Hi Linus,

Thanks for the reviews.

-----Original Message-----
From: Linus Walleij [mailto:linus.walleij@linaro.org]
Sent: Friday, June 09, 2017 4:15 AM
To: Mani, Rajmohan <redacted>
Cc: linux-kernel@vger.kernel.org; linux-gpio@vger.kernel.org; ACPI Devel
Maling List [off-list ref]; Lee Jones [off-list ref];
Alexandre Courbot [off-list ref]; Rafael J. Wysocki
[off-list ref]; Len Brown [off-list ref]
Subject: Re: [PATCH v1 2/3] gpio: Add support for TPS68470 GPIOs

On Tue, Jun 6, 2017 at 1:55 PM, Rajmohan Mani [off-list ref]
wrote:

quoted

This patch adds support for TPS68470 GPIOs.
There are 7 GPIOs and a few sensor related GPIOs.
These GPIOs can be requested and configured as appropriate.

Signed-off-by: Rajmohan Mani <redacted>

Same comments as Andy already sent, plus:

quoted

+static inline struct tps68470_gpio_data *to_gpio_data(struct
+gpio_chip *gpiochp) {
+       return container_of(gpiochp, struct tps68470_gpio_data, gc); }

Please use the data pointe inside gpio_chip.

This is not clear to me.
The driver already gets the data pointer inside gpio_chip (which is gpiochp)
Is the name gpiochp misleading? 
I had to get rid of "i" in gpiochip, to meet 80 char limit.

struct tps68470_gpio_data *foo = gpiochip_get_data(gc);

quoted

+       ret = tps68470_reg_read(tps, reg, &val);

(...)

quoted

+       tps68470_update_bits(tps, reg, BIT(offset), value ?
+ BIT(offset) : 0);

(...)

quoted

+       return tps68470_update_bits(tps, TPS68470_GPIO_CTL_REG_A(offset),
+                                TPS68470_GPIO_MODE_MASK,
+                                TPS68470_GPIO_MODE_OUT_CMOS);

(...)

quoted

+       return tps68470_update_bits(tps, TPS68470_GPIO_CTL_REG_A(offset),
+                                  TPS68470_GPIO_MODE_MASK, 0x00);

This looks like a reimplementation of regmap. Is it not possible to create a
regmap in the MFD driver and pass that around instead?

Ack
Will be addressed in v2 of this patch series.

quoted

+struct gpiod_lookup_table gpios_table = {
+       .dev_id = NULL,
+       .table = {
+                 GPIO_LOOKUP("tps68470-gpio", 0, "gpio.0", GPIO_ACTIVE_HIGH),
+                 GPIO_LOOKUP("tps68470-gpio", 1, "gpio.1", GPIO_ACTIVE_HIGH),
+                 GPIO_LOOKUP("tps68470-gpio", 2, "gpio.2", GPIO_ACTIVE_HIGH),
+                 GPIO_LOOKUP("tps68470-gpio", 3, "gpio.3", GPIO_ACTIVE_HIGH),
+                 GPIO_LOOKUP("tps68470-gpio", 4, "gpio.4", GPIO_ACTIVE_HIGH),
+                 GPIO_LOOKUP("tps68470-gpio", 5, "gpio.5", GPIO_ACTIVE_HIGH),
+                 GPIO_LOOKUP("tps68470-gpio", 6, "gpio.6", GPIO_ACTIVE_HIGH),
+                 GPIO_LOOKUP("tps68470-gpio", 7, "s_enable",

GPIO_ACTIVE_HIGH),

quoted

+                 GPIO_LOOKUP("tps68470-gpio", 8, "s_idle", GPIO_ACTIVE_HIGH),
+                 GPIO_LOOKUP("tps68470-gpio", 9, "s_resetn",

GPIO_ACTIVE_HIGH),

quoted

+                 {},
+       },
+};

Hm that's why you include <linux/gpio/machine.h> I guess.

Ack

This warrants a big comment above it explaining why this is done like that and
what the use is inside any system with this chip mounted.

Ack
I have added comments in the MFD driver, inside which the lookup table has moved.

quoted

+       tps68470_gpio->gc.label = "tps68470-gpio";
+       tps68470_gpio->gc.owner = THIS_MODULE;
+       tps68470_gpio->gc.direction_input = tps68470_gpio_input;
+       tps68470_gpio->gc.direction_output = tps68470_gpio_output;

Please implement .get_direction()

Ack

quoted

+       tps68470_gpio->gc.get = tps68470_gpio_get;
+       tps68470_gpio->gc.set = tps68470_gpio_set;
+       tps68470_gpio->gc.can_sleep = true;
+       tps68470_gpio->gc.ngpio = TPS68470_N_GPIO;
+       tps68470_gpio->gc.base = -1;
+       tps68470_gpio->gc.parent = &pdev->dev;

Consider assigning the .names() array some sensible line names.

Ack

quoted

+static int tps68470_gpio_remove(struct platform_device *pdev) {
+       struct tps68470_gpio_data *tps68470_gpio =
+platform_get_drvdata(pdev);
+
+       gpiod_remove_lookup_table(&gpios_table);
+       gpiochip_remove(&tps68470_gpio->gc);

You can't use devm_gpiochip_add()?

Originally I couldn't, because the driver can not remove the lookup table upon exit/removal. I moved this code inside the MFD driver, which is modified to use .shutdown() to remove the lookup table, so it can use dev_mfd_* call.