[PATCH 0/8] Implement get_multiple for ACCES and PC104 drivers

[PATCH 0/8] Implement get_multiple for ACCES and PC104 drivers

[William Breathitt Gray]

This patchset implements get_multiple callbacks for the PC104 GPIO
drivers as well as the PCI-IDIO-16 and PCIe-IDIO-24 GPIO drivers. These
devices all acquire the multiple input lines with a single read, so
utilizing the get_multiple callback can provide improvement for those
users who regularly access multiple input lines.

While developing this patchset I noticed many of these devices make use
of Intel 8255 compatible interfaces for their I/O. I may write a generic
8255 GPIO driver in the future to reduce some of the redundant code I
see pop among the drivers for these devices.

William Breathitt Gray (8):
  iio: stx104: Implement get_multiple callback
  gpio: 104-idio-16: Implement get_multiple callback
  gpio: pci-idio-16: Implement get_multiple callback
  gpio: pcie-idio-24: Implement get_multiple callback
  gpio: 104-dio-48e: Implement get_multiple callback
  gpio: 104-idi-48: Implement get_multiple callback
  gpio: gpio-mm: Implement get_multiple callback
  gpio: ws16c48: Implement get_multiple callback

 drivers/gpio/gpio-104-dio-48e.c  | 41 ++++++++++++++++++++++++++
 drivers/gpio/gpio-104-idi-48.c   | 41 ++++++++++++++++++++++++++
 drivers/gpio/gpio-104-idio-16.c  | 15 ++++++++++
 drivers/gpio/gpio-gpio-mm.c      | 41 ++++++++++++++++++++++++++
 drivers/gpio/gpio-pci-idio-16.c  | 48 ++++++++++++++++++++++++++++++
 drivers/gpio/gpio-pcie-idio-24.c | 63 ++++++++++++++++++++++++++++++++++++++++
 drivers/gpio/gpio-ws16c48.c      | 39 +++++++++++++++++++++++++
 drivers/iio/adc/stx104.c         | 11 +++++++
 8 files changed, 299 insertions(+)

-- 
2.16.2

[PATCH 1/8] iio: stx104: Implement get_multiple callback

[William Breathitt Gray]

The Apex Embedded Systems STX104 series of devices provides 4 TTL
compatible lines of inputs accessed via a single 4-bit port. Since four
input lines are acquired on a single port input read, the STX104 GPIO
driver may improve multiple input reads by utilizing a get_multiple
callback. This patch implements the stx104_gpio_get_multiple function
which serves as the respective get_multiple callback.

Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/iio/adc/stx104.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/iio/adc/stx104.c b/drivers/iio/adc/stx104.c
index 17b021f33180..0662ca199eb0 100644
--- a/drivers/iio/adc/stx104.c
+++ b/drivers/iio/adc/stx104.c
@@ -233,6 +233,16 @@ static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset)
 	return !!(inb(stx104gpio->base) & BIT(offset));
 }
 
+static int stx104_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
+	unsigned long *bits)
+{
+	struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
+
+	*bits = inb(stx104gpio->base);
+
+	return 0;
+}
+
 static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset,
 	int value)
 {
@@ -342,6 +352,7 @@ static int stx104_probe(struct device *dev, unsigned int id)
 	stx104gpio->chip.direction_input = stx104_gpio_direction_input;
 	stx104gpio->chip.direction_output = stx104_gpio_direction_output;
 	stx104gpio->chip.get = stx104_gpio_get;
+	stx104gpio->chip.get_multiple = stx104_gpio_get_multiple;
 	stx104gpio->chip.set = stx104_gpio_set;
 	stx104gpio->chip.set_multiple = stx104_gpio_set_multiple;
 	stx104gpio->base = base[id] + 3;
-- 
2.16.2

[PATCH 2/8] gpio: 104-idio-16: Implement get_multiple callback

[William Breathitt Gray]

