Re: [PATCH v6 003/164] pwm: Provide pwmchip_alloc() function and a devm variant of it
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: 2024-02-14 12:49:52
Also in:
asahi, chrome-platform, linux-amlogic, linux-gpio, linux-leds, linux-mediatek, linux-mips, linux-pwm, linux-riscv, linux-samsung-soc, linux-sunxi, linux-tegra, platform-driver-x86
On Wed, Feb 14, 2024 at 10:30:50AM +0100, Uwe Kleine-König wrote:
This function allocates a struct pwm_chip and driver data. Compared to the status quo the split into pwm_chip and driver data is new, otherwise it doesn't change anything relevant (yet). The intention is that after all drivers are switched to use this allocation function, its possible to add a struct device to struct pwm_chip to properly track the latter's lifetime without touching all drivers again. Proper lifetime tracking is a necessary precondition to introduce character device support for PWMs (that implements atomic setting and doesn't suffer from the sysfs overhead of the /sys/class/pwm userspace support). The new function pwmchip_priv() (obviously?) only works for chips allocated with pwmchip_alloc().
...
+#define PWMCHIP_ALIGN ARCH_DMA_MINALIGN
+
+static void *pwmchip_priv(struct pwm_chip *chip)
+{
+ return (void *)chip + ALIGN(sizeof(*chip), PWMCHIP_ALIGN);
+}Why not use dma_get_cache_alignment() ? ...
+/* This is the counterpart to pwmchip_alloc */
pwmchip_alloc() ...
+EXPORT_SYMBOL_GPL(pwmchip_put);
+EXPORT_SYMBOL_GPL(pwmchip_alloc);
+EXPORT_SYMBOL_GPL(devm_pwmchip_alloc);
Are these exported via namespace? If no, can they be from day 1? ...
+static inline void pwmchip_put(struct pwm_chip *chip)
+{
+}Can be one line, but it's up to the present style in this header. -- With Best Regards, Andy Shevchenko