spi/pl022: add support for the PL023 derivate

This adds support for a further ST variant of the PL022 called
PL023. Some differences in the control registers due to being
stripped down to SPI mode only, and a new clock feedback sample
delay config setting is available.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

2 files changed, 104 insertions, 18 deletions

diff --git a/drivers/spi/amba-pl022.c b/drivers/spi/amba-pl022.c
index 65092171cec3..c75831c1deda 100644
--- a/drivers/spi/amba-pl022.c
+++ b/drivers/spi/amba-pl022.c
@@ -135,6 +135,8 @@
 #define SSP_CR1_MASK_MWAIT_ST   (0x1UL << 6)
 #define SSP_CR1_MASK_RXIFLSEL_ST (0x7UL << 7)
 #define SSP_CR1_MASK_TXIFLSEL_ST (0x7UL << 10)
+/* This one is only in the PL023 variant */
+#define SSP_CR1_MASK_FBCLKDEL_ST (0x7UL << 13)
 
 /*
  * SSP Status Register - SSP_SR
@@ -317,12 +319,14 @@ enum ssp_writing {
  * @unidir: supports unidirection transfers
  * @extended_cr: 32 bit wide control register 0 with extra
  * features and extra features in CR1 as found in the ST variants
+ * @pl023: supports a subset of the ST extensions called "PL023"
  */
 struct vendor_data {
         int fifodepth;
         int max_bpw;
         bool unidir;
         bool extended_cr;
+        bool pl023;
 };
 
 /**
@@ -541,11 +545,6 @@ static void restore_state(struct pl022 *pl022)
         writew(CLEAR_ALL_INTERRUPTS, SSP_ICR(pl022->virtbase));
 }
 
-/**
- * load_ssp_default_config - Load default configuration for SSP
- * @pl022: SSP driver private data structure
- */
-
 /*
  * Default SSP Register Values
  */
@@ -568,6 +567,14 @@ static void restore_state(struct pl022 *pl022)
         GEN_MASK_BITS(SSP_INTERFACE_MOTOROLA_SPI, SSP_CR0_MASK_FRF_ST, 21) \
 )
 
+/* The PL023 version is slightly different again */
+#define DEFAULT_SSP_REG_CR0_ST_PL023 ( \
+        GEN_MASK_BITS(SSP_DATA_BITS_12, SSP_CR0_MASK_DSS_ST, 0) | \
+        GEN_MASK_BITS(SSP_CLK_POL_IDLE_LOW, SSP_CR0_MASK_SPO, 6) | \
+        GEN_MASK_BITS(SSP_CLK_SECOND_EDGE, SSP_CR0_MASK_SPH, 7) | \
+        GEN_MASK_BITS(SSP_DEFAULT_CLKRATE, SSP_CR0_MASK_SCR, 8) \
+)
+
 #define DEFAULT_SSP_REG_CR1 ( \
         GEN_MASK_BITS(LOOPBACK_DISABLED, SSP_CR1_MASK_LBM, 0) | \
         GEN_MASK_BITS(SSP_DISABLED, SSP_CR1_MASK_SSE, 1) | \
@@ -585,6 +592,20 @@ static void restore_state(struct pl022 *pl022)
         GEN_MASK_BITS(SSP_TX_1_OR_MORE_EMPTY_LOC, SSP_CR1_MASK_TXIFLSEL_ST, 10) \
 )
 
+/*
+ * The PL023 variant has further differences: no loopback mode, no microwire
+ * support, and a new clock feedback delay setting.
+ */
+#define DEFAULT_SSP_REG_CR1_ST_PL023 ( \
+        GEN_MASK_BITS(SSP_DISABLED, SSP_CR1_MASK_SSE, 1) | \
+        GEN_MASK_BITS(SSP_MASTER, SSP_CR1_MASK_MS, 2) | \
+        GEN_MASK_BITS(DO_NOT_DRIVE_TX, SSP_CR1_MASK_SOD, 3) | \
+        GEN_MASK_BITS(SSP_RX_MSB, SSP_CR1_MASK_RENDN_ST, 4) | \
+        GEN_MASK_BITS(SSP_TX_MSB, SSP_CR1_MASK_TENDN_ST, 5) | \
+        GEN_MASK_BITS(SSP_RX_1_OR_MORE_ELEM, SSP_CR1_MASK_RXIFLSEL_ST, 7) | \
+        GEN_MASK_BITS(SSP_TX_1_OR_MORE_EMPTY_LOC, SSP_CR1_MASK_TXIFLSEL_ST, 10) | \
+        GEN_MASK_BITS(SSP_FEEDBACK_CLK_DELAY_NONE, SSP_CR1_MASK_FBCLKDEL_ST, 13) \
+)
 
 #define DEFAULT_SSP_REG_CPSR ( \
         GEN_MASK_BITS(SSP_DEFAULT_PRESCALE, SSP_CPSR_MASK_CPSDVSR, 0) \
@@ -595,10 +616,16 @@ static void restore_state(struct pl022 *pl022)
         GEN_MASK_BITS(SSP_DMA_DISABLED, SSP_DMACR_MASK_TXDMAE, 1) \
 )
 
-
+/**
+ * load_ssp_default_config - Load default configuration for SSP
+ * @pl022: SSP driver private data structure
+ */
 static void load_ssp_default_config(struct pl022 *pl022)
 {
-        if (pl022->vendor->extended_cr) {
+        if (pl022->vendor->pl023) {
+                writel(DEFAULT_SSP_REG_CR0_ST_PL023, SSP_CR0(pl022->virtbase));
+                writew(DEFAULT_SSP_REG_CR1_ST_PL023, SSP_CR1(pl022->virtbase));
+        } else if (pl022->vendor->extended_cr) {
                 writel(DEFAULT_SSP_REG_CR0_ST, SSP_CR0(pl022->virtbase));
                 writew(DEFAULT_SSP_REG_CR1_ST, SSP_CR1(pl022->virtbase));
         } else {
@@ -1629,20 +1656,27 @@ static int pl022_setup(struct spi_device *spi)
 
         /* Special setup for the ST micro extended control registers */
         if (pl022->vendor->extended_cr) {
+                if (pl022->vendor->pl023) {
+                        /* These bits are only in the PL023 */
+                        SSP_WRITE_BITS(chip->cr1, chip_info->clkdelay,
+                                       SSP_CR1_MASK_FBCLKDEL_ST, 13);
+                } else {
+                        /* These bits are in the PL022 but not PL023 */
+                        SSP_WRITE_BITS(chip->cr0, chip_info->duplex,
+                                       SSP_CR0_MASK_HALFDUP_ST, 5);
+                        SSP_WRITE_BITS(chip->cr0, chip_info->ctrl_len,
+                                       SSP_CR0_MASK_CSS_ST, 16);
+                        SSP_WRITE_BITS(chip->cr0, chip_info->iface,
+                                       SSP_CR0_MASK_FRF_ST, 21);
+                        SSP_WRITE_BITS(chip->cr1, chip_info->wait_state,
+                                       SSP_CR1_MASK_MWAIT_ST, 6);
+                }
                 SSP_WRITE_BITS(chip->cr0, chip_info->data_size,
                                SSP_CR0_MASK_DSS_ST, 0);
-                SSP_WRITE_BITS(chip->cr0, chip_info->duplex,
-                               SSP_CR0_MASK_HALFDUP_ST, 5);
-                SSP_WRITE_BITS(chip->cr0, chip_info->ctrl_len,
-                               SSP_CR0_MASK_CSS_ST, 16);
-                SSP_WRITE_BITS(chip->cr0, chip_info->iface,
-                               SSP_CR0_MASK_FRF_ST, 21);
                 SSP_WRITE_BITS(chip->cr1, chip_info->endian_rx,
                                SSP_CR1_MASK_RENDN_ST, 4);
                 SSP_WRITE_BITS(chip->cr1, chip_info->endian_tx,
                                SSP_CR1_MASK_TENDN_ST, 5);
-                SSP_WRITE_BITS(chip->cr1, chip_info->wait_state,
-                               SSP_CR1_MASK_MWAIT_ST, 6);
                 SSP_WRITE_BITS(chip->cr1, chip_info->rx_lev_trig,
                                SSP_CR1_MASK_RXIFLSEL_ST, 7);
                 SSP_WRITE_BITS(chip->cr1, chip_info->tx_lev_trig,
@@ -1657,7 +1691,9 @@ static int pl022_setup(struct spi_device *spi)
         SSP_WRITE_BITS(chip->cr0, chip_info->clk_pol, SSP_CR0_MASK_SPO, 6);
         SSP_WRITE_BITS(chip->cr0, chip_info->clk_phase, SSP_CR0_MASK_SPH, 7);
         SSP_WRITE_BITS(chip->cr0, chip_info->clk_freq.scr, SSP_CR0_MASK_SCR, 8);
-        SSP_WRITE_BITS(chip->cr1, chip_info->lbm, SSP_CR1_MASK_LBM, 0);
+        /* Loopback is available on all versions except PL023 */
+        if (!pl022->vendor->pl023)
+                SSP_WRITE_BITS(chip->cr1, chip_info->lbm, SSP_CR1_MASK_LBM, 0);
         SSP_WRITE_BITS(chip->cr1, SSP_DISABLED, SSP_CR1_MASK_SSE, 1);
         SSP_WRITE_BITS(chip->cr1, chip_info->hierarchy, SSP_CR1_MASK_MS, 2);
         SSP_WRITE_BITS(chip->cr1, chip_info->slave_tx_disable, SSP_CR1_MASK_SOD, 3);
@@ -1874,6 +1910,7 @@ static struct vendor_data vendor_arm = {
         .max_bpw = 16,
         .unidir = false,
         .extended_cr = false,
+        .pl023 = false,
 };
 