The ACCES I/O 104-IDIO-16 series of devices provides 16
optically-isolated digital inputs accessed via two 8-bit ports. Since
eight input lines are acquired on a single port input read, the
104-IDIO-16 GPIO driver may improve multiple input reads by utilizing a
get_multiple callback. This patch implements the
idio_16_gpio_get_multiple function which serves as the respective
get_multiple callback.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-104-idio-16.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/gpio/gpio-104-idio-16.c b/drivers/gpio/gpio-104-idio-16.c
index 2f16638a0589..5de5819e5156 100644
--- a/drivers/gpio/gpio-104-idio-16.c
+++ b/drivers/gpio/gpio-104-idio-16.c
@@ -90,6 +90,20 @@ static int idio_16_gpio_get(struct gpio_chip *chip, unsigned offset)
 	return !!(inb(idio16gpio->base + 5) & (mask>>8));
 }
 
+static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
+	unsigned long *mask, unsigned long *bits)
+{
+	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
+
+	*bits = 0;
+	if (*mask & 0xFF0000)
+		*bits |= (unsigned long)inb(idio16gpio->base + 1) << 16;
+	if (*mask & 0xFF000000)
+		*bits |= (unsigned long)inb(idio16gpio->base + 5) << 24;
+
+	return 0;
+}
+
 static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
@@ -244,6 +258,7 @@ static int idio_16_probe(struct device *dev, unsigned int id)
 	idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
 	idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
 	idio16gpio->chip.get = idio_16_gpio_get;
+	idio16gpio->chip.get_multiple = idio_16_gpio_get_multiple;
 	idio16gpio->chip.set = idio_16_gpio_set;
 	idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;
 	idio16gpio->base = base[id];
-- 
2.16.2

[PATCH 3/8] gpio: pci-idio-16: Implement get_multiple callback

[William Breathitt Gray]

The ACCES I/O PCI-IDIO-16 series of devices provides 16
optically-isolated digital inputs accessed via two 8-bit ports. Since
eight input lines are acquired on a single port input read, the
PCI-IDIO-16 GPIO driver may improve multiple input reads by utilizing a
get_multiple callback. This patch implements the
idio_16_gpio_get_multiple function which serves as the respective
get_multiple callback.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-pci-idio-16.c | 48 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/drivers/gpio/gpio-pci-idio-16.c b/drivers/gpio/gpio-pci-idio-16.c
index 57d1b7fbf07b..8c5ec301c7ff 100644
--- a/drivers/gpio/gpio-pci-idio-16.c
+++ b/drivers/gpio/gpio-pci-idio-16.c
@@ -103,6 +103,53 @@ static int idio_16_gpio_get(struct gpio_chip *chip, unsigned int offset)
 	return !!(ioread8(&idio16gpio->reg->in8_15) & (mask >> 24));
 }
 
+static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
+	unsigned long *mask, unsigned long *bits)
+{
+	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
+	unsigned int i;
+	const unsigned int gpio_reg_size = 8;
+	unsigned int bit_word_offset;
+	unsigned int bits_mask;
+	const unsigned long reg_mask = GENMASK(gpio_reg_size, 0);
+	unsigned long port_state;
+
+	/* clear bits array to a clean slate */
+	for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
+		bits[i / BITS_PER_LONG] = 0;
+
+	/* get bits are evaluated a gpio register size at a time */
+	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
+		bit_word_offset = i % BITS_PER_LONG;
+		bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
+		if (!bits_mask) {
+			/* no get bits in this register so skip to next one */
+			continue;
+		}
+
+		/* read bits from current gpio register */
+		switch (i / gpio_reg_size) {
+		case 0:
+			port_state = ioread8(&idio16gpio->reg->out0_7);
+			break;
+		case 1:
+			port_state = ioread8(&idio16gpio->reg->out8_15);
+			break;
+		case 2:
+			port_state = ioread8(&idio16gpio->reg->in0_7);
+			break;
+		case 3:
+			port_state = ioread8(&idio16gpio->reg->in8_15);
+			break;
+		}
+
+		/* store acquired bits */
+		bits[BIT_WORD(i)] |= port_state << bit_word_offset;
+	}
+
+	return 0;
+}
+
 static void idio_16_gpio_set(struct gpio_chip *chip, unsigned int offset,
 	int value)
 {
@@ -299,6 +346,7 @@ static int idio_16_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
 	idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
 	idio16gpio->chip.get = idio_16_gpio_get;
+	idio16gpio->chip.get_multiple = idio_16_gpio_get_multiple;
 	idio16gpio->chip.set = idio_16_gpio_set;
 	idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;
 
