From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: William Breathitt Gray <vilhelm.gray@gmail.com>,
linus.walleij@linaro.org, akpm@linux-foundation.org
Cc: linux-gpio@vger.kernel.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org, andriy.shevchenko@linux.intel.com
Subject: Re: [RESEND PATCH v4 3/8] gpio: 104-dio-48e: Utilize for_each_set_clump macro
Date: Tue, 2 Oct 2018 09:00:45 +0200 [thread overview]
Message-ID: <822be05b-092b-41c2-3c31-8981acd5cb9e@rasmusvillemoes.dk> (raw)
In-Reply-To: <5906381114b14d5b0359510a1d23accbd239eaa5.1538441919.git.vilhelm.gray@gmail.com>
On 2018-10-02 03:14, William Breathitt Gray wrote:
> /* clear bits array to a clean slate */
> bitmap_zero(bits, chip->ngpio);
>
> - /* get bits are evaluated a gpio port register at a time */
> - for (i = 0; i < ARRAY_SIZE(ports); i++) {
> - /* gpio offset in bits array */
> - bits_offset = i * gpio_reg_size;
> -
> - /* word index for bits array */
> - word_index = BIT_WORD(bits_offset);
> -
> - /* gpio offset within current word of bits array */
> - word_offset = bits_offset % BITS_PER_LONG;
> -
> - /* mask of get bits for current gpio within current word */
> - word_mask = mask[word_index] & (port_mask << word_offset);
> - if (!word_mask) {
> - /* no get bits in this port so skip to next one */
> - continue;
> - }
> -
> - /* read bits from current gpio port */
> + for_each_set_clump(i, word, offset, mask, ARRAY_SIZE(ports), 8) {
> port_state = inb(dio48egpio->base + ports[i]);
> -
> - /* store acquired bits at respective bits array offset */
> - bits[word_index] |= port_state << word_offset;
> + bits[word] |= port_state << offset;
Somewhat unrelated to this series, but is the existing code correct? I'd
expect the RHS to be masked by word_mask; otherwise we might set bits in
bits[] that were not requested? And if one does that, the !word_mask
test is merely an optimization to avoid reading the gpios when the
result would be ignored anyway. Perhaps no caller cares.
Rasmus
next prev parent reply other threads:[~2018-10-02 7:00 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-02 1:12 [RESEND PATCH v4 0/8] Introduce the for_each_set_clump macro William Breathitt Gray
2018-10-02 1:13 ` [RESEND PATCH v4 1/8] bitops: " William Breathitt Gray
2018-10-02 7:42 ` Rasmus Villemoes
2018-10-02 8:21 ` Andy Shevchenko
2018-10-03 11:48 ` Andy Shevchenko
2018-10-04 10:36 ` William Breathitt Gray
2018-10-04 12:10 ` Andy Shevchenko
2018-10-04 10:30 ` William Breathitt Gray
2018-10-04 10:03 ` William Breathitt Gray
2018-10-02 1:14 ` [RESEND PATCH v4 2/8] lib/test_bitmap.c: Add for_each_set_clump test cases William Breathitt Gray
2018-10-02 1:14 ` [RESEND PATCH v4 3/8] gpio: 104-dio-48e: Utilize for_each_set_clump macro William Breathitt Gray
2018-10-02 7:00 ` Rasmus Villemoes [this message]
2018-10-14 4:19 ` William Breathitt Gray
2018-10-15 11:59 ` Rasmus Villemoes
2018-10-17 1:54 ` William Breathitt Gray
2018-10-02 1:15 ` [RESEND PATCH v4 4/8] gpio: 104-idi-48: " William Breathitt Gray
2018-10-02 1:15 ` [RESEND PATCH v4 5/8] gpio: gpio-mm: " William Breathitt Gray
2018-10-02 1:15 ` [RESEND PATCH v4 6/8] gpio: ws16c48: " William Breathitt Gray
2018-10-02 1:16 ` [RESEND PATCH v4 7/8] gpio: pci-idio-16: " William Breathitt Gray
2018-10-02 1:16 ` [RESEND PATCH v4 8/8] gpio: pcie-idio-24: " William Breathitt Gray
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