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serial: max310x: Try to get crystal clock rate from property

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[ 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@linux.intel.com>
Link: https://lore.kernel.org/r/20210517172930.83353-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 8afa6c6decea ("serial: max310x: fail probe if clock crystal is unstable")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Andy Shevchenko
2021-05-17 20:29:30 +03:00
committed by Sasha Levin
parent 569154b29a
commit c2b9cbf09e
1 changed files with 26 additions and 14 deletions
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40
drivers/tty/serial/max310x.c
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@@ -556,7 +556,7 @@ static int max310x_update_best_err(unsigned long f, long *besterr)
return 1; 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 long freq, bool xtal)
{ {
unsigned int div, clksrc, pllcfg = 0; 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"); 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) 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, static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
struct regmap *regmap, int irq) struct regmap *regmap, int irq)
{ {
int i, ret, fmin, fmax, freq, uartclk; int i, ret, fmin, fmax, freq;
struct max310x_port *s; struct max310x_port *s;
bool xtal = false; u32 uartclk = 0;
bool xtal;
if (IS_ERR(regmap)) if (IS_ERR(regmap))
return PTR_ERR(regmap); return PTR_ERR(regmap);
@@ -1278,24 +1279,20 @@ static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
return -ENOMEM; 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"); s->clk = devm_clk_get_optional(dev, "osc");
if (IS_ERR(s->clk)) if (IS_ERR(s->clk))
return PTR_ERR(s->clk); return PTR_ERR(s->clk);
if (s->clk) { if (s->clk) {
fmin = 500000; xtal = false;
fmax = 35000000;
} else { } else {
s->clk = devm_clk_get_optional(dev, "xtal"); s->clk = devm_clk_get_optional(dev, "xtal");
if (IS_ERR(s->clk)) if (IS_ERR(s->clk))
return PTR_ERR(s->clk); return PTR_ERR(s->clk);
if (s->clk) {
fmin = 1000000; xtal = true;
fmax = 4000000;
xtal = true;
} else {
dev_err(dev, "Cannot get clock\n");
return -EINVAL;
}
} }
ret = clk_prepare_enable(s->clk); ret = clk_prepare_enable(s->clk);
@@ -1303,6 +1300,21 @@ static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
return ret; return ret;
freq = clk_get_rate(s->clk); 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 */ /* Check frequency limits */
if (freq < fmin || freq > fmax) { if (freq < fmin || freq > fmax) {
ret = -ERANGE; ret = -ERANGE;