-- 
2.16.2

[PATCH 4/8] gpio: pcie-idio-24: Implement get_multiple callback

[William Breathitt Gray]

The ACCES I/O PCIe-IDIO-24 series of devices provides 24
optically-isolated digital inputs accessed via three 8-bit ports. Since
eight input lines are acquired on a single port input read, the
PCIe-IDIO-24 GPIO driver may improve multiple input reads by utilizing a
get_multiple callback. This patch implements the
idio_24_gpio_get_multiple function which serves as the respective
get_multiple callback.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-pcie-idio-24.c | 63 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/drivers/gpio/gpio-pcie-idio-24.c b/drivers/gpio/gpio-pcie-idio-24.c
index f666e2e69074..6efc85292c49 100644
--- a/drivers/gpio/gpio-pcie-idio-24.c
+++ b/drivers/gpio/gpio-pcie-idio-24.c
@@ -193,6 +193,68 @@ static int idio_24_gpio_get(struct gpio_chip *chip, unsigned int offset)
 	return !!(ioread8(&idio24gpio->reg->ttl_in0_7) & offset_mask);
 }
 
+static int idio_24_gpio_get_multiple(struct gpio_chip *chip,
+	unsigned long *mask, unsigned long *bits)
+{
+	struct idio_24_gpio *const idio24gpio = gpiochip_get_data(chip);
+	struct idio_24_gpio_reg __iomem *const reg = idio24gpio->reg;
+	unsigned int i;
+	const unsigned int gpio_reg_size = 8;
+	unsigned int bit_word_offset;
+	unsigned int bits_mask;
+	const unsigned long reg_mask = GENMASK(gpio_reg_size, 0);
+	unsigned long port_state;
+	const unsigned long out_mode_mask = BIT(1);
+
+	/* clear bits array to a clean slate */
+	for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
+		bits[i / BITS_PER_LONG] = 0;
+
+	/* get bits are evaluated a gpio register size at a time */
+	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
+		bit_word_offset = i % BITS_PER_LONG;
+		bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
+		if (!bits_mask) {
+			/* no get bits in this register so skip to next one */
+			continue;
+		}
+
+		/* read bits from current gpio register */
+		switch (i / gpio_reg_size) {
+		case 0:
+			port_state = ioread8(&reg->out0_7);
+			break;
+		case 1:
+			port_state = ioread8(&reg->out8_15);
+			break;
+		case 2:
+			port_state = ioread8(&reg->out16_23);
+			break;
+		case 3:
+			port_state = ioread8(&reg->in0_7);
+			break;
+		case 4:
+			port_state = ioread8(&reg->in8_15);
+			break;
+		case 5:
+			port_state = ioread8(&reg->in16_23);
+			break;
+		case 6:
+			/* TTL/CMOS Outputs/Inputs */
+			if (ioread8(&reg->ctl) & out_mode_mask)
+				port_state = ioread8(&reg->ttl_out0_7);
+			else
+				port_state = ioread8(&reg->ttl_in0_7);
+			break;
+		}
+
+		/* store acquired bits */
+		bits[BIT_WORD(i)] |= port_state << bit_word_offset;
+	}
+
+	return 0;
+}
+
 static void idio_24_gpio_set(struct gpio_chip *chip, unsigned int offset,
 	int value)
 {
@@ -397,6 +459,7 @@ static int idio_24_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	idio24gpio->chip.direction_input = idio_24_gpio_direction_input;
 	idio24gpio->chip.direction_output = idio_24_gpio_direction_output;
 	idio24gpio->chip.get = idio_24_gpio_get;
+	idio24gpio->chip.get_multiple = idio_24_gpio_get_multiple;
 	idio24gpio->chip.set = idio_24_gpio_set;
 
 	raw_spin_lock_init(&idio24gpio->lock);
-- 
2.16.2

[PATCH 5/8] gpio: 104-dio-48e: Implement get_multiple callback

[William Breathitt Gray]

