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Diffstat (limited to 'drivers/i2c/busses/i2c-exynos5.c')
-rw-r--r--drivers/i2c/busses/i2c-exynos5.c116
1 files changed, 32 insertions, 84 deletions
diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
index 736a82472101..23ed4d67ecad 100644
--- a/drivers/i2c/busses/i2c-exynos5.c
+++ b/drivers/i2c/busses/i2c-exynos5.c
@@ -22,6 +22,7 @@
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/of_address.h>
+#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/spinlock.h>
@@ -168,8 +169,6 @@
*/
#define HSI2C_HS_TX_CLOCK 1000000
#define HSI2C_FS_TX_CLOCK 100000
-#define HSI2C_HIGH_SPD 1
-#define HSI2C_FAST_SPD 0
#define EXYNOS5_I2C_TIMEOUT (msecs_to_jiffies(1000))
@@ -200,18 +199,10 @@ struct exynos5_i2c {
int trans_done;
/* Controller operating frequency */
- unsigned int fs_clock;
- unsigned int hs_clock;
-
- /*
- * HSI2C Controller can operate in
- * 1. High speed upto 3.4Mbps
- * 2. Fast speed upto 1Mbps
- */
- int speed_mode;
+ unsigned int op_clock;
/* Version of HS-I2C Hardware */
- struct exynos_hsi2c_variant *variant;
+ const struct exynos_hsi2c_variant *variant;
};
/**
@@ -257,15 +248,6 @@ static const struct of_device_id exynos5_i2c_match[] = {
};
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),
@@ -279,7 +261,7 @@ static void exynos5_i2c_clr_pend_irq(struct exynos5_i2c *i2c)
* Returns 0 on success, -EINVAL if the cycle length cannot
* be calculated.
*/
-static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, int mode)
+static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, bool hs_timings)
{
u32 i2c_timing_s1;
u32 i2c_timing_s2;
@@ -292,9 +274,10 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, int mode)
unsigned int t_sr_release;
unsigned int t_ftl_cycle;
unsigned int clkin = clk_get_rate(i2c->clk);
- unsigned int div, utemp0 = 0, utemp1 = 0, clk_cycle;
- unsigned int op_clk = (mode == HSI2C_HIGH_SPD) ?
- i2c->hs_clock : i2c->fs_clock;
+ unsigned int op_clk = hs_timings ? i2c->op_clock :
+ (i2c->op_clock >= HSI2C_HS_TX_CLOCK) ? HSI2C_FS_TX_CLOCK :
+ i2c->op_clock;
+ int div, clk_cycle, temp;
/*
* In case of HSI2C controller in Exynos5 series
@@ -305,33 +288,22 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, int mode)
* FPCLK / FI2C =
* (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + FLT_CYCLE
*
- * utemp0 = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2)
- * utemp1 = (TSCLK_L + TSCLK_H + 2)
+ * clk_cycle := TSCLK_L + TSCLK_H
+ * temp := (CLK_DIV + 1) * (clk_cycle + 2)
+ *
+ * Constraints: 4 <= temp, 0 <= CLK_DIV < 256, 2 <= clk_cycle <= 510
+ *
*/
t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7;
- utemp0 = (clkin / op_clk) - 8;
-
- if (i2c->variant->hw == HSI2C_EXYNOS7)
- utemp0 -= t_ftl_cycle;
- else
- utemp0 -= 2 * t_ftl_cycle;
-
- /* CLK_DIV max is 256 */
- for (div = 0; div < 256; div++) {
- utemp1 = utemp0 / (div + 1);
-
- /*
- * SCL_L and SCL_H each has max value of 255
- * Hence, For the clk_cycle to the have right value
- * utemp1 has to be less then 512 and more than 4.
