From fdb7e884ad617f8aa69abdd7f39e3fdac85e081e Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Sat, 1 Jun 2019 00:37:56 +0200 Subject: i2c: iop: Use GPIO descriptors The IOP3xx has some elaborate code to directly slam the GPIO lines multiplexed with I2C down low before enablement, apparently a workaround for a hardware bug found in the early chips. After consulting the developer documentation for IOP80321 and IOP80331 I can clearly see that this may be useful for IOP80321 family (mach-iop32x) but it is highly dubious for any 80331 series or later chip: in these chips the lines are not multiplexed for UARTs. We convert the code to pass optional GPIO descriptors and register these only on the 80321-based boards where it makes sense, optionally obtain them in the driver and use the gpiod_set_raw_value() to ascertain the line gets driven low when needed. The GPIO driver does not give the GPIO chip a reasonable label so the patch also adds that so that these machine descriptor tables can be used. Signed-off-by: Linus Walleij Acked-by: Arnd Bergmann Acked-by: Dan Williams Signed-off-by: Wolfram Sang --- arch/arm/plat-iop/i2c.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'arch/arm/plat-iop/i2c.c') diff --git a/arch/arm/plat-iop/i2c.c b/arch/arm/plat-iop/i2c.c index 88215ad031a2..bac20f7f5f8a 100644 --- a/arch/arm/plat-iop/i2c.c +++ b/arch/arm/plat-iop/i2c.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -37,6 +38,29 @@ #define IRQ_IOP3XX_I2C_1 IRQ_IOP33X_I2C_1 #endif +/* + * Each of the I2C busses have corresponding GPIO lines, and the driver + * need to access these directly to drive the bus low at times. + */ + +struct gpiod_lookup_table iop3xx_i2c0_gpio_lookup = { + .dev_id = "IOP3xx-I2C.0", + .table = { + GPIO_LOOKUP("gpio-iop", 7, "scl", GPIO_ACTIVE_HIGH), + GPIO_LOOKUP("gpio-iop", 6, "sda", GPIO_ACTIVE_HIGH), + { } + }, +}; + +struct gpiod_lookup_table iop3xx_i2c1_gpio_lookup = { + .dev_id = "IOP3xx-I2C.1", + .table = { + GPIO_LOOKUP("gpio-iop", 5, "scl", GPIO_ACTIVE_HIGH), + GPIO_LOOKUP("gpio-iop", 4, "sda", GPIO_ACTIVE_HIGH), + { } + }, +}; + static struct resource iop3xx_i2c0_resources[] = { [0] = { .start = 0xfffff680, -- cgit v1.2.3