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Commit 8958262a authored by Marek Vasut's avatar Marek Vasut Committed by Linus Walleij
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gpio: pca953x: Repair multi-byte IO address increment on PCA9575 



The multi-byte IO on various pca953x chips requires the auto-increment bit,
while other chips toggle the LSbit automatically. Note that LSbit toggling
only alternates between two registers during the IO, it is not the same as
address auto-increment. The driver currently assumes that #gpios > 16 implies
auto-increment, while #gpios <= 16 implies LSbit toggling. This is incorrect
at there are chips with 16 GPIOs which require the auto-increment bit.

The PCA9575, according to NXP datasheet rev. 4.2 from 16 April 2015, section
7.3 Command Register, the bit 7 in command register is the auto-increment
bit, which allows programming multiple registers sequentially.

Set this bit both in pca953x_gpio_set_multiple(), where it fixes the multi
register programming, and in pca957x_write_regs_16(), where is simplifies
the function. In fact, the pca957x_write_regs_16() now looks rather similar
to pca953x_write_regs_24() and pca953x_write_regs_16(), which is intended
for subsequent patches.

Signed-off-by: default avatarMarek Vasut <marek.vasut+renesas@gmail.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 92f45ebe

drivers/gpio/gpio-pca953x.c

+11 −8
Original line number Diff line number Diff line
@@ -215,13 +215,10 @@ static int pca953x_write_regs_16(struct pca953x_chip *chip, int reg, u8 *val) 


static int pca957x_write_regs_16(struct pca953x_chip *chip, int reg, u8 *val)

{

	int ret;



	ret = i2c_smbus_write_byte_data(chip->client, reg << 1, val[0]);

	if (ret < 0)

		return ret;

	u32 regaddr = (reg << 1) | REG_ADDR_AI;



	return i2c_smbus_write_byte_data(chip->client, (reg << 1) + 1, val[1]);

	return i2c_smbus_write_i2c_block_data(chip->client, regaddr,

					      NBANK(chip), val);

}



static int pca953x_write_regs_24(struct pca953x_chip *chip, int reg, u8 *val)
@@ -408,6 +405,7 @@ static void pca953x_gpio_set_multiple(struct gpio_chip *gc, 
{

	struct pca953x_chip *chip = gpiochip_get_data(gc);

	int bank_shift = pca953x_bank_shift(chip);

	u32 regaddr = chip->regs->output << bank_shift;

	unsigned int bank_mask, bank_val;

	int bank;

	u8 reg_val[MAX_BANK];
@@ -426,8 +424,13 @@ static void pca953x_gpio_set_multiple(struct gpio_chip *gc, 
		}

	}



	ret = i2c_smbus_write_i2c_block_data(chip->client,

					     chip->regs->output << bank_shift,

	/* PCA9575 needs address-increment on multi-byte writes */

	if ((PCA_CHIP_TYPE(chip->driver_data) == PCA957X_TYPE) &&

	    (NBANK(chip) > 1)) {

		regaddr |= REG_ADDR_AI;

	}



	ret = i2c_smbus_write_i2c_block_data(chip->client, regaddr,

					     NBANK(chip), reg_val);

	if (ret)

		goto exit;