The ACCES I/O 104-DIO-48E series of devices contain two Programmable
Peripheral Interface (PPI) chips of type 82C55, which each feature three
8-bit ports of I/O. Since eight input lines are acquired on a single
port input read, the 104-DIO-48E GPIO driver may improve multiple input
reads by utilizing a get_multiple callback. This patch implements the
dio48e_gpio_get_multiple function which serves as the respective
get_multiple callback.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-104-dio-48e.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/gpio/gpio-104-dio-48e.c b/drivers/gpio/gpio-104-dio-48e.c
index bab3b94c5cbc..35ae2357d2ba 100644
--- a/drivers/gpio/gpio-104-dio-48e.c
+++ b/drivers/gpio/gpio-104-dio-48e.c
@@ -182,6 +182,46 @@ static int dio48e_gpio_get(struct gpio_chip *chip, unsigned offset)
 	return !!(port_state & mask);
 }
 
+static int dio48e_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
+	unsigned long *bits)
+{
+	struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
+	unsigned int i;
+	const unsigned int gpio_reg_size = 8;
+	unsigned int bit_word_offset;
+	unsigned int bits_mask;
+	const unsigned long reg_mask = GENMASK(gpio_reg_size, 0);
+	unsigned int port;
+	unsigned int in_port;
+	unsigned long port_state;
+
+	/* clear bits array to a clean slate */
+	for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
+		bits[i / BITS_PER_LONG] = 0;
+
+	/* get bits are evaluated a gpio register size at a time */
+	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
+		bit_word_offset = i % BITS_PER_LONG;
+		bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
+		if (!bits_mask) {
+			/* no get bits in this register so skip to next one */
+			continue;
+		}
+
+		/* compute input port offset */
+		port = i / gpio_reg_size;
+		in_port = (port > 2) ? port + 1 : port;
+
+		/* get input bits */
+		port_state = inb(dio48egpio->base + in_port);
+
+		/* store acquired bits */
+		bits[BIT_WORD(i)] |= port_state << bit_word_offset;
+	}
+
+	return 0;
+}
+
 static void dio48e_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
@@ -384,6 +424,7 @@ static int dio48e_probe(struct device *dev, unsigned int id)
 	dio48egpio->chip.direction_input = dio48e_gpio_direction_input;
 	dio48egpio->chip.direction_output = dio48e_gpio_direction_output;
 	dio48egpio->chip.get = dio48e_gpio_get;
+	dio48egpio->chip.get_multiple = dio48e_gpio_get_multiple;
 	dio48egpio->chip.set = dio48e_gpio_set;
 	dio48egpio->chip.set_multiple = dio48e_gpio_set_multiple;
 	dio48egpio->base = base[id];
-- 
2.16.2

[PATCH 6/8] gpio: 104-idi-48: Implement get_multiple callback

[William Breathitt Gray]

The ACCES I/O 104-IDI-48 series of devices provides 48
optically-isolated inputs accessed via six 8-bit ports. Since eight
input lines are acquired on a single port input read, the 104-IDI-48
GPIO driver may improve multiple input reads by utilizing a get_multiple
callback. This patch implements the idi_48_gpio_get_multiple function
which serves as the respective get_multiple callback.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-104-idi-48.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/gpio/gpio-104-idi-48.c b/drivers/gpio/gpio-104-idi-48.c
index add859d59766..d82139c3117a 100644
--- a/drivers/gpio/gpio-104-idi-48.c
+++ b/drivers/gpio/gpio-104-idi-48.c
@@ -88,6 +88,46 @@ static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
 	return 0;
 }
 
