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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 /drivers/i2c | |
parent | ed7357c9f9b6a560992446c37260be25e514c4ab (diff) | |
download | linux-fdb7e884ad617f8aa69abdd7f39e3fdac85e081e.tar.gz linux-fdb7e884ad617f8aa69abdd7f39e3fdac85e081e.tar.bz2 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 'drivers/i2c')
-rw-r--r-- | drivers/i2c/busses/i2c-iop3xx.c | 32 | ||||
-rw-r--r-- | drivers/i2c/busses/i2c-iop3xx.h | 2 |
2 files changed, 23 insertions, 11 deletions
diff --git a/drivers/i2c/busses/i2c-iop3xx.c b/drivers/i2c/busses/i2c-iop3xx.c index a34cb3848280..eafc1a4d8656 100644 --- a/drivers/i2c/busses/i2c-iop3xx.c +++ b/drivers/i2c/busses/i2c-iop3xx.c @@ -38,7 +38,7 @@ #include <linux/platform_device.h> #include <linux/i2c.h> #include <linux/io.h> -#include <linux/gpio.h> +#include <linux/gpio/consumer.h> #include "i2c-iop3xx.h" @@ -71,17 +71,16 @@ iop3xx_i2c_enable(struct i2c_algo_iop3xx_data *iop3xx_adap) /* * Every time unit enable is asserted, GPOD needs to be cleared - * on IOP3XX to avoid data corruption on the bus. + * on IOP3XX to avoid data corruption on the bus. We use the + * gpiod_set_raw_value() to make sure the 0 hits the hardware + * GPOD register. These descriptors are only passed along to + * the device if this is necessary. */ -#if defined(CONFIG_ARCH_IOP32X) || defined(CONFIG_ARCH_IOP33X) - if (iop3xx_adap->id == 0) { - gpio_set_value(7, 0); - gpio_set_value(6, 0); - } else { - gpio_set_value(5, 0); - gpio_set_value(4, 0); - } -#endif + if (iop3xx_adap->gpio_scl) + gpiod_set_raw_value(iop3xx_adap->gpio_scl, 0); + if (iop3xx_adap->gpio_sda) + gpiod_set_raw_value(iop3xx_adap->gpio_sda, 0); + /* NB SR bits not same position as CR IE bits :-( */ iop3xx_adap->SR_enabled = IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD | @@ -434,6 +433,17 @@ iop3xx_i2c_probe(struct platform_device *pdev) goto free_adapter; } + adapter_data->gpio_scl = devm_gpiod_get_optional(&pdev->dev, + "scl", + GPIOD_ASIS); + if (IS_ERR(adapter_data->gpio_scl)) + return PTR_ERR(adapter_data->gpio_scl); + adapter_data->gpio_sda = devm_gpiod_get_optional(&pdev->dev, + "sda", + GPIOD_ASIS); + if (IS_ERR(adapter_data->gpio_sda)) + return PTR_ERR(adapter_data->gpio_sda); + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) { ret = -ENODEV; diff --git a/drivers/i2c/busses/i2c-iop3xx.h b/drivers/i2c/busses/i2c-iop3xx.h index 2d6929c2bd92..231897838386 100644 --- a/drivers/i2c/busses/i2c-iop3xx.h +++ b/drivers/i2c/busses/i2c-iop3xx.h @@ -98,6 +98,8 @@ struct i2c_algo_iop3xx_data { spinlock_t lock; u32 SR_enabled, SR_received; int id; + struct gpio_desc *gpio_scl; + struct gpio_desc *gpio_sda; }; #endif /* I2C_IOP3XX_H */ |