diff mbox series

[v5,5/6] pinctrl: meson: add support of drive-strength-microamp

Message ID 20190510082324.21181-6-glaroque@baylibre.com
State New
Headers show
Series Add drive-strength in Meson pinctrl driver | expand

Commit Message

Guillaume LA ROQUE May 10, 2019, 8:23 a.m. UTC 
drive-strength-microamp is a new feature needed for G12A SoC.
the default DS setting after boot is usually 500uA and it is not enough for
many functions. We need to be able to set the drive strength to reliably
enable things like MMC, I2C, etc ...

Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
---
 drivers/pinctrl/meson/pinctrl-meson.c | 99 +++++++++++++++++++++++++++
 drivers/pinctrl/meson/pinctrl-meson.h | 18 ++++-
 2 files changed, 116 insertions(+), 1 deletion(-)

Comments

Martin Blumenstingl May 11, 2019, 4:46 p.m. UTC | #1 
Hi Guillaume,

On Fri, May 10, 2019 at 10:23 AM Guillaume La Roque
<glaroque@baylibre.com> wrote:
>
> drive-strength-microamp is a new feature needed for G12A SoC.
> the default DS setting after boot is usually 500uA and it is not enough for
> many functions. We need to be able to set the drive strength to reliably
> enable things like MMC, I2C, etc ...
>
> Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
Reviewed-by: Martin Blumenstingl<martin.blumenstingl@googlemail.com>

the warning messages when printing pinconf-pins (in debugfs) are gone
on my Meson8m2 board so:
Tested-by: Martin Blumenstingl<martin.blumenstingl@googlemail.com>

[...]
> +static int meson_pinconf_set_drive_strength(struct meson_pinctrl *pc,
> +                                           unsigned int pin,
> +                                           u16 drive_strength_ua)
> +{
> +       struct meson_bank *bank;
> +       unsigned int reg, bit, ds_val;
> +       int ret;
> +
> +       if (!pc->reg_ds) {
> +               dev_err(pc->dev, "drive-strength not supported\n");
> +               return -ENOTSUPP;
> +       }
> +
> +       ret = meson_get_bank(pc, pin, &bank);
> +       if (ret)
> +               return ret;
> +
> +       meson_calc_reg_and_bit(bank, pin, REG_DS, &reg, &bit);
> +       bit = bit << 1;
I was confused by this shifting (not sure why I haven't noticed this
in earlier revisions). however, it all made sense after I did the
maths for two examples:

BOOT_0 uses drive-strength register 0x0 bits [1:0] so the result
should be "bit = 0"
meson_calc_reg_and_bit returns bit = 0
0 << 1 = 0, so this seems right

BOOT_15 uses drive-strength register 0x0 bits [31:30] so the result
should be "bit = 30"
meson_calc_reg_and_bit returns bit = 15
15 << 1 = 30

so all seems fine, even though it wasn't obvious to me at first sight
that it's all good


Martin
diff mbox series

Patch

diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c
index 8ea5c1527064..33b4b141baac 100644
--- a/drivers/pinctrl/meson/pinctrl-meson.c
+++ b/drivers/pinctrl/meson/pinctrl-meson.c
@@ -220,11 +220,54 @@  static int meson_pinconf_enable_bias(struct meson_pinctrl *pc, unsigned int pin,
 	return 0;
 }
 
+static int meson_pinconf_set_drive_strength(struct meson_pinctrl *pc,
+					    unsigned int pin,
+					    u16 drive_strength_ua)
+{
+	struct meson_bank *bank;
+	unsigned int reg, bit, ds_val;
+	int ret;
+
+	if (!pc->reg_ds) {
+		dev_err(pc->dev, "drive-strength not supported\n");
+		return -ENOTSUPP;
+	}
+
+	ret = meson_get_bank(pc, pin, &bank);
+	if (ret)
+		return ret;
+
+	meson_calc_reg_and_bit(bank, pin, REG_DS, &reg, &bit);
+	bit = bit << 1;
+
+	if (drive_strength_ua <= 500) {
+		ds_val = MESON_PINCONF_DRV_500UA;
+	} else if (drive_strength_ua <= 2500) {
+		ds_val = MESON_PINCONF_DRV_2500UA;
+	} else if (drive_strength_ua <= 3000) {
+		ds_val = MESON_PINCONF_DRV_3000UA;
+	} else if (drive_strength_ua <= 4000) {
+		ds_val = MESON_PINCONF_DRV_4000UA;
+	} else {
+		dev_warn_once(pc->dev,
+			      "pin %u: invalid drive-strength : %d , default to 4mA\n",
+			      pin, drive_strength_ua);
+		ds_val = MESON_PINCONF_DRV_4000UA;
+	}
+
+	ret = regmap_update_bits(pc->reg_ds, reg, 0x3 << bit, ds_val << bit);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
 static int meson_pinconf_set(struct pinctrl_dev *pcdev, unsigned int pin,
 			     unsigned long *configs, unsigned num_configs)
 {
 	struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
 	enum pin_config_param param;
+	unsigned int drive_strength_ua;
 	int i, ret;
 
