@@ -5,6 +5,7 @@
* Copyright 2016 Freescale Semiconductor, Inc.
*/
+#include <linux/atomic.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
@@ -99,6 +100,8 @@ struct lpi2c_imx_struct {
__u8 *rx_buf;
__u8 *tx_buf;
struct completion complete;
+ struct notifier_block clk_change_nb;
+ atomic_t rate_per;
unsigned int msglen;
unsigned int delivered;
unsigned int block_data;
@@ -197,6 +200,20 @@ static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx)
} while (1);
}
+static int lpi2c_imx_clk_change_cb(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct clk_notifier_data *ndata = data;
+ struct lpi2c_imx_struct *lpi2c_imx = container_of(nb,
+ struct lpi2c_imx_struct,
+ clk_change_nb);
+
+ if (action & POST_RATE_CHANGE)
+ atomic_set(&lpi2c_imx->rate_per, ndata->new_rate);
+
+ return NOTIFY_OK;
+}
+
/* CLKLO = I2C_CLK_RATIO * CLKHI, SETHOLD = CLKHI, DATAVD = CLKHI/2 */
static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
{
@@ -207,7 +224,7 @@ static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
lpi2c_imx_set_mode(lpi2c_imx);
- clk_rate = clk_get_rate(lpi2c_imx->clks[0].clk);
+ clk_rate = atomic_read(&lpi2c_imx->rate_per);
if (!clk_rate)
return -EINVAL;
@@ -590,6 +607,28 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
if (ret)
return ret;
+ lpi2c_imx->clk_change_nb.notifier_call = lpi2c_imx_clk_change_cb;
+ ret = devm_clk_notifier_register(&pdev->dev, lpi2c_imx->clks[0].clk,
+ &lpi2c_imx->clk_change_nb);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "can't register peripheral clock notifier\n");
+ /*
+ * Lock the clock rate to avoid rate change between clk_get_rate() and
+ * atomic_set()
+ */
+ ret = clk_rate_exclusive_get(lpi2c_imx->clks[0].clk);
+ if (ret) {
+ dev_err(&pdev->dev, "can't lock I2C peripheral clock rate\n");
+ return ret;
+ }
+ atomic_set(&lpi2c_imx->rate_per, clk_get_rate(lpi2c_imx->clks[0].clk));
+ clk_rate_exclusive_put(lpi2c_imx->clks[0].clk);
+ if (!atomic_read(&lpi2c_imx->rate_per)) {
+ dev_err(&pdev->dev, "can't get I2C peripheral clock rate\n");
+ return -EINVAL;
+ }
+
pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_get_noresume(&pdev->dev);