ExternalVendorCode/openwrt
1
0
Fork 0
mirror of https://github.com/openwrt/openwrt.git synced 2025-02-20 17:32:57 +00:00
Code Issues Actions 2 Packages Projects Releases Wiki Activity

generic: RTC7301 byte-addressed IO

Browse Source 
This is a backport of the patch for byte addressed IO to the
Epson RTC7301 driver. This is used by the IXP4xx-based
USRobotics USR8200.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Linus Walleij 2023-10-23 08:43:04 +02:00 committed by Christian Marangi
parent fcd1c9cbcc
commit 16f929ed47
No known key found for this signature in database
GPG Key ID: AC001D09ADBFEAD7
1 changed files with 93 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

93
target/linux/generic/backport-6.1/831-v6.7-rtc-rtc7301-Support-byte-addressed-IO.patch Normal file
View File

@ -0,0 +1,93 @@
From edd25a77e69b7c546c28077e5dffe72c54c0afe8 Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@linaro.org>
Date: Thu, 21 Sep 2023 22:18:12 +0200
Subject: [PATCH 2/4] rtc: rtc7301: Support byte-addressed IO
The old RTC7301 driver in OpenWrt used byte access, but the
current mainline Linux driver uses 32bit word access.
Make this configurable using device properties using the
standard property "reg-io-width" in e.g. device tree.
This is needed for the USRobotics USR8200 which has the
chip connected using byte accesses.
Debugging and testing by Howard Harte.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/rtc/rtc-r7301.c | 35 +++++++++++++++++++++++++++++++++--
1 file changed, 33 insertions(+), 2 deletions(-)
--- a/drivers/rtc/rtc-r7301.c
+++ b/drivers/rtc/rtc-r7301.c
@@ -14,6 +14,7 @@
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/delay.h>
+#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
@@ -55,12 +56,23 @@ struct rtc7301_priv {
u8 bank;
};
-static const struct regmap_config rtc7301_regmap_config = {
+/*
+ * When the device is memory-mapped, some platforms pack the registers into
+ * 32-bit access using the lower 8 bits at each 4-byte stride, while others
+ * expose them as simply consecutive bytes.
+ */
+static const struct regmap_config rtc7301_regmap_32_config = {
.reg_bits = 32,
.val_bits = 8,
.reg_stride = 4,
};
+static const struct regmap_config rtc7301_regmap_8_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .reg_stride = 1,
+};
+
static u8 rtc7301_read(struct rtc7301_priv *priv, unsigned int reg)
{
int reg_stride = regmap_get_reg_stride(priv->regmap);
@@ -356,7 +368,9 @@ static int __init rtc7301_rtc_probe(stru
void __iomem *regs;
struct rtc7301_priv *priv;
struct rtc_device *rtc;
+ static const struct regmap_config *mapconf;
int ret;
+ u32 val;
priv = devm_kzalloc(&dev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
@@ -366,8 +380,25 @@ static int __init rtc7301_rtc_probe(stru
if (IS_ERR(regs))
return PTR_ERR(regs);
+ ret = device_property_read_u32(&dev->dev, "reg-io-width", &val);
+ if (ret)
+ /* Default to 32bit accesses */
+ val = 4;
+
+ switch (val) {
+ case 1:
+ mapconf = &rtc7301_regmap_8_config;
+ break;
+ case 4:
+ mapconf = &rtc7301_regmap_32_config;
+ break;
+ default:
+ dev_err(&dev->dev, "invalid reg-io-width %d\n", val);
+ return -EINVAL;
+ }
+
priv->regmap = devm_regmap_init_mmio(&dev->dev, regs,
- &rtc7301_regmap_config);
+ mapconf);
if (IS_ERR(priv->regmap))
return PTR_ERR(priv->regmap);