQ_TYPE_SENSE_MASK) {
> + case IRQ_TYPE_EDGE_BOTH:
> + val = NPCM_IXOEVCFG_BOTH;
> + handler = handle_edge_irq;
> + break;
> + case IRQ_TYPE_EDGE_RISING:
> + val = NPCM_IXOEVCFG_RISING;
> + handler = handle_edge_irq;
> + break;
> + case IRQ_TYPE_EDGE_FALLING:
> + val = NPCM_IXOEVCFG_FALLING;
> + handler = handle_edge_irq;
> + break;
> + case IRQ_TYPE_LEVEL_HIGH:
> + val = NPCM_IXOEVCFG_RISING;
> + handler = handle_level_irq;
> + break;
> + case IRQ_TYPE_LEVEL_LOW:
> + val = NPCM_IXOEVCFG_FALLING;
> + handler = handle_level_irq;
> + break;
> + default:
> + return -EINVAL;
> + }
You can split the handler setup and make this function less by 5 LoCs or so.
See, for example, gpio-tangier.c.
...
> + for (i = 0; i < ARRAY_SIZE(npcm_sgpio_banks); i++) {
> + const struct npcm_sgpio_bank *bank = &npcm_sgpio_banks[i];
> +
> + reg = ioread8(bank_reg(gpio, bank, EVENT_STS));
> + for_each_set_bit(j, ®, 8) {
> + girq = irq_find_mapping(gc->irq.domain, i * 8 + gpio->nout_sgpio + j);
> + generic_handle_irq(girq);
generic_handle_domain_irq()
> + }
> + }
...
> +static int npcm_sgpio_setup_irqs(struct npcm_sgpio *gpio,
> + struct platform_device *pdev)
> +{
> + int rc, i;
> + struct gpio_irq_chip *irq;
> +
> + rc = platform_get_irq(pdev, 0);
> + if (rc < 0)
> + return rc;
> +
> + gpio->irq = rc;
> +
> + npcm_sgpio_setup_enable(gpio, false);
> +
> + /* Disable IRQ and clear Interrupt status registers for all SGPIO Pins. */
> + for (i = 0; i < ARRAY_SIZE(npcm_sgpio_banks); i++) {
> + const struct npcm_sgpio_bank *bank = &npcm_sgpio_banks[i];
> + iowrite16(0x0000, bank_reg(gpio, bank, EVENT_CFG));
0 is enough.
> + iowrite8(0xff, bank_reg(gpio, bank, EVENT_STS));
GENMASK() ?
> + }
> +
> + irq = &gpio->chip.irq;
> + gpio_irq_chip_set_chip(irq, &sgpio_irq_chip);
> + irq->init_valid_mask = npcm_sgpio_irq_init_valid_mask;
> + irq->handler = handle_bad_irq;
> + irq->default_type = IRQ_TYPE_NONE;
> + irq->parent_handler = npcm_sgpio_irq_handler;
> + irq->parent_handler_data = gpio;
> + irq->parents = &gpio->irq;
> + irq->num_parents = 1;
> +
> + return 0;
> +}
...
> +static struct npcm_clk_cfg npcm750_sgpio_pdata = {
> + .sft_clk = npcm750_SFT_CLK,
> + .clk_sel = npcm750_CLK_SEL,
> + .cfg_opt = 6,
Define this magic and use it in the above arrays as the capacity.
> +};
> +
> +static const struct npcm_clk_cfg npcm845_sgpio_pdata = {
> + .sft_clk = npcm845_SFT_CLK,
> + .clk_sel = npcm845_CLK_SEL,
> + .cfg_opt = 5,
Ditto.
> +};
...
> +static const struct of_device_id npcm_sgpio_of_table[] = {
> + { .compatible = "nuvoton,npcm750-sgpio", .data = &npcm750_sgpio_pdata, },
> + { .compatible = "nuvoton,npcm845-sgpio", .data = &npcm845_sgpio_pdata, },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, npcm_sgpio_of_table);
Move this closer to its user below.
...
> + if (gpio->nin_sgpio > MAX_NR_HW_SGPIO || gpio->nout_sgpio > MAX_NR_HW_SGPIO) {
> + dev_err(&pdev->dev, "Number of GPIOs exceeds the maximum of %d: input: %d output: %d\n",
> + MAX_NR_HW_SGPIO, nin_gpios, nout_gpios);
> + return -EINVAL;
return dev_err_probe(...);
> + }
> +
> + gpio->pclk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(gpio->pclk)) {
> + dev_err(&pdev->dev, "Could not get pclk\n");
> + return PTR_ERR(gpio->pclk);
Ditto.
> + }
...
> + rc = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
> + if (rc < 0)
Here and in the other cases, why ' < 0'? Does it have positive value
to be returned in some cases?
> + return rc;
--
With Best Regards,
Andy Shevchenko