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authorSongjun Wu <songjun.wu@atmel.com>2016-06-20 13:22:38 +0800
committerAndreas Bießmann <andreas@biessmann.org>2016-08-15 22:12:00 +0200
commit8800e0fa20c89df846559d85341c55439405cab6 (patch)
treebd01e6be0945d3d7f3e8ff0e195348849f9016ec /drivers/i2c/at91_i2c.c
parentf4b0df1823921ad3bc39820466e9c5201cef6210 (diff)
i2c: atmel: add i2c driver
Add i2c driver. Signed-off-by: Songjun Wu <songjun.wu@atmel.com> Reviewed-by: Heiko Schocher <hs@denx.de> Acked-by: Heiko Schocher <hs@denx.de>
Diffstat (limited to 'drivers/i2c/at91_i2c.c')
-rw-r--r--drivers/i2c/at91_i2c.c338
1 files changed, 338 insertions, 0 deletions
diff --git a/drivers/i2c/at91_i2c.c b/drivers/i2c/at91_i2c.c
new file mode 100644
index 0000000000..8e9c3ad552
--- /dev/null
+++ b/drivers/i2c/at91_i2c.c
@@ -0,0 +1,338 @@
+/*
+ * Atmel I2C driver.
+ *
+ * (C) Copyright 2016 Songjun Wu <songjun.wu@atmel.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <asm/io.h>
+#include <common.h>
+#include <clk_client.h>
+#include <dm.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <i2c.h>
+#include <linux/bitops.h>
+#include <mach/clk.h>
+
+#include "at91_i2c.h"
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define I2C_TIMEOUT_MS 100
+
+static int at91_wait_for_xfer(struct at91_i2c_bus *bus, u32 status)
+{
+ struct at91_i2c_regs *reg = bus->regs;
+ ulong start_time = get_timer(0);
+ u32 sr;
+
+ bus->status = 0;
+
+ do {
+ sr = readl(&reg->sr);
+ bus->status |= sr;
+
+ if (sr & TWI_SR_NACK)
+ return -EREMOTEIO;
+ else if (sr & status)
+ return 0;
+ } while (get_timer(start_time) < I2C_TIMEOUT_MS);
+
+ return -ETIMEDOUT;
+}
+
+static int at91_i2c_xfer_msg(struct at91_i2c_bus *bus, struct i2c_msg *msg)
+{
+ struct at91_i2c_regs *reg = bus->regs;
+ bool is_read = msg->flags & I2C_M_RD;
+ u32 i;
+ int ret = 0;
+
+ readl(&reg->sr);
+ if (is_read) {
+ writel(TWI_CR_START, &reg->cr);
+
+ for (i = 0; !ret && i < (msg->len - 1); i++) {
+ ret = at91_wait_for_xfer(bus, TWI_SR_RXRDY);
+ msg->buf[i] = readl(&reg->rhr);
+ }
+
+ if (ret)
+ goto error;
+
+ writel(TWI_CR_STOP, &reg->cr);
+
+ ret = at91_wait_for_xfer(bus, TWI_SR_RXRDY);
+ if (ret)
+ goto error;
+
+ msg->buf[i] = readl(&reg->rhr);
+
+ } else {
+ writel(msg->buf[0], &reg->thr);
+ for (i = 1; !ret && (i < msg->len); i++) {
+ writel(msg->buf[i], &reg->thr);
+ ret = at91_wait_for_xfer(bus, TWI_SR_TXRDY);
+ }
+
+ if (ret)
+ goto error;
+
+ writel(TWI_CR_STOP, &reg->cr);
+ }
+
+ if (!ret)
+ ret = at91_wait_for_xfer(bus, TWI_SR_TXCOMP);
+
+ if (ret)
+ goto error;
+
+ if (bus->status & (TWI_SR_OVRE | TWI_SR_UNRE | TWI_SR_LOCK)) {
+ ret = -EIO;
+ goto error;
+ }
+
+ return 0;
+
+error:
+ if (bus->status & TWI_SR_LOCK)
+ writel(TWI_CR_LOCKCLR, &reg->cr);
+
+ return ret;
+}
+
+static int at91_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
