[PATCH 0/2] pinctrl: meson: add g12a drive strength support

[PATCH 0/2] pinctrl: meson: add g12a drive strength support

[Jerome Brunet]

The purpose of this patchset is to add drive-strength support in meson pinconf
driver. This is a new feature that was added on the g12a. It is critical for us
to support this since many functions are failing with default pad drive-strength.

Now the slightly annoying part :(
The value achievable by the SoC are 0.5mA, 2.5mA, 3mA and 4mA and the DT property
'drive-strength' is expressed in mA.

1) Rounding down the value, we could be requesting a 0mA drive strength.
   That would look weird.
2) Rounding up, we can't distinguish between 2.5mA and 3mA

To solve this issue in this in this v1, we chose to document that, on Amlogic,
drive-strength is expressed in uA instead of mA.
It works well and there is no impact on the other platforms but I'm not sure this
is really OK with the DT rules ?

Linus, if this is not OK with you, here are 2 other options we are
considering. We would be very interested to get your opinion on the matter:

1) instead the generic 'drive-strength' property, we could add an amlogic
specific property, 'amlogic,drive-strength'. It would be expressed in uA
and parsed in amlogic specific code.
I think this option is kind of overkill. Expressing drive strength in uA is
not really amlogic specific so it does not make much sense, but it would
work ...

2) Add another generic property "drive-strength-uA". The change to do so
would be minimal and could be benefit to other platforms later on.

Cheers
Jerome

Guillaume La Roque (2):
  dt-bindings: pinctrl: meson: Add drive-strength property
  pinctrl: meson: add support of drive-strength

 .../bindings/pinctrl/meson,pinctrl.txt        |   3 +
 drivers/pinctrl/meson/pinctrl-meson-g12a.c    |  36 ++--
 drivers/pinctrl/meson/pinctrl-meson.c         | 166 +++++++++++++-----
 drivers/pinctrl/meson/pinctrl-meson.h         |  20 ++-
 4 files changed, 165 insertions(+), 60 deletions(-)

-- 
2.20.1

[PATCH 0/2] pinctrl: meson: add g12a drive strength support

[Jerome Brunet]

The purpose of this patchset is to add drive-strength support in meson pinconf
driver. This is a new feature that was added on the g12a. It is critical for us
to support this since many functions are failing with default pad drive-strength.

Now the slightly annoying part :(
The value achievable by the SoC are 0.5mA, 2.5mA, 3mA and 4mA and the DT property
'drive-strength' is expressed in mA.

1) Rounding down the value, we could be requesting a 0mA drive strength.
   That would look weird.
2) Rounding up, we can't distinguish between 2.5mA and 3mA

To solve this issue in this in this v1, we chose to document that, on Amlogic,
drive-strength is expressed in uA instead of mA.
It works well and there is no impact on the other platforms but I'm not sure this
is really OK with the DT rules ?

Linus, if this is not OK with you, here are 2 other options we are
considering. We would be very interested to get your opinion on the matter:

1) instead the generic 'drive-strength' property, we could add an amlogic
specific property, 'amlogic,drive-strength'. It would be expressed in uA
and parsed in amlogic specific code.
I think this option is kind of overkill. Expressing drive strength in uA is
not really amlogic specific so it does not make much sense, but it would
work ...

2) Add another generic property "drive-strength-uA". The change to do so
would be minimal and could be benefit to other platforms later on.

Cheers
Jerome

Guillaume La Roque (2):
  dt-bindings: pinctrl: meson: Add drive-strength property
  pinctrl: meson: add support of drive-strength

 .../bindings/pinctrl/meson,pinctrl.txt        |   3 +
 drivers/pinctrl/meson/pinctrl-meson-g12a.c    |  36 ++--
 drivers/pinctrl/meson/pinctrl-meson.c         | 166 +++++++++++++-----
 drivers/pinctrl/meson/pinctrl-meson.h         |  20 ++-
 4 files changed, 165 insertions(+), 60 deletions(-)

-- 
2.20.1


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linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic

[PATCH 1/2] dt-bindings: pinctrl: meson: Add drive-strength property

[Jerome Brunet]

From: Guillaume La Roque <glaroque@baylibre.com>

Add optional drive-strength property

Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
index a47dd990a8d3..4e3d5a27c91c 100644
--- a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
+++ b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
@@ -51,6 +51,9 @@ Configuration nodes support the generic properties "bias-disable",
 "bias-pull-up" and "bias-pull-down", described in file
 pinctrl-bindings.txt
 
+Optional properties :
+ - drive-strength: Drive strength for the specified pins in uA.
+
 === Example ===
 
 	pinctrl: pinctrl@c1109880 {
-- 
2.20.1

[PATCH 1/2] dt-bindings: pinctrl: meson: Add drive-strength property

[Jerome Brunet]

From: Guillaume La Roque <glaroque@baylibre.com>

Add optional drive-strength property

Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
index a47dd990a8d3..4e3d5a27c91c 100644
--- a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
+++ b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
@@ -51,6 +51,9 @@ Configuration nodes support the generic properties "bias-disable",
 "bias-pull-up" and "bias-pull-down", described in file
 pinctrl-bindings.txt
 
+Optional properties :
+ - drive-strength: Drive strength for the specified pins in uA.
+
 === Example ===
 
 	pinctrl: pinctrl@c1109880 {
-- 
2.20.1


_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic

[PATCH 2/2] pinctrl: meson: add support of drive-strength

[Jerome Brunet]

