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 8afa6c6decea37e7cb473d2c60473f37f46cea35 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2024021913-outmatch-nuclear-240b@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^.. Possible dependencies: 8afa6c6decea ("serial: max310x: fail probe if clock crystal is unstable") 93cd256ab224 ("serial: max310x: improve crystal stable clock detection") 0419373333c2 ("serial: max310x: set default value when reading clock ready bit") d4d6f03c4fb3 ("serial: max310x: Try to get crystal clock rate from property") 974e454d6f96 ("serial: max310x: Use devm_clk_get_optional() to get the input clock") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 8afa6c6decea37e7cb473d2c60473f37f46cea35 Mon Sep 17 00:00:00 2001 From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> Date: Tue, 16 Jan 2024 16:30:00 -0500 Subject: [PATCH] serial: max310x: fail probe if clock crystal is unstable MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A stable clock is really required in order to use this UART, so log an error message and bail out if the chip reports that the clock is not stable. Fixes: 4cf9a888fd3c ("serial: max310x: Check the clock readiness") Cc: stable@xxxxxxxxxxxxxxx Suggested-by: Jan Kundrát <jan.kundrat@xxxxxxxxx> Link: https://www.spinics.net/lists/linux-serial/msg35773.html Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20240116213001.3691629-4-hugo@xxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c index c0eb0615d945..552e153a24e0 100644 --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -587,7 +587,7 @@ static int max310x_update_best_err(unsigned long f, long *besterr) return 1; } -static u32 max310x_set_ref_clk(struct device *dev, struct max310x_port *s, +static s32 max310x_set_ref_clk(struct device *dev, struct max310x_port *s, unsigned long freq, bool xtal) { unsigned int div, clksrc, pllcfg = 0; @@ -657,7 +657,8 @@ static u32 max310x_set_ref_clk(struct device *dev, struct max310x_port *s, } while (!stable && (++try < MAX310X_XTAL_WAIT_RETRIES)); if (!stable) - dev_warn(dev, "clock is not stable yet\n"); + return dev_err_probe(dev, -EAGAIN, + "clock is not stable\n"); } return bestfreq; @@ -1282,7 +1283,7 @@ static int max310x_probe(struct device *dev, const struct max310x_devtype *devty { int i, ret, fmin, fmax, freq; struct max310x_port *s; - u32 uartclk = 0; + s32 uartclk = 0; bool xtal; for (i = 0; i < devtype->nr; i++) @@ -1360,6 +1361,11 @@ static int max310x_probe(struct device *dev, const struct max310x_devtype *devty } uartclk = max310x_set_ref_clk(dev, s, freq, xtal); + if (uartclk < 0) { + ret = uartclk; + goto out_uart; + } + dev_dbg(dev, "Reference clock set to %i Hz\n", uartclk); for (i = 0; i < devtype->nr; i++) {
