The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x dbf4ab821804df071c8b566d9813083125e6d97b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2024012610-grumbly-purge-ae51@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^.. Possible dependencies: dbf4ab821804 ("serial: sc16is7xx: convert from _raw_ to _noinc_ regmap functions for FIFO") 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port") 049994292834 ("serial: sc16is7xx: fix regression with GPIO configuration") dabc54a45711 ("serial: sc16is7xx: remove obsolete out_thread label") c8f71b49ee4d ("serial: sc16is7xx: setup GPIO controller later in probe") 267913ecf737 ("serial: sc16is7xx: Fill in rs485_supported") 21144bab4f11 ("sc16is7xx: Handle modem status lines") cc4c1d05eb10 ("sc16is7xx: Properly resume TX after stop") d4ab5487cc77 ("Merge 5.17-rc6 into tty-next") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From dbf4ab821804df071c8b566d9813083125e6d97b Mon Sep 17 00:00:00 2001 From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> Date: Mon, 11 Dec 2023 12:13:52 -0500 Subject: [PATCH] serial: sc16is7xx: convert from _raw_ to _noinc_ regmap functions for FIFO The SC16IS7XX IC supports a burst mode to access the FIFOs where the initial register address is sent ($00), followed by all the FIFO data without having to resend the register address each time. In this mode, the IC doesn't increment the register address for each R/W byte. The regmap_raw_read() and regmap_raw_write() are functions which can perform IO over multiple registers. They are currently used to read/write from/to the FIFO, and although they operate correctly in this burst mode on the SPI bus, they would corrupt the regmap cache if it was not disabled manually. The reason is that when the R/W size is more than 1 byte, these functions assume that the register address is incremented and handle the cache accordingly. Convert FIFO R/W functions to use the regmap _noinc_ versions in order to remove the manual cache control which was a workaround when using the _raw_ versions. FIFO registers are properly declared as volatile so cache will not be used/updated for FIFO accesses. Fixes: dfeae619d781 ("serial: sc16is7xx") Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20231211171353.2901416-6-hugo@xxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index 0bda9b74d096..7e4b9b52841d 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -381,9 +381,7 @@ static void sc16is7xx_fifo_read(struct uart_port *port, unsigned int rxlen) struct sc16is7xx_port *s = dev_get_drvdata(port->dev); struct sc16is7xx_one *one = to_sc16is7xx_one(port, port); - regcache_cache_bypass(one->regmap, true); - regmap_raw_read(one->regmap, SC16IS7XX_RHR_REG, s->buf, rxlen); - regcache_cache_bypass(one->regmap, false); + regmap_noinc_read(one->regmap, SC16IS7XX_RHR_REG, s->buf, rxlen); } static void sc16is7xx_fifo_write(struct uart_port *port, u8 to_send) @@ -398,9 +396,7 @@ static void sc16is7xx_fifo_write(struct uart_port *port, u8 to_send) if (unlikely(!to_send)) return; - regcache_cache_bypass(one->regmap, true); - regmap_raw_write(one->regmap, SC16IS7XX_THR_REG, s->buf, to_send); - regcache_cache_bypass(one->regmap, false); + regmap_noinc_write(one->regmap, SC16IS7XX_THR_REG, s->buf, to_send); } static void sc16is7xx_port_update(struct uart_port *port, u8 reg, @@ -492,6 +488,11 @@ static bool sc16is7xx_regmap_precious(struct device *dev, unsigned int reg) return false; } +static bool sc16is7xx_regmap_noinc(struct device *dev, unsigned int reg) +{ + return reg == SC16IS7XX_RHR_REG; +} + static int sc16is7xx_set_baud(struct uart_port *port, int baud) { struct sc16is7xx_one *one = to_sc16is7xx_one(port, port); @@ -1709,6 +1710,10 @@ static struct regmap_config regcfg = { .cache_type = REGCACHE_RBTREE, .volatile_reg = sc16is7xx_regmap_volatile, .precious_reg = sc16is7xx_regmap_precious, + .writeable_noinc_reg = sc16is7xx_regmap_noinc, + .readable_noinc_reg = sc16is7xx_regmap_noinc, + .max_raw_read = SC16IS7XX_FIFO_SIZE, + .max_raw_write = SC16IS7XX_FIFO_SIZE, .max_register = SC16IS7XX_EFCR_REG, };