+{
+ struct at91_i2c_bus *bus = dev_get_priv(dev);
+ struct at91_i2c_regs *reg = bus->regs;
+ struct i2c_msg *m_start = msg;
+ bool is_read;
+ u32 int_addr_flag = 0;
+ int ret = 0;
+
+ if (nmsgs == 2) {
+ int internal_address = 0;
+ int i;
+
+ /* 1st msg is put into the internal address, start with 2nd */
+ m_start = &msg[1];
+
+ /* the max length of internal address is 3 bytes */
+ if (msg->len > 3)
+ return -EFAULT;
+
+ for (i = 0; i < msg->len; ++i) {
+ const unsigned addr = msg->buf[msg->len - 1 - i];
+
+ internal_address |= addr << (8 * i);
+ int_addr_flag += TWI_MMR_IADRSZ_1;
+ }
+
+ writel(internal_address, &reg->iadr);
+ }
+
+ is_read = m_start->flags & I2C_M_RD;
+
+ writel((m_start->addr << 16) | int_addr_flag |
+ (is_read ? TWI_MMR_MREAD : 0), &reg->mmr);
+
+ ret = at91_i2c_xfer_msg(bus, m_start);
+
+ return ret;
+}
+
+/*
+ * Calculate symmetric clock as stated in datasheet:
+ * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
+ */
+static void at91_calc_i2c_clock(struct udevice *dev, int i2c_clk)
+{
+ struct at91_i2c_bus *bus = dev_get_priv(dev);
+ const struct at91_i2c_pdata *pdata = bus->pdata;
+ int offset = pdata->clk_offset;
+ int max_ckdiv = pdata->clk_max_div;
+ int ckdiv, cdiv, div;
+ unsigned long src_rate;
+
+ src_rate = bus->bus_clk_rate;
+
+ div = max(0, (int)DIV_ROUND_UP(src_rate, 2 * i2c_clk) - offset);
+ ckdiv = fls(div >> 8);
+ cdiv = div >> ckdiv;
+
+ if (ckdiv > max_ckdiv) {
+ ckdiv = max_ckdiv;
+ cdiv = 255;
+ }
+
+ bus->speed = DIV_ROUND_UP(src_rate,
+ (cdiv * (1 << ckdiv) + offset) * 2);
+
+ bus->cwgr_val = (ckdiv << 16) | (cdiv << 8) | cdiv;
+}
+
+static int at91_i2c_enable_clk(struct udevice *dev)
+{
+ struct at91_i2c_bus *bus = dev_get_priv(dev);
+ struct udevice *dev_clk;
+ struct clk clk;
+ ulong clk_rate;
+ int periph;
+ int ret;
+
+ ret = clk_get_by_index(dev, 0, &clk);
+ if (ret)
+ return -EINVAL;
+
+ periph = fdtdec_get_uint(gd->fdt_blob, clk.dev->of_offset, "reg", -1);
+ if (periph < 0)
+ return -EINVAL;
+
+ dev_clk = dev_get_parent(clk.dev);
+ ret = clk_request(dev_clk, &clk);
+ if (ret)
+ return ret;
+
+ clk.id = periph;
+ ret = clk_enable(&clk);
+ if (ret)
+ return ret;
+
+ ret = clk_get_by_index(dev_clk, 0, &clk);
+ if (ret)
+ return ret;
+
+ clk_rate = clk_get_rate(&clk);
+ if (!clk_rate)
+ return -ENODEV;
+
+ bus->bus_clk_rate = clk_rate;
+
+ clk_free(&clk);
+
+ return 0;
+}
+
+static int at91_i2c_probe(struct udevice *dev, uint chip, uint chip_flags)
+{
+ struct at91_i2c_bus *bus = dev_get_priv(dev);
+ struct at91_i2c_regs *reg = bus->regs;
+ int ret;
+
+ ret = at91_i2c_enable_clk(dev);
+ if (ret)
+ return ret;
+
+ writel(TWI_CR_SWRST, &reg->cr);
+
+ at91_calc_i2c_clock(dev, bus->clock_frequency);
+
+ writel(bus->cwgr_val, &reg->cwgr);
+ writel(TWI_CR_MSEN, &reg->cr);
