From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> [ Upstream commit d4d6f03c4fb3a91dadfe147b47edd40e4d7e4d36 ] In some configurations, mainly ACPI-based, the clock frequency of the device is supplied by very well established 'clock-frequency' property. Hence, try to get it from the property at last if no other providers are available. Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210517172930.83353-1-andriy.shevchenko@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Stable-dep-of: 8afa6c6decea ("serial: max310x: fail probe if clock crystal is unstable") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/tty/serial/max310x.c | 40 +++++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 14 deletions(-) diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c index 8bf3c5ab59431..0e0f778d75cd4 100644 --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -556,7 +556,7 @@ static int max310x_update_best_err(unsigned long f, long *besterr) return 1; } -static int max310x_set_ref_clk(struct device *dev, struct max310x_port *s, +static u32 max310x_set_ref_clk(struct device *dev, struct max310x_port *s, unsigned long freq, bool xtal) { unsigned int div, clksrc, pllcfg = 0; @@ -629,7 +629,7 @@ static int max310x_set_ref_clk(struct device *dev, struct max310x_port *s, dev_warn(dev, "clock is not stable yet\n"); } - return (int)bestfreq; + return bestfreq; } static void max310x_batch_write(struct uart_port *port, u8 *txbuf, unsigned int len) @@ -1264,9 +1264,10 @@ static int max310x_gpio_set_config(struct gpio_chip *chip, unsigned int offset, static int max310x_probe(struct device *dev, struct max310x_devtype *devtype, struct regmap *regmap, int irq) { - int i, ret, fmin, fmax, freq, uartclk; + int i, ret, fmin, fmax, freq; struct max310x_port *s; - bool xtal = false; + u32 uartclk = 0; + bool xtal; if (IS_ERR(regmap)) return PTR_ERR(regmap); @@ -1278,24 +1279,20 @@ static int max310x_probe(struct device *dev, struct max310x_devtype *devtype, return -ENOMEM; } + /* Always ask for fixed clock rate from a property. */ + device_property_read_u32(dev, "clock-frequency", &uartclk); + s->clk = devm_clk_get_optional(dev, "osc"); if (IS_ERR(s->clk)) return PTR_ERR(s->clk); if (s->clk) { - fmin = 500000; - fmax = 35000000; + xtal = false; } else { s->clk = devm_clk_get_optional(dev, "xtal"); if (IS_ERR(s->clk)) return PTR_ERR(s->clk); - if (s->clk) { - fmin = 1000000; - fmax = 4000000; - xtal = true; - } else { - dev_err(dev, "Cannot get clock\n"); - return -EINVAL; - } + + xtal = true; } ret = clk_prepare_enable(s->clk); @@ -1303,6 +1300,21 @@ static int max310x_probe(struct device *dev, struct max310x_devtype *devtype, return ret; freq = clk_get_rate(s->clk); + if (freq == 0) + freq = uartclk; + if (freq == 0) { + dev_err(dev, "Cannot get clock rate\n"); + return -EINVAL; + } + + if (xtal) { + fmin = 1000000; + fmax = 4000000; + } else { + fmin = 500000; + fmax = 35000000; + } + /* Check frequency limits */ if (freq < fmin || freq > fmax) { ret = -ERANGE; -- 2.43.0
