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From: "Andreas Färber" <afaerber@suse.de>
To: linux-realtek-soc@lists.infradead.org, linux-leds@vger.kernel.org
Cc: "Jacek Anaszewski" <jacek.anaszewski@gmail.com>,
	"Pavel Machek" <pavel@ucw.cz>, "Dan Murphy" <dmurphy@ti.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, "Andreas Färber" <afaerber@suse.de>,
	"Mark Brown" <broonie@kernel.org>,
	linux-spi@vger.kernel.org
Subject: [RFC 04/25] spi: gpio: Implement LSB First bitbang support
Date: Thu, 12 Dec 2019 04:39:31 +0100	[thread overview]
Message-ID: <20191212033952.5967-5-afaerber@suse.de> (raw)
In-Reply-To: <20191212033952.5967-1-afaerber@suse.de>

Add support for slave DT property spi-lsb-first, i.e., SPI_LSB_FIRST mode.

Duplicate the inline helpers bitbang_txrx_be_cpha{0,1} as LE versions.
Make checkpatch.pl happy by changing "unsigned" to "unsigned int".

Conditionally call them from all the spi-gpio txrx_word callbacks.

Signed-off-by: Andreas Färber <afaerber@suse.de>
---
 drivers/spi/spi-bitbang-txrx.h | 68 ++++++++++++++++++++++++++++++++++++++++--
 drivers/spi/spi-gpio.c         | 42 ++++++++++++++++++++------
 2 files changed, 99 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/spi-bitbang-txrx.h b/drivers/spi/spi-bitbang-txrx.h
index ae61d72c7d28..999a89325325 100644
--- a/drivers/spi/spi-bitbang-txrx.h
+++ b/drivers/spi/spi-bitbang-txrx.h
@@ -45,7 +45,7 @@
 
 static inline u32
 bitbang_txrx_be_cpha0(struct spi_device *spi,
-		unsigned nsecs, unsigned cpol, unsigned flags,
+		unsigned int nsecs, unsigned int cpol, unsigned int flags,
 		u32 word, u8 bits)
 {
 	/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */
@@ -77,7 +77,7 @@ bitbang_txrx_be_cpha0(struct spi_device *spi,
 
 static inline u32
 bitbang_txrx_be_cpha1(struct spi_device *spi,
-		unsigned nsecs, unsigned cpol, unsigned flags,
+		unsigned int nsecs, unsigned int cpol, unsigned int flags,
 		u32 word, u8 bits)
 {
 	/* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */
@@ -106,3 +106,67 @@ bitbang_txrx_be_cpha1(struct spi_device *spi,
 	}
 	return word;
 }
+
+static inline u32
+bitbang_txrx_le_cpha0(struct spi_device *spi,
+		unsigned int nsecs, unsigned int cpol, unsigned int flags,
+		u32 word, u8 bits)
+{
+	/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */
+
+	u32 oldbit = !(word & 1);
+	/* clock starts at inactive polarity */
+	for (; likely(bits); bits--) {
+
+		/* setup LSB (to slave) on trailing edge */
+		if ((flags & SPI_MASTER_NO_TX) == 0) {
+			if ((word & 1) != oldbit) {
+				setmosi(spi, word & 1);
+				oldbit = word & 1;
+			}
+		}
+		spidelay(nsecs);	/* T(setup) */
+
+		setsck(spi, !cpol);
+		spidelay(nsecs);
+
+		/* sample LSB (from slave) on leading edge */
+		word >>= 1;
+		if ((flags & SPI_MASTER_NO_RX) == 0)
+			word |= getmiso(spi) << (bits - 1);
+		setsck(spi, cpol);
+	}
+	return word;
+}
+
+static inline u32
+bitbang_txrx_le_cpha1(struct spi_device *spi,
+		unsigned int nsecs, unsigned int cpol, unsigned int flags,
+		u32 word, u8 bits)
+{
+	/* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */
+
+	u32 oldbit = !(word & 1);
+	/* clock starts at inactive polarity */
+	for (; likely(bits); bits--) {
+
+		/* setup LSB (to slave) on leading edge */
+		setsck(spi, !cpol);
+		if ((flags & SPI_MASTER_NO_TX) == 0) {
+			if ((word & 1) != oldbit) {
+				setmosi(spi, word & 1);
+				oldbit = word & 1;
+			}
+		}
+		spidelay(nsecs); /* T(setup) */
+
+		setsck(spi, cpol);
+		spidelay(nsecs);
+
+		/* sample LSB (from slave) on trailing edge */
+		word >>= 1;
+		if ((flags & SPI_MASTER_NO_RX) == 0)
+			word |= getmiso(spi) << (bits - 1);
+	}
+	return word;
+}
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index 7ceb0ba27b75..493723eda844 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -135,25 +135,37 @@ static inline int getmiso(const struct spi_device *spi)
 static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
 }
 
