spi: sh-msiof: Fix handling of write value for SISTR register

Hiromitsu Yamasaki · broonie · commit 31a5fae4c5a0 · 2018-09-05T12:39:57.000+01:00
This patch changes writing to the SISTR register according to the H/W
user's manual.

The TDREQ bit and RDREQ bits of SISTR are read-only, and must be written
their initial values of zero.

Signed-off-by: Hiromitsu Yamasaki &lt;hiromitsu.yamasaki.ym@renesas.com&gt;
[geert: reword]
Signed-off-by: Geert Uytterhoeven &lt;geert+renesas@glider.be&gt;
Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Cc: stable@vger.kernel.org
diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c
@@ -397,7 +397,8 @@ static void sh_msiof_spi_set_mode_regs(struct sh_msiof_spi_priv *p,
 
 static void sh_msiof_reset_str(struct sh_msiof_spi_priv *p)
 {
-	sh_msiof_write(p, STR, sh_msiof_read(p, STR));
+	sh_msiof_write(p, STR,
+		       sh_msiof_read(p, STR) & ~(STR_TDREQ | STR_RDREQ));
 }
 
 static void sh_msiof_spi_write_fifo_8(struct sh_msiof_spi_priv *p,

Original file line number	Diff line number	Diff line change
`@@ -397,7 +397,8 @@ static void sh_msiof_spi_set_mode_regs(struct sh_msiof_spi_priv *p,`
`397`	`397`
`398`	`398`	`static void sh_msiof_reset_str(struct sh_msiof_spi_priv *p)`
`399`	`399`	`{`
`400`		`- sh_msiof_write(p, STR, sh_msiof_read(p, STR));`
	`400`	`+ sh_msiof_write(p, STR,`
	`401`	`+ sh_msiof_read(p, STR) & ~(STR_TDREQ \| STR_RDREQ));`
`401`	`402`	`}`
`402`	`403`
`403`	`404`	`static void sh_msiof_spi_write_fifo_8(struct sh_msiof_spi_priv *p,`