On Thu, 15 Jul 2021, Linus Walleij wrote:

The Tosa device (Sharp SL-6000) has a mishmash driver set-up
for the Toshiba TC6393xb MFD that includes a battery charger
and touchscreen and has some kind of relationship to the SoC
sound driver for the AC97 codec. Other devices define a chip
like this but seem only half-implemented, not really handling
battery charging etc.

This patch switches the Toshiba MFD device to provide GPIO
descriptors to the battery charger and SoC codec. As a result
some descriptors need to be moved out of the Tosa boardfile
and new one added: all SoC GPIO resources to these drivers
now comes from the main boardfile, while the MFD provide
GPIOs for its portions.

As a result we can request one GPIO from our own GPIO chip
and drop two hairy callbacks into the board file.

This platform badly needs to have its drivers split up and
converted to device tree probing to handle this quite complex
relationship in an orderly manner. I just do my best in solving
the GPIO descriptor part of the puzzle. Please don't ask me
to fix everything that is wrong with these driver to todays
standards, I am just trying to fix one aspect. I do try to
use modern devres resource management and handle deferred
probe using new functions where appropriate.

Cc: Dmitry Eremin-Solenikov <redacted>
Cc: Dirk Opfer <redacted>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Daniel Mack <daniel@zonque.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Lee Jones <redacted>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Linus Walleij <redacted>
---
Dmitry/Dirk: it'd be great if you could test this patch on
the Tosa and try to help me iron out any bugs.

Merging strategy: please provide ACKs and I will attempt
to merge this through the SoC tree.
---
 arch/arm/mach-pxa/eseries.c           |   2 -
 arch/arm/mach-pxa/include/mach/tosa.h |  18 ---
 arch/arm/mach-pxa/tosa.c              |  68 +++-------
 drivers/mfd/tc6393xb.c                | 147 ++++++++++++++++------
 drivers/power/supply/tosa_battery.c   | 171 ++++++++++++++++----------
 include/linux/mfd/tc6393xb.h          |   1 -
 sound/soc/pxa/tosa.c                  |  20 ++-
 7 files changed, 246 insertions(+), 181 deletions(-)

[...]

Are these comments really necessary?

Missing an "are" for clarity?

+ * platforms using this chip, rewrite things to use device tree and register GPIO

Not sure we should be dictating extension methods in this way.

What if DT is deprecated by the time this is expanded?

+ * resources there.
+ */
+#define TOSA_GC_NAME			"tc6393xb"

Please use the name string in-place.

+#define TOSA_GPIO_TG_ON			0
+#define TOSA_GPIO_L_MUTE		1
+#define TOSA_GPIO_BL_C20MA		3
+#define TOSA_GPIO_CARD_VCC_ON		4
+#define TOSA_GPIO_CHARGE_OFF		6
+#define TOSA_GPIO_CHARGE_OFF_JC		7
+#define TOSA_GPIO_BAT0_V_ON		9
+#define TOSA_GPIO_BAT1_V_ON		10
+#define TOSA_GPIO_BU_CHRG_ON		11
+#define TOSA_GPIO_BAT_SW_ON		12
+#define TOSA_GPIO_BAT0_TH_ON		14
+#define TOSA_GPIO_BAT1_TH_ON		15

Okay, I have to ask - what are 5, 8 and 13?

+static struct gpiod_lookup_table tosa_lcd_gpio_lookup = {
+	.dev_id = "spi2.0",
+	.table = {
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_TG_ON, "tg #pwr", GPIO_ACTIVE_HIGH),
+		{ },
+	},
+};
+
+static struct gpiod_lookup_table tosa_lcd_bl_gpio_lookup = {
+	.dev_id = "i2c-tosa-bl",
+	.table = {
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_BL_C20MA, "backlight", GPIO_ACTIVE_HIGH),
+		{ },
+	},
+};
+
+static struct gpiod_lookup_table tosa_audio_gpio_lookup = {
+	.dev_id = "tosa-audio",
+	.table = {
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_L_MUTE, NULL, GPIO_ACTIVE_HIGH),
+		{ },
+	},
+};

Are these structures going to be peppered all over the kernel now?

