From 69b921acae8a5b7feef03921d9b42c3634f3b9d1 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Wed, 6 Mar 2019 10:32:05 +0000 Subject: [PATCH] spi: spi-fsl-spi: support use of the SPISEL_BOOT signal on MPC8309 The MPC8309 has a dedicated signal, SPISEL_BOOT, usually used as chip select for the flash device from which the bootloader is loaded. It is not an ordinary gpio, but is simply controlled via the SPI_CS register in the system configuration. To allow accessing such a spi slave, we need to teach fsl_spi_cs_control() how to control the SPISEL_BOOT signal. To distinguish the gpio-controlled slaves, continue to have those use chip_select values of 0..ngpios-1, and use chip_select == ngpios for the boot flash. I'm not too happy with all the ifdeffery, but it seems to be necessary for guarding the sysdev/fsl_soc.h and use of get_immrbase() (spi-fsl-lib.c already contains similar ifdeffery). Googling suggests that the MPC8306 is similar, with the SPI_CS register at the same offset. Signed-off-by: Rasmus Villemoes Signed-off-by: Mark Brown --- .../devicetree/bindings/spi/fsl-spi.txt | 4 ++ drivers/spi/spi-fsl-lib.h | 2 + drivers/spi/spi-fsl-spi.c | 40 ++++++++++++++++--- 3 files changed, 41 insertions(+), 5 deletions(-) diff --git a/Documentation/devicetree/bindings/spi/fsl-spi.txt b/Documentation/devicetree/bindings/spi/fsl-spi.txt index 8854004a1d3a..411375eac54d 100644 --- a/Documentation/devicetree/bindings/spi/fsl-spi.txt +++ b/Documentation/devicetree/bindings/spi/fsl-spi.txt @@ -18,6 +18,10 @@ Optional properties: - gpios : specifies the gpio pins to be used for chipselects. The gpios will be referred to as reg = in the SPI child nodes. If unspecified, a single SPI device without a chip select can be used. +- fsl,spisel_boot : for the MPC8306 and MPC8309, specifies that the + SPISEL_BOOT signal is used as chip select for a slave device. Use + reg = in the corresponding child node, i.e. 0 if + the gpios property is not present. Example: spi@4c0 { diff --git a/drivers/spi/spi-fsl-lib.h b/drivers/spi/spi-fsl-lib.h index f303f306b38e..483734bc1b1e 100644 --- a/drivers/spi/spi-fsl-lib.h +++ b/drivers/spi/spi-fsl-lib.h @@ -95,8 +95,10 @@ static inline u32 mpc8xxx_spi_read_reg(__be32 __iomem *reg) struct mpc8xxx_spi_probe_info { struct fsl_spi_platform_data pdata; + int ngpios; int *gpios; bool *alow_flags; + __be32 __iomem *immr_spi_cs; }; extern u32 mpc8xxx_spi_tx_buf_u8(struct mpc8xxx_spi *mpc8xxx_spi); diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c index 8f2e97857e8b..3d7b50c65f36 100644 --- a/drivers/spi/spi-fsl-spi.c +++ b/drivers/spi/spi-fsl-spi.c @@ -39,6 +39,14 @@ #include #include +#ifdef CONFIG_FSL_SOC +#include +#endif + +/* Specific to the MPC8306/MPC8309 */ +#define IMMR_SPI_CS_OFFSET 0x14c +#define SPI_BOOT_SEL_BIT 0x80000000 + #include "spi-fsl-lib.h" #include "spi-fsl-cpm.h" #include "spi-fsl-spi.h" @@ -701,10 +709,17 @@ static void fsl_spi_cs_control(struct spi_device *spi, bool on) struct fsl_spi_platform_data *pdata = dev_get_platdata(dev); struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(pdata); u16 cs = spi->chip_select; - int gpio = pinfo->gpios[cs]; - bool alow = pinfo->alow_flags[cs]; - gpio_set_value(gpio, on ^ alow); + if (cs < pinfo->ngpios) { + int gpio = pinfo->gpios[cs]; + bool alow = pinfo->alow_flags[cs]; + + gpio_set_value(gpio, on ^ alow); + } else { + if (WARN_ON_ONCE(cs > pinfo->ngpios || !pinfo->immr_spi_cs)) + return; + iowrite32be(on ? SPI_BOOT_SEL_BIT : 0, pinfo->immr_spi_cs); + } } static int of_fsl_spi_get_chipselects(struct device *dev) @@ -712,12 +727,15 @@ static int of_fsl_spi_get_chipselects(struct device *dev) struct device_node *np = dev->of_node; struct fsl_spi_platform_data *pdata = dev_get_platdata(dev); struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(pdata); + bool spisel_boot = IS_ENABLED(CONFIG_FSL_SOC) && + of_property_read_bool(np, "fsl,spisel_boot"); int ngpios; int i = 0; int ret; ngpios = of_gpio_count(np); - if (ngpios <= 0) { + ngpios = max(ngpios, 0); + if (ngpios == 0 && !spisel_boot) { /* * SPI w/o chip-select line. One SPI device is still permitted * though. @@ -726,6 +744,7 @@ static int of_fsl_spi_get_chipselects(struct device *dev) return 0; } + pinfo->ngpios = ngpios; pinfo->gpios = kmalloc_array(ngpios, sizeof(*pinfo->gpios), GFP_KERNEL); if (!pinfo->gpios) @@ -769,7 +788,18 @@ static int of_fsl_spi_get_chipselects(struct device *dev) } } - pdata->max_chipselect = ngpios; +#if IS_ENABLED(CONFIG_FSL_SOC) + if (spisel_boot) { + pinfo->immr_spi_cs = ioremap(get_immrbase() + IMMR_SPI_CS_OFFSET, 4); + if (!pinfo->immr_spi_cs) { + ret = -ENOMEM; + i = ngpios - 1; + goto err_loop; + } + } +#endif + + pdata->max_chipselect = ngpios + spisel_boot; pdata->cs_control = fsl_spi_cs_control; return 0; -- 2.45.2