From: Guillaume La Roque <glaroque@baylibre.com>

drive-strength is a new feature needed for G12A SoC.
the default DS setting after boot is usually 0.5mA 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>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 drivers/pinctrl/meson/pinctrl-meson-g12a.c |  36 ++---
 drivers/pinctrl/meson/pinctrl-meson.c      | 166 ++++++++++++++++-----
 drivers/pinctrl/meson/pinctrl-meson.h      |  20 ++-
 3 files changed, 162 insertions(+), 60 deletions(-)

diff --git a/drivers/pinctrl/meson/pinctrl-meson-g12a.c b/drivers/pinctrl/meson/pinctrl-meson-g12a.c
index d494492e98e9..3475cd7bd2af 100644
--- a/drivers/pinctrl/meson/pinctrl-meson-g12a.c
+++ b/drivers/pinctrl/meson/pinctrl-meson-g12a.c
@@ -1304,28 +1304,28 @@ static struct meson_pmx_func meson_g12a_aobus_functions[] = {
 };
 
 static struct meson_bank meson_g12a_periphs_banks[] = {
-	/* name  first  last  irq  pullen  pull  dir  out  in */
-	BANK("Z",    GPIOZ_0,    GPIOZ_15, 12, 27,
-	     4,  0,  4,  0,  12,  0,  13, 0,  14, 0),
-	BANK("H",    GPIOH_0,    GPIOH_8, 28, 36,
-	     3,  0,  3,  0,  9,  0,  10,  0,  11,  0),
-	BANK("BOOT", BOOT_0,     BOOT_15,  37, 52,
-	     0,  0,  0,  0,  0, 0,  1, 0,  2, 0),
-	BANK("C",    GPIOC_0,    GPIOC_7,  53, 60,
-	     1,  0,  1,  0,  3, 0,  4, 0,  5, 0),
-	BANK("A",    GPIOA_0,    GPIOA_15,  61, 76,
-	     5,  0,  5,  0,  16,  0,  17,  0,  18,  0),
-	BANK("X",    GPIOX_0,    GPIOX_19,   77, 96,
-	     2,  0,  2,  0,  6,  0,  7,  0,  8,  0),
+	/* name  first  last  irq  pullen  pull  dir  out  in  ds */
+	BANK_DS("Z",    GPIOZ_0,    GPIOZ_15, 12, 27,
+		4,  0,  4,  0,  12,  0,  13, 0,  14, 0, 5, 0),
+	BANK_DS("H",    GPIOH_0,    GPIOH_8, 28, 36,
+		3,  0,  3,  0,  9,  0,  10,  0,  11,  0, 4, 0),
+	BANK_DS("BOOT", BOOT_0,     BOOT_15,  37, 52,
+		0,  0,  0,  0,  0, 0,  1, 0,  2, 0, 0, 0),
+	BANK_DS("C",    GPIOC_0,    GPIOC_7,  53, 60,
+		1,  0,  1,  0,  3, 0,  4, 0,  5, 0, 1, 0),
+	BANK_DS("A",    GPIOA_0,    GPIOA_15,  61, 76,
+		5,  0,  5,  0,  16,  0,  17,  0,  18,  0, 6, 0),
+	BANK_DS("X",    GPIOX_0,    GPIOX_19,   77, 96,
+		2,  0,  2,  0,  6,  0,  7,  0,  8,  0, 2, 0),
 };
 
 static struct meson_bank meson_g12a_aobus_banks[] = {
-	/* name  first  last  irq  pullen  pull  dir  out  in  */
-	BANK("AO",   GPIOAO_0,  GPIOAO_11,  0, 11,
-	     3,  0,  2, 0,  0,  0,  4, 0,  1,  0),
+	/* name  first  last  irq  pullen  pull  dir  out  in  ds */
+	BANK_DS("AO", GPIOAO_0, GPIOAO_11, 0, 11, 3, 0, 2, 0, 0, 0, 4, 0, 1, 0,
+		0, 0),
 	/* GPIOE actually located in the AO bank */
-	BANK("E",   GPIOE_0,  GPIOE_2,   97, 99,
-	     3,  16,  2, 16,  0,  16,  4, 16,  1,  16),
+	BANK_DS("E", GPIOE_0, GPIOE_2, 97, 99, 3, 16, 2, 16, 0, 16, 4, 16, 1,
+		16, 1, 0),
 };
 
 static struct meson_pmx_bank meson_g12a_periphs_pmx_banks[] = {
diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c
index 96a4a72708e4..786640f98f83 100644
--- a/drivers/pinctrl/meson/pinctrl-meson.c
+++ b/drivers/pinctrl/meson/pinctrl-meson.c
@@ -174,65 +174,108 @@ int meson_pmx_get_groups(struct pinctrl_dev *pcdev, unsigned selector,
 	return 0;
 }
 
-static int meson_pinconf_set(struct pinctrl_dev *pcdev, unsigned int pin,
-			     unsigned long *configs, unsigned num_configs)
+static int meson_pinconf_set_bias(struct meson_pinctrl *pc, unsigned int pin,
+				  enum pin_config_param conf)
+{
+	struct meson_bank *bank;
+	unsigned int reg, bit, val = 0;
+	int ret;
+
+	ret = meson_get_bank(pc, pin, &bank);
+	if (ret)
+		return ret;
+
+	meson_calc_reg_and_bit(bank, pin, REG_PULLEN, &reg, &bit);
+
+	if (conf == PIN_CONFIG_BIAS_DISABLE) {
+		ret = regmap_update_bits(pc->reg_pullen, reg, BIT(bit),	0);
+		if (ret)
+			return ret;
+	} else {
+		meson_calc_reg_and_bit(bank, pin, REG_PULL, &reg, &bit);
+		if (conf == PIN_CONFIG_BIAS_PULL_UP)
+			val = BIT(bit);
+
+		ret = regmap_update_bits(pc->reg_pull, reg, BIT(bit), val);
+		if (ret)
+			return ret;
+
+		meson_calc_reg_and_bit(bank, pin, REG_PULLEN, &reg, &bit);
+		ret = regmap_update_bits(pc->reg_pullen, reg, BIT(bit),
+					 BIT(bit));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int meson_pinconf_set_drive_strength(struct meson_pinctrl *pc,
+					    unsigned int pin, u16 arg)
 {
-	struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
 	struct meson_bank *bank;
-	enum pin_config_param param;
 	unsigned int reg, bit;
-	int i, ret;
+	unsigned int 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 (arg <= 500) {
+		ds_val = MESON_PINCONF_DRV_500UA;
+	} else if (arg <= 2500) {
+		ds_val = MESON_PINCONF_DRV_2500UA;
+	} else if (arg <= 3000) {
+		ds_val = MESON_PINCONF_DRV_3000UA;
+	} else if (arg <= 4000) {
+		ds_val = MESON_PINCONF_DRV_4000UA;
+	} else {
+		dev_warn_once(pc->dev,
+			      "pin %u: invalid drive-strength : %d , default to 4mA\n",
+			      pin, arg);
+		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 arg;
+	int i, ret;
+
 	for (i = 0; i < num_configs; i++) {
 		param = pinconf_to_config_param(configs[i]);
 
