cygnus: Implement I2C driver
BUG=chrome-os-partner:35810
BRANCH=purin
TEST=Enable I2C1, reset devboard codec, read a register.
Here is the code that demonstrates how I2C works:
i2c_init(1, 100*KHz);
mdelay(50);
int rc = i2c_writeb(1, 0x18, 1, 0x80); // reset codec
printk(BIOS_INFO, "I2C reset rc=%d\n", rc);
mdelay(50);
uint8_t data = 0;
rc = i2c_readb(1, 0x18, 43, &data);
printk(BIOS_INFO, "I2C read rc=%d data=%x\n", rc, data); // data == 0x80
Signed-off-by: Anatol Pomazau <anatol@google.com>
Reviewed-on: https://chrome-internal-review.googlesource.com/195706
Reviewed-by: Daisuke Nojiri <dnojiri@google.com>
Reviewed-by: Anatol Pomazau <anatol@google.com>
Commit-Queue: Anatol Pomazau <anatol@google.com>
Tested-by: Anatol Pomazau <anatol@google.com>
Change-Id: I178acef9de18fa854983294edcd2c05886795e2a
Reviewed-on: https://chromium-review.googlesource.com/263496
Commit-Queue: Daisuke Nojiri <dnojiri@chromium.org>
Trybot-Ready: Daisuke Nojiri <dnojiri@chromium.org>
Tested-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
diff --git a/src/soc/broadcom/cygnus/i2c.c b/src/soc/broadcom/cygnus/i2c.c
index a6865b9..118120d 100644
--- a/src/soc/broadcom/cygnus/i2c.c
+++ b/src/soc/broadcom/cygnus/i2c.c
@@ -17,16 +17,252 @@
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#include <arch/io.h>
+#include <assert.h>
#include <console/console.h>
+#include <delay.h>
#include <device/i2c.h>
#include <soc/i2c.h>
+struct cygnus_i2c_regs {
+ u32 i2c_con;
+ u32 i2c_timing_con;
+ u32 i2c_addr;
+ u32 i2c_fifo_master;
+ u32 i2c_fifo_slave;
+ u32 i2c_bit_bang;
+ u32 reserved0[(0x30 - 0x18) / 4];
+ u32 i2c_master_comm;
+ u32 i2c_slave_comm;
+ u32 i2c_int_en;
+ u32 i2c_int_status;
+ u32 i2c_master_data_wr;
+ u32 i2c_master_data_rd;
+ u32 i2c_slave_data_wr;
+ u32 i2c_slave_data_rd;
+ u32 reserved1[(0xb0 - 0x50) / 4];
+ u32 i2c_timing_con2;
+};
+
+static struct cygnus_i2c_regs *i2c_bus[] = {
+ (struct cygnus_i2c_regs *)0x18008000,
+ (struct cygnus_i2c_regs *)0x1800b000,
+};
+
+#define I2C_TIMEOUT_US 100000 /* 100ms */
+#define I2C_FIFO_MAX_SIZE 64
+
+#define ETIMEDOUT 1
+#define EINVAL 2
+#define EBUSY 3
+
+/* Configuration (0x0) */
+#define I2C_SMB_RESET (1 << 31)
+#define I2C_SMB_EN (1 << 30)
+
+/* Timing configuration (0x4) */
+#define I2C_MODE_400 (1 << 31)
+
+/* Master FIFO control (0xc) */
+#define I2C_MASTER_RX_FIFO_FLUSH (1 << 31)
+#define I2C_MASTER_TX_FIFO_FLUSH (1 << 30)
+
+/* Master command (0x30) */
+#define I2C_MASTER_START_BUSY (1 << 31)
+#define I2C_MASTER_STATUS_SFT 25
+#define I2C_MASTER_STATUS_MASK (0x7 << I2C_MASTER_STATUS_SFT)
+#define I2C_MASTER_PROT_SFT 9
+#define I2C_MASTER_PROT_BLK_WR (0x7 << I2C_MASTER_PROT_SFT)
+#define I2C_MASTER_PROT_BLK_RD (0x8 << I2C_MASTER_PROT_SFT)
+
+/* Master data write (0x40) */
+#define I2C_MASTER_WR_STATUS (1 << 31)
+
+/* Master data read (0x44) */
+#define I2C_MASTER_RD_DATA_MASK 0xff
+
+static unsigned int i2c_bus_busy(struct cygnus_i2c_regs *reg_addr)
+{
+ return readl(®_addr->i2c_master_comm) & I2C_MASTER_START_BUSY;
+}
+
+static int i2c_wait_bus_busy(struct cygnus_i2c_regs *reg_addr)
+{
+ int timeout = I2C_TIMEOUT_US;
+ while (timeout--) {
+ if (!i2c_bus_busy(reg_addr))
+ break;
+ udelay(1);
+ }
+
+ if (timeout <= 0)
+ return ETIMEDOUT;
+
+ return 0;
+}
+
+static void i2c_flush_fifo(struct cygnus_i2c_regs *reg_addr)
+{
+ writel(I2C_MASTER_RX_FIFO_FLUSH | I2C_MASTER_TX_FIFO_FLUSH,
+ ®_addr->i2c_fifo_master);
+}
+
+static int i2c_write(struct cygnus_i2c_regs *reg_addr, struct i2c_seg *segment)
+{
+ uint8_t *data = segment->buf;
+ unsigned int val, status;
+ int i, ret;
+
+ writel(segment->chip << 1, ®_addr->i2c_master_data_wr);
+
+ for (i = 0; i < segment->len; i++) {
+ val = data[i];
+
+ /* mark the last byte */
+ if (i == segment->len - 1)
+ val |= I2C_MASTER_WR_STATUS;
+
+ writel(val, ®_addr->i2c_master_data_wr);
+ }
+ if (segment->len == 0)
+ writel(I2C_MASTER_WR_STATUS, ®_addr->i2c_master_data_wr);
+
+ /*
+ * Now we can activate the transfer.
