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gpio: gpio-pca953x, Add get_multiple function

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Implement a get_multiple function for gpio-pca953x. If a driver
leaves get_multiple unimplemented then gpio_chip_get_multiple()
in gpiolib.c takes care of it by calling chip->get() as needed.
For i2c chips this is very inefficient. For example if you do an
8-bit read then instead of a single i2c transaction there are
8 transactions reading the same byte!

Signed-off-by: Paul Thomas <pthomas8589@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
This commit is contained in:
Paul Thomas 2020-04-14 11:28:42 -04:00 committed by Bartosz Golaszewski
parent ea06a482a4
commit 96d7c7b3e6
1 changed files with 37 additions and 0 deletions
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37
drivers/gpio/gpio-pca953x.c
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@ -115,6 +115,7 @@ MODULE_DEVICE_TABLE(acpi, pca953x_acpi_ids);
#define MAX_BANK 5
#define BANK_SZ 8
#define BANK_SFT 3 /* ilog2(BANK_SZ) */
#define MAX_LINE (MAX_BANK * BANK_SZ)
#define NBANK(chip) DIV_ROUND_UP(chip->gpio_chip.ngpio, BANK_SZ)
@ -466,6 +467,41 @@ static int pca953x_gpio_get_direction(struct gpio_chip *gc, unsigned off)
return GPIO_LINE_DIRECTION_OUT;
}
static int pca953x_gpio_get_multiple(struct gpio_chip *gc,
unsigned long *mask, unsigned long *bits)
{
struct pca953x_chip *chip = gpiochip_get_data(gc);
unsigned int reg_val;
int offset, value, i, ret = 0;
u8 inreg;
/* Force offset outside the range of i so that
* at least the first relevant register is read
*/
offset = gc->ngpio;
for_each_set_bit(i, mask, gc->ngpio) {
/* whenever i goes into a new bank update inreg
* and read the register
*/
if ((offset >> BANK_SFT) != (i >> BANK_SFT)) {
offset = i;
inreg = pca953x_recalc_addr(chip, chip->regs->input,
offset, true, false);
mutex_lock(&chip->i2c_lock);
ret = regmap_read(chip->regmap, inreg, &reg_val);
mutex_unlock(&chip->i2c_lock);
if (ret < 0)
return ret;
}
/* reg_val is relative to the last read byte,
* so only shift the relative bits
*/
value = (reg_val >> (i % 8)) & 0x01;
__assign_bit(i, bits, value);
}
return ret;
}
static void pca953x_gpio_set_multiple(struct gpio_chip *gc,
unsigned long *mask, unsigned long *bits)
{
@ -551,6 +587,7 @@ static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
gc->get = pca953x_gpio_get_value;
gc->set = pca953x_gpio_set_value;
gc->get_direction = pca953x_gpio_get_direction;
gc->get_multiple = pca953x_gpio_get_multiple;
gc->set_multiple = pca953x_gpio_set_multiple;
gc->set_config = pca953x_gpio_set_config;
gc->can_sleep = true;