 		switch (param) {
 		case PIN_CONFIG_BIAS_DISABLE:
-			dev_dbg(pc->dev, "pin %u: disable bias\n", pin);
-
-			meson_calc_reg_and_bit(bank, pin, REG_PULLEN, &reg,
-					       &bit);
-			ret = regmap_update_bits(pc->reg_pullen, reg,
-						 BIT(bit), 0);
-			if (ret)
-				return ret;
-			break;
 		case PIN_CONFIG_BIAS_PULL_UP:
-			dev_dbg(pc->dev, "pin %u: enable pull-up\n", pin);
-
-			meson_calc_reg_and_bit(bank, pin, REG_PULLEN,
-					       &reg, &bit);
-			ret = regmap_update_bits(pc->reg_pullen, reg,
-						 BIT(bit), BIT(bit));
-			if (ret)
-				return ret;
-
-			meson_calc_reg_and_bit(bank, pin, REG_PULL, &reg, &bit);
-			ret = regmap_update_bits(pc->reg_pull, reg,
-						 BIT(bit), BIT(bit));
-			if (ret)
-				return ret;
-			break;
 		case PIN_CONFIG_BIAS_PULL_DOWN:
-			dev_dbg(pc->dev, "pin %u: enable pull-down\n", pin);
-
-			meson_calc_reg_and_bit(bank, pin, REG_PULLEN,
-					       &reg, &bit);
-			ret = regmap_update_bits(pc->reg_pullen, reg,
-						 BIT(bit), BIT(bit));
+			ret = meson_pinconf_set_bias(pc, pin, param);
 			if (ret)
 				return ret;
-
-			meson_calc_reg_and_bit(bank, pin, REG_PULL, &reg, &bit);
-			ret = regmap_update_bits(pc->reg_pull, reg,
-						 BIT(bit), 0);
+			break;
+		case PIN_CONFIG_DRIVE_STRENGTH:
+			arg = pinconf_to_config_argument(configs[i]);
+			ret = meson_pinconf_set_drive_strength(pc, pin, arg);
 			if (ret)
 				return ret;
-			break;
 		default:
 			return -ENOTSUPP;
 		}
@@ -275,12 +318,51 @@ 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 *arg)
+{
+	struct meson_bank *bank;
+	unsigned int reg, bit;
+	unsigned int val;
+	int ret;
+
+	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:
+		*arg = 500;
+		break;
+	case MESON_PINCONF_DRV_2500UA:
+		*arg = 2500;
+		break;
+	case MESON_PINCONF_DRV_3000UA:
+		*arg = 3000;
+		break;
+	case MESON_PINCONF_DRV_4000UA:
+		*arg = 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:
@@ -291,6 +373,10 @@ static int meson_pinconf_get(struct pinctrl_dev *pcdev, unsigned int pin,
 		else
 			return -EINVAL;
 		break;
+	case PIN_CONFIG_DRIVE_STRENGTH:
+		ret = meson_pinconf_get_drive_strength(pc, pin, &arg);
+		if (ret)
+			return ret;
 	default:
 		return -ENOTSUPP;
 	}
diff --git a/drivers/pinctrl/meson/pinctrl-meson.h b/drivers/pinctrl/meson/pinctrl-meson.h
index 5eaab925f427..1a88103dcb9b 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,					\
@@ -145,8 +157,12 @@ 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)
 
-- 
2.20.1

[PATCH 2/2] pinctrl: meson: add support of drive-strength

[Jerome Brunet]

From: Guillaume La Roque <glaroque@baylibre.com>

drive-strength is a new feature needed for G12A SoC.
the default DS setting after boot is usually 0.5mA 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>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 drivers/pinctrl/meson/pinctrl-meson-g12a.c |  36 ++---
 drivers/pinctrl/meson/pinctrl-meson.c      | 166 ++++++++++++++++-----
 drivers/pinctrl/meson/pinctrl-meson.h      |  20 ++-
 3 files changed, 162 insertions(+), 60 deletions(-)

diff --git a/drivers/pinctrl/meson/pinctrl-meson-g12a.c b/drivers/pinctrl/meson/pinctrl-meson-g12a.c
index d494492e98e9..3475cd7bd2af 100644
--- a/drivers/pinctrl/meson/pinctrl-meson-g12a.c
+++ b/drivers/pinctrl/meson/pinctrl-meson-g12a.c
@@ -1304,28 +1304,28 @@ static struct meson_pmx_func meson_g12a_aobus_functions[] = {
 };
 
 static struct meson_bank meson_g12a_periphs_banks[] = {
-	/* name  first  last  irq  pullen  pull  dir  out  in */
-	BANK("Z",    GPIOZ_0,    GPIOZ_15, 12, 27,
-	     4,  0,  4,  0,  12,  0,  13, 0,  14, 0),
-	BANK("H",    GPIOH_0,    GPIOH_8, 28, 36,
-	     3,  0,  3,  0,  9,  0,  10,  0,  11,  0),
-	BANK("BOOT", BOOT_0,     BOOT_15,  37, 52,
-	     0,  0,  0,  0,  0, 0,  1, 0,  2, 0),
-	BANK("C",    GPIOC_0,    GPIOC_7,  53, 60,
-	     1,  0,  1,  0,  3, 0,  4, 0,  5, 0),
-	BANK("A",    GPIOA_0,    GPIOA_15,  61, 76,
-	     5,  0,  5,  0,  16,  0,  17,  0,  18,  0),
-	BANK("X",    GPIOX_0,    GPIOX_19,   77, 96,
-	     2,  0,  2,  0,  6,  0,  7,  0,  8,  0),
+	/* name  first  last  irq  pullen  pull  dir  out  in  ds */
+	BANK_DS("Z",    GPIOZ_0,    GPIOZ_15, 12, 27,
+		4,  0,  4,  0,  12,  0,  13, 0,  14, 0, 5, 0),
+	BANK_DS("H",    GPIOH_0,    GPIOH_8, 28, 36,
+		3,  0,  3,  0,  9,  0,  10,  0,  11,  0, 4, 0),
+	BANK_DS("BOOT", BOOT_0,     BOOT_15,  37, 52,
+		0,  0,  0,  0,  0, 0,  1, 0,  2, 0, 0, 0),
+	BANK_DS("C",    GPIOC_0,    GPIOC_7,  53, 60,
+		1,  0,  1,  0,  3, 0,  4, 0,  5, 0, 1, 0),
+	BANK_DS("A",    GPIOA_0,    GPIOA_15,  61, 76,
+		5,  0,  5,  0,  16,  0,  17,  0,  18,  0, 6, 0),
+	BANK_DS("X",    GPIOX_0,    GPIOX_19,   77, 96,
+		2,  0,  2,  0,  6,  0,  7,  0,  8,  0, 2, 0),
 };
 
