i2c: exynos5: add support for HSI2C on Exynos5260 SoC

HSI2C module on Exynos5260 differs from current modules in
following ways:
1.  HSI2C on Exynos5260 has fifo_depth of 16bytes
2.  Module needs to be reset as a part of init sequence.

Hence, Following changes are involved.
1. Add a new compatible string and Updates the Documentation dt bindings.
2. Introduce a variant struct to support the changes in H/W
3. Reset the module during init. Thus, bringing the module back
to default state irrespective of what firmware did with it.

Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt b/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
index 056732c..d4745e3 100644 (file)
--- a/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
@@ -5,7 +5,14 @@ at various speeds ranging from 100khz to 3.4Mhz.
 
 Required properties:
   - compatible: value should be.
-      -> "samsung,exynos5-hsi2c", for i2c compatible with exynos5 hsi2c.
+       -> "samsung,exynos5-hsi2c", (DEPRECATED)
+                               for i2c compatible with HSI2C available
+                               on Exynos5250 and Exynos5420 SoCs.
+       -> "samsung,exynos5250-hsi2c", for i2c compatible with HSI2C available
+                               on Exynos5250 and Exynos5420 SoCs.
+       -> "samsung,exynos5260-hsi2c", for i2c compatible with HSI2C available
+                               on Exynos5260 SoCs.
+
   - reg: physical base address of the controller and length of memory mapped
     region.
   - interrupts: interrupt number to the cpu.
@@ -26,7 +33,7 @@ Optional properties:
 Example:
 
 hsi2c@12ca0000 {
-       compatible = "samsung,exynos5-hsi2c";
+       compatible = "samsung,exynos5250-hsi2c";
        reg = <0x12ca0000 0x100>;
        interrupts = <56>;
        clock-frequency = <100000>;

diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
index 29f4b66..398ea50 100644 (file)
--- a/drivers/i2c/busses/i2c-exynos5.c
+++ b/drivers/i2c/busses/i2c-exynos5.c
@@ -77,12 +77,6 @@
 #define HSI2C_RXFIFO_TRIGGER_LEVEL(x)          ((x) << 4)
 #define HSI2C_TXFIFO_TRIGGER_LEVEL(x)          ((x) << 16)
 
-/* As per user manual FIFO max depth is 64bytes */
-#define HSI2C_FIFO_MAX                         0x40
-/* default trigger levels for Tx and Rx FIFOs */
-#define HSI2C_DEF_TXFIFO_LVL                   (HSI2C_FIFO_MAX - 0x30)
-#define HSI2C_DEF_RXFIFO_LVL                   (HSI2C_FIFO_MAX - 0x10)
-
 /* I2C_TRAILING_CTL Register bits */
 #define HSI2C_TRAILING_COUNT                   (0xf)
 
@@ -184,14 +178,54 @@ struct exynos5_i2c {
         * 2. Fast speed upto 1Mbps
         */
        int                     speed_mode;
+
+       /* Version of HS-I2C Hardware */
+       struct exynos_hsi2c_variant     *variant;
+};
+
+/**
+ * struct exynos_hsi2c_variant - platform specific HSI2C driver data
+ * @fifo_depth: the fifo depth supported by the HSI2C module
+ *
+ * Specifies platform specific configuration of HSI2C module.
+ * Note: A structure for driver specific platform data is used for future
+ * expansion of its usage.
+ */
+struct exynos_hsi2c_variant {
+       unsigned int    fifo_depth;
+};
+
+static const struct exynos_hsi2c_variant exynos5250_hsi2c_data = {
+       .fifo_depth     = 64,
+};
+
+static const struct exynos_hsi2c_variant exynos5260_hsi2c_data = {
+       .fifo_depth     = 16,
 };
 
 static const struct of_device_id exynos5_i2c_match[] = {
-       { .compatible = "samsung,exynos5-hsi2c" },
-       {},
+       {
+               .compatible = "samsung,exynos5-hsi2c",
+               .data = &exynos5250_hsi2c_data
+       }, {
+               .compatible = "samsung,exynos5250-hsi2c",
+               .data = &exynos5250_hsi2c_data
+       }, {
+               .compatible = "samsung,exynos5260-hsi2c",
+               .data = &exynos5260_hsi2c_data
+       }, {},
 };
 MODULE_DEVICE_TABLE(of, exynos5_i2c_match);
 
+static inline struct exynos_hsi2c_variant *exynos5_i2c_get_variant
+                                       (struct platform_device *pdev)
+{
+       const struct of_device_id *match;
+
+       match = of_match_node(exynos5_i2c_match, pdev->dev.of_node);
+       return (struct exynos_hsi2c_variant *)match->data;
+}
+
 static void exynos5_i2c_clr_pend_irq(struct exynos5_i2c *i2c)
 {
        writel(readl(i2c->regs + HSI2C_INT_STATUS),
@@ -416,7 +450,7 @@ static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id)
                fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS);
                fifo_level = HSI2C_TX_FIFO_LVL(fifo_status);
 
-               len = HSI2C_FIFO_MAX - fifo_level;
+               len = i2c->variant->fifo_depth - fifo_level;
                if (len > (i2c->msg->len - i2c->msg_ptr))
                        len = i2c->msg->len - i2c->msg_ptr;
 
@@ -484,6 +518,7 @@ static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop)
        u32 i2c_auto_conf = 0;
        u32 fifo_ctl;
        unsigned long flags;
+       unsigned short trig_lvl;
 
        i2c_ctl = readl(i2c->regs + HSI2C_CTL);
        i2c_ctl &= ~(HSI2C_TXCHON | HSI2C_RXCHON);
@@ -494,13 +529,19 @@ static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop)
 
                i2c_auto_conf = HSI2C_READ_WRITE;
 
-               fifo_ctl |= HSI2C_RXFIFO_TRIGGER_LEVEL(HSI2C_DEF_TXFIFO_LVL);
+               trig_lvl = (i2c->msg->len > i2c->variant->fifo_depth) ?
+                       (i2c->variant->fifo_depth * 3 / 4) : i2c->msg->len;
+               fifo_ctl |= HSI2C_RXFIFO_TRIGGER_LEVEL(trig_lvl);
+
                int_en |= (HSI2C_INT_RX_ALMOSTFULL_EN |
                        HSI2C_INT_TRAILING_EN);
        } else {
                i2c_ctl |= HSI2C_TXCHON;
 
-               fifo_ctl |= HSI2C_TXFIFO_TRIGGER_LEVEL(HSI2C_DEF_RXFIFO_LVL);
+               trig_lvl = (i2c->msg->len > i2c->variant->fifo_depth) ?
+                       (i2c->variant->fifo_depth * 1 / 4) : i2c->msg->len;
+               fifo_ctl |= HSI2C_TXFIFO_TRIGGER_LEVEL(trig_lvl);
+
                int_en |= HSI2C_INT_TX_ALMOSTEMPTY_EN;
        }
 
@@ -692,7 +733,9 @@ static int exynos5_i2c_probe(struct platform_device *pdev)
        if (ret)
                goto err_clk;
 
-       exynos5_i2c_init(i2c);
+       i2c->variant = exynos5_i2c_get_variant(pdev);
+
+       exynos5_i2c_reset(i2c);
 
        ret = i2c_add_adapter(&i2c->adap);
        if (ret < 0) {