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| author | Linus Walleij <linus.walleij@linaro.org> | 2019-06-01 00:37:56 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2019-06-12 13:20:23 +0200 |
| commit | fdb7e884ad617f8aa69abdd7f39e3fdac85e081e (patch) | |
| tree | 8040de47cccdb9797aa15272df7d0afde3431307 /arch/arm/plat-iop | |
| parent | i2c: s3c2410: Convert to use GPIO descriptors (diff) | |
| download | linux-fdb7e884ad617f8aa69abdd7f39e3fdac85e081e.tar.xz linux-fdb7e884ad617f8aa69abdd7f39e3fdac85e081e.zip | |
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 <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'arch/arm/plat-iop')
| -rw-r--r-- | arch/arm/plat-iop/i2c.c | 24 |
1 files changed, 24 insertions, 0 deletions
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 <linux/tty.h> #include <linux/serial_core.h> #include <linux/io.h> +#include <linux/gpio/machine.h> #include <asm/pgtable.h> #include <asm/page.h> #include <asm/mach/map.h> @@ -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, |