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path: root/drivers/gpio/gpio-aspeed.c
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* gpio/aspeed: Use a cache of output data registersBenjamin Herrenschmidt2018-05-111-2/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | The current driver does a read/modify/write of the output registers when changing a bit in __aspeed_gpio_set(). This is sub-optimal for a couple of reasons: - If any of the neighbouring GPIOs (sharing the shared register) isn't (yet) configured as an output, it will read the current input value, and then apply it to the output latch, which may not be what the user expects. There should be no bug in practice as aspeed_gpio_dir_out() will establish a new value but it's not great either. - The GPIO block in the aspeed chip is clocked rather slowly (typically 25Mhz). That extra MMIO read halves the maximum speed at which we can toggle the GPIO. This provides a significant performance improvement to the GPIO based FSI master. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com> Reviewed-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Joel Stanley <joel@jms.id.au>
* gpio/aspeed: Set output latch before changing directionBenjamin Herrenschmidt2018-05-111-2/+1
| | | | | | | | | | | | In aspeed_gpio_dir_out(), we need to establish the new output value in the output latch *before* we change the direction to output in order to avoid a glitch on the output line if the previous value of the latch was different. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com> Reviewed-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Joel Stanley <joel@jms.id.au>
* gpio: aspeed: Add support for reset toleranceAndrew Jeffery2018-02-081-2/+37
| | | | | | | | | | | Use the new pinconf parameter for state persistence to expose the associated capability of the Aspeed GPIO controller. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Reviewed-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> (cherry picked from commit 1b43d26985745901c87e0dca44c9b57896062306) Signed-off-by: Joel Stanley <joel@jms.id.au>
* gpio: aspeed: Remove reference to clock name in debounce warning messageAndrew Jeffery2017-11-281-1/+1
| | | | | | | | | | | HPLL is in fact not the clock we need. Remove the description of which clock we failed to find a phandle to in order to avoid any further error. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Acked-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> (cherry picked from commit 754c04582a98fa2a24ff1b4c4b88964b114eb526) Signed-off-by: Joel Stanley <joel@jms.id.au>
* gpio: aspeed: Don't attempt to debounce if disabledJoel Stanley2017-05-221-0/+3
| | | | | | | | | | | | | | We warn the user at driver probe time that debouncing is disabled. However, if they request debouncing later on we print a confusing error message: gpio_aspeed 1e780000.gpio: Failed to convert 5000us to cycles at 0Hz: -524 Instead bail out when the clock is not present. Fixes: 5ae4cb94b3133 (gpio: aspeed: Add debounce support) Signed-off-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* gpio: aspeed: Add open-source and open-drain supportAndrew Jeffery2017-04-241-0/+4
| | | | | | | | | | | | As per the datasheet, manage the IO and value states to implement open-source/open-drain, but do this by falling back to gpiolib's emulation. This commit simply makes the behaviour explicit for clarity, rather than relying on the implicit return of -ENOTSUPP to trigger the emulation. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* gpio: aspeed: Add debounce supportAndrew Jeffery2017-04-241-5/+276
| | | | | | | | | | | | | | | | | | | | | | | | | Each GPIO in the Aspeed GPIO controller can choose one of four input debounce states: to disable debouncing for an input, or select from one of three programmable debounce timer values. Each GPIO in a four-bank-set is assigned one bit in each of two debounce configuration registers dedicated to the set, and selects a debounce state by configuring the two bits to select one of the four options. The limitation on debounce timer values is managed by mapping offsets onto a configured timer value and keeping count of the number of users a timer has. Timer values are configured on a first-come-first-served basis. A small twist in the hardware design is that the debounce configuration register numbering is reversed with respect to the binary representation of the debounce timer of interest (i.e. debounce register 1 represents bit 1, and debounce register 2 represents bit 0 of the timer numbering). Tested on an AST2500EVB with additional inspection under QEMU's romulus-bmc machine. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* gpio: aspeed: Remove dependence on GPIOF_* macrosAndrew Jeffery2017-02-041-3/+2
| | | | | | | | | | | | | | | 1736f75d35e47409ad776273133d0f558a4c8253 is a (v2) patch which had unresolved review comments[1]. Address the comments by removing the use of macros from the consumer header (this patch represents the diff between v2 and v3[2]). [1] https://lkml.org/lkml/2017/1/26/337 [2] https://lkml.org/lkml/2017/1/26/786 Fixes: 1736f75d35e4 ("gpio: aspeed: Add banks Y, Z, AA, AB and AC") Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Acked-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* gpio: aspeed: Add banks Y, Z, AA, AB and ACAndrew Jeffery2017-01-261-14/+160
| | | | | | | | | | | | | | This is less straight-forward than one would hope, as some banks only have 4 pins rather than 8, others are output only, yet more (W and X, already supported) are input-only, and in the case of the g4 SoC bank AC doesn't exist. Add some structs to describe the varying properties of different banks and integrate mechanisms to deny requests for unsupported configurations. Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* gpio: aspeed: Make bank names stringsJoel Stanley2017-01-261-7/+7
| | | | | | | | | | The Aspeed SoCs have more GPIOs than can be represented with A-Z. The documentation uses two letter names such as AA and AB, so make the names a three-character array in the bank struct to accommodate this. Signed-off-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* gpio: aspeed: remove redundant return value checkWei Yongjun2016-09-231-3/+0
| | | | | | | | | Remove unneeded error handling on the result of a call to platform_get_resource() when the value is passed to devm_ioremap_resource(). Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* gpio: aspeed: fix return value check in aspeed_gpio_probe()Wei Yongjun2016-09-151-2/+2
| | | | | | | | | | In case of error, the function devm_ioremap_resource() returns ERR_PTR() and never returns NULL. The NULL test in the return value check should be replaced with IS_ERR(). Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Acked-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* gpio: aspeed: add MODULE_LICENSE()Linus Walleij2016-09-131-0/+1
| | | | | | | | | | | | | The build complains about missing MODULE_LICENSE() in the Aspeed GPIO driver. The license is evident from the file header, put in "GPL". Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Alistair Popple <alistair@popple.id.au> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Andrew Jeffery <andrew@aj.id.au> Acked-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* gpio: Add Aspeed driverJoel Stanley2016-09-071-0/+457
The Aspeed SoCs contain GPIOs banked by letter, where each bank contains 8 pins. The GPIO banks are then grouped in sets of four in the register layout. The implementation exposes multiple banks through the one driver and requests and releases pins via the pinctrl subsystem. The hardware supports generation of interrupts from all GPIO-capable pins. A number of hardware features are not yet supported: Configuration of interrupt direction (ARM or LPC), debouncing, and WDT reset tolerance for output ports. Signed-off-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Jeremy Kerr <jk@ozlabs.org> Signed-off-by: Andrew Jeffery <andrew@aj.id.au> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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