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Message-ID: <20240207111516.2563218-4-tudor.ambarus@linaro.org>
Date: Wed, 7 Feb 2024 11:15:15 +0000
From: Tudor Ambarus <tudor.ambarus@...aro.org>
To: broonie@...nel.org,
andi.shyti@...nel.org,
semen.protsenko@...aro.org
Cc: krzysztof.kozlowski@...aro.org,
alim.akhtar@...sung.com,
linux-spi@...r.kernel.org,
linux-samsung-soc@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org,
andre.draszik@...aro.org,
peter.griffin@...aro.org,
kernel-team@...roid.com,
willmcvicker@...gle.com,
robh+dt@...nel.org,
conor+dt@...nel.org,
devicetree@...r.kernel.org,
Tudor Ambarus <tudor.ambarus@...aro.org>
Subject: [PATCH v2 3/4] spi: s3c64xx: add s3c64xx_iowrite{8,16}_32_rep accessors
Allow SoCs that require 32 bits register accesses to write data in
chunks of 8 or 16 bits. One SoC that requires 32 bit register accesses
is the google gs101. The operation is rare, thus open code it in the
driver rather than making it generic (through asm-generic/io.h).
Signed-off-by: Tudor Ambarus <tudor.ambarus@...aro.org>
---
drivers/spi/spi-s3c64xx.c | 36 ++++++++++++++++++++++++++++++++++--
1 file changed, 34 insertions(+), 2 deletions(-)
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index eb79c6e4f509..014fcc933c90 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -142,6 +142,7 @@ struct s3c64xx_spi_dma_data {
* prescaler unit.
* @clk_ioclk: True if clock is present on this device
* @has_loopback: True if loopback mode can be supported
+ * @use_32bit_io: True if the SoC allows only 32-bit register accesses.
*
* The Samsung s3c64xx SPI controller are used on various Samsung SoC's but
* differ in some aspects such as the size of the fifo and spi bus clock
@@ -158,6 +159,7 @@ struct s3c64xx_spi_port_config {
bool clk_from_cmu;
bool clk_ioclk;
bool has_loopback;
+ bool use_32bit_io;
};
/**
@@ -414,6 +416,30 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
}
+static void s3c64xx_iowrite8_32_rep(volatile void __iomem *addr,
+ const void *buffer, unsigned int count)
+{
+ if (count) {
+ const u8 *buf = buffer;
+
+ do {
+ __raw_writel(*buf++, addr);
+ } while (--count);
+ }
+}
+
+static void s3c64xx_iowrite16_32_rep(volatile void __iomem *addr,
+ const void *buffer, unsigned int count)
+{
+ if (count) {
+ const u16 *buf = buffer;
+
+ do {
+ __raw_writel(*buf++, addr);
+ } while (--count);
+ }
+}
+
static void s3c64xx_iowrite_rep(const struct s3c64xx_spi_driver_data *sdd,
struct spi_transfer *xfer)
{
@@ -426,10 +452,16 @@ static void s3c64xx_iowrite_rep(const struct s3c64xx_spi_driver_data *sdd,
iowrite32_rep(addr, buf, len / 4);
break;
case 16:
- iowrite16_rep(addr, buf, len / 2);
+ if (sdd->port_conf->use_32bit_io)
+ s3c64xx_iowrite16_32_rep(addr, buf, len / 2);
+ else
+ iowrite16_rep(addr, buf, len / 2);
break;
default:
- iowrite8_rep(addr, buf, len);
+ if (sdd->port_conf->use_32bit_io)
+ s3c64xx_iowrite8_32_rep(addr, buf, len);
+ else
+ iowrite8_rep(addr, buf, len);
break;
}
}
--
2.43.0.687.g38aa6559b0-goog
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