 static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
-	return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
 }
 
 static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
 }
 
 static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
-	return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
 }
 
 /*
@@ -170,28 +182,40 @@ static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
 	flags = spi->master->flags;
-	return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha0(spi, nsecs, 0, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
 }
 
 static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
 	flags = spi->master->flags;
-	return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha1(spi, nsecs, 0, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
 }
 
 static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
 	flags = spi->master->flags;
-	return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha0(spi, nsecs, 1, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
 }
 
 static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits, unsigned flags)
 {
 	flags = spi->master->flags;
-	return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
+	if (unlikely(spi->mode & SPI_LSB_FIRST))
+		return bitbang_txrx_le_cpha1(spi, nsecs, 1, flags, word, bits);
+	else
+		return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
 }
 
 /*----------------------------------------------------------------------*/
@@ -389,7 +413,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
 
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
 	master->mode_bits = SPI_3WIRE | SPI_3WIRE_HIZ | SPI_CPHA | SPI_CPOL |
-			    SPI_CS_HIGH;
+			    SPI_CS_HIGH | SPI_LSB_FIRST;
 	if (!spi_gpio->mosi) {
 		/* HW configuration without MOSI pin
 		 *
-- 
2.16.4


  parent reply	other threads:[~2019-12-12  3:41 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-12  3:39 [RFC 00/25] arm64: realtek: Add Xnano X5 and implement TM1628/FD628/AiP1618 LED controllers Andreas Färber
2019-12-12  3:39 ` [RFC 01/25] dt-bindings: vendor-prefixes: Add Xnano Andreas Färber
2019-12-19 22:26   ` Rob Herring
2019-12-12  3:39 ` [RFC 02/25] dt-bindings: arm: realtek: Add Xnano X5 Andreas Färber
2019-12-19 22:27   ` Rob Herring
2019-12-12  3:39 ` [RFC 03/25] arm64: dts: realtek: rtd1295: " Andreas Färber
2019-12-12  3:39 ` Andreas Färber [this message]
2019-12-12  8:40   ` [RFC 04/25] spi: gpio: Implement LSB First bitbang support Geert Uytterhoeven
2019-12-12 15:14     ` Andreas Färber
2019-12-12 17:19       ` Mark Brown
2019-12-12 21:08         ` Andreas Färber
2019-12-13 11:42           ` Mark Brown
2019-12-12  3:39 ` [RFC 05/25] dt-bindings: vendor-prefixes: Add Titan Micro Electronics Andreas Färber
2019-12-19 22:31   ` Rob Herring
2019-12-12  3:39 ` [RFC 06/25] dt-bindings: leds: Add Titan Micro Electronics TM1628 Andreas Färber
2019-12-19 23:04   ` Rob Herring