+ */
+ writel(I2C_MASTER_START_BUSY | I2C_MASTER_PROT_BLK_WR,
+ ®_addr->i2c_master_comm);
+
+ ret = i2c_wait_bus_busy(reg_addr);
+ if (ret) {
+ printk(BIOS_ERR, "I2C bus timeout\n");
+ goto flush_fifo;
+ }
+
+ /* check transaction successful */
+ status = readl(®_addr->i2c_master_comm);
+ ret = (status & I2C_MASTER_STATUS_MASK) >> I2C_MASTER_STATUS_SFT;
+ if (ret) {
+ printk(BIOS_ERR, "I2C write error %u\n", status);
+ goto flush_fifo;
+ }
+
+ return 0;
+
+flush_fifo:
+ i2c_flush_fifo(reg_addr);
+ return ret;
+}
+
+static int i2c_read(struct cygnus_i2c_regs *reg_addr, struct i2c_seg *segment)
+{
+ uint8_t *data = segment->buf;
+ int i, ret;
+ unsigned int status;
+
+ writel(segment->chip << 1 | 1, ®_addr->i2c_master_data_wr);
+
+ /*
+ * Now we can activate the transfer. Specify the number of bytes to read
+ */
+ writel(I2C_MASTER_START_BUSY | I2C_MASTER_PROT_BLK_RD | segment->len,
+ ®_addr->i2c_master_comm);
+
+ ret = i2c_wait_bus_busy(reg_addr);
+ if (ret) {
+ printk(BIOS_ERR, "I2C bus timeout\n");
+ goto flush_fifo;
+ }
+
+ /* check transaction successful */
+ status = readl(®_addr->i2c_master_comm);
+ ret = (status & I2C_MASTER_STATUS_MASK) >> I2C_MASTER_STATUS_SFT;
+ if (ret) {
+ printk(BIOS_ERR, "I2C read error %u\n", status);
+ goto flush_fifo;
+ }
+
+ for (i = 0; i < segment->len; i++)
+ data[i] = readl(®_addr->i2c_master_data_rd) &
+ I2C_MASTER_RD_DATA_MASK;
+
+ return 0;
+
+flush_fifo:
+ i2c_flush_fifo(reg_addr);
+ return ret;
+}
+
+static int i2c_do_xfer(struct cygnus_i2c_regs *reg_addr,
+ struct i2c_seg *segment)
+{
+ int ret;
+
+ if (segment->len > I2C_FIFO_MAX_SIZE - 1) {
+ printk(BIOS_ERR,
+ "I2C transfer error: segment size (%d) is larger than limit (%d)\n",
+ segment->len, I2C_FIFO_MAX_SIZE);
+ return EINVAL;
+ }
+
+ if (i2c_bus_busy(reg_addr)) {
+ printk(BIOS_WARNING, "I2C transfer error: bus is busy\n");
+ return EBUSY;
+ }
+
+ if (segment->read)
+ ret = i2c_read(reg_addr, segment);
+ else
+ ret = i2c_write(reg_addr, segment);
+
+ return ret;
+}
+
int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int seg_count)
{
- return 0;
+ int i;
+ int res = 0;
+ struct cygnus_i2c_regs *regs = i2c_bus[bus];
+ struct i2c_seg *seg = segments;
+
+ for (i = 0; i < seg_count; i++, seg++) {
+ res = i2c_do_xfer(regs, seg);
+ if (res)
+ break;
+ }
+ return res;
}
void i2c_init(unsigned int bus, unsigned int hz)
{
- printk(BIOS_INFO, "i2c initialization is not implemented\n");
+ struct cygnus_i2c_regs *regs = i2c_bus[bus];
+
+ assert(bus >= 0 && bus <= 1);
+
+ setbits_le32(®s->i2c_con, I2C_SMB_RESET);
+ udelay(100); /* wait 100 usec per spec */
+ clrbits_le32(®s->i2c_con, I2C_SMB_RESET);
+
+ switch (hz) {
+ case 100000:
+ clrbits_le32(®s->i2c_timing_con, I2C_MODE_400);
+ break;
+ case 400000:
+ setbits_le32(®s->i2c_timing_con, I2C_MODE_400);
+ break;
+ default:
+ printk(BIOS_ERR, "I2C bus does not support frequency %d Hz\n",
+ hz);
+ break;
+ }
+
+ i2c_flush_fifo(regs);
+
+ /* disable all interrupts */
+ writel(0, ®s->i2c_int_en);
+
+ /* clear all pending interrupts */
+ writel(0xffffffff, ®s->i2c_int_status);
+
+ writel(I2C_SMB_EN, ®s->i2c_con);
}