 static struct meson_bank meson_g12a_aobus_banks[] = {
-	/* name  first  last  irq  pullen  pull  dir  out  in  */
-	BANK("AO",   GPIOAO_0,  GPIOAO_11,  0, 11,
-	     3,  0,  2, 0,  0,  0,  4, 0,  1,  0),
+	/* name  first  last  irq  pullen  pull  dir  out  in  ds */
+	BANK_DS("AO", GPIOAO_0, GPIOAO_11, 0, 11, 3, 0, 2, 0, 0, 0, 4, 0, 1, 0,
+		0, 0),
 	/* GPIOE actually located in the AO bank */
-	BANK("E",   GPIOE_0,  GPIOE_2,   97, 99,
-	     3,  16,  2, 16,  0,  16,  4, 16,  1,  16),
+	BANK_DS("E", GPIOE_0, GPIOE_2, 97, 99, 3, 16, 2, 16, 0, 16, 4, 16, 1,
+		16, 1, 0),
 };
 
 static struct meson_pmx_bank meson_g12a_periphs_pmx_banks[] = {
diff --git a/drivers/pinctrl/meson/pinctrl-meson.c b/drivers/pinctrl/meson/pinctrl-meson.c
index 96a4a72708e4..786640f98f83 100644
--- a/drivers/pinctrl/meson/pinctrl-meson.c
+++ b/drivers/pinctrl/meson/pinctrl-meson.c
@@ -174,65 +174,108 @@ int meson_pmx_get_groups(struct pinctrl_dev *pcdev, unsigned selector,
 	return 0;
 }
 
-static int meson_pinconf_set(struct pinctrl_dev *pcdev, unsigned int pin,
-			     unsigned long *configs, unsigned num_configs)
+static int meson_pinconf_set_bias(struct meson_pinctrl *pc, unsigned int pin,
+				  enum pin_config_param conf)
+{
+	struct meson_bank *bank;
+	unsigned int reg, bit, val = 0;
+	int ret;
+
+	ret = meson_get_bank(pc, pin, &bank);
+	if (ret)
+		return ret;
+
+	meson_calc_reg_and_bit(bank, pin, REG_PULLEN, &reg, &bit);
+
+	if (conf == PIN_CONFIG_BIAS_DISABLE) {
+		ret = regmap_update_bits(pc->reg_pullen, reg, BIT(bit),	0);
+		if (ret)
+			return ret;
+	} else {
+		meson_calc_reg_and_bit(bank, pin, REG_PULL, &reg, &bit);
+		if (conf == PIN_CONFIG_BIAS_PULL_UP)
+			val = BIT(bit);
+
+		ret = regmap_update_bits(pc->reg_pull, reg, BIT(bit), val);
+		if (ret)
+			return ret;
+
+		meson_calc_reg_and_bit(bank, pin, REG_PULLEN, &reg, &bit);
+		ret = regmap_update_bits(pc->reg_pullen, reg, BIT(bit),
+					 BIT(bit));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int meson_pinconf_set_drive_strength(struct meson_pinctrl *pc,
+					    unsigned int pin, u16 arg)
 {
-	struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
 	struct meson_bank *bank;
-	enum pin_config_param param;
 	unsigned int reg, bit;
-	int i, ret;
+	unsigned int 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 (arg <= 500) {
+		ds_val = MESON_PINCONF_DRV_500UA;
+	} else if (arg <= 2500) {
+		ds_val = MESON_PINCONF_DRV_2500UA;
+	} else if (arg <= 3000) {
+		ds_val = MESON_PINCONF_DRV_3000UA;
+	} else if (arg <= 4000) {
+		ds_val = MESON_PINCONF_DRV_4000UA;
+	} else {
+		dev_warn_once(pc->dev,
+			      "pin %u: invalid drive-strength : %d , default to 4mA\n",
+			      pin, arg);
+		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 arg;
+	int i, ret;
+
 	for (i = 0; i < num_configs; i++) {
 		param = pinconf_to_config_param(configs[i]);
 
