From 16f929ed473cba45023389870a5ba4a820f3ff36 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Mon, 23 Oct 2023 08:43:04 +0200 Subject: [PATCH] generic: RTC7301 byte-addressed IO 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 --- ...tc-rtc7301-Support-byte-addressed-IO.patch | 93 +++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 target/linux/generic/backport-6.1/831-v6.7-rtc-rtc7301-Support-byte-addressed-IO.patch diff --git a/target/linux/generic/backport-6.1/831-v6.7-rtc-rtc7301-Support-byte-addressed-IO.patch b/target/linux/generic/backport-6.1/831-v6.7-rtc-rtc7301-Support-byte-addressed-IO.patch new file mode 100644 index 0000000000..ddda6e4e78 --- /dev/null +++ b/target/linux/generic/backport-6.1/831-v6.7-rtc-rtc7301-Support-byte-addressed-IO.patch @@ -0,0 +1,93 @@ +From edd25a77e69b7c546c28077e5dffe72c54c0afe8 Mon Sep 17 00:00:00 2001 +From: Linus Walleij +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 +--- + 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 + #include + #include ++#include + #include + #include + #include +@@ -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); + -- 2.30.2