 
@@ -1882,6 +1919,15 @@ static struct vendor_data vendor_st = {
         .max_bpw = 32,
         .unidir = false,
         .extended_cr = true,
+        .pl023 = false,
+};
+
+static struct vendor_data vendor_st_pl023 = {
+        .fifodepth = 32,
+        .max_bpw = 32,
+        .unidir = false,
+        .extended_cr = true,
+        .pl023 = true,
 };
 
 static struct amba_id pl022_ids[] = {
@@ -1903,6 +1949,18 @@ static struct amba_id pl022_ids[] = {
                 .mask   = 0xffffffff,
                 .data   = &vendor_st,
         },
+        {
+                /*
+                 * ST-Ericsson derivative "PL023" (this is not
+                 * an official ARM number), this is a PL022 SSP block
+                 * stripped to SPI mode only, it has 32bit wide
+                 * and 32 locations deep TX/RX FIFO but no extended
+                 * CR0/CR1 register
+                 */
+                .id     = 0x00080023,
+                .mask   = 0xffffffff,
+                .data   = &vendor_st_pl023,
+        },
         { 0, 0 },
 };
 
diff --git a/include/linux/amba/pl022.h b/include/linux/amba/pl022.h
index 612f39913340..abf26cc47a2b 100644
--- a/include/linux/amba/pl022.h
+++ b/include/linux/amba/pl022.h
@@ -182,8 +182,8 @@ enum ssp_microwire_wait_state {
 };
 
 /**
- * enum Microwire - whether Full/Half Duplex, only available
- * in the ST Micro variant.
+ * enum ssp_duplex - whether Full/Half Duplex on microwire, only
+ * available in the ST Micro variant.
  * @SSP_MICROWIRE_CHANNEL_FULL_DUPLEX: SSPTXD becomes bi-directional,
  *     SSPRXD not used
  * @SSP_MICROWIRE_CHANNEL_HALF_DUPLEX: SSPTXD is an output, SSPRXD is
@@ -195,6 +195,31 @@ enum ssp_duplex {
 };
 
 /**
+ * enum ssp_clkdelay - an optional clock delay on the feedback clock
+ * only available in the ST Micro PL023 variant.
+ * @SSP_FEEDBACK_CLK_DELAY_NONE: no delay, the data coming in from the
+ * slave is sampled directly
+ * @SSP_FEEDBACK_CLK_DELAY_1T: the incoming slave data is sampled with
+ * a delay of T-dt
+ * @SSP_FEEDBACK_CLK_DELAY_2T: dito with a delay if 2T-dt
+ * @SSP_FEEDBACK_CLK_DELAY_3T: dito with a delay if 3T-dt
+ * @SSP_FEEDBACK_CLK_DELAY_4T: dito with a delay if 4T-dt
+ * @SSP_FEEDBACK_CLK_DELAY_5T: dito with a delay if 5T-dt
+ * @SSP_FEEDBACK_CLK_DELAY_6T: dito with a delay if 6T-dt
+ * @SSP_FEEDBACK_CLK_DELAY_7T: dito with a delay if 7T-dt
+ */
+enum ssp_clkdelay {
+        SSP_FEEDBACK_CLK_DELAY_NONE,
+        SSP_FEEDBACK_CLK_DELAY_1T,
+        SSP_FEEDBACK_CLK_DELAY_2T,
+        SSP_FEEDBACK_CLK_DELAY_3T,
+        SSP_FEEDBACK_CLK_DELAY_4T,
+        SSP_FEEDBACK_CLK_DELAY_5T,
+        SSP_FEEDBACK_CLK_DELAY_6T,
+        SSP_FEEDBACK_CLK_DELAY_7T
+};
+
+/**
  * CHIP select/deselect commands
  */
 enum ssp_chip_select {
@@ -237,6 +262,8 @@ struct pl022_ssp_controller {
  * @ctrl_len: Microwire interface: Control length
  * @wait_state: Microwire interface: Wait state
  * @duplex: Microwire interface: Full/Half duplex
+ * @clkdelay: on the PL023 variant, the delay in feeback clock cycles
+ * before sampling the incoming line
  * @cs_control: function pointer to board-specific function to
  * assert/deassert I/O port to control HW generation of devices chip-select.
  * @dma_xfer_type: Type of DMA xfer (Mem-to-periph or Periph-to-Periph)
@@ -260,6 +287,7 @@ struct pl022_config_chip {
         enum ssp_microwire_ctrl_len ctrl_len;
         enum ssp_microwire_wait_state wait_state;
         enum ssp_duplex duplex;
+        enum ssp_clkdelay clkdelay;
         void (*cs_control) (u32 control);
 };