 		switch (param) {
 		case PIN_CONFIG_BIAS_DISABLE:
-			dev_dbg(pc->dev, "pin %u: disable bias\n", pin);
-
-			meson_calc_reg_and_bit(bank, pin, REG_PULLEN, &reg,
-					       &bit);
-			ret = regmap_update_bits(pc->reg_pullen, reg,
-						 BIT(bit), 0);
-			if (ret)
-				return ret;
-			break;
 		case PIN_CONFIG_BIAS_PULL_UP:
-			dev_dbg(pc->dev, "pin %u: enable pull-up\n", pin);
-
-			meson_calc_reg_and_bit(bank, pin, REG_PULLEN,
-					       &reg, &bit);
-			ret = regmap_update_bits(pc->reg_pullen, reg,
-						 BIT(bit), BIT(bit));
-			if (ret)
-				return ret;
-
-			meson_calc_reg_and_bit(bank, pin, REG_PULL, &reg, &bit);
-			ret = regmap_update_bits(pc->reg_pull, reg,
-						 BIT(bit), BIT(bit));
-			if (ret)
-				return ret;
-			break;
 		case PIN_CONFIG_BIAS_PULL_DOWN:
-			dev_dbg(pc->dev, "pin %u: enable pull-down\n", pin);
-
-			meson_calc_reg_and_bit(bank, pin, REG_PULLEN,
-					       &reg, &bit);
-			ret = regmap_update_bits(pc->reg_pullen, reg,
-						 BIT(bit), BIT(bit));
+			ret = meson_pinconf_set_bias(pc, pin, param);
 			if (ret)
 				return ret;
-
-			meson_calc_reg_and_bit(bank, pin, REG_PULL, &reg, &bit);
-			ret = regmap_update_bits(pc->reg_pull, reg,
-						 BIT(bit), 0);
+			break;
+		case PIN_CONFIG_DRIVE_STRENGTH:
+			arg = pinconf_to_config_argument(configs[i]);
+			ret = meson_pinconf_set_drive_strength(pc, pin, arg);
 			if (ret)
 				return ret;
-			break;
 		default:
 			return -ENOTSUPP;
 		}
@@ -275,12 +318,51 @@ 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 *arg)
+{
+	struct meson_bank *bank;
+	unsigned int reg, bit;
+	unsigned int val;
+	int ret;
+
+	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:
+		*arg = 500;
+		break;
+	case MESON_PINCONF_DRV_2500UA:
+		*arg = 2500;
+		break;
+	case MESON_PINCONF_DRV_3000UA:
+		*arg = 3000;
+		break;
+	case MESON_PINCONF_DRV_4000UA:
+		*arg = 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:
@@ -291,6 +373,10 @@ static int meson_pinconf_get(struct pinctrl_dev *pcdev, unsigned int pin,
 		else
 			return -EINVAL;
 		break;
+	case PIN_CONFIG_DRIVE_STRENGTH:
+		ret = meson_pinconf_get_drive_strength(pc, pin, &arg);
+		if (ret)
+			return ret;
 	default:
 		return -ENOTSUPP;
 	}
diff --git a/drivers/pinctrl/meson/pinctrl-meson.h b/drivers/pinctrl/meson/pinctrl-meson.h
index 5eaab925f427..1a88103dcb9b 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,					\
@@ -145,8 +157,12 @@ 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)
 
-- 
2.20.1


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Re: [PATCH 2/2] pinctrl: meson: add support of drive-strength

[Neil Armstrong]

On 14/03/2019 17:37, Jerome Brunet wrote:
> From: Guillaume La Roque <glaroque@baylibre.com>
> 
> drive-strength is a new feature needed for G12A SoC.
> the default DS setting after boot is usually 0.5mA 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>
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> ---
>  drivers/pinctrl/meson/pinctrl-meson-g12a.c |  36 ++---
>  drivers/pinctrl/meson/pinctrl-meson.c      | 166 ++++++++++++++++-----
>  drivers/pinctrl/meson/pinctrl-meson.h      |  20 ++-
>  3 files changed, 162 insertions(+), 60 deletions(-)
> 
> diff --git a/drivers/pinctrl/meson/pinctrl-meson-g12a.c b/drivers/pinctrl/meson/pinctrl-meson-g12a.c
> index d494492e98e9..3475cd7bd2af 100644
> --- a/drivers/pinctrl/meson/pinctrl-meson-g12a.c
> +++ b/drivers/pinctrl/meson/pinctrl-meson-g12a.c

[...]

>  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:
> @@ -291,6 +373,10 @@ static int meson_pinconf_get(struct pinctrl_dev *pcdev, unsigned int pin,
>  		else
>  			return -EINVAL;
>  		break;
> +	case PIN_CONFIG_DRIVE_STRENGTH:
> +		ret = meson_pinconf_get_drive_strength(pc, pin, &arg);
> +		if (ret)
> +			return ret;

Missing break here !

Neil


>  	default:
>  		return -ENOTSUPP;
>  	}
> diff --git a/drivers/pinctrl/meson/pinctrl-meson.h b/drivers/pinctrl/meson/pinctrl-meson.h
> index 5eaab925f427..1a88103dcb9b 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,					\
> @@ -145,8 +157,12 @@ 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)
>  
> 

Re: [PATCH 2/2] pinctrl: meson: add support of drive-strength

[Neil Armstrong]

On 14/03/2019 17:37, Jerome Brunet wrote:
> From: Guillaume La Roque <glaroque@baylibre.com>
> 
> drive-strength is a new feature needed for G12A SoC.
> the default DS setting after boot is usually 0.5mA 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>
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> ---
>  drivers/pinctrl/meson/pinctrl-meson-g12a.c |  36 ++---
>  drivers/pinctrl/meson/pinctrl-meson.c      | 166 ++++++++++++++++-----
>  drivers/pinctrl/meson/pinctrl-meson.h      |  20 ++-
>  3 files changed, 162 insertions(+), 60 deletions(-)
> 
> diff --git a/drivers/pinctrl/meson/pinctrl-meson-g12a.c b/drivers/pinctrl/meson/pinctrl-meson-g12a.c
> index d494492e98e9..3475cd7bd2af 100644
> --- a/drivers/pinctrl/meson/pinctrl-meson-g12a.c
> +++ b/drivers/pinctrl/meson/pinctrl-meson-g12a.c

[...]

>  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:
> @@ -291,6 +373,10 @@ static int meson_pinconf_get(struct pinctrl_dev *pcdev, unsigned int pin,
>  		else
>  			return -EINVAL;
>  		break;
> +	case PIN_CONFIG_DRIVE_STRENGTH:
> +		ret = meson_pinconf_get_drive_strength(pc, pin, &arg);
> +		if (ret)
> +			return ret;

Missing break here !

Neil


>  	default:
>  		return -ENOTSUPP;
>  	}
> diff --git a/drivers/pinctrl/meson/pinctrl-meson.h b/drivers/pinctrl/meson/pinctrl-meson.h
> index 5eaab925f427..1a88103dcb9b 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,					\
> @@ -145,8 +157,12 @@ 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)
>  
> 


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Re: [PATCH 0/2] pinctrl: meson: add g12a drive strength support

[Jerome Brunet]

On Thu, 2019-03-14 at 17:37 +0100, Jerome Brunet wrote:
> The purpose of this patchset is to add drive-strength support in meson pinconf
> driver. This is a new feature that was added on the g12a. It is critical for us
> to support this since many functions are failing with default pad drive-strength.
> 
> Now the slightly annoying part :(
> The value achievable by the SoC are 0.5mA, 2.5mA, 3mA and 4mA and the DT property
> 'drive-strength' is expressed in mA.
> 
> 1) Rounding down the value, we could be requesting a 0mA drive strength.
>    That would look weird.
> 2) Rounding up, we can't distinguish between 2.5mA and 3mA
> 
> To solve this issue in this in this v1, we chose to document that, on Amlogic,
> drive-strength is expressed in uA instead of mA.
> It works well and there is no impact on the other platforms but I'm not sure this
> is really OK with the DT rules ?
> 
> Linus, if this is not OK with you, here are 2 other options we are
> considering. We would be very interested to get your opinion on the matter:
> 
> 1) instead the generic 'drive-strength' property, we could add an amlogic
> specific property, 'amlogic,drive-strength'. It would be expressed in uA
> and parsed in amlogic specific code.
> I think this option is kind of overkill. Expressing drive strength in uA is
> not really amlogic specific so it does not make much sense, but it would
> work ...
> 
> 2) Add another generic property "drive-strength-uA". The change to do so
> would be minimal and could be benefit to other platforms later on.

Hi Linus,

I know it has only been 10 days and you must be busy but I was wondering if we
could get your view on the issue above ?

Since the vast majority of SoC functions need a drive strength setting, DT
patches are somehow blocked until we decide which binding to use for it.

Sorry for this early ping.
Jerome


> 
> Cheers
> Jerome
> 
> Guillaume La Roque (2):
>   dt-bindings: pinctrl: meson: Add drive-strength property
>   pinctrl: meson: add support of drive-strength
> 
>  .../bindings/pinctrl/meson,pinctrl.txt        |   3 +
>  drivers/pinctrl/meson/pinctrl-meson-g12a.c    |  36 ++--
>  drivers/pinctrl/meson/pinctrl-meson.c         | 166 +++++++++++++-----
>  drivers/pinctrl/meson/pinctrl-meson.h         |  20 ++-
>  4 files changed, 165 insertions(+), 60 deletions(-)
> 

Re: [PATCH 0/2] pinctrl: meson: add g12a drive strength support

[Jerome Brunet]

On Thu, 2019-03-14 at 17:37 +0100, Jerome Brunet wrote:
> The purpose of this patchset is to add drive-strength support in meson pinconf
> driver. This is a new feature that was added on the g12a. It is critical for us
> to support this since many functions are failing with default pad drive-strength.
> 
> Now the slightly annoying part :(
> The value achievable by the SoC are 0.5mA, 2.5mA, 3mA and 4mA and the DT property
> 'drive-strength' is expressed in mA.
> 
> 1) Rounding down the value, we could be requesting a 0mA drive strength.
>    That would look weird.
> 2) Rounding up, we can't distinguish between 2.5mA and 3mA
> 
> To solve this issue in this in this v1, we chose to document that, on Amlogic,
> drive-strength is expressed in uA instead of mA.
> It works well and there is no impact on the other platforms but I'm not sure this
> is really OK with the DT rules ?
> 
> Linus, if this is not OK with you, here are 2 other options we are
> considering. We would be very interested to get your opinion on the matter:
> 
> 1) instead the generic 'drive-strength' property, we could add an amlogic
> specific property, 'amlogic,drive-strength'. It would be expressed in uA
> and parsed in amlogic specific code.
> I think this option is kind of overkill. Expressing drive strength in uA is
> not really amlogic specific so it does not make much sense, but it would
> work ...
> 
> 2) Add another generic property "drive-strength-uA". The change to do so
> would be minimal and could be benefit to other platforms later on.

Hi Linus,

I know it has only been 10 days and you must be busy but I was wondering if we
could get your view on the issue above ?

Since the vast majority of SoC functions need a drive strength setting, DT
patches are somehow blocked until we decide which binding to use for it.

Sorry for this early ping.
Jerome


> 
> Cheers
> Jerome
> 
> Guillaume La Roque (2):
>   dt-bindings: pinctrl: meson: Add drive-strength property
>   pinctrl: meson: add support of drive-strength
> 
>  .../bindings/pinctrl/meson,pinctrl.txt        |   3 +
>  drivers/pinctrl/meson/pinctrl-meson-g12a.c    |  36 ++--
>  drivers/pinctrl/meson/pinctrl-meson.c         | 166 +++++++++++++-----
>  drivers/pinctrl/meson/pinctrl-meson.h         |  20 ++-
>  4 files changed, 165 insertions(+), 60 deletions(-)
> 

Re: [PATCH 0/2] pinctrl: meson: add g12a drive strength support

[Jerome Brunet]

On Thu, 2019-03-14 at 17:37 +0100, Jerome Brunet wrote:
> The purpose of this patchset is to add drive-strength support in meson pinconf
> driver. This is a new feature that was added on the g12a. It is critical for us
> to support this since many functions are failing with default pad drive-strength.
> 
> Now the slightly annoying part :(
> The value achievable by the SoC are 0.5mA, 2.5mA, 3mA and 4mA and the DT property
> 'drive-strength' is expressed in mA.
> 
> 1) Rounding down the value, we could be requesting a 0mA drive strength.
>    That would look weird.
> 2) Rounding up, we can't distinguish between 2.5mA and 3mA
> 
> To solve this issue in this in this v1, we chose to document that, on Amlogic,
> drive-strength is expressed in uA instead of mA.
> It works well and there is no impact on the other platforms but I'm not sure this
> is really OK with the DT rules ?
> 
> Linus, if this is not OK with you, here are 2 other options we are
> considering. We would be very interested to get your opinion on the matter:
> 
> 1) instead the generic 'drive-strength' property, we could add an amlogic
> specific property, 'amlogic,drive-strength'. It would be expressed in uA
> and parsed in amlogic specific code.
> I think this option is kind of overkill. Expressing drive strength in uA is
> not really amlogic specific so it does not make much sense, but it would
> work ...
> 
> 2) Add another generic property "drive-strength-uA". The change to do so
> would be minimal and could be benefit to other platforms later on.