+static int idi_48_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
+	unsigned long *bits)
+{
+	struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
+	unsigned int i;
+	const unsigned int gpio_reg_size = 8;
+	unsigned int bit_word_offset;
+	unsigned int bits_mask;
+	const unsigned long reg_mask = GENMASK(gpio_reg_size, 0);
+	unsigned int port;
+	unsigned int in_port;
+	unsigned long port_state;
+
+	/* clear bits array to a clean slate */
+	for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
+		bits[i / BITS_PER_LONG] = 0;
+
+	/* get bits are evaluated a gpio register size at a time */
+	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
+		bit_word_offset = i % BITS_PER_LONG;
+		bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
+		if (!bits_mask) {
+			/* no get bits in this register so skip to next one */
+			continue;
+		}
+
+		/* compute input port offset */
+		port = i / gpio_reg_size;
+		in_port = (port > 2) ? port + 1 : port;
+
+		/* get input bits */
+		port_state = inb(idi48gpio->base + in_port);
+
+		/* store acquired bits */
+		bits[BIT_WORD(i)] |= port_state << bit_word_offset;
+	}
+
+	return 0;
+}
+
 static void idi_48_irq_ack(struct irq_data *data)
 {
 }
@@ -256,6 +296,7 @@ static int idi_48_probe(struct device *dev, unsigned int id)
 	idi48gpio->chip.get_direction = idi_48_gpio_get_direction;
 	idi48gpio->chip.direction_input = idi_48_gpio_direction_input;
 	idi48gpio->chip.get = idi_48_gpio_get;
+	idi48gpio->chip.get_multiple = idi_48_gpio_get_multiple;
 	idi48gpio->base = base[id];
 
 	raw_spin_lock_init(&idi48gpio->lock);
-- 
2.16.2

[PATCH 7/8] gpio: gpio-mm: Implement get_multiple callback

[William Breathitt Gray]

The Diamond Systems GPIO-MM series of devices contain two 82C55A
devices, which each feature three 8-bit ports of I/O. Since eight input
lines are acquired on a single port input read, the GPIO-MM GPIO driver
may improve multiple input reads by utilizing a get_multiple callback.
This patch implements the gpiomm_gpio_get_multiple function which serves
as the respective get_multiple callback.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-gpio-mm.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/gpio/gpio-gpio-mm.c b/drivers/gpio/gpio-gpio-mm.c
index 11ade5b288f8..5bacfa1f2c02 100644
--- a/drivers/gpio/gpio-gpio-mm.c
+++ b/drivers/gpio/gpio-gpio-mm.c
@@ -171,6 +171,46 @@ static int gpiomm_gpio_get(struct gpio_chip *chip, unsigned int offset)
 	return !!(port_state & mask);
 }
 
+static int gpiomm_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
+	unsigned long *bits)
+{
+	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
+	unsigned int i;
+	const unsigned int gpio_reg_size = 8;
+	unsigned int bit_word_offset;
+	unsigned int bits_mask;
+	const unsigned long reg_mask = GENMASK(gpio_reg_size, 0);
+	unsigned int port;
+	unsigned int in_port;
+	unsigned long port_state;
+
+	/* clear bits array to a clean slate */
+	for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
+		bits[i / BITS_PER_LONG] = 0;
+
+	/* get bits are evaluated a gpio register size at a time */
+	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
+		bit_word_offset = i % BITS_PER_LONG;
+		bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
+		if (!bits_mask) {
+			/* no get bits in this register so skip to next one */
+			continue;
+		}
+
+		/* compute input port offset */
+		port = i / gpio_reg_size;
+		in_port = (port > 2) ? port + 1 : port;
+
+		/* get input bits */
+		port_state = inb(gpiommgpio->base + in_port);
+
+		/* store acquired bits */
+		bits[BIT_WORD(i)] |= port_state << bit_word_offset;
+	}
+
+	return 0;
+}
+
 static void gpiomm_gpio_set(struct gpio_chip *chip, unsigned int offset,
 	int value)
 {
@@ -268,6 +308,7 @@ static int gpiomm_probe(struct device *dev, unsigned int id)
 	gpiommgpio->chip.direction_input = gpiomm_gpio_direction_input;
 	gpiommgpio->chip.direction_output = gpiomm_gpio_direction_output;
 	gpiommgpio->chip.get = gpiomm_gpio_get;
+	gpiommgpio->chip.get_multiple = gpiomm_gpio_get_multiple;
 	gpiommgpio->chip.set = gpiomm_gpio_set;
 	gpiommgpio->chip.set_multiple = gpiomm_gpio_set_multiple;
 	gpiommgpio->base = base[id];
-- 
2.16.2