Maybe a helper can be added to make these single line entries one line
each?

+static struct gpiod_lookup_table tosa_battery_gpio_lookup = {
+	.dev_id = "wm97xx-battery",
+	.table = {
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_CHARGE_OFF,
+			    "main charge off", GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_CHARGE_OFF_JC,
+			    "jacket charge off", GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_BAT0_V_ON,
+			    "main battery", GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_BAT1_V_ON,
+			    "jacket battery", GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_BU_CHRG_ON,
+			    "backup battery", GPIO_ACTIVE_HIGH),
+		/* BAT1 and BAT0 thermistors appear to be swapped */
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_BAT1_TH_ON,
+			    "main battery temp", GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_BAT0_TH_ON,
+			    "jacket battery temp", GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP(TOSA_GC_NAME, TOSA_GPIO_BAT_SW_ON,
+			    "battery switch", GPIO_ACTIVE_HIGH),

These are soooo close to being <100 chars.

What does Checkpatch currently warn on?  Is it 100 or 120?

+		{ },
+	},
+};
+
+static struct gpiod_lookup_table *tc6393xb_gpio_lookups[] = {
+	&tosa_lcd_gpio_lookup,
+	&tosa_lcd_bl_gpio_lookup,
+	&tosa_audio_gpio_lookup,
+	&tosa_battery_gpio_lookup,
+};
+
+static int tc6393xb_register_gpio(struct tc6393xb *tc6393xb)
 {
-	tc6393xb->gpio.label = "tc6393xb";
-	tc6393xb->gpio.base = gpio_base;
-	tc6393xb->gpio.ngpio = 16;
-	tc6393xb->gpio.set = tc6393xb_gpio_set;
-	tc6393xb->gpio.get = tc6393xb_gpio_get;
-	tc6393xb->gpio.direction_input = tc6393xb_gpio_direction_input;
-	tc6393xb->gpio.direction_output = tc6393xb_gpio_direction_output;
-
-	return gpiochip_add_data(&tc6393xb->gpio, tc6393xb);
+	struct gpio_chip *gc = &tc6393xb->gpio;
+	struct device *dev = tc6393xb->dev;
+	int ret;
+
+	gc->label = TOSA_GC_NAME;
+	gc->base = -1; /* Dynamic allocation */

Global define?

+	gc->ngpio = 16;
+	gc->set = tc6393xb_gpio_set;
+	gc->get = tc6393xb_gpio_get;
+	gc->direction_input = tc6393xb_gpio_direction_input;
+	gc->direction_output = tc6393xb_gpio_direction_output;
+
+	ret = devm_gpiochip_add_data(dev, gc, tc6393xb);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to add GPIO chip\n");
+
+	/* Register descriptor look-ups for consumers */
+	gpiod_add_lookup_tables(tc6393xb_gpio_lookups, ARRAY_SIZE(tc6393xb_gpio_lookups));
+
+	/* Request some of our own GPIOs */
+	tc6393xb->vcc_on = gpiochip_request_own_desc(gc, TOSA_GPIO_CARD_VCC_ON, "VCC ON",
+						     GPIO_ACTIVE_HIGH, GPIOD_OUT_HIGH);
+	if (IS_ERR(tc6393xb->vcc_on))
+		return dev_err_probe(dev, PTR_ERR(tc6393xb->vcc_on),
+				     "failed to request VCC ON GPIO\n");
+

So much more code to do the same thing?

That confused me at first.

Please consider changing the platform_device to pdev (separately).

Taking away all of these lines is nice.

 	ret = tcpd->disable(dev);
 	clk_disable_unprepare(tc6393xb->clk);
 	iounmap(tc6393xb->scr);

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog