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[v4,3/6] can: sja1000: Add Quirk for RZ/N1 SJA1000 CAN controller

Message ID 20220710115248.190280-4-biju.das.jz@bp.renesas.com (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series Add support for RZ/N1 SJA1000 CAN controller | expand

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Context Check Description
netdev/tree_selection success Guessed tree name to be net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 12 of 12 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 29 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Biju Das July 10, 2022, 11:52 a.m. UTC
As per Chapter 6.5.16 of the RZ/N1 Peripheral Manual, The SJA1000
CAN controller does not support Clock Divider Register compared to
the reference Philips SJA1000 device.

This patch adds a device quirk to handle this difference.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v3->v4:
 * Optimized the code as per Vincent's suggestion.
v2->v3:
 * No Change
v1->v2:
 * Updated commit description
 * Removed the quirk macro SJA1000_NO_HW_LOOPBACK_QUIRK
 * Added prefix SJA1000_QUIRK_* for quirk macro.
---
 drivers/net/can/sja1000/sja1000.c | 8 +++++---
 drivers/net/can/sja1000/sja1000.h | 3 ++-
 2 files changed, 7 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index 2e7638f98cf1..d9da471f1bb9 100644
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -183,8 +183,9 @@  static void chipset_init(struct net_device *dev)
 {
 	struct sja1000_priv *priv = netdev_priv(dev);
 
-	/* set clock divider and output control register */
-	priv->write_reg(priv, SJA1000_CDR, priv->cdr | CDR_PELICAN);
+	if (!(priv->flags & SJA1000_QUIRK_NO_CDR_REG))
+		/* set clock divider and output control register */
+		priv->write_reg(priv, SJA1000_CDR, priv->cdr | CDR_PELICAN);
 
 	/* set acceptance filter (accept all) */
 	priv->write_reg(priv, SJA1000_ACCC0, 0x00);
@@ -209,7 +210,8 @@  static void sja1000_start(struct net_device *dev)
 		set_reset_mode(dev);
 
 	/* Initialize chip if uninitialized at this stage */
-	if (!(priv->read_reg(priv, SJA1000_CDR) & CDR_PELICAN))
+	if (!(priv->flags & SJA1000_QUIRK_NO_CDR_REG ||
+	      priv->read_reg(priv, SJA1000_CDR) & CDR_PELICAN))
 		chipset_init(dev);
 
 	/* Clear error counters and error code capture */
diff --git a/drivers/net/can/sja1000/sja1000.h b/drivers/net/can/sja1000/sja1000.h
index 9d46398f8154..7f736f1df547 100644
--- a/drivers/net/can/sja1000/sja1000.h
+++ b/drivers/net/can/sja1000/sja1000.h
@@ -145,7 +145,8 @@ 
 /*
  * Flags for sja1000priv.flags
  */
-#define SJA1000_CUSTOM_IRQ_HANDLER 0x1
+#define SJA1000_CUSTOM_IRQ_HANDLER	BIT(0)
+#define SJA1000_QUIRK_NO_CDR_REG	BIT(1)
 
 /*
  * SJA1000 private data structure