[PATCH 8/8] gpio: ws16c48: Implement get_multiple callback

[William Breathitt Gray]

The WinSystems WS16C48 device provides 48 lines of digital I/O accessed
via six 8-bit ports. Since eight input lines are acquired on a single
port input read, the WS16C48 GPIO driver may improve multiple input
reads by utilizing a get_multiple callback. This patch implements the
ws16c48_gpio_get_multiple function which serves as the respective
get_multiple callback.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-ws16c48.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/gpio/gpio-ws16c48.c b/drivers/gpio/gpio-ws16c48.c
index 746648244bf3..6d911f8e92c1 100644
--- a/drivers/gpio/gpio-ws16c48.c
+++ b/drivers/gpio/gpio-ws16c48.c
@@ -129,6 +129,44 @@ static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset)
 	return !!(port_state & mask);
 }
 
+static int ws16c48_gpio_get_multiple(struct gpio_chip *chip,
+	unsigned long *mask, unsigned long *bits)
+{
+	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
+	unsigned int i;
+	const unsigned int gpio_reg_size = 8;
+	unsigned int bit_word_offset;
+	unsigned int bits_mask;
+	const unsigned long reg_mask = GENMASK(gpio_reg_size, 0);
+	unsigned int in_port;
+	unsigned long port_state;
+
+	/* clear bits array to a clean slate */
+	for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
+		bits[i / BITS_PER_LONG] = 0;
+
+	/* get bits are evaluated a gpio register size at a time */
+	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
+		bit_word_offset = i % BITS_PER_LONG;
+		bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
+		if (!bits_mask) {
+			/* no get bits in this register so skip to next one */
+			continue;
+		}
+
+		/* compute input port offset */
+		in_port = i / gpio_reg_size;
+
+		/* get input bits */
+		port_state = inb(ws16c48gpio->base + in_port);
+
+		/* store acquired bits */
+		bits[BIT_WORD(i)] |= port_state << bit_word_offset;
+	}
+
+	return 0;
+}
+
 static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
@@ -383,6 +421,7 @@ static int ws16c48_probe(struct device *dev, unsigned int id)
 	ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input;
 	ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output;
 	ws16c48gpio->chip.get = ws16c48_gpio_get;
+	ws16c48gpio->chip.get_multiple = ws16c48_gpio_get_multiple;
 	ws16c48gpio->chip.set = ws16c48_gpio_set;
 	ws16c48gpio->chip.set_multiple = ws16c48_gpio_set_multiple;
 	ws16c48gpio->base = base[id];
-- 
2.16.2

Re: [PATCH 3/8] gpio: pci-idio-16: Implement get_multiple callback

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2916 bytes --]

Hi William,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v4.16-rc5 next-20180313]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/William-Breathitt-Gray/Implement-get_multiple-for-ACCES-and-PC104-drivers/20180313-202244
config: x86_64-randconfig-x015-201810 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers//gpio/gpio-pci-idio-16.c: In function 'idio_16_gpio_get_multiple':
>> drivers//gpio/gpio-pci-idio-16.c:147:35: warning: 'port_state' may be used uninitialized in this function [-Wmaybe-uninitialized]
      bits[BIT_WORD(i)] |= port_state << bit_word_offset;
                           ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~