2019-12-12  3:39 ` [RFC 07/25] " Andreas Färber
2019-12-14  9:48   ` Andreas Färber
2019-12-12  3:39 ` [RFC 08/25] arm64: dts: realtek: rtd129x-zidoo-x9s: Add TM1628 LED controller Andreas Färber
2019-12-12  3:39 ` [RFC 09/25] arm64: dts: realtek: rtd1295-zidoo-x9s: Add regular LEDs to TM1628 Andreas Färber
2019-12-12  3:39 ` [RFC 10/25] dt-bindings: vendor-prefixes: Add Fuda Hisi Microelectronics Andreas Färber
2019-12-19 23:04   ` Rob Herring
2019-12-12  3:39 ` [RFC 11/25] dt-bindings: leds: tm1628: Add Fuda Hisi Microelectronics FD628 Andreas Färber
2019-12-19 23:05   ` Rob Herring
2019-12-12  3:39 ` [RFC 12/25] " Andreas Färber
2019-12-12  3:39 ` [RFC 13/25] arm64: dts: realtek: rtd1295-xnano-x5: Add FD628 LED controller Andreas Färber
2019-12-12  3:39 ` [RFC 14/25] arm64: dts: realtek: rtd1295-xnano-x5: Add regular LEDs to FD628 Andreas Färber
2019-12-21 20:21   ` Pavel Machek
2019-12-12  3:39 ` [RFC 15/25] dt-bindings: vendor-prefixes: Add Fude Microelectronics Andreas Färber
2019-12-19 23:05   ` Rob Herring
2019-12-12  3:39 ` [RFC 16/25] dt-bindings: leds: tm1628: Add Fude Microelectronics AiP1618 Andreas Färber
2019-12-19 23:06   ` Rob Herring
2019-12-12  3:39 ` [RFC 17/25] leds: tm1628: Prepare " Andreas Färber
2019-12-21 19:55   ` Andreas Färber
2019-12-12  3:39 ` [RFC 18/25] dt-bindings: leds: tm1628: Define display child nodes Andreas Färber
2019-12-12  3:39 ` [RFC 19/25] leds: tm1628: Add 7-segment display support Andreas Färber
2019-12-12  8:33   ` Geert Uytterhoeven
2019-12-12 14:10     ` Andreas Färber
2019-12-21 20:23   ` Pavel Machek
2019-12-12  3:39 ` [RFC 20/25] arm64: dts: realtek: rtd1295-zidoo-x9s: Add display to TM1628 Andreas Färber
2019-12-12  3:39 ` [RFC 21/25] arm64: dts: realtek: rtd1295-xnano-x5: Add display to FD628 Andreas Färber
2019-12-12  3:39 ` [RFC 22/25] leds: tm1826: Add combined glyph support Andreas Färber
2019-12-21 20:27   ` Pavel Machek
2019-12-21 20:41     ` Andreas Färber
2019-12-21 21:04       ` Pavel Machek
2019-12-21 21:49         ` Andreas Färber
     [not found]           ` <CANiq72nA9OLa0SjY8W055J_2A32tcp7S98SruKSdWH2dm25VKw@mail.gmail.com>
2019-12-22  3:14             ` Andreas Färber
2020-01-15 14:31               ` Miguel Ojeda
2019-12-12  3:39 ` [RFC 23/25] WIP: leds: tm1628: Prepare TM1628 keys Andreas Färber
2019-12-12  3:39 ` [RFC 24/25] WIP: leds: tm1628: Prepare FD628 keys Andreas Färber
2019-12-12  3:39 ` [RFC 25/25] WIP: leds: tm1628: Prepare AiP1618 keys Andreas Färber
2019-12-12 13:14 ` [RFC 00/25] arm64: realtek: Add Xnano X5 and implement TM1628/FD628/AiP1618 LED controllers Robin Murphy
2019-12-12 20:55   ` Andreas Färber
2019-12-13 14:07     ` Robin Murphy
2019-12-13 14:36       ` Geert Uytterhoeven
2020-02-25 21:42       ` Ezra Buehler
2020-02-26 13:03         ` Pavel Machek
2019-12-21 18:20 ` Pavel Machek
2019-12-21 21:07   ` Andreas Färber
2020-01-15 13:34 ` Andreas Färber

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