From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooks Subject: [PATCH] gpio-pca953x: fall back to byte-at-a-time for 24-bit io Date: Tue, 5 Dec 2017 12:17:22 +1000 Message-ID: <1512440242-8983-1-git-send-email-andrew.cooks@opengear.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mail-bl2nam02on0073.outbound.protection.outlook.com ([104.47.38.73]:38086 "EHLO NAM02-BL2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751756AbdLECSH (ORCPT ); Mon, 4 Dec 2017 21:18:07 -0500 Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Linus Walleij , "open list:GPIO SUBSYSTEM" , open list Cc: platypus-sw@opengear.com, Andrew Cooks Using TCA6424A with i2c-piix4 bus driver requires byte-at-a-time IO, because the i2c-piix4 driver (and probably some SMBus controllers) don't support I2C_SMBUS_I2C_BLOCK_DATA. Signed-off-by: Andrew Cooks --- drivers/gpio/gpio-pca953x.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index 1b9dbf6..9e74934 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -205,11 +205,23 @@ static int pca957x_write_regs_16(struct pca953x_chip *chip, int reg, u8 *val) static int pca953x_write_regs_24(struct pca953x_chip *chip, int reg, u8 *val) { + int ret, i; int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ); - return i2c_smbus_write_i2c_block_data(chip->client, + if (i2c_check_functionality(chip->client->adapter, + I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) { + return i2c_smbus_write_i2c_block_data(chip->client, (reg << bank_shift) | REG_ADDR_AI, NBANK(chip), val); + } else { + for (i = 0; i < NBANK(chip); i++) { + ret = i2c_smbus_write_byte_data(chip->client, + (reg << 1) + i, val[i]); + if (ret < 0) + return ret; + } + return ret; + } } static int pca953x_write_regs(struct pca953x_chip *chip, int reg, u8 *val) @@ -249,7 +261,7 @@ static int pca953x_read_regs_24(struct pca953x_chip *chip, int reg, u8 *val) { int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ); - return i2c_smbus_read_i2c_block_data(chip->client, + return i2c_smbus_read_i2c_block_data_or_emulated(chip->client, (reg << bank_shift) | REG_ADDR_AI, NBANK(chip), val); } -- 2.7.4