vim +/port_state +147 drivers//gpio/gpio-pci-idio-16.c

   105	
   106	static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
   107		unsigned long *mask, unsigned long *bits)
   108	{
   109		struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
   110		unsigned int i;
   111		const unsigned int gpio_reg_size = 8;
   112		unsigned int bit_word_offset;
   113		unsigned int bits_mask;
   114		const unsigned long reg_mask = GENMASK(gpio_reg_size, 0);
   115		unsigned long port_state;
   116	
   117		/* clear bits array to a clean slate */
   118		for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
   119			bits[i / BITS_PER_LONG] = 0;
   120	
   121		/* get bits are evaluated a gpio register size at a time */
   122		for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
   123			bit_word_offset = i % BITS_PER_LONG;
   124			bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
   125			if (!bits_mask) {
   126				/* no get bits in this register so skip to next one */
   127				continue;
   128			}
   129	
   130			/* read bits from current gpio register */
   131			switch (i / gpio_reg_size) {
   132			case 0:
   133				port_state = ioread8(&idio16gpio->reg->out0_7);
   134				break;
   135			case 1:
   136				port_state = ioread8(&idio16gpio->reg->out8_15);
   137				break;
   138			case 2:
   139				port_state = ioread8(&idio16gpio->reg->in0_7);
   140				break;
   141			case 3:
   142				port_state = ioread8(&idio16gpio->reg->in8_15);
   143				break;
   144			}
   145	
   146			/* store acquired bits */
 > 147			bits[BIT_WORD(i)] |= port_state << bit_word_offset;
   148		}
   149	
   150		return 0;
   151	}
   152	

---
0-DAY kernel test infrastructure                Open Source Technology Center
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[-- Attachment #2: .config.gz --]
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Re: [PATCH 4/8] gpio: pcie-idio-24: Implement get_multiple callback

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 3396 bytes --]

Hi William,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v4.16-rc5 next-20180313]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/William-Breathitt-Gray/Implement-get_multiple-for-ACCES-and-PC104-drivers/20180313-202244
config: x86_64-randconfig-x014-201810 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers//gpio/gpio-pcie-idio-24.c: In function 'idio_24_gpio_get_multiple':
>> drivers//gpio/gpio-pcie-idio-24.c:252:35: warning: 'port_state' may be used uninitialized in this function [-Wmaybe-uninitialized]
      bits[BIT_WORD(i)] |= port_state << bit_word_offset;
                           ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~

vim +/port_state +252 drivers//gpio/gpio-pcie-idio-24.c

   195	
   196	static int idio_24_gpio_get_multiple(struct gpio_chip *chip,
   197		unsigned long *mask, unsigned long *bits)
   198	{
   199		struct idio_24_gpio *const idio24gpio = gpiochip_get_data(chip);
   200		struct idio_24_gpio_reg __iomem *const reg = idio24gpio->reg;
   201		unsigned int i;
   202		const unsigned int gpio_reg_size = 8;
   203		unsigned int bit_word_offset;
   204		unsigned int bits_mask;
   205		const unsigned long reg_mask = GENMASK(gpio_reg_size, 0);
   206		unsigned long port_state;
   207		const unsigned long out_mode_mask = BIT(1);
   208	
   209		/* clear bits array to a clean slate */
   210		for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
   211			bits[i / BITS_PER_LONG] = 0;
   212	
   213		/* get bits are evaluated a gpio register size at a time */
   214		for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
   215			bit_word_offset = i % BITS_PER_LONG;
   216			bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
   217			if (!bits_mask) {
   218				/* no get bits in this register so skip to next one */
   219				continue;
   220			}
   221	
   222			/* read bits from current gpio register */
   223			switch (i / gpio_reg_size) {
   224			case 0:
   225				port_state = ioread8(&reg->out0_7);
   226				break;
   227			case 1:
   228				port_state = ioread8(&reg->out8_15);
   229				break;
   230			case 2:
   231				port_state = ioread8(&reg->out16_23);
   232				break;
   233			case 3:
   234				port_state = ioread8(&reg->in0_7);
   235				break;
   236			case 4:
   237				port_state = ioread8(&reg->in8_15);
   238				break;
   239			case 5:
   240				port_state = ioread8(&reg->in16_23);
   241				break;
   242			case 6:
   243				/* TTL/CMOS Outputs/Inputs */
   244				if (ioread8(&reg->ctl) & out_mode_mask)
   245					port_state = ioread8(&reg->ttl_out0_7);
   246				else
   247					port_state = ioread8(&reg->ttl_in0_7);
   248				break;
   249			}
   250	
   251			/* store acquired bits */
 > 252			bits[BIT_WORD(i)] |= port_state << bit_word_offset;
   253		}
   254	
   255		return 0;
   256	}
   257	

