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authorLinus Walleij <linus.walleij@linaro.org>2018-02-12 13:45:30 +0100
committerMark Brown <broonie@kernel.org>2018-02-14 16:02:41 +0000
commit9b00bc7b901ff672a9252002d3810fdf9489bc64 (patch)
tree533b0c9c3d81ed36732c69350139a0ca56d085cb /arch/arm/mach-pxa/cm-x300.c
parent7928b2cbe55b2a410a0f5c1f154610059c57b1b2 (diff)
spi: spi-gpio: Rewrite to use GPIO descriptors
This converts the bit-banged GPIO SPI driver to looking up and using GPIO descriptors to get a handle on GPIO lines for SCK, MOSI, MISO and all CS lines. All existing board files are converted in one go to keep it all consistent. With these conversions I rarely find any interrim steps that makes any sense. Device tree probing and GPIO handling should work like before also after this patch. For board files, we stop using controller data to pass the GPIO line for chip select, instead we pass this as a GPIO descriptor lookup like everything else. In some s3c24xx machines the names of the SPI devices were set to "spi-gpio" rather than "spi_gpio" which can never have worked, I fixed it working (I guess) as part of this patch set. Sometimes I wonder how this code got upstream in the first place, it obviously is not tested. mach-s3c64xx/mach-smartq.c has the same problem and additionally defines the *same* GPIO line for MOSI and MISO which is not going to be accepted by gpiolib. As the lines were number 1,2,2 I assumed it was a typo and use lines 1,2,3. A comment gives awat that line 0 is chip select though no actual SPI device is provided for the LCD supposed to be on this bit-banged SPI bus. I left it intact instead of just deleting the bus though. Kill off board file code that try to initialize the SPI lines to the same values that they will later be set by the spi_gpio driver anyways. Given the huge number of weird things in these board files I do not think this code is very tested or put in with much afterthought anyways. In order to assert that we do not get performance regressions on this crucial bing-banged driver, a ran a script like this dumping the Ilitek ILI9322 regmap 10000 times (it has no caching obviously) on an otherwise idle system in two iterations before and after the patches: #!/bin/sh for run in `seq 10000` do cat /debug/regmap/spi0.0/registers > /dev/null done Before the patch: time test.sh real 3m 41.03s user 0m 29.41s sys 3m 7.22s time test.sh real 3m 44.24s user 0m 32.31s sys 3m 7.60s After the patch: time test.sh real 3m 41.32s user 0m 28.92s sys 3m 8.08s time test.sh real 3m 39.92s user 0m 30.20s sys 3m 5.56s So any performance differences seems to be in the error margin. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'arch/arm/mach-pxa/cm-x300.c')
-rw-r--r--arch/arm/mach-pxa/cm-x300.c21
1 files changed, 17 insertions, 4 deletions
diff --git a/arch/arm/mach-pxa/cm-x300.c b/arch/arm/mach-pxa/cm-x300.c
index c487401b6fdb..69d7f48a4183 100644
--- a/arch/arm/mach-pxa/cm-x300.c
+++ b/arch/arm/mach-pxa/cm-x300.c
@@ -23,6 +23,7 @@
#include <linux/clk.h>
#include <linux/gpio.h>
+#include <linux/gpio/machine.h>
#include <linux/dm9000.h>
#include <linux/leds.h>
#include <linux/platform_data/rtc-v3020.h>
@@ -343,9 +344,6 @@ static inline void cm_x300_init_bl(void) {}
#define LCD_SPI_BUS_NUM (1)
static struct spi_gpio_platform_data cm_x300_spi_gpio_pdata = {
- .sck = GPIO_LCD_SCL,
- .mosi = GPIO_LCD_DIN,
- .miso = GPIO_LCD_DOUT,
.num_chipselect = 1,
};
@@ -357,6 +355,21 @@ static struct platform_device cm_x300_spi_gpio = {
},
};
+static struct gpiod_lookup_table cm_x300_spi_gpiod_table = {
+ .dev_id = "spi_gpio",
+ .table = {
+ GPIO_LOOKUP("gpio-pxa", GPIO_LCD_SCL,
+ "sck", GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP("gpio-pxa", GPIO_LCD_DIN,
+ "mosi", GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP("gpio-pxa", GPIO_LCD_DOUT,
+ "miso", GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP("gpio-pxa", GPIO_LCD_CS,
+ "cs", GPIO_ACTIVE_HIGH),
+ { },
+ },
+};
+
static struct tdo24m_platform_data cm_x300_tdo24m_pdata = {
.model = TDO35S,
};
@@ -367,7 +380,6 @@ static struct spi_board_info cm_x300_spi_devices[] __initdata = {
.max_speed_hz = 1000000,
.bus_num = LCD_SPI_BUS_NUM,
.chip_select = 0,
- .controller_data = (void *) GPIO_LCD_CS,
.platform_data = &cm_x300_tdo24m_pdata,
},
};
@@ -376,6 +388,7 @@ static void __init cm_x300_init_spi(void)
{
spi_register_board_info(cm_x300_spi_devices,
ARRAY_SIZE(cm_x300_spi_devices));
+ gpiod_add_lookup_table(&cm_x300_spi_gpiod_table);
platform_device_register(&cm_x300_spi_gpio);
}
#else