rtc: max31335: fix interrupt status reg

Fix the register value comparison in the `max31335_volatile_reg`
function for the interrupt status register.

MAX31335_STATUS1 macro definition corresponds to the actual
interrupt status register.

Fixes: dedaf03b99d6 ("rtc: max31335: add driver support")
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240219091616.24480-1-antoniu.miclaus@analog.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: max31335: Fix comparison in max31335_volatile_reg()

Clang warns (or errors with CONFIG_WERROR=y):

drivers/rtc/rtc-max31335.c:211:36: error: use of logical '||' with constant operand [-Werror,-Wconstant-logical-operand]
211 | if (reg == MAX31335_TEMP_DATA_MSB || MAX31335_TEMP_DATA_LSB)
| ^ ~~~~~~~~~~~~~~~~~~~~~~
drivers/rtc/rtc-max31335.c:211:36: note: use '|' for a bitwise operation
211 | if (reg == MAX31335_TEMP_DATA_MSB || MAX31335_TEMP_DATA_LSB)
| ^~
| |
1 error generated.

This clearly should be a comparison against reg. Fix the comparison so
that max31335_volatile_reg() does not always return true.

Closes: https://github.com/ClangBuiltLinux/linux/issues/1980
Fixes: dedaf03b99d6 ("rtc: max31335: add driver support")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240117-rtc-max3133-fix-comparison-v1-1-91e98b29d564@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: max31335: use regmap_update_bits_check

Simplify the IRQ handler by using regmap_update_bits_check.

Reviewed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://lore.kernel.org/r/20240115232215.273374-2-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: max31335: remove unecessary locking

There is no race condition when accessing MAX31335_STATUS1 because it is
always about clearing the alarm interrupt bit.

Reviewed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://lore.kernel.org/r/20240115232215.273374-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: max31335: add driver support

RTC driver for MAX31335 ±2ppm Automotive Real-Time Clock with
Integrated MEMS Resonator.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://lore.kernel.org/r/20231120120114.48657-2-antoniu.miclaus@analog.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>