---
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[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 31983 bytes --]

Re: [PATCH 3/8] gpio: pci-idio-16: Implement get_multiple callback

[Andy Shevchenko]

On Mon, Mar 12, 2018 at 10:49 PM, William Breathitt Gray
<vilhelm.gray@gmail.com> wrote:

> +static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
> +       unsigned long *mask, unsigned long *bits)
> +{


> +       /* clear bits array to a clean slate */
> +       for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
> +               bits[i / BITS_PER_LONG] = 0;

bitmap_clear() or bitmap_zero()

> +       /* get bits are evaluated a gpio register size at a time */
> +       for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
> +               bit_word_offset = i % BITS_PER_LONG;
> +               bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
> +               if (!bits_mask) {
> +                       /* no get bits in this register so skip to next one */
> +                       continue;
> +               }

for_each_set_bit() ?

> +               /* store acquired bits */
> +               bits[BIT_WORD(i)] |= port_state << bit_word_offset;

__set_bit()
__clear_bit()

We have bitmap API for *ages*. Is it too hard to check?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 8/8] gpio: ws16c48: Implement get_multiple callback

[Andy Shevchenko]

On Mon, Mar 12, 2018 at 10:50 PM, William Breathitt Gray
<vilhelm.gray@gmail.com> wrote:

For all your patches, just read the bitmap API.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 3/8] gpio: pci-idio-16: Implement get_multiple callback

[William Breathitt Gray]

On Tue, Mar 13, 2018 at 06:04:33PM +0200, Andy Shevchenko wrote:
>On Mon, Mar 12, 2018 at 10:49 PM, William Breathitt Gray
><vilhelm.gray@gmail.com> wrote:
>
>> +static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
>> +       unsigned long *mask, unsigned long *bits)
>> +{
>
>
>> +       /* clear bits array to a clean slate */
>> +       for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
>> +               bits[i / BITS_PER_LONG] = 0;
>
>bitmap_clear() or bitmap_zero()

bitmap_zero() would be perfect for this situation. I'll submit a version
2 of this patchset with this change for the various drivers herein.

>
>> +       /* get bits are evaluated a gpio register size at a time */
>> +       for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
>> +               bit_word_offset = i % BITS_PER_LONG;
>> +               bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
>> +               if (!bits_mask) {
>> +                       /* no get bits in this register so skip to next one */
>> +                       continue;
>> +               }
>
>for_each_set_bit() ?
>
>> +               /* store acquired bits */
>> +               bits[BIT_WORD(i)] |= port_state << bit_word_offset;
>
>__set_bit()
>__clear_bit()

I'm not sure for_each_set_bit() and __set_bit()/__clear_bit() would be
good for this particular situation since I'm working with the entire
register word (8 bits for this specific device) at a time.

Since I know each register word is 8-bits, I can make 8-bit jumps and
skips rather than evaluating each bit individually. Similarly, it seems
more efficient to store the input 8 bits at a time rather than breaking
it up to individual bits.

However, I do see how all these inline bitwise operations could make it
difficult to follow the code, so perhaps I can break it up across more
lines so that the logic of the loop becomes easier to read.

William Breathitt Gray

>
>We have bitmap API for *ages*. Is it too hard to check?
>
>-- 
>With Best Regards,
>Andy Shevchenko