Hi Linus,

I know it has only been 10 days and you must be busy but I was wondering if we
could get your view on the issue above ?

Since the vast majority of SoC functions need a drive strength setting, DT
patches are somehow blocked until we decide which binding to use for it.

Sorry for this early ping.
Jerome


> 
> Cheers
> Jerome
> 
> Guillaume La Roque (2):
>   dt-bindings: pinctrl: meson: Add drive-strength property
>   pinctrl: meson: add support of drive-strength
> 
>  .../bindings/pinctrl/meson,pinctrl.txt        |   3 +
>  drivers/pinctrl/meson/pinctrl-meson-g12a.c    |  36 ++--
>  drivers/pinctrl/meson/pinctrl-meson.c         | 166 +++++++++++++-----
>  drivers/pinctrl/meson/pinctrl-meson.h         |  20 ++-
>  4 files changed, 165 insertions(+), 60 deletions(-)
> 



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Re: [PATCH 1/2] dt-bindings: pinctrl: meson: Add drive-strength property

[Rob Herring]

On Thu, Mar 14, 2019 at 05:37:24PM +0100, Jerome Brunet wrote:
> From: Guillaume La Roque <glaroque@baylibre.com>
> 
> Add optional drive-strength property
> 
> Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> ---
>  Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> index a47dd990a8d3..4e3d5a27c91c 100644
> --- a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> +++ b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> @@ -51,6 +51,9 @@ Configuration nodes support the generic properties "bias-disable",
>  "bias-pull-up" and "bias-pull-down", described in file
>  pinctrl-bindings.txt
>  
> +Optional properties :
> + - drive-strength: Drive strength for the specified pins in uA.

The standard definition says this is in mA.

> +
>  === Example ===
>  
>  	pinctrl: pinctrl@c1109880 {
> -- 
> 2.20.1
> 

Re: [PATCH 1/2] dt-bindings: pinctrl: meson: Add drive-strength property

[Rob Herring]

On Thu, Mar 14, 2019 at 05:37:24PM +0100, Jerome Brunet wrote:
> From: Guillaume La Roque <glaroque@baylibre.com>
> 
> Add optional drive-strength property
> 
> Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> ---
>  Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> index a47dd990a8d3..4e3d5a27c91c 100644
> --- a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> +++ b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> @@ -51,6 +51,9 @@ Configuration nodes support the generic properties "bias-disable",
>  "bias-pull-up" and "bias-pull-down", described in file
>  pinctrl-bindings.txt
>  
> +Optional properties :
> + - drive-strength: Drive strength for the specified pins in uA.

The standard definition says this is in mA.

> +
>  === Example ===
>  
>  	pinctrl: pinctrl@c1109880 {
> -- 
> 2.20.1
> 


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Re: [PATCH 1/2] dt-bindings: pinctrl: meson: Add drive-strength property

[Jerome Brunet]

On Sun, 2019-03-31 at 01:40 -0500, Rob Herring wrote:
> On Thu, Mar 14, 2019 at 05:37:24PM +0100, Jerome Brunet wrote:
> > From: Guillaume La Roque <glaroque@baylibre.com>
> > 
> > Add optional drive-strength property
> > 
> > Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
> > Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> > ---
> >  Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> > index a47dd990a8d3..4e3d5a27c91c 100644
> > --- a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> > +++ b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> > @@ -51,6 +51,9 @@ Configuration nodes support the generic properties "bias-disable",
> >  "bias-pull-up" and "bias-pull-down", described in file
> >  pinctrl-bindings.txt
> >  
> > +Optional properties :
> > + - drive-strength: Drive strength for the specified pins in uA.
> 
> The standard definition says this is in mA.

Yes, the problem we have and the solutions we are thinking about are explained
in detail in the cover letter of this patchset. Could you share your opinion
on it ?

Thx

> 
> > +
> >  === Example ===
> >  
> >  	pinctrl: pinctrl@c1109880 {
> > -- 
> > 2.20.1
> > 

Re: [PATCH 1/2] dt-bindings: pinctrl: meson: Add drive-strength property

[Jerome Brunet]

On Sun, 2019-03-31 at 01:40 -0500, Rob Herring wrote:
> On Thu, Mar 14, 2019 at 05:37:24PM +0100, Jerome Brunet wrote:
> > From: Guillaume La Roque <glaroque@baylibre.com>
> > 
> > Add optional drive-strength property
> > 
> > Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
> > Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> > ---
> >  Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> > index a47dd990a8d3..4e3d5a27c91c 100644
> > --- a/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> > +++ b/Documentation/devicetree/bindings/pinctrl/meson,pinctrl.txt
> > @@ -51,6 +51,9 @@ Configuration nodes support the generic properties "bias-disable",
> >  "bias-pull-up" and "bias-pull-down", described in file
> >  pinctrl-bindings.txt
> >  
> > +Optional properties :
> > + - drive-strength: Drive strength for the specified pins in uA.
> 
> The standard definition says this is in mA.

Yes, the problem we have and the solutions we are thinking about are explained
in detail in the cover letter of this patchset. Could you share your opinion
on it ?

Thx

> 
> > +
> >  === Example ===
> >  
> >  	pinctrl: pinctrl@c1109880 {
> > -- 
> > 2.20.1
> > 



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Re: [PATCH 0/2] pinctrl: meson: add g12a drive strength support

[Linus Walleij]

On Thu, Mar 14, 2019 at 11:37 PM Jerome Brunet <jbrunet@baylibre.com> wrote:

> Now the slightly annoying part :(
> The value achievable by the SoC are 0.5mA, 2.5mA, 3mA and 4mA and the DT property
> 'drive-strength' is expressed in mA.
>
> 1) Rounding down the value, we could be requesting a 0mA drive strength.
>    That would look weird.
> 2) Rounding up, we can't distinguish between 2.5mA and 3mA
>
> To solve this issue in this in this v1, we chose to document that, on Amlogic,
> drive-strength is expressed in uA instead of mA.
> It works well and there is no impact on the other platforms but I'm not sure this
> is really OK with the DT rules ?

I want the DT people to say what they think about this.

