Messages in this thread | | | From | Piyush Mehta <> | Subject | RE: [PATCH 2/2] gpio: modepin: Add driver support for modepin GPIO controller | Date | Mon, 21 Jun 2021 17:09:31 +0000 |
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Hello Linus,
Thanks for the review comments. We will address all the reviews in the next version.
Regards, Piyush Mehta
-----Original Message----- From: Linus Walleij <linus.walleij@linaro.org> Sent: Friday, June 18, 2021 3:14 PM To: Piyush Mehta <piyushm@xilinx.com> Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>; Rob Herring <robh+dt@kernel.org>; open list:GPIO SUBSYSTEM <linux-gpio@vger.kernel.org>; open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS <devicetree@vger.kernel.org>; linux-kernel <linux-kernel@vger.kernel.org>; Linux ARM <linux-arm-kernel@lists.infradead.org>; git <git@xilinx.com>; Srinivas Goud <sgoud@xilinx.com>; Michal Simek <michals@xilinx.com> Subject: Re: [PATCH 2/2] gpio: modepin: Add driver support for modepin GPIO controller
Hi Piyush!
thanks for your patch!
On Tue, Jun 15, 2021 at 10:06 AM Piyush Mehta <piyush.mehta@xilinx.com> wrote:
> This patch adds support for the mode pin GPIO controller. GPIO Modepin > driver set and get the value and status of the PS_MODE pin, based on > device-tree pin configuration. These 4-bits boot-mode pins are > dedicated configurable as input/output. After the stabilization of the > system, these mode pins are sampled. > > Signed-off-by: Piyush Mehta <piyush.mehta@xilinx.com>
OK, sounds interesting!
> +#include <linux/slab.h>
I think I saw somewhere that this is not needed anymore, check if you need it.
> +#define GET_OUTEN_PIN(pin) (1U << (pin))
Delete this macro and just use BIT(pin) inline. #include <linux/bits.h>
> +static int modepin_gpio_get_value(struct gpio_chip *chip, unsigned > +int pin) { > + u32 out_en; > + u32 regval = 0; > + int ret; > + > + out_en = GET_OUTEN_PIN(pin);
Drop this and out_en
> + ret = zynqmp_pm_bootmode_read(®val); > + if (ret) { > + pr_err("modepin: get value err %d\n", ret); > + return ret; > + } > + > + return (out_en & (regval >> 8U)) ? 1 : 0;
return !!(regval & BIT(pin + 8));
should work and is easier to read IMO. We just check the right bit immediately.
> +static void modepin_gpio_set_value(struct gpio_chip *chip, unsigned int pin, > + int state) { > + u32 out_en; > + u32 bootpin_val = 0; > + int ret; > + > + out_en = GET_OUTEN_PIN(pin);
Skip this helper variable.
> + state = state != 0 ? out_en : 0;
Uh that is really hard to read and modified a parameter. Skip that too.
> + bootpin_val = (state << (8U)) | out_en;
What you want is mask and set.
bootpin_val = BIT(pin + 8);
> + /* Configure bootpin value */ > + ret = zynqmp_pm_bootmode_write(bootpin_val);
This just looks weird.
Why are you not reading the value first since you are using read/modify/write?
I *think* you want to do this:
ret = zynqmp_pm_bootmode_read(&val); if (ret) /* error handling */ if (state) val |= BIT(pin + 8); else val &= ~BIT(pin + 8); ret = zynqmp_pm_bootmode_write(val); if (ret) /* error handling */
> +/* > + * modepin_gpio_dir_in - Set the direction of the specified GPIO pin as input > + * @chip: gpio_chip instance to be worked on > + * @pin: gpio pin number within the device > + * > + * Return: 0 always > + */ > +static int modepin_gpio_dir_in(struct gpio_chip *chip, unsigned int > +pin) { > + return 0; > +}
I think you said this was configurable in the commit message.
Use the define GPIO_LINE_DIRECTION_OUT rather than 0.
> +static int modepin_gpio_dir_out(struct gpio_chip *chip, unsigned int pin, > + int state) { > + return 0; > +}
Configurable?
> + status = devm_gpiochip_add_data(&pdev->dev, chip, chip); > + if (status) > + dev_err_probe(&pdev->dev, status, > + "Failed to add GPIO chip\n");
just return dev_err_probe(...)
Yours, Linus Walleij
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