+ writel(TWI_CR_SVDIS, &reg->cr);
+
+ return 0;
+}
+
+static int at91_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
+{
+ struct at91_i2c_bus *bus = dev_get_priv(dev);
+
+ at91_calc_i2c_clock(dev, speed);
+
+ writel(bus->cwgr_val, &bus->regs->cwgr);
+
+ return 0;
+}
+
+int at91_i2c_get_bus_speed(struct udevice *dev)
+{
+ struct at91_i2c_bus *bus = dev_get_priv(dev);
+
+ return bus->speed;
+}
+
+static int at91_i2c_ofdata_to_platdata(struct udevice *dev)
+{
+ const void *blob = gd->fdt_blob;
+ struct at91_i2c_bus *bus = dev_get_priv(dev);
+ int node = dev->of_offset;
+
+ bus->regs = (struct at91_i2c_regs *)dev_get_addr(dev);
+ bus->pdata = (struct at91_i2c_pdata *)dev_get_driver_data(dev);
+ bus->clock_frequency = fdtdec_get_int(blob, node,
+ "clock-frequency", 100000);
+
+ return 0;
+}
+
+static const struct dm_i2c_ops at91_i2c_ops = {
+ .xfer = at91_i2c_xfer,
+ .probe_chip = at91_i2c_probe,
+ .set_bus_speed = at91_i2c_set_bus_speed,
+ .get_bus_speed = at91_i2c_get_bus_speed,
+};
+
+static const struct at91_i2c_pdata at91rm9200_config = {
+ .clk_max_div = 5,
+ .clk_offset = 3,
+};
+
+static const struct at91_i2c_pdata at91sam9261_config = {
+ .clk_max_div = 5,
+ .clk_offset = 4,
+};
+
+static const struct at91_i2c_pdata at91sam9260_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+};
+
+static const struct at91_i2c_pdata at91sam9g20_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+};
+
+static const struct at91_i2c_pdata at91sam9g10_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+};
+
+static const struct at91_i2c_pdata at91sam9x5_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+};
+
+static const struct at91_i2c_pdata sama5d4_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+};
+
+static const struct at91_i2c_pdata sama5d2_config = {
+ .clk_max_div = 7,
+ .clk_offset = 3,
+};
+
+static const struct udevice_id at91_i2c_ids[] = {
+{ .compatible = "atmel,at91rm9200-i2c", .data = (long)&at91rm9200_config },
+{ .compatible = "atmel,at91sam9260-i2c", .data = (long)&at91sam9260_config },
+{ .compatible = "atmel,at91sam9261-i2c", .data = (long)&at91sam9261_config },
+{ .compatible = "atmel,at91sam9g20-i2c", .data = (long)&at91sam9g20_config },
+{ .compatible = "atmel,at91sam9g10-i2c", .data = (long)&at91sam9g10_config },
+{ .compatible = "atmel,at91sam9x5-i2c", .data = (long)&at91sam9x5_config },
+{ .compatible = "atmel,sama5d4-i2c", .data = (long)&sama5d4_config },
+{ .compatible = "atmel,sama5d2-i2c", .data = (long)&sama5d2_config },
+{ }
+};
+
+U_BOOT_DRIVER(i2c_at91) = {
+ .name = "i2c_at91",
+ .id = UCLASS_I2C,
+ .of_match = at91_i2c_ids,
+ .ofdata_to_platdata = at91_i2c_ofdata_to_platdata,
+ .per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
+ .priv_auto_alloc_size = sizeof(struct at91_i2c_bus),
+ .ops = &at91_i2c_ops,
+};