- */
- if ((utemp1 < 512) && (utemp1 > 4)) {
- clk_cycle = utemp1 - 2;
- break;
- } else if (div == 255) {
- dev_warn(i2c->dev, "Failed to calculate divisor");
- return -EINVAL;
- }
+ temp = clkin / op_clk - 8 - t_ftl_cycle;
+ if (i2c->variant->hw != HSI2C_EXYNOS7)
+ temp -= t_ftl_cycle;
+ div = temp / 512;
+ clk_cycle = temp / (div + 1) - 2;
+ if (temp < 4 || div >= 256 || clk_cycle < 2) {
+ dev_err(i2c->dev, "%s clock set-up failed\n",
+ hs_timings ? "HS" : "FS");
+ return -EINVAL;
}
t_scl_l = clk_cycle / 2;
@@ -356,7 +328,7 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, int mode)
div, t_sr_release);
dev_dbg(i2c->dev, "tDATA_HD: %X\n", t_data_hd);
- if (mode == HSI2C_HIGH_SPD) {
+ if (hs_timings) {
writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_HS1);
writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_HS2);
writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_HS3);
@@ -372,24 +344,13 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, int mode)
static int exynos5_hsi2c_clock_setup(struct exynos5_i2c *i2c)
{
- /*
- * Configure the Fast speed timing values
- * Even the High Speed mode initially starts with Fast mode
- */
- if (exynos5_i2c_set_timing(i2c, HSI2C_FAST_SPD)) {
- dev_err(i2c->dev, "HSI2C FS Clock set up failed\n");
- return -EINVAL;
- }
+ /* always set Fast Speed timings */
+ int ret = exynos5_i2c_set_timing(i2c, false);
- /* configure the High speed timing values */
- if (i2c->speed_mode == HSI2C_HIGH_SPD) {
- if (exynos5_i2c_set_timing(i2c, HSI2C_HIGH_SPD)) {
- dev_err(i2c->dev, "HSI2C HS Clock set up failed\n");
- return -EINVAL;
- }
- }
+ if (ret < 0 || i2c->op_clock < HSI2C_HS_TX_CLOCK)
+ return ret;
- return 0;
+ return exynos5_i2c_set_timing(i2c, true);
}
/*
@@ -409,7 +370,7 @@ static void exynos5_i2c_init(struct exynos5_i2c *i2c)
i2c->regs + HSI2C_CTL);
writel(HSI2C_TRAILING_COUNT, i2c->regs + HSI2C_TRAILIG_CTL);
- if (i2c->speed_mode == HSI2C_HIGH_SPD) {
+ if (i2c->op_clock >= HSI2C_HS_TX_CLOCK) {
writel(HSI2C_MASTER_ID(MASTER_ID(i2c->adap.nr)),
i2c->regs + HSI2C_ADDR);
i2c_conf |= HSI2C_HS_MODE;
@@ -747,26 +708,14 @@ static int exynos5_i2c_probe(struct platform_device *pdev)
struct device_node *np = pdev->dev.of_node;
struct exynos5_i2c *i2c;
struct resource *mem;
- unsigned int op_clock;
int ret;
i2c = devm_kzalloc(&pdev->dev, sizeof(struct exynos5_i2c), GFP_KERNEL);
if (!i2c)
return -ENOMEM;
- if (of_property_read_u32(np, "clock-frequency", &op_clock)) {
- i2c->speed_mode = HSI2C_FAST_SPD;
- i2c->fs_clock = HSI2C_FS_TX_CLOCK;
- } else {
- if (op_clock >= HSI2C_HS_TX_CLOCK) {
- i2c->speed_mode = HSI2C_HIGH_SPD;
- i2c->fs_clock = HSI2C_FS_TX_CLOCK;
- i2c->hs_clock = op_clock;
- } else {
- i2c->speed_mode = HSI2C_FAST_SPD;
- i2c->fs_clock = op_clock;
- }
- }
+ if (of_property_read_u32(np, "clock-frequency", &i2c->op_clock))
+ i2c->op_clock = HSI2C_FS_TX_CLOCK;
strlcpy(i2c->adap.name, "exynos5-i2c", sizeof(i2c->adap.name));
i2c->adap.owner = THIS_MODULE;
@@ -817,8 +766,7 @@ static int exynos5_i2c_probe(struct platform_device *pdev)
goto err_clk;
}
- /* Need to check the variant before setting up. */
- i2c->variant = exynos5_i2c_get_variant(pdev);
+ i2c->variant = of_device_get_match_data(&pdev->dev);
ret = exynos5_hsi2c_clock_setup(i2c);
if (ret)
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.