> Linus, if this is not OK with you, here are 2 other options we are
> considering. We would be very interested to get your opinion on the matter:
>
> 1) instead the generic 'drive-strength' property, we could add an amlogic
> specific property, 'amlogic,drive-strength'. It would be expressed in uA
> and parsed in amlogic specific code.
> I think this option is kind of overkill. Expressing drive strength in uA is
> not really amlogic specific so it does not make much sense, but it would
> work ...
>
> 2) Add another generic property "drive-strength-uA". The change to do so
> would be minimal and could be benefit to other platforms later on.

I would go for 2).

But we really need input from bindings people on this.

Yours,
Linus Walleij

Re: [PATCH 0/2] pinctrl: meson: add g12a drive strength support

[Linus Walleij]

On Thu, Mar 14, 2019 at 11:37 PM Jerome Brunet <jbrunet@baylibre.com> wrote:

> Now the slightly annoying part :(
> The value achievable by the SoC are 0.5mA, 2.5mA, 3mA and 4mA and the DT property
> 'drive-strength' is expressed in mA.
>
> 1) Rounding down the value, we could be requesting a 0mA drive strength.
>    That would look weird.
> 2) Rounding up, we can't distinguish between 2.5mA and 3mA
>
> To solve this issue in this in this v1, we chose to document that, on Amlogic,
> drive-strength is expressed in uA instead of mA.
> It works well and there is no impact on the other platforms but I'm not sure this
> is really OK with the DT rules ?

I want the DT people to say what they think about this.

> Linus, if this is not OK with you, here are 2 other options we are
> considering. We would be very interested to get your opinion on the matter:
>
> 1) instead the generic 'drive-strength' property, we could add an amlogic
> specific property, 'amlogic,drive-strength'. It would be expressed in uA
> and parsed in amlogic specific code.
> I think this option is kind of overkill. Expressing drive strength in uA is
> not really amlogic specific so it does not make much sense, but it would
> work ...
>
> 2) Add another generic property "drive-strength-uA". The change to do so
> would be minimal and could be benefit to other platforms later on.

I would go for 2).

But we really need input from bindings people on this.

Yours,
Linus Walleij

Re: [PATCH 0/2] pinctrl: meson: add g12a drive strength support

[Linus Walleij]

On Thu, Mar 14, 2019 at 11:37 PM Jerome Brunet <jbrunet@baylibre.com> wrote:

> Now the slightly annoying part :(
> The value achievable by the SoC are 0.5mA, 2.5mA, 3mA and 4mA and the DT property
> 'drive-strength' is expressed in mA.
>
> 1) Rounding down the value, we could be requesting a 0mA drive strength.
>    That would look weird.
> 2) Rounding up, we can't distinguish between 2.5mA and 3mA
>
> To solve this issue in this in this v1, we chose to document that, on Amlogic,
> drive-strength is expressed in uA instead of mA.
> It works well and there is no impact on the other platforms but I'm not sure this
> is really OK with the DT rules ?

I want the DT people to say what they think about this.

> Linus, if this is not OK with you, here are 2 other options we are
> considering. We would be very interested to get your opinion on the matter:
>
> 1) instead the generic 'drive-strength' property, we could add an amlogic
> specific property, 'amlogic,drive-strength'. It would be expressed in uA
> and parsed in amlogic specific code.
> I think this option is kind of overkill. Expressing drive strength in uA is
> not really amlogic specific so it does not make much sense, but it would
> work ...
>
> 2) Add another generic property "drive-strength-uA". The change to do so
> would be minimal and could be benefit to other platforms later on.

I would go for 2).

But we really need input from bindings people on this.

Yours,
Linus Walleij

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Re: [PATCH 1/2] dt-bindings: pinctrl: meson: Add drive-strength property

[Linus Walleij]

On Sun, Mar 31, 2019 at 2:04 PM Jerome Brunet <jbrunet@baylibre.com> wrote:
> On Sun, 2019-03-31 at 01:40 -0500, Rob Herring wrote:
> > On Thu, Mar 14, 2019 at 05:37:24PM +0100, Jerome Brunet wrote:
> > > From: Guillaume La Roque <glaroque@baylibre.com>

> > > +Optional properties :
> > > + - drive-strength: Drive strength for the specified pins in uA.
> >
> > The standard definition says this is in mA.
>
> Yes, the problem we have and the solutions we are thinking about are explained
> in detail in the cover letter of this patchset. Could you share your opinion
> on it ?

I like your idea with drive-strength-uA but I need the second opinion from the
device tree people.

Yours,
Linus Walleij

Re: [PATCH 1/2] dt-bindings: pinctrl: meson: Add drive-strength property

[Linus Walleij]

On Sun, Mar 31, 2019 at 2:04 PM Jerome Brunet <jbrunet@baylibre.com> wrote:
> On Sun, 2019-03-31 at 01:40 -0500, Rob Herring wrote:
> > On Thu, Mar 14, 2019 at 05:37:24PM +0100, Jerome Brunet wrote:
> > > From: Guillaume La Roque <glaroque@baylibre.com>

> > > +Optional properties :
> > > + - drive-strength: Drive strength for the specified pins in uA.
> >
> > The standard definition says this is in mA.
>
> Yes, the problem we have and the solutions we are thinking about are explained
> in detail in the cover letter of this patchset. Could you share your opinion
> on it ?

I like your idea with drive-strength-uA but I need the second opinion from the
device tree people.

Yours,
Linus Walleij

Re: [PATCH 1/2] dt-bindings: pinctrl: meson: Add drive-strength property

[Linus Walleij]

On Sun, Mar 31, 2019 at 2:04 PM Jerome Brunet <jbrunet@baylibre.com> wrote:
> On Sun, 2019-03-31 at 01:40 -0500, Rob Herring wrote:
> > On Thu, Mar 14, 2019 at 05:37:24PM +0100, Jerome Brunet wrote:
> > > From: Guillaume La Roque <glaroque@baylibre.com>

> > > +Optional properties :
> > > + - drive-strength: Drive strength for the specified pins in uA.
> >
> > The standard definition says this is in mA.
>
> Yes, the problem we have and the solutions we are thinking about are explained
> in detail in the cover letter of this patchset. Could you share your opinion
> on it ?

I like your idea with drive-strength-uA but I need the second opinion from the
device tree people.

Yours,
Linus Walleij

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