 	for (i = 0; i < num_configs; i++) {
@@ -246,6 +289,14 @@  static int meson_pinconf_set(struct pinctrl_dev *pcdev, unsigned int pin,
 			if (ret)
 				return ret;
 			break;
+		case PIN_CONFIG_DRIVE_STRENGTH_UA:
+			drive_strength_ua =
+				pinconf_to_config_argument(configs[i]);
+			ret = meson_pinconf_set_drive_strength
+				(pc, pin, drive_strength_ua);
+			if (ret)
+				return ret;
+			break;
 		default:
 			return -ENOTSUPP;
 		}
@@ -288,12 +339,55 @@  static int meson_pinconf_get_pull(struct meson_pinctrl *pc, unsigned int pin)
 	return conf;
 }
 
+static int meson_pinconf_get_drive_strength(struct meson_pinctrl *pc,
+					    unsigned int pin,
+					    u16 *drive_strength_ua)
+{
+	struct meson_bank *bank;
+	unsigned int reg, bit;
+	unsigned int val;
+	int ret;
+
+	if (!pc->reg_ds)
+		return -ENOTSUPP;
+
+	ret = meson_get_bank(pc, pin, &bank);
+	if (ret)
+		return ret;
+
+	meson_calc_reg_and_bit(bank, pin, REG_DS, &reg, &bit);
+
+	ret = regmap_read(pc->reg_ds, reg, &val);
+	if (ret)
+		return ret;
+
+	switch ((val >> bit) & 0x3) {
+	case MESON_PINCONF_DRV_500UA:
+		*drive_strength_ua = 500;
+		break;
+	case MESON_PINCONF_DRV_2500UA:
+		*drive_strength_ua = 2500;
+		break;
+	case MESON_PINCONF_DRV_3000UA:
+		*drive_strength_ua = 3000;
+		break;
+	case MESON_PINCONF_DRV_4000UA:
+		*drive_strength_ua = 4000;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int meson_pinconf_get(struct pinctrl_dev *pcdev, unsigned int pin,
 			     unsigned long *config)
 {
 	struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
 	enum pin_config_param param = pinconf_to_config_param(*config);
 	u16 arg;
+	int ret;
 
 	switch (param) {
 	case PIN_CONFIG_BIAS_DISABLE:
@@ -304,6 +398,11 @@  static int meson_pinconf_get(struct pinctrl_dev *pcdev, unsigned int pin,
 		else
 			return -EINVAL;
 		break;
+	case PIN_CONFIG_DRIVE_STRENGTH_UA:
+		ret = meson_pinconf_get_drive_strength(pc, pin, &arg);
+		if (ret)
+			return ret;
+		break;
 	default:
 		return -ENOTSUPP;
 	}
diff --git a/drivers/pinctrl/meson/pinctrl-meson.h b/drivers/pinctrl/meson/pinctrl-meson.h
index 5eaab925f427..cd955fb7c2ce 100644
--- a/drivers/pinctrl/meson/pinctrl-meson.h
+++ b/drivers/pinctrl/meson/pinctrl-meson.h
@@ -71,9 +71,20 @@  enum meson_reg_type {
 	REG_DIR,
 	REG_OUT,
 	REG_IN,
+	REG_DS,
 	NUM_REG,
 };
 
+/**
+ * enum meson_pinconf_drv - value of drive-strength supported
+ */
+enum meson_pinconf_drv {
+	MESON_PINCONF_DRV_500UA,
+	MESON_PINCONF_DRV_2500UA,
+	MESON_PINCONF_DRV_3000UA,
+	MESON_PINCONF_DRV_4000UA,
+};
+
 /**
  * struct meson bank
  *
@@ -132,7 +143,8 @@  struct meson_pinctrl {
 		.num_groups = ARRAY_SIZE(fn ## _groups),		\
 	}
 
-#define BANK(n, f, l, fi, li, per, peb, pr, pb, dr, db, or, ob, ir, ib)	\
+#define BANK_DS(n, f, l, fi, li, per, peb, pr, pb, dr, db, or, ob, ir, ib,     \
+		dsr, dsb)                                                      \
 	{								\
 		.name		= n,					\
 		.first		= f,					\
@@ -145,9 +157,13 @@  struct meson_pinctrl {
 			[REG_DIR]	= { dr, db },			\
 			[REG_OUT]	= { or, ob },			\
 			[REG_IN]	= { ir, ib },			\
+			[REG_DS]	= { dsr, dsb },			\
 		},							\
 	 }
 
+#define BANK(n, f, l, fi, li, per, peb, pr, pb, dr, db, or, ob, ir, ib) \
+	BANK_DS(n, f, l, fi, li, per, peb, pr, pb, dr, db, or, ob, ir, ib, 0, 0)
+
 #define MESON_PIN(x) PINCTRL_PIN(x, #x)
 
 /* Common pmx functions */