Hi Andrei, thanks for your patch! Sorry for being so late in giving any deeper review of it. On Thu, Sep 26, 2024 at 4:32 PM Andrei Stefanescu <andrei.stefanescu@xxxxxxxxxxx> wrote: > Add the GPIO driver for S32G2/S32G3 SoCs. This driver uses the SIUL2 > (System Integration Unit Lite2) hardware module. There are two > SIUL2 hardware modules present, SIUL2_0(controlling GPIOs 0-101) and > SIUL2_1 for the rest. > > The GPIOs are not fully contiguous, there are some gaps: > - GPIO102 up to GPIO111(inclusive) are invalid > - GPIO123 up to GPIO143(inclusive) are invalid > > Some GPIOs are input only(i.e. GPI182) though this restriction > is not yet enforced in code. > > This patch adds basic GPIO functionality(no interrupts, no > suspend/resume functions). > > Signed-off-by: Ghennadi Procopciuc <ghennadi.procopciuc@xxxxxxx> > Signed-off-by: Larisa Grigore <larisa.grigore@xxxxxxx> > Signed-off-by: Phu Luu An <phu.luuan@xxxxxxx> > Signed-off-by: Andrei Stefanescu <andrei.stefanescu@xxxxxxxxxxx> (...) > +#include <linux/err.h> > +#include <linux/init.h> > +#include <linux/io.h> > +#include <linux/platform_device.h> > +#include <linux/module.h> > +#include <linux/gpio/driver.h> > +#include <linux/pinctrl/consumer.h> Hm, are you sure you don't want one of those combined GPIO+pinctrl drivers? Look in drivers/pinctrl for examples such as drivers/pinctrl/pinctrl-stmfx.c > +/* PGPDOs are 16bit registers that come in big endian > + * order if they are grouped in pairs of two. > + * > + * For example, the order is PGPDO1, PGPDO0, PGPDO3, PGPDO2... > + */ > +#define SIUL2_PGPDO(N) (((N) ^ 1) * 2) > +#define S32G2_SIUL2_NUM 2 > +#define S32G2_PADS_DTS_TAG_LEN 7 > + > +#define SIUL2_GPIO_16_PAD_SIZE 16 You seem to be manipulating "pads" which is pin control territory. That should be done in a pin control driver. > +/** > + * struct siul2_device_data - platform data attached to the compatible. > + * @pad_access: access table for I/O pads, consists of S32G2_SIUL2_NUM tables. > + * @reset_cnt: reset the pin name counter to zero when switching to SIUL2_1. > + */ > +struct siul2_device_data { > + const struct regmap_access_table **pad_access; > + const bool reset_cnt; I don't understand the reset_cnt variable at all. Explain why it exists in the kerneldoc please. > +/** > + * struct siul2_desc - describes a SIUL2 hw module. > + * @pad_access: array of valid I/O pads. Now that is really pin control isn't it. > + * @opadmap: the regmap of the Parallel GPIO Pad Data Out Register. > + * @ipadmap: the regmap of the Parallel GPIO Pad Data In Register. > + * @gpio_base: the first GPIO pin. > + * @gpio_num: the number of GPIO pins. > + */ > +struct siul2_desc { > + const struct regmap_access_table *pad_access; > + struct regmap *opadmap; > + struct regmap *ipadmap; > + u32 gpio_base; > + u32 gpio_num; > +}; (...) > +static int siul2_get_gpio_pinspec(struct platform_device *pdev, > + struct of_phandle_args *pinspec, > + unsigned int range_index) > +{ > + struct device_node *np = pdev->dev.of_node; > + > + return of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, > + range_index, pinspec); > +} I do not see why a driver would parse gpio-ranges since the gpiolib core should normally deal with the translation between GPIO lines and pins. This looks hacky and probably an indication that you want to use a combined pinctrl+gpio driver so the different parts of the driver can access the same structures easily without hacks. > +static void siul2_gpio_set_direction(struct siul2_gpio_dev *dev, > + unsigned int gpio, int dir) > +{ > + guard(raw_spinlock_irqsave)(&dev->lock); > + > + if (dir == GPIO_LINE_DIRECTION_IN) > + __clear_bit(gpio, dev->pin_dir_bitmap); > + else > + __set_bit(gpio, dev->pin_dir_bitmap); > +} This looks like a job for gpio regmap? select GPIO_REGMAP, look in other driver for examples of how to use it. > +static int siul2_get_direction(struct siul2_gpio_dev *dev, > + unsigned int gpio) > +{ > + return test_bit(gpio, dev->pin_dir_bitmap) ? GPIO_LINE_DIRECTION_OUT : > + GPIO_LINE_DIRECTION_IN; > +} Also looks like a reimplementation of GPIO_REGMAP. > +static int siul2_gpio_dir_out(struct gpio_chip *chip, unsigned int gpio, > + int val) > +{ > + struct siul2_gpio_dev *gpio_dev; > + int ret = 0; > + > + gpio_dev = to_siul2_gpio_dev(chip); > + siul2_gpio_set_val(chip, gpio, val); > + > + ret = pinctrl_gpio_direction_output(chip, gpio); (...) This is nice, pin control is properly used as the back-end. > +static int siul2_gpio_remove_reserved_names(struct device *dev, > + struct siul2_gpio_dev *gpio_dev, > + char **names) > +{ > + struct device_node *np = dev->of_node; > + int num_ranges, i, j, ret; > + u32 base_gpio, num_gpio; > + > + /* Parse the gpio-reserved-ranges to know which GPIOs to exclude. */ > + > + num_ranges = of_property_count_u32_elems(dev->of_node, > + "gpio-reserved-ranges"); > + > + /* The "gpio-reserved-ranges" is optional. */ > + if (num_ranges < 0) > + return 0; > + num_ranges /= 2; > + > + for (i = 0; i < num_ranges; i++) { > + ret = of_property_read_u32_index(np, "gpio-reserved-ranges", > + i * 2, &base_gpio); > + if (ret) { > + dev_err(dev, "Could not parse the start GPIO: %d\n", > + ret); > + return ret; > + } > + > + ret = of_property_read_u32_index(np, "gpio-reserved-ranges", > + i * 2 + 1, &num_gpio); > + if (ret) { > + dev_err(dev, "Could not parse num. GPIOs: %d\n", ret); > + return ret; > + } > + > + if (base_gpio + num_gpio > gpio_dev->gc.ngpio) { > + dev_err(dev, "Reserved GPIOs outside of GPIO range\n"); > + return -EINVAL; > + } > + > + /* Remove names set for reserved GPIOs. */ > + for (j = base_gpio; j < base_gpio + num_gpio; j++) { > + devm_kfree(dev, names[j]); > + names[j] = NULL; > + } > + } > + > + return 0; > +} I don't get this. gpio-reserved-ranges is something that is parsed and handled by gpiolib. Read the code in gpiolib.c and you'll probably figure out how to let gpiolib take care of this for you. > +static int siul2_gpio_populate_names(struct device *dev, > + struct siul2_gpio_dev *gpio_dev) > +{ > + unsigned int num_index = 0; > + char ch_index = 'A'; > + char **names; > + int i, ret; > + > + names = devm_kcalloc(dev, gpio_dev->gc.ngpio, sizeof(*names), > + GFP_KERNEL); > + if (!names) > + return -ENOMEM; > + > + for (i = 0; i < S32G2_SIUL2_NUM; i++) { > + ret = siul2_gen_names(dev, gpio_dev->siul2[i].gpio_num, > + names + gpio_dev->siul2[i].gpio_base, > + &ch_index, &num_index); > + if (ret) { > + dev_err(dev, "Could not set names for SIUL2_%d GPIOs\n", > + i); > + return ret; > + } > + > + if (gpio_dev->platdata->reset_cnt) > + num_index = 0; > + > + ch_index++; > + } > + > + ret = siul2_gpio_remove_reserved_names(dev, gpio_dev, names); > + if (ret) > + return ret; > + > + gpio_dev->gc.names = (const char *const *)names; > + > + return 0; > +} Interesting! I'm not against, on the contrary this looks really helpful to users. > + gc = &gpio_dev->gc; No poking around in the gpiolib internals please. Look at what other drivers do and do like they do. On top of these comments: everywhere you do [raw_spin_]locks: try to use guards or scoped guards instead. git grep guard drivers/gpio for